JP3525529B2 - Engine electronic control unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control unit for an engine, which is provided with a microcomputer and totally controls the drive of an engine and its peripheral devices. The present invention relates to an implementation of a device having a load driving transistor to be driven, which realizes thermal protection of those elements appropriately.

[0002]

2. Description of the Related Art In recent years, in such an electronic control unit for an engine, an igniter has been incorporated in the control unit.
There is a movement to make the engine and its peripherals compact.

However, by incorporating this igniter, which controls the energization of a device such as an ignition coil through which a large current flows, into the electronic control device, the problem of heat generation is greatly highlighted. In other words, simply incorporating such an igniter into the electronic control unit causes thermal severeness, and there is a possibility that the temperature range which is the limit of use of the switching element such as the transistor may be exceeded.

Therefore, conventionally, heat dissipation measures have been taken such as mounting these transistors on a radiation fin or mounting a heat sink on the transistors themselves.

[0005]

By providing such a heat dissipation measure for the transistor or the like which constitutes the switching element of the above igniter, not only the transistor but also the electronic control device itself incorporating the transistor can be surely used. Its reliability will be improved.

However, from the viewpoint of its economical efficiency or an electronic control device which controls a special device such as an engine, it is not always the best measure.

That is, when the igniter is built in the electronic control unit, the operating temperature limit of the switching element such as the transistor may be exceeded, but in reality, such a situation is caused. This is limited to special cases, for example, when the ambient temperature is high and the engine is rotating at high speed.

Therefore, even if the above heat dissipation measures are taken in preparation for such a special situation, the technical effect thereof is weak, and it cannot be said that the cost is economically effective. In addition, if the ambient temperature itself becomes high even if the heat dissipation measures in the above-described mode are taken, effective heat dissipation is not performed, and it is not a fundamental measure against the heat generation.

[0009]

The present invention has been made in view of these circumstances, and accurately suppresses heat generation beyond the operating limit temperature range of the output transistor of the built-in igniter, without unnecessarily costing heat dissipation. An object of the present invention is to provide an electronic control device for an engine that can surely protect those elements.

[0011]

In order to achieve such an object, in the invention according to claim 1, a microcomputer for comprehensively managing the drive of the engine and its peripheral devices.
If, igniter for controlling the energization of the ignition coil based on the drive command output from the microcomputer
Output transistor and output from the microcomputer
Drive to drive the fuel injection valve based on the drive command input
And an electronic control unit for an engine having a circuit ,
Ambient temperature monitoring means for monitoring the ambient temperature of the output transistor and, when the monitored ambient temperature or its equivalent value is equal to or higher than a predetermined limit value, burns when the engine rotates at high speed.
Lowered the judgment value of the material cut rotation speed
By limiting the maximum engine speed to the above judgment value
Fuel cut to limit the current week period to the serial output transistor
And a judgment value changing means .

[0012]

According to the second aspect of the invention, the engine is
And a micro that comprehensively manages the drive of peripheral devices
Computer and output from the microcomputer
Control the energization of the ignition coil based on the drive command
The output transistor of the igniter and the microcomputer
The fuel injection valve based on the drive command output from the computer.
In an electronic control unit for an engine having a drive circuit for driving
There is a circuit that monitors the ambient temperature of the output transistor.
Surrounding temperature monitoring means and the monitored ambient temperature or its
When the equivalent value is equal to or greater than a predetermined limit value , fuel injection thinning is performed by thinning fuel injection into the engine for a predetermined short time to reduce the maximum rotation speed of the engine, thereby limiting the energization cycle to the output transistor. It is configured to include a means.

According to the third aspect of the invention, the engine is equivalent to the engine.
Microcomputer that controls the drive of each peripheral device
Computer and output from the microcomputer
Control the energization of the ignition coil based on the drive command
The output transistor of the igniter and the micro computer
Drive the fuel injection valve based on the drive command output from the engine.
In an electronic control unit for an engine having a moving drive circuit
To monitor the ambient temperature of the output transistor
Temperature monitoring means and the monitored ambient temperature or its phase
When this value exceeds the specified limit value , fuel injection into any cylinder of the engine is stopped and the high rotation operation of the engine is controlled.
Constituting as comprising a cylinder cut control means for limiting the energization period to the output transistor by limit.

According to the fourth aspect of the invention, the engine
Microcomputer that controls the drive of each peripheral device
Computer and output from the microcomputer
Control the energization of the ignition coil based on the drive command
The output transistor of the igniter and the micro computer
Drive the fuel injection valve based on the drive command output from the engine.
In an electronic control unit for an engine having a moving drive circuit
To monitor the ambient temperature of the output transistor
Temperature monitoring means and the monitored ambient temperature or its phase
When the present value is equal to or more than a predetermined limit value, an injection amount reduction means for limiting the energization cycle to the output transistor by reducing the fuel injection amount to the engine in a predetermined manner to reduce the maximum rotation speed of the engine. Configure as an item.

Further, in the invention according to claim 5 , the engine is
And a micro that comprehensively manages the drive of peripheral devices
Computer and output from the microcomputer
Control the energization of the ignition coil based on the drive command
The output transistor of the igniter and the microcomputer
The fuel injection valve based on the drive command output from the computer.
In an electronic control unit for an engine having a drive circuit for driving
There is a circuit that monitors the ambient temperature of the output transistor.
Surrounding temperature monitoring means and the monitored ambient temperature or its
When the corresponding value is equal to or greater than a predetermined limit value, to the output transient <br/> Star by forcing driving the intake throttle valve of the engine on a side where the intake air amount is suppressed allowed to decrease the maximum rotational speed of the engine It is configured to include intake restriction means for restricting the energization cycle.

Further, in the invention according to claim 6 , in the configuration according to any one of the inventions according to claims 1 to 5 ,
It said ambient temperature monitoring means, configured as those comprising a thermistor disposed in the vicinity of said output transistor, and a calculating means for calculating ambient temperature of the output transistor based on the voltage between the terminals of the thermistor.

Further, in the invention according to claim 7 , in the configuration according to any one of the inventions according to claims 1 to 5 ,
The ambient temperature monitoring means comprises a diode arranged in the electronic control device and driven by a constant current, and a computing means for computing the ambient temperature of the output transistor based on the forward voltage of the diode. Constitute.

According to the invention of claim 8 , in the structure of the invention of claim 7 , the diode is separately provided as the ambient temperature monitoring means in the electronic control unit.

According to a ninth aspect of the invention, in the same configuration as the seventh aspect of the invention, the diode is
The electronic parts provided in advance as control parts in the electronic control unit are used.

[0021] In the invention of claim 1 0, wherein, in the configuration of the invention of claim 7 or 8 or 9, wherein a diode is used, the arithmetic means, it is within the predetermined time after power-on, and Based on the fact that both the engine cooling water temperature and the intake air temperature are below a predetermined first temperature and the temperature difference between them is also below a predetermined second temperature, and that the logical product condition that the engine is not rotating is satisfied. A means for calibrating the forward voltage-temperature characteristic of the diode, and when any one of the conditions is not satisfied, the temperature is output based on the calibrated forward voltage-temperature characteristic of the diode. And a means for calculating the ambient temperature of the transistor.

[0022] And the invention of claim 1 1, wherein, in the configuration of any one of the invention of the preceding claims 1 to 5, wherein,
The ambient temperature monitoring means monitors the ambient temperature of the output transistor by converting it into a voltage value of a battery,
Said output transistor, when the voltage value of the converted been battery is equal to or greater than a predetermined limit value, it is assumed that the current cycle is braking <br/> limit.

[0023]

[Action] When integrated output preparative <br/> Rungis data igniter to the electronic control unit of the engine, although there is a possibility that the operating limits temperature range thereof elements, in such a situation in real As described above, the falling is limited to a special case such as when the ambient temperature is high and the engine is rotating at high speed.

[0024]

[0025]

Therefore , according to the invention of claim 1 , the ambient temperature for monitoring the ambient temperature of the output transistor
Monitoring means: -decreasing the judgment value of the fuel cut speed associated with the high-speed rotation of the engine , and using this lowered judgment value of the engine
By configuring the fuel cut determination value change means for limiting the on-period of the output transistor in Rukoto to limit the maximum engine speed (current period), the so comprises each output Trang
The heat dissipation measures described above are not necessarily applied to the transistor.
Even if it exceeds the operating temperature limit of the same output transistor
Such heat generation will be properly suppressed.
Therefore, even if you don't need to spend money on heat dissipation,
In the case of a retrograde, you can certainly protect those elements.
Will be able to In the invention according to claim 1,
However, unlike simply taking measures to dissipate heat, the output
The ambient temperature of the transistor or its equivalent value is the specified limit.
When the value exceeds the value, the fuel cut judgment value changing means
To limit the power supply to the same output transistor.
I am trying to do it. Therefore, even if the ambient temperature is high
Even if it happens, it is necessary to fundamentally suppress the heat generation of the element.
You will also be able to. Especially, the fuel cut judgment value
According to the above-mentioned configuration as the changing means, the fuel injection is completely prohibited at the rotational speed equal to or higher than the changed fuel cut determination value, and the engine rotational speed is prevented from further increasing.

Therefore, it is possible to suppress abnormal heat generation of the output transistor and to protect it, without affecting the normal running of the vehicle.
Note the way, even in the on-time of the upper SL output transistor is constant, thus if it is limited engine speed, naturally the ON period is limited, so that consequently the power generated is also well restricted.

Further, in such an electronic control unit for an engine, since the ignition control system and the fuel control system are usually integrated into one device, the control contents of the fuel control system are controlled, for example, for controlling the igniter. It is also relatively easy to operate.

Further, instead of the fuel cut judgment value changing means,
Ete, for example, as by the invention of claim 2, wherein the on-period of the output <br/> transistor by allowed to lower the maximum speed of thinned out injection of fuel into engine by a predetermined short time the engine With limiting fuel injection decimation means. Alternatively, according to the invention as set forth in claim 3, a cut-off cylinder control means for limiting the ON period of the output transistor by stopping the fuel injection to an arbitrary cylinder of the engine to limit the high rotation operation of the engine. What you get. Alternatively, as in the invention according to claim 4, the injection for limiting the ON period of the output transistor by decreasing the fuel injection amount to the engine in a predetermined manner to reduce the maximum rotation speed of the engine. Those equipped with means for weight loss. Alternatively, according to the invention of claim 5 , the intake throttle valve (throttle valve, etc.) of the engine is sucked.
An intake restriction means for restricting the on-cycle of the output transistor by forcibly driving the engine to the side where the air volume is suppressed to lower the maximum engine speed of the engine. Can also be configured as.

With such a structure as the energization period limiting means, the engine speed can be limited and the on-duty of the output transistor can be limited. Therefore, also in this case, the power generated by the output transistor is limited, and the abnormal heat generation can be fundamentally suppressed.

On the other hand, according to the invention as set forth in claim 6 , in each of the above-mentioned constitutions, the ambient temperature monitoring means includes: a thermistor arranged in the vicinity of the output transistor, and a terminal of the thermistor. And a calculation means for calculating the ambient temperature of the output transistor based on the inter-voltage. Can be configured as. With such a configuration as the ambient temperature monitoring means, it becomes possible to directly and easily monitor the ambient temperature of the output transistor.

Further, according to the invention as set forth in claim 7 , the ambient temperature monitoring means is provided with: a diode arranged in the electronic control unit and driven by a constant current; and a forward voltage of the diode. Calculating means for calculating the ambient temperature of the output transistor based on the output transistor. Can also be configured as. Particularly, according to such a configuration as the ambient temperature monitoring means, the diode is separately provided as the ambient temperature monitoring means in the electronic control device, for example, according to the invention of claim 8. . Alternatively, as in the ninth aspect of the present invention, (b) the electronic parts provided in advance as the control parts in the electronic control unit are diverted. It becomes possible to use it in such a mode.

According to the former configuration (a), the diode can be arranged at an arbitrary position in the vicinity of the output transistor to be monitored for temperature, and an arbitrary constant current source can be used. There is freedom to do so.

Further, according to the latter construction (b), although there is no such degree of freedom, it is not necessary to newly add an electronic component, and the ambient temperature monitoring means can be constructed more economically. Become. It should be noted that the diode, which is previously provided as a control component in the electronic control unit and is driven with a constant current, is a comparison reference potential for binarizing the sensor signal in a waveform shaping circuit such as a vehicle speed sensor. There is a diode to generate.

Further, as by the invention of claim 1 0, wherein it be in these configurations using a diode as ambient temperature monitoring means, said calculating means is within a predetermined time after the power is supplied, and Based on the fact that both the engine cooling water temperature and the intake air temperature are below a predetermined first temperature and the temperature difference between them is also below a predetermined second temperature, and that the logical product condition that the engine is not rotating is satisfied. Means for calibrating the forward voltage-temperature characteristic of the diode; and, when any one of the above conditions is no longer satisfied, the respective temperature is determined based on the calibrated forward voltage-temperature characteristic of the diode. by configuring comprises means for calculating the ambient temperature of the output transistors, respectively, thus even when realizing the ambient temperature monitoring means using a diode, its The variation in temperature characteristics due to forward current to properly absorb, it is possible to perform a highly accurate monitoring of the ambient temperature.

By the way, generation power of the output transistor is its power supply voltage, i.e. there is a battery voltage and strong correlation, acceptable ambient temperature the output transistors can also be monitored in terms of the battery voltage.

[0037] Therefore, in the configuration of the invention of the previous claims 1 to 5, wherein, as by the invention of claim 1 1, wherein,
The ambient temperature monitoring means converts the ambient temperature of the output transistor into a battery voltage value and monitors it. Configured as, it also output transistor, - when the voltage value of the converted been battery is equal to or greater than a predetermined limit value, which the energizing period is limited. With such a configuration, the heat generation of the output transistor can be suppressed and the element can be reliably protected with a very simple configuration that basically only measures the battery voltage.

[0038]

【Example】

(First Embodiment) FIGS. 1 to 8 show a first embodiment of an electronic control unit for an engine according to the present invention.

The device of the first embodiment is an electronic control unit for an engine in which an igniter is built in, and monitors the ambient temperature through a thermistor arranged near the output transistor of the igniter, and the temperature is set to a predetermined value. When the value is equal to or more than the value, it is configured as a device that lowers the high rotation fuel cut determination value of the engine.

First, with reference to FIG. 1, the configuration of an engine and its peripheral devices to be controlled by the electronic control unit will be described. As shown in FIG. 1, the engine 1 is
A combustion chamber 5 is formed by the cylinder 2, the piston 3, and the cylinder head 4. A spark plug 6 is arranged in the combustion chamber 5.

In the engine 1, the intake system communicates with the combustion chamber 5 via an intake valve 7, an intake manifold 8, a fuel injection valve 9 for injecting fuel into the intake manifold 8, and the intake manifold 8. Intake pipe 10, surge tank 1 for absorbing pulsation of intake air
1, a throttle valve 12, and an air cleaner 13 are provided.

On the other hand, the exhaust system of the engine 1 has an exhaust manifold 15 which communicates with the above-mentioned combustion chamber 5 via an exhaust valve 14. Further, the engine 1 has an ignition coil 1 for outputting a high voltage required for ignition.
6, and a distributor 17 that supplies the high voltage generated in the ignition coil 16 to the ignition plug 6 of each cylinder in conjunction with a crankshaft (not shown). The ignition coil 16 is configured so that its energization is controlled by an igniter (driving circuit), which will be described later, incorporated in the electronic control unit 30.

On the other hand, the engine 1 is also provided with the following various sensors. Water temperature sensor 20: provided in the cooling system of the engine 1 to detect the temperature of the cooling water. Intake air temperature sensor 21: The intake air temperature sensor 21 is provided in the air cleaner 13 and detects the temperature of intake air sent to the engine 1. Throttle position sensor 22: Interlocks with the throttle valve 12 to detect the opening of the throttle valve 12. Intake pipe pressure sensor 23: measures the pressure in the intake pipe 10. Oxygen concentration sensor 24: Provided in the exhaust manifold 15 to detect the residual oxygen concentration in the exhaust gas. Rotation angle sensor 25: mounted inside the distributor 17, and every 1/24 rotation of the cam shaft of the distributor 17, that is, every integer multiple of 0 ° CA (crank angle) to 30 ° CA of the crankshaft (not shown). The rotation angle signal (pulse) is output to. It also serves as a rotation speed sensor of the engine 1.・ Cylinder discrimination sensor 26: Similarly, distributor 17
The reference signal (pulse) for cylinder discrimination is output once for each rotation of the cam shaft of the distributor 17, that is, for every two rotations of a crankshaft (not shown). -Vehicle speed sensor 28: Generates a pulse corresponding to the rotation of the wheel through the signal rotor 27 provided on the axle of the vehicle on which the engine 1 is mounted.

All outputs from these sensors are input to the electronic control unit 30. The electronic control unit 30 is basically a device that drives the fuel injection valve 9 and the ignition coil 16 based on the output contents of these sensors to control the operation of the engine 1.

Next, the configuration of the electronic control unit 30 will be described with reference to FIG. As shown in FIG. 2, the electronic control unit 30 outputs the outputs of the microcomputer 310 and the various sensors to the microcomputer 310.
It is mainly configured by a circuit for pre-processing for taking in and a circuit for processing the drive command output from the microcomputer 310 to drive the ignition coil 16 and the fuel injection valve 9.

Here, the microcomputer 310 itself is configured as a logical operation circuit basically including a CPU 311, a ROM 312, a RAM 313 and a backup RAM 314.

Of these, the CPU 311 inputs the outputs of the various sensors in accordance with a control program, executes a predetermined calculation based on the control program, and controls the ignition coil 16 and the fuel injection valve 9 to drive a control command. Is the part that outputs.

The ROM 312 is a read-only memory in which the control program, the initial data, etc. are stored in advance, and the RAM 313 is necessary for executing the various sensor outputs to be input and the calculation or control. This is a memory in which data is temporarily stored.

The backup RAM 314 is a non-volatile RAM (random access memory) backed up by a battery. Data that is continuously used even after the key switch (not shown) is turned off and the power supply to the control device is stopped is the backup RAM.
314 will be stored.

Further, in the microcomputer 310, the input / output port 315 and the input port 316 both output the outputs of the various sensors described above.
This is a part to be incorporated into 10.

On the other hand, the output port 317 is connected to the CPU 311.
Ignition coil 16 and fuel injection valve 9 generated through
Is a part for outputting a drive command to the outside. Inside the microcomputer 310, the CPU 311, the ROM 312, and the RA that constitute the logical operation circuit are included.
The M313 and the backup RAM 314 are electrically and logically connected to the ports 315 to 317 by a common bus 318.

The clock generator 319 supplies the operation clock CK to each unit of the microcomputer 310.
Is the part that supplies. In the electronic control unit 30, buffer circuits 321 to 324, a multiplexer 325, and A / are used as circuits for preprocessing the outputs of the various sensors to the microcomputer 310.
D converter 326, buffer 331, comparator 33
2, and there are waveform shaping circuits 333 and 334.

Here, the multiplexer 325 includes the intake pipe pressure sensor 23, the water temperature sensor 20, and the intake air temperature sensor 2 which are respectively input to the buffer circuits 321 to 324.
1 and each output of the throttle position sensor 22, and an output (voltage between terminals) of a thermistor 352, which will be described later, are selected and output based on a command from the microcomputer 310. The selected sensor output or the output of the thermistor 352 is input to the A / D converter 326.

The A / D converter 326 outputs the input sensor output or output of the thermistor 352 based on the command from the microcomputer 310.
It is a circuit for performing / D (analog / digital) conversion. The output of each sensor and the output of the thermistor 352 are thus converted into digital signals, and the input / output port 3
It will be taken into the microcomputer 310 via 15.

On the other hand, the comparator 332 is a circuit for generating a binarized signal indicating rich or lean based on a comparison between the output of the oxygen concentration sensor 24 input to the buffer circuit 331 and a predetermined reference voltage. . The generated binarized signal is a signal used as a monitor signal in the air-fuel ratio feedback control, and is taken into the microcomputer 310 via the input port 316.

The waveform shaping circuit 333 is a circuit for shaping the output signal waveforms of the cylinder discrimination sensor 26 and the rotation angle sensor 25 into binary pulse signal waveforms. Each of these waveform shaping signals is also taken into the microcomputer 310 via the input port 316.

The waveform shaping circuit 334 is a circuit for shaping the output signal waveform of the vehicle speed sensor 28 into a binary pulse signal waveform. The waveform-shaped signal is also similarly input to the microcomputer 3 via the input port 316.
Taken in 10.

In the electronic control unit 30, a drive circuit (igniter) 341 and a drive circuit are respectively provided as circuits for processing the drive command output from the microcomputer 310 to drive the ignition coil 16 and the fuel injection valve 9. There is 342.

Of these, the igniter 341 is a circuit for driving (sparking) the spark plug by controlling the energization of the ignition coil 16 based on a drive command (ignition signal) output from the microcomputer 310.

The drive circuit 342 is a circuit for driving the fuel injection valve 9 to open for a predetermined time based on a drive command (time signal corresponding to the fuel injection amount) output from the microcomputer 310. In the engine 1 shown in FIG. 1, the fuel pumped from a fuel pump (not shown) is injected and supplied into the intake manifold 8 by an amount proportional to the opening time of the fuel injection valve 9.

In the igniter 341, a considerably large current flows through its output transistor due to the fact that the energization of the ignition coil 16 is controlled, so that the temperature exceeds the temperature range at which the elements are used. As mentioned above, there is a possibility that it will happen.

Therefore, in the device of the first embodiment, a thermistor 352 is disposed near the output transistor of the igniter 341 as shown in FIG.
The ambient temperature of the terminal 52 is monitored based on the voltage across the terminal. The thermistor 352 is pulled up by the resistor 351 to the power supply voltage potential of the A / D converter 326, and the potential of the connection point with the pulled-up resistor 351 is multiplexed as the output voltage of the thermistor 352. It is adapted to be taken into the A / D converter 326 via 325.

Next, with reference to FIGS. 3 and 4, a circuit example of the igniter 341 and a physical positional relationship between the output transistor and the thermistor 352 will be described. FIG. 3 shows a circuit configuration of the igniter 341 and the ignition coil 16 driven by the igniter 341.

As shown in FIG. 3, the drive command (ie, the ignition signal) output from the microcomputer 310 to the igniter 341 is amplified by the drive transistor 3413, and then the power transistor (output transistor). ) 3417 base electrode.

On the other hand, the spark plug 6 is connected to the collector electrode of the power transistor 3417 via the ignition coil 16 (to be precise, the spark plug of each cylinder is selectively supplied via the distributor 17). Connected).

Therefore, the same power transistor 3417 is used.
Is turned on and then turned off, the current flowing through the primary coil 16a of the ignition coil 16 is cut off, and a high voltage is generated on the secondary coil 16b side. Then, the generated high voltage drives (sparks) the spark plug 6 connected thereto. That is, each time the power transistor 3417 is turned on, the engine 1 is ignited.

In this igniter 341, the Zener diode 3415 is connected to the power transistor 341.
This is a so-called flyback diode that clamps a high voltage (flyback voltage) generated due to the ignition coil 16 that is an inductance load when the transistor 7 is turned off below a withstand voltage between the collector electrode and the emitter electrode of the transistor 3417.

Now, with respect to the power transistor 3417 of the igniter 341, the thermistor 352 is used.
Are arranged in the electronic control unit 30 in the manner shown in FIG.

FIG. 4 shows an overview of the electronic control unit 30 described above, and in FIG.
Is a case of the device 30, reference numeral 302 is a connector used for connection with an external harness, reference numeral 303 is a printed circuit board on which various circuits and elements shown in FIG. 2 are mounted, and reference numeral 304 is these circuits and elements. Shown are covers for protecting the components from dust and the like.

Electronic control unit 30 having such an overview
In the above, each of the above-mentioned elements constituting the igniter 341 is
If the resistors 3411, 3412, 3414, and 3416 are also mounted on the printed circuit board 303 in the manner shown in FIG. 4, the thermistor 352 and its pull-up resistor 351 are also shown in FIG. It is implemented in its vicinity in the manner shown. Especially the thermistor 352
Accurately monitors the ambient temperature of the power transistor 3417 (here, the flyback diode 3415 is integrally packaged).
To measure, for example, 1 from the same transistor 3417
It shall be placed within cm.

FIG. 5 shows the power transistor 3417.
Voltage and current chart of
With reference to FIG. 5 in combination, the power generated from the transistor 3417 and the allowable value of the monitored ambient temperature will be considered.

In the igniter 341, as shown in FIG. 3 above, when the drive command (ignition signal) output from the microcomputer 310 becomes the logic L (low) level, the transistor 3413 is turned on. Become,
Base current is supplied to the power transistor 3417.

By supplying the base current in this way, the power transistor 3417 is turned on, and its collector-emitter voltage VCE becomes a small value.
As shown in FIG. 5B, a voltage VCEsat called a saturation voltage is generated.

At this time, the power transistor 34
A collector current as shown in FIG. 5C flows through the collector electrode of 17. In FIG. 5C, the current value ICO indicates the saturation value of the collector current.

On the other hand, as shown in FIGS. 5A and 5D, the period of the drive command (ignition signal), that is, the ignition period (ON period of the power transistor 3417) is set to TO,
Further, when the energization time to the transistor 3417 at that time is T, the on-duty thereof is expressed as (T / TO).

Therefore, at this time, the electric power generated from the power transistor 3417 is given by the following equation, where P is P. P = VCEsat × ICO × (T / TO) (1) Here, the energization time T is the ignition coil (primary side).
The time is determined by the inductance of 16 and the power supply voltage, and the same energization time T can be set to a constant value. The energization time longer than that is a wasteful time for being converted into heat. On the contrary, when the same energizing time T is set to a short time, a sufficient spark voltage cannot be obtained through the ignition coil 16 and there is a risk of misfire.

Therefore, normally, if the power supply voltage is constant, the same energization time T is set to a constant time at which reliable ignition can be obtained. This means that the higher the engine speed, the more the on-duty (T / T
It means that (O) becomes large (ON period becomes short), and the electric power P generated from the power transistor 3417 also becomes large.

After all, according to the above equation (1), (A) The larger the on-duty (T / TO) (the shorter the on-cycle), that is, the higher the engine speed, the more the generated power P of the power transistor 3417 becomes. Grows. Alternatively, (B) the collector current saturation value ICO is larger, that is, the power supply voltage is higher, the generated power P of the power transistor 3417 becomes larger. I understand.

Continuing, such power transistor 3
The permissible ambient temperature of the transistor 3417 that is naturally determined based on the generated power P of 417 will be considered. For example, if the engine 1 is a 6-cylinder engine,
As noted in (d), the ignition cycle TO is 120 ° C.
Assuming A (crank angle), each element of the above formula (1) is (a) VCEsat (collector-emitter saturation voltage) = 0.5 V, (b) ICO (collector current saturation value) = 10 A , (C) + B (power supply voltage) = 16V,
(D) Primary coil resistance value of ignition coil 16 = 1.6Ω,
(E) T (energization time) = 3 ms, (f) TO (ignition cycle = 120 ° CA) = 3.3 ms (engine speed 600)
(Corresponding to 0 rpm), the generated power P of the power transistor 3417 is P = 0.5V × 10A × (3ms / 3.3ms) = 4.5W.

Here, if the power transistor 341
If the maximum rating of the junction temperature of No. 7 is 150 ° C. and the thermal resistance at the ambient temperature of the junction is 15 ° C./W, the same transistor 3
The allowable ambient temperature of 417 is 150 ° C.-15 ° C./W×4.5 W = 82.5 ° C.

That is, the power transistor 341.
When the generated power P of No. 7 is 4.5 W, the operating limit temperature range is not exceeded until the ambient temperature reaches 82.5 ° C., and the safety of the transistor 3417 is guaranteed.

A method of monitoring the ambient temperature of the power transistor 3417 through the thermistor 352 will be described below with reference to FIGS. 6 and 7. The thermistor 352 has a resistance (Rx) -temperature (Ta) characteristic of Rx = 2.45 * EXP [3500 * {(1 / (273 + Ta))-(1/293)}] (2).

Here, for example, the pull-up resistor 351 is used.
Is 1 kΩ and the power supply voltage of the A / D converter 326 is 5 V, the input voltage of the A / D converter 326 with respect to the output of the thermistor 352 is input voltage = 5 V × {Rx / (1 + Rx )}, And the characteristics are as shown in FIG.

In the apparatus of this embodiment, the thermistor 352
On the basis of these characteristics of (1), the relationship between the input voltage and the temperature Ta is mapped in the manner shown in FIG. 7, for example, and is stored in the ROM 312 or the backup RAM 314 in advance. Then, the temperature Ta obtained by performing map calculation in the mode shown in FIG. 7 on the basis of the respective values A / D processed by the A / D converter 326 is monitored as the ambient temperature of the power transistor 3417 to be monitored. I am trying.

The fuel cut judgment value changing process executed in the apparatus of the first embodiment under the monitoring of the ambient temperature of the power transistor 3417 in such a mode will be described in detail below.

The predicted maximum temperature in the electronic control unit 30 (ambient temperature of the transistor 3417) is now 90
C., under the operating conditions illustrated as the above (a) to (f) of the engine 1, the transistor 3417 exceeds the allowable value of its junction temperature and may be destroyed in the range of 82.5 to 90.degree. The sex comes out.

Therefore, in the device of the first embodiment, the transistor 3417 is prevented from being heated above its allowable value by lowering the fuel cut rotational speed at the time of high rotation in accordance with the ambient temperature to be monitored. To prevent.

That is, the fuel cut (F /
C) The rotation speed is set according to the maximum rotation speed allowed by the engine 1. However, if the rotation speed is lowered according to the ambient temperature, the power P generated by the transistor 3417 is naturally limited. Therefore, it is possible to prevent heating exceeding the allowable value.

The specific method will be described below. Here, first, the permissible generated power at the predicted maximum temperature of 90 ° C. in the electronic control unit 30 is obtained. As mentioned above,
Maximum rating of junction temperature of power transistor 3417 is 1
If the thermal resistance at 50 ° C. and the ambient temperature of the junction is 15 ° C./W, this is (150 ° C.-90 ° C.) ÷ 15 ° C./W=4 W.

In order to suppress the generated power P of the transistor 3417 to this 4W, from the above equation (1), 4W = 0.5V × 10A × (3ms / TO), and the ignition cycle at that time is TO becomes TO = 3.75 ms. This is a value corresponding to 5330 rpm in engine speed.

Therefore, the engine speed is set to 5330r.
If it is pm or less, even if the ambient temperature of the transistor 3417 reaches 90 ° C., the ignition cycle TO will not become shorter than this cycle “3.75 ms”.
As a result, the transistor 3417 will not be heated beyond its allowable value.

FIG. 8 shows a fuel cut determination value changing routine executed by the apparatus of the first embodiment based on such a principle. The routine is registered in advance in the ROM 312 and is activated by, for example, a time interrupt every 16 ms.

That is, assuming that the routine is started, the electronic control unit 30 first causes the thermistor 35 through the multiplexer 325 and the A / D converter 326.
The output of 2 (A / D converter input voltage) is taken in. Then, based on the map shown in FIG. 7, the ambient temperature is calculated from the captured value, and it is determined whether the calculated ambient temperature is equal to or higher than the limit value (82.5 ° C. in this example) ( Step S101).

As a result, when it is determined that the calculated ambient temperature does not reach the limit value, the process is finished as it is. On the other hand, when it is determined that the calculated ambient temperature is equal to or higher than the limit value, for example, the determination value is 6000 rpm.
The high speed fuel cut rotation speed of the engine 1 set to the above is reduced to the above rotation speed 5330 rpm (step S
102).

This high rotation fuel cutoff determination value is normally loaded from the ROM 312 to the RAM 313 and referred to when the fuel cut control is executed.
Therefore, by reducing and updating the determination value in this way, the electronic control unit 30 completely prohibits fuel injection at a rotational speed equal to or higher than the updated value, and the engine rotational speed is also updated. It will not rise above the specified value. As described above, if the maximum engine speed is limited, the electric power P generated by the transistor 3417 is naturally limited, and heating exceeding the permissible value can be prevented. .

As described above, according to the device of the first embodiment, the power transistor (output transistor) of the igniter is mounted on the heat radiation fin, or an expensive heat resistant transistor is used as the transistor. Even without doing so, it is possible to properly suppress heat generation beyond the temperature range for which it is used.

Therefore, it becomes possible to surely protect those elements in the unlikely event that the heat radiation is not costly. Further, according to the above-described fuel cutoff determination value changing process by the device of the first embodiment, such element protection can be realized without any influence on the normal running of the vehicle.

Further, in the device of the embodiment, the thermistor is arranged in the vicinity of the transistor to be monitored, and the ambient temperature of the transistor is calculated based on the output of the thermistor. The temperature can be monitored directly and easily.

(Second Embodiment) FIGS. 9 and 10 show a second embodiment of the electronic control unit for an engine according to the present invention.

The apparatus of the second embodiment is an electronic control unit for an engine in which an igniter is built in, and monitors the ambient temperature through a thermistor arranged near the output transistor of the igniter, and the temperature is set to a predetermined value. When the value is equal to or more than the value, it is configured as a device that controls thinning of fuel injection to the engine for a predetermined short time.

However, even in the device of the second embodiment, the configuration shown in FIGS. 1 to 7 or the characteristics of the thermistor 352 and the power transistor 3417 are common to the device of the first embodiment. However, duplicate explanations of common elements are omitted.

Hereinafter, the power transistor 3 in the above-mentioned mode
The fuel injection thinning control executed in the apparatus of the second embodiment under the monitoring of the ambient temperature of 417 will be described in detail. For example, if the allowable ambient temperature of the transistor 3417 is 82.5 ° C. and the predicted electronic controller 30
When the maximum temperature inside is 90 ° C, 82.5-9
As described above, in the range of 0 ° C., the transistor 3417 may exceed its allowable junction temperature and may be destroyed.

Therefore, in the device of the second embodiment, the fuel injection into the engine is controlled by thinning out for a predetermined short period of time to prevent the transistor 3417 from being heated beyond its allowable value.

That is, if the fuel injection to the engine is thinned out for a predetermined short period of time, the engine speed can be reduced without significantly affecting the operation of the engine, and thus the speed of the transistor 3417 can be reduced. It becomes possible to limit the generated power P.

The specific method will be described below. Here, first, 100 m according to the timing routine shown in FIG.
Repeat the timing of s.

This time counting routine is started by a time interrupt every 1 ms, and each time the routine is started, the electronic control unit 30 (CPU 311) increments the count value TC of the time counting counter (step S201). ).

As a result of this increment, if the count value TC is less than "100", the routine is exited as it is (step S202). On the other hand, if the count value TC is greater than or equal to "100" as a result of the increment, the count value TC is reset to "0" and the routine exits (steps S202 and S203).

By repeating such a time counting routine, the count value TC of the time counting counter is “1” → “2” → “3” ... “100” → “1” → “2” every 1 ms.
The increment is repeated in such a mode. Note that this timing routine is executed by the ROM 312.
It is registered in advance in (FIG. 2).

On the other hand, the electronic control unit 30 (CPU 31
In 1), the fuel injection thinning-out routine shown in FIG. 10 is executed in parallel with such a timing routine. The fuel injection thinning-out routine is similar to the time counting routine in the ROM.
It is registered in advance in 312. However, it is assumed that the routine is started and executed at each fuel injection timing for each cylinder of the engine 1.

If the routine is started, the electronic control unit 30 operates the multiplexer 32 as described above.
5 and the A / D converter 326, the output of the thermistor 352 is taken in, and the ambient temperature is calculated from the value obtained based on the map shown in FIG. 7, and the calculated ambient temperature is a limit value (an example here). Then, it is determined whether the temperature is 82.5 ° C. or higher (step S211).

As a result, when it is determined that the calculated ambient temperature does not reach the limit value, the well-known normal fuel injection operation is executed (step S212). On the other hand, when it is determined that the calculated ambient temperature is equal to or higher than the limit value, the count value TC of the clock counter is referred to, and it is determined again whether the same value TC is “0 ≦ TC ≦ 30”. Yes (step S213).

As a result, the count value TC is "0≤T
When it is determined that the value is out of the range of “C ≦ 30”, the normal fuel injection operation is similarly executed (step S212).

On the other hand, if the count value TC is "0≤TC≤3.
If it is determined that it is "0", the fuel injection operation to be executed at that time is forcibly stopped (step S21).
4). By executing such a fuel injection thinning-out routine, when the calculated ambient temperature becomes equal to or higher than the limit value, the fuel injection is stopped (cut) for 100 ms for 30 ms. The engine speed will also decrease.

When the engine speed is reduced in this way, the electric power P generated by the transistor 3417 is naturally limited, and in turn heating exceeding the allowable value can be prevented.

As described above, according to the device of the second embodiment as well, the power transistor (output transistor) of the igniter 341 is not mounted on the radiation fin, or a heat-resistant and expensive transistor is not used as the transistor. In addition, it is possible to accurately suppress heat generation beyond the temperature range for which it is used.

Therefore, even in the apparatus of the same embodiment, it is possible to surely protect those elements in the unlikely event that the heat dissipation is not costly. (Third Embodiment) FIG. 11 shows a third embodiment of the electronic control unit for an engine according to the present invention.

The device of the third embodiment is an electronic control unit for an engine in which an igniter is built in, and monitors the ambient temperature through a thermistor arranged near the output transistor of the igniter, and the temperature is kept at a predetermined level. When the value is equal to or more than the value, the fuel injection into any cylinder of the engine is stopped, that is, a device for controlling the cylinder reduction is configured.

Further, even in the device of the third embodiment,
The configuration shown in FIGS. 1 to 7 or the thermistor 35.
2 and the characteristics of the power transistor 3417 are common to the device of the first or second embodiment, and redundant description of the common elements will be omitted.

Hereinafter, the power transistor 3 in the above-mentioned mode
The cylinder cut-off control executed in the apparatus of the third embodiment under the monitoring of the ambient temperature of 417 will be described in detail. As described above, the allowable ambient temperature of the transistor 3417 is 82.5 ° C., and the predicted electronic control unit 3 is
When the maximum temperature in 0 is 90 ° C., for example, 8
In the range of 2.5 to 90 ° C., the transistor 3417 may exceed its allowable junction temperature and may be destroyed.

Therefore, in the device of the third embodiment, when the fuel injection into the engine is stopped, the fuel injection into an arbitrary cylinder of the engine is stopped, so that the transistor 3417 is heated beyond its allowable value. Prevent.

That is, if the cut-off cylinder control is executed in this way, for example, in the case of a 4-cylinder engine, a specific 2
By forcibly stopping the fuel injection to the cylinders or to any two randomly determined cylinders, the generated torque becomes about 1/2. Therefore, also in this case, the high rotation operation of the engine 1 can be favorably limited, and the electric power P generated by the transistor 3417 can be limited accordingly.

The specific method will be described below. In the device of the third embodiment, the electronic control unit 30 (CPU
311) executes the cut-off cylinder control routine shown in FIG. This cut-off cylinder control routine is also started and executed at each fuel injection timing for each cylinder of the engine 1, and is registered in the ROM 312 in advance.

If the routine is started, the electronic control unit 30 operates the multiplexer 32 as described above.
5 and the A / D converter 326, the output of the thermistor 352 is taken in, and the ambient temperature is calculated from the value obtained based on the map shown in FIG. 7, and the calculated ambient temperature is a limit value (an example here). Then, it is determined whether the temperature is 82.5 ° C. or higher (step S301).

As a result, when it is determined that the calculated ambient temperature does not reach the limit value, the well-known normal fuel injection operation is executed for all the cylinders regardless of the cylinder. (Step S302).

On the other hand, when it is determined that the calculated ambient temperature is equal to or higher than the limit value, (1) if the cylinder is the first or third cylinder, the fuel injection to those cylinders is forcibly stopped. (2) If the cylinder is the second or fourth cylinder, the fuel injection to those cylinders is executed normally. Such a cylinder reduction control is executed (step S303).

When such a cut-off cylinder control is executed, as described above, the generated torque becomes about 1/2, and the high rotation operation of the engine 1 is naturally restricted. If the high-speed operation of the engine 1 is restricted in this way, the electric power P generated by the transistor 3417 is naturally restricted, and in turn, heating exceeding its allowable value can be prevented.

As described above, also in the device of the third embodiment, the output transistor of the igniter 341 is mounted on the radiating fin or the same transistor as the device of the first or second embodiment. Even if an expensive transistor having heat resistance is not used, it is possible to accurately suppress heat generation beyond the temperature range for which it is used.

(Fourth Embodiment) FIG. 12 shows a fourth embodiment of the electronic control unit for the engine according to the present invention. The device of the fourth embodiment is an electronic control device for an engine in which an igniter is built in, and monitors the ambient temperature through a thermistor arranged in the vicinity of the output transistor of the igniter, and if the temperature exceeds a predetermined value. In this case, the device is configured to reduce the fuel injection amount to the engine to a predetermined value.

Further, even in the apparatus of the fourth embodiment,
The configuration shown in FIGS. 1 to 7 or the thermistor 35.
The characteristics of No. 2 and the power transistor 3417 are common to the devices of the first to third embodiments, and redundant description of the common elements will be omitted.

Hereinafter, the power transistor 3 in the above-mentioned mode
The injection amount reduction control executed in the apparatus of the fourth embodiment under the monitoring of the ambient temperature of 417 will be described in detail.
For example, assuming that the allowable ambient temperature of the transistor 3417 is 82.5 ° C. and the predicted maximum temperature in the electronic control unit 30 is 90 ° C., 82.5 to 90 ° C.
It has already been described that the transistor 3417 exceeds the allowable value of the junction temperature in the range of (3) and may be destroyed.

Therefore, in the device of the fourth embodiment, when the fuel is injected into the engine, the amount of fuel injected into each cylinder of the engine is reduced, so that the transistor 3417 is heated above its allowable value. Prevent that.

That is, when the fuel injection amount is reduced by 20% from the proper amount, the generated torque is also reduced accordingly. Therefore, also in this case, the maximum rotation speed of the engine 1 can be limited, and by extension, the transistor 3
It becomes possible to limit the generated power P of 417.

The specific method will be described below. In the device of the fourth embodiment, the electronic control unit 30 (CPU
311) executes the injection amount reduction routine shown in FIG. It is assumed that this injection amount reduction routine is started and executed after the calculation of the fuel injection amount for the engine 1. This is also registered in the ROM 312 in advance.

If the routine is started, the electronic control unit 30 operates the multiplexer 32 as described above.
5 and the A / D converter 326, the output of the thermistor 352 is taken in, and the ambient temperature is calculated from the value obtained based on the map shown in FIG. 7, and the calculated ambient temperature is a limit value (an example here). Then, it is determined whether the temperature is 82.5 ° C. or higher (step S401).

As a result, when it is determined that the calculated ambient temperature does not reach the limit value, the routine directly exits. On the other hand, when it is determined that the calculated ambient temperature is equal to or higher than the limit value, the fuel injection amount is set to a value that is 20% less than the appropriate fuel injection amount calculated by the well-known method. The data about the same fuel injection amount registered in the predetermined area of the RAM 313 is updated (step S402).

When such a fuel injection amount reduction control is executed, the generated torque is reduced according to the reduced amount, and the maximum engine speed of the engine 1 is naturally limited.

When the maximum engine speed of the engine 1 is limited in this way, the electric power P generated by the transistor 3417 is naturally limited, and in turn heating exceeding the allowable value is prevented.

As described above, also in the device of the fourth embodiment, the output transistor of the igniter 341 is mounted on the radiating fin or as the same transistor as the device of the first to third embodiments. Even if an expensive transistor having heat resistance is not used, it is possible to accurately suppress heat generation beyond the temperature range for which it is used.

(Fifth Embodiment) Next, a fifth embodiment of the engine electronic control unit according to the present invention will be described.

The device of the fifth embodiment is an electronic control unit for an engine in which an igniter is built-in, and the ambient temperature is monitored through a thermistor arranged near the output transistor of the igniter, and the temperature is kept at a predetermined level. When the value is equal to or more than the value, it is configured as a device for forcibly driving the intake throttle valve of the engine, that is, the throttle valve to the side where the intake amount is suppressed.

The device of the fifth embodiment basically has the same structure as the device of the first to fourth embodiments, but in the case of the device of the fifth embodiment, Particularly, it is assumed that the electronic control unit 30 can control the opening degree of the throttle valve 12 shown in FIG.

That is, in the device of the fifth embodiment, when it is determined that the ambient temperature calculated as described above becomes equal to or higher than the limit value, the electronic control unit 30 controls the intake air amount to the engine to be suppressed. The maximum rotational speed of the engine is limited by forcibly driving the opening of the throttle valve 12.

Therefore, even with the device of the fifth embodiment, the operating limit temperature range of the power transistor (output transistor) 3417 of the igniter 341 is set in a manner similar to the devices of the first to fourth embodiments described above. It will be possible to accurately suppress the excess heat generation.

In addition, as a constitution of the device of the fifth embodiment, it is also possible to adopt a constitution in which an opening of the sub-throttle is controlled in the above-mentioned manner in an engine provided with a well-known sub-throttle. it can.

(Sixth Embodiment) By the way, the above-mentioned first to fifth
In the embodiment described above, the thermistor 352 is used to monitor the ambient temperature of the electronic control unit 30 (power transistor 3417). However, for example, if there is a diode driven by a constant current, its forward voltage is reduced. It is possible to monitor such ambient temperature based on

13 to 16 show a sixth embodiment of the electronic control unit for an engine according to the present invention, in which the ambient temperature is monitored based on the forward voltage of the diode driven by the constant current. An example of an apparatus is shown.

In the device of the sixth embodiment, as shown in FIG. 13 and FIG. 14, in the waveform shaping circuit 334 of the vehicle speed sensor 28, the sensor signal of the diode is driven by the constant current as the diode driven by the constant current. A diode 3342 that generates a comparison reference potential for quantifying is diverted. The forward voltage VF of the diode 3342 is applied to the multiplexer 3
25 to be taken into the A / D converter 326. The other configuration of the electronic control unit 30 shown in FIG. 13 is the same as that of the electronic control unit 30 shown in FIG.
The duplicate explanation here is omitted.

First, the outline of the waveform shaping circuit 334 will be described with reference to FIG. As shown in FIG. 14, the waveform shaping circuit 334 uses the diode 3342.
Besides, a resistor 3341 connected in series with the diode 3342 and having a power supply voltage applied to the other end, a comparator 3344, and an input resistance 3 of the comparator 3344.
343, and the output resistance 334 of the comparator 3344.
It is configured with 5 each.

In the waveform shaping circuit 334, since it is difficult to compare the power source voltage or less by the comparator 3344, the diode 3342 is used to generate a voltage floating from the ground potential by the forward voltage VF. Then, the output signal of the vehicle speed sensor (pickup coil) 28 is input to the non-inverting input terminal (+ terminal) of the comparator 3344 in a state where the potential of the inverting input terminal (-terminal) is floated by the voltage VF. A binary pulse signal having a cycle corresponding to the rotation speed of the wheel is output from the comparator 3344.

According to such a waveform shaping circuit 334,
Basically, only a current flows through the diode 3342, which is determined by the resistance value of the resistor 3341 connected in series with the diode 3342 and its applied voltage.

Therefore, in the device of the sixth embodiment, based on the forward voltage VF-temperature characteristic of the diode 3342 which is thus driven by the constant current, the temperature in the electronic control unit 30, that is, the power transistor 3417 (see FIG. 3,
The ambient temperature (Fig. 4) is monitored.

FIG. 15 shows the VF (forward voltage) -temperature characteristic when the diode 3342 is driven at a constant current. The diode 3342 ideally has the characteristics shown by the solid line in FIG. Therefore, if the resolution of the A / D converter 326 is 5 mV, the ambient temperature can be monitored with a resolution of about 3 ° C.

However, there is usually a variation in the VF-current characteristics of the diode. The variation in the VF-current characteristic also causes variation in the VF-temperature characteristic in the manner shown by the broken line in FIG. 15, making accurate temperature measurement based on the voltage VF difficult.

Therefore, in the apparatus of the sixth embodiment, as shown in FIG.
The above variation is calibrated through the calibration / temperature-control routine shown in (1) to obtain an accurate temperature based on the calibrated characteristics. Note that this calibration / temperature-increasing routine is shown in FIG.
16 is registered in advance in the ROM 312 shown in FIG.
It shall be activated by a time interrupt every ms.

In the device of the sixth embodiment, the electronic control unit 30 (CPU 311) first (1) avoids the influence of the voltage fluctuation after turning on the power supply + B based on the start of the routine. In step S501, it is determined whether it is within a predetermined time (for example, 1 second) after the power is turned on. (2) Next, in step S502, it is determined whether the cooling water temperature and the intake air temperature are both in the range of 0 to 30 ° C. (3) Further, in step S503, it is determined whether or not the difference between the cooling water temperature and the intake air temperature is within 3 ° C. (4) Then, in step S504, the engine speed N
It is determined whether E is 0 rpm. When all the conditions (1) to (4) are satisfied, it is considered that the entire vehicle is at a constant temperature, and the next VF (forward voltage) is determined.
Perform the calibration process of.

In the calibration process, the electronic control unit 30
First, in step S511, the (CPU 311) converts the forward voltage VF of the diode 3342 into the A / D converter 3.
Read through 26.

At the time when all the above conditions (1) to (4) are satisfied, the diode 3
Since the temperature of 342 is also considered to be equal to the cooling water temperature, the ideal value of the forward voltage VF is obtained from this cooling water temperature based on the characteristics of FIG. For example, assuming that the cooling water temperature = intake air temperature = 10 ° C., the ideal forward voltage VF is “0.7” due to the characteristics of FIG.
2 "V.

The electronic control unit 30 that has obtained the ideal value for the forward voltage VF in this way next determines, in step S512, the difference between the ideal value for the forward voltage VF and the read actual measured value as the offset voltage. Obtained and stored in the backup RAM 314 (FIG. 13). For example, the measured value of the read forward voltage VF is “0.
73 "V, the ideal value is" 0.72 "V
The difference “−0.01” V from the above is stored in the backup RAM 314 as an offset voltage.

On the other hand, if any one of the above conditions (1) to (4) is not satisfied, the electronic control unit 30 executes the temperature-increasing process after step S521. That is, in this temperature-increasing process, the electronic control unit 30 (CPU 31
1) First, in step S521, the forward voltage VF of the diode 3342 is converted to the A / D converter 32 in the same manner as described above.
Read through 6.

Then, in the next step S522, the read forward voltage VF is calibrated based on the stored offset voltage. For example, if the measured value of the read forward voltage VF is "0.7" V, the calibration value is "0.69" by adding the offset voltage "-0.01" V to this value. It becomes V.

The electronic control unit 30 that has obtained the calibration value for the forward voltage VF in this manner further proceeds to step S52.
At 3, the temperature to be monitored is obtained from this calibration value based on the ideal characteristics shown in FIG. In this example, a temperature of 25 ° C. is obtained as the ambient temperature based on the calibration value “0.69” V.

As described above, according to the apparatus of the sixth embodiment, the ambient temperature can be accurately obtained without providing a thermistor dedicated to temperature measurement as in the apparatus of the first to fifth embodiments. Will be able to.

Even in the device of the sixth embodiment, however, after the ambient temperature is obtained in this way, the first temperature is calculated based on the comparison with the limit value (82.5 ° C. in the above example). -In a mode according to the device of the fifth embodiment, the fuel cut speed of the engine 1 is restricted, the maximum speed is restricted, and the like.
A process for limiting the power generated by the power transistor 3417 will be executed.

In the device of the sixth embodiment, the vehicle speed sensor 2 is used as a diode for monitoring the ambient temperature.
Diode 3 used in the waveform shaping circuit 334 of FIG.
Although the 342 is used, the selection of the diodes to be used is arbitrary as long as it is driven by a constant current.

Further, for example, the diode for monitoring the ambient temperature may be added separately. In this case, although a little economically disadvantageous, it is possible to select the arrangement with a high degree of freedom, such as arranging the diode closer to the power transistor 3417.

(Seventh Embodiment) In the first embodiment, it is assumed that the engine 1 is a 6-cylinder engine, and each element of the equation (1) is (a) VCEsat (collector-emitter saturation). Voltage) = 0.5V, (b) ICO (collector current saturation value) = 10A, (c) + B (power supply voltage)
= 16V, (d) Primary coil resistance value of ignition coil 16 =
1.6Ω, (e) T (energization time) = 3 ms, (f) TO
The power P generated by the power transistor 3417 was calculated (P = 4.5 W) by assuming a value such as (ignition cycle = 120 ° CA) = 3.3 ms (engine speed 6000 rpm).

However, the power supply voltage + B is, for example, 1
Even when the voltage is 4.0 V or less, the engine 1 operates normally. In this case, each element of the equation (1) is: (a) VCEsat (collector-emitter saturation voltage) = 0.5V, (b) ICO (collector current saturation value)
= 8.75A, (c) + B (power supply voltage) = 14V,
(D) Primary coil resistance value of ignition coil 16 = 1.6Ω,
(E) T (energization time) = 3 ms, (f) TO (ignition cycle = 120 ° CA) = 3.3 ms (engine speed 600)
0 rpm), the generated power P of the power transistor 3417 is P = 0.5V × 8.75A × (3ms / 3.3ms) = 3.9W.

Therefore, also here, assuming that the maximum rating of the junction temperature of the power transistor 3417 is 150 ° C. and the thermal resistance of the junction one ambient temperature is 15 ° C./W, the ambient temperature allowed for the transistor 3417 is the same. Is 150 ° C.-15 ° C./W×3.9 W = 91 ° C.

The temperature of 91.degree. C. is the predicted maximum temperature in the electronic control unit 30 (the transistor 341 described above).
Ambient temperature of 7) of 90 ° C. That is, if the power supply voltage does not exceed 14V, the power P generated by the transistor 3417 will never exceed the allowable temperature of 91 ° C.
Never exceeds.

Therefore, according to the example here, only when the power supply voltage exceeds 14 V, the fuel cut speed of the engine 1 is limited and the generated power P of the transistor 3417 is limited. , Its destruction, etc. will surely be avoided.

17 and 18 show a seventh embodiment of the electronic control unit for an engine according to the present invention, which is constructed on the basis of such a principle. That is, the device of the seventh embodiment is an electronic control unit for an engine in which an igniter is built in, and the temperature around the output transistor of the igniter is converted into a battery voltage (power supply voltage) for monitoring and the converted battery is used. It is configured as a device that lowers the high rotation speed fuel cutoff determination value of the engine when the voltage becomes equal to or higher than a predetermined limit value.

The details will be described below. Figure 1
As shown in FIG. 7, in the device of the seventh embodiment, the voltage is extracted from the battery 29 of the vehicle through an appropriate voltage dividing circuit, and the extracted battery voltage is applied to the multiplexer 32.
It is designed to be taken into the A / D converter 326 via the A.D.

FIG. 18 shows a fuel cut judgment value changing routine executed by the apparatus of the seventh embodiment. Note that this routine is also registered in the ROM 312 in advance, for example, 16
It shall be activated by a time interrupt every ms.

That is, if the routine is started now, the electronic control unit 30 first takes in the voltage value of the battery 29 through the multiplexer 325 and the A / D converter 326, and the taken-in voltage value corresponds to the ambient temperature. Predetermined value corresponding to the limit value (14V in this example)
It is determined whether or not this is the case (step S601).

As a result, when it is determined that the voltage value of the battery 29 has not reached the above-mentioned predetermined value, the process is finished as it is. On the other hand, when it is determined that the voltage value of the battery 29 is equal to or higher than the predetermined value, for example, the determination value 6
The high revolution fuel cut rotation speed of the engine 1 set to 000 rpm is reduced to, for example, the rotation speed 5330 rpm (step S602).

This high rotation fuel cutoff judgment value is usually RO
As described above in the apparatus of the first embodiment, the M312 is loaded into the RAM 313 and is referred to when the fuel cut control is executed.

By thus lowering and updating the determination value, the electronic control unit 30 completely prohibits fuel injection at a rotational speed equal to or higher than the updated value, and the engine rotational speed is also updated. It will not rise above the specified value. If the maximum engine speed is limited in this way, the electric power P generated by the transistor 3417 is naturally limited, and in turn, heating exceeding the permissible value can be prevented. As described above in the apparatus of the first embodiment.

As described above, according to the device of the seventh embodiment, the power transistor (output transistor) of the igniter is mounted on the heat radiation fin, or an expensive heat resistant transistor is used as the transistor. Without, and even without directly monitoring the ambient temperature of the transistor, heat generation beyond its operating temperature limit can be accurately suppressed.

In the device of the seventh embodiment, the means for converting the ambient temperature into the power supply voltage (battery voltage) and monitoring it is the high rotation fuel cut rotation speed by the device of the first embodiment. Is applied to the energization limit control for limiting the energization cycle to the igniter output transistor by lowering the judgment value of No. 1. However, the same monitoring means controls each energization limit by the devices of the second to fifth embodiments. It is needless to say that the above can be similarly applied.

[0180]

[0181]

[0182]

[0183] Then, as the ambient temperature monitoring means, a thermistor disposed in the vicinity of, the output transistor, and calculates the ambient temperature of the output Trang <br/> register based on the voltage between the terminals of the thermistor It is equipped with a calculation means. A device provided with a diode which is arranged in the electronic control device and is driven with a constant current, and a calculation unit which calculates the ambient temperature of the output transistor based on the forward voltage of the diode. A device for converting the ambient temperature of the output transistor into a battery voltage value and monitoring it. And so on, and the energization cycle to the output transistor
As the energization limit control for limiting , the fuel cut speed judgment value associated with the high speed rotation of the engine is lowered, and the lower judgment value of the engine is set to this lowered judgment value.
A means for changing the fuel cutoff judgment value for limiting the energization cycle to the output transistor by limiting the maximum number of revolutions . A fuel injection thinning means for limiting the energization cycle to the output transistor by thinning out the fuel injection to the engine for a predetermined short time to reduce the maximum engine speed of the engine. A cylinder cut-off control means for restricting the energization cycle to the output transistor by stopping the fuel injection to an arbitrary cylinder of the engine to restrict the high rotation operation of the engine. An injection amount reducing means for limiting the energization cycle to the output transistor by reducing the fuel injection amount to the engine by a predetermined amount to reduce the maximum rotation speed of the engine.・ The energization cycle to the output transistor is limited by forcibly driving the intake throttle valve (throttle valve, sub-throttle) of the engine to the side where the intake amount can be suppressed to lower the maximum rotation speed of the engine. Those equipped with a means for restricting intake. And so on.

[0184]

As described above, according to the present invention, the igniter incorporated in the electronic control unit of the engine is incorporated .
It is possible to properly suppress heat generation of the output transistor beyond the temperature range that is the limit of use.

Therefore, it is possible to surely protect the elements without incurring a cost for heat radiation.

[Brief description of drawings]

FIG. 1 is a schematic diagram schematically showing an example of an engine to be controlled by an electronic control unit for an engine according to the present invention and its peripheral devices.

FIG. 2 is a block diagram showing a device configuration of a first embodiment of an electronic control unit for an engine according to the present invention.

FIG. 3 is a circuit diagram showing a circuit configuration example of an igniter built in the apparatus of the embodiment and an ignition coil externally attached to the igniter.

FIG. 4 is a perspective view showing a schematic configuration on a printed circuit board mainly for an igniter portion of the apparatus of the embodiment.

FIG. 5 is a time chart showing voltage and current waveforms of the output transistor (switching element) of the igniter.

FIG. 6 is a schematic diagram showing a temperature-voltage characteristic table of a thermistor arranged near the output transistor of the igniter.

FIG. 7 is a graph showing an example of a temperature calculation map mapped based on a temperature-voltage characteristic table of the thermistor.

FIG. 8 is a flowchart showing a processing procedure of a fuel cut determination value changing processing executed by the apparatus of the first embodiment.

FIG. 9 is a flowchart showing a processing procedure of a timing processing executed through a second embodiment of the electronic control unit for an engine according to the present invention.

FIG. 10 is a flowchart showing a processing procedure of a fuel injection thinning-out processing executed by the apparatus of the second embodiment.

FIG. 11 is a flow chart showing a control procedure for a cylinder cut-off control executed through a third embodiment of the electronic control unit for an engine according to the present invention.

FIG. 12 is a flowchart showing a processing procedure of a fuel injection amount reduction processing executed through a fourth embodiment of the electronic control unit for an engine according to the present invention.

FIG. 13 is a block diagram showing the configuration of an electronic control unit for an engine according to a sixth embodiment of the present invention.

FIG. 14 is a circuit diagram showing an example of a circuit configuration mainly for a vehicle speed sensor waveform shaping circuit of the device of the sixth embodiment.

15 is a graph showing forward voltage-temperature characteristics when the diode shown in FIG. 14 is driven with a constant current.

FIG. 16 is a flow chart showing the procedure of the calibration processing of the diode characteristics and the temperature-increasing processing based on the diode characteristics, which is executed through the apparatus of the sixth embodiment.

FIG. 17 is a block diagram showing the configuration of an electronic control device for an engine according to a seventh embodiment of the present invention.

FIG. 18 is a flowchart showing a processing procedure of a fuel cut determination value change processing executed by the apparatus of the seventh embodiment.

[Explanation of symbols]

1 ... Engine, 2 ... Cylinder, 3 ... Piston, 4 ... Cylinder head, 5 ... Combustion chamber, 6 ... Spark plug, 7 ... Intake valve, 8 ... Intake manifold, 9 ... Fuel injection valve, 10 ...
Intake pipe, 11 ... Surge tank, 12 ... Throttle valve, 13 ... Air cleaner, 14 ... Exhaust valve, 15 ... Exhaust manifold, 16 ... Ignition coil, 17 ... Distributor, 20 ... Water temperature sensor, 21 ... Intake temperature sensor, 2
2 ... Throttle position sensor, 23 ... Intake pipe pressure sensor, 24 ... Oxygen concentration sensor, 25 ... Rotation angle sensor,
26 ... Cylinder discrimination sensor, 27 ... Signal rotor, 28 ...
Vehicle speed sensor, 29 ... Battery, 30 ... Electronic control device, 3
01 ... Case, 302 ... Connector, 303 ... Printed circuit board, 304 ... Cover, 310 ... Microcomputer,
311 ... CPU, 312 ... ROM, 313 ... RAM, 3
14 ... Backup RAM, 315 ... Input / output port, 3
16 ... Input port, 317 ... Output port, 318 ... Common bus, 319 ... Clock generator, 321, 322, 3
23, 324, 331 ... Buffer circuit, 325 ... Multiplexer, 326 ... A / D converter, 332 ... Comparator, 333 ... 334 ... Waveform shaping circuit, 335 ... Wiring (diode forward voltage fetch wiring), 341 ... Driving circuit ( Igniter), 342 ... Drive circuit, 351 ... Resistor (pull-up resistor), 352 ... Thermistor, 353 ... Wiring (thermistor output taking-in wiring), 361 ... Wiring (battery voltage taking-in wiring), 3341, 3343, 33
45, 3411, 3412, 3414, 3416 ... Resistor, 3342 ... Diode, 3344 ... Comparator,
3413, 3417 ... Transistor, 3415 ... Zener diode (flyback diode).

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-52-67425 (JP, A) JP-A-5-231291 (JP, A) JP-A-60-128957 (JP, A) JP-A-6- 167228 (JP, A) JP 62-233476 (JP, A) JP 6-272597 (JP, A) JP 5-157035 (JP, A) Actual development 2-101054 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F02P 11/00 F02D 41/22 F02D 45/00 F02P 3/055

Claims (11)

(57) [Claims] 1. A engine and a microcomputer which generally manages operation of the peripheral device, the ignition carp based on the drive command output from the microcomputer
Igniter output transistor that controls power to the module
And a drive command output from the microcomputer
An electronic control unit for an engine, comprising: a drive circuit for driving a fuel injection valve based on the following: ambient temperature monitoring means for monitoring the ambient temperature of the output transistor; and the monitored ambient temperature or its equivalent value is predetermined. when the the above limit, the fuel due to the high speed rotation of the engine cut
Lowering the judgment value of the rotation speed,
Fuel cut determination value to limit the current periodic to the output <br/> transistor by limiting the maximum engine speed to value
An electronic control unit for an engine, comprising: a changing unit . 2. Control of driving of an engine and its peripheral devices
And a microcomputer that manages the
Ignition coil based on the drive command output from the computer
Igniter output transistor that controls power to the module
And a drive command output from the microcomputer
And a drive circuit for driving the fuel injection valve based on
An electronic control device for an engine, comprising: an ambient temperature monitor for monitoring the ambient temperature of the output transistor.
The visual means and the monitored ambient temperature or its equivalent value has a predetermined limit.
When the value exceeds the specified value, the fuel injection to the engine is
Decrease the maximum rpm of the engine by thinning out each time
Limit the energization cycle to the output transistor
Electronic engine control apparatus wherein the Rukoto comprises a fuel injection thinning means. 3. Control of driving of an engine and its peripheral devices
And a microcomputer that manages the
Ignition coil based on the drive command output from the computer
Igniter output transistor that controls power to the module
And a drive command output from the microcomputer
And a drive circuit for driving the fuel injection valve based on
An electronic control device for an engine, comprising: an ambient temperature monitor for monitoring the ambient temperature of the output transistor.
The visual means and the monitored ambient temperature or its equivalent value has a predetermined limit.
When the value exceeds the value, fuel injection into any cylinder of the engine
By stopping and limiting high-speed operation of the engine,
Electronic engine control apparatus wherein the Rukoto comprises a cylinder cut control means <br/> for limiting the energization period of the output transistor. 4. Controlling drive of an engine and its peripheral devices
And a microcomputer that manages the
Ignition coil based on the drive command output from the computer
Igniter output transistor that controls power to the module
And a drive command output from the microcomputer
And a drive circuit for driving the fuel injection valve based on
An electronic control device for an engine, comprising: an ambient temperature monitor for monitoring the ambient temperature of the output transistor.
The visual means and the monitored ambient temperature or its equivalent value has a predetermined limit.
When the value exceeds the specified value, the fuel injection amount to the engine is reduced to the specified value.
By measuring and lowering the maximum engine speed
Injection amount reduction that limits the energization cycle to the output transistor
Electronic engine control apparatus wherein the Rukoto comprises means. 5. Control of driving of an engine and its peripheral devices
And a microcomputer that manages the
Ignition coil based on the drive command output from the computer
Igniter output transistor that controls power to the module
And a drive command output from the microcomputer
And a drive circuit for driving the fuel injection valve based on
An electronic control device for an engine, comprising: an ambient temperature monitor for monitoring the ambient temperature of the output transistor.
The visual means and the monitored ambient temperature or its equivalent value has a predetermined limit.
When the value exceeds this value, the intake amount is suppressed by the intake throttle valve of the engine.
The maximum speed of the engine is lowered by forcibly driving to the side
The energization period to the output transistor in Rukoto allowed under
Electronic control device for engine <br/> down, wherein Rukoto comprises an intake limiting means limiting for. 6. The ambient temperature monitoring means includes the output transformer.
A thermistor arranged near the transistor and the thermistor
Ambient temperature of the same output transistor
And a computing means for computing
The electronic control unit for the engine according to any one of 5 above. 7. The electronic control unit for the ambient temperature monitoring means
A diode that is placed inside the device and is driven with a constant current;
Of the output transistor based on the forward voltage of the
The electronic control unit for an engine according to any one of claims 1 to 5 , wherein the electronic control unit is configured to include a calculation unit that calculates an ambient temperature . 8. The diode has the same circumference in an electronic control unit.
The engine electronic control unit according to claim 7 , wherein the electronic control unit is separately provided as the surrounding temperature monitoring means . 9. The diode is controlled within an electronic control unit.
Claims that are previously arranged as parts are used
7. The electronic control unit for the engine according to 7 . 10. The calculating means is within a predetermined time after power-on, and the engine
If the cooling water temperature and the intake air temperature are both below the specified first temperature,
The temperature difference between the two is less than or equal to a predetermined second temperature, and
The logical product condition that the gin is not rotating is satisfied.
The forward voltage-temperature characteristic of the diode is calculated based on
If any one of the above conditions is no longer met, the
Based on the calibrated forward voltage-temperature characteristic of the ion
The temperature of each case is set as the ambient temperature of the output transistor.
D of claim 7 or 8 or 9, wherein constituted comprising a means for calculating Te
Electronic control unit of engine. 11. The ambient temperature monitoring means is the output transistor.
Monitor the ambient temperature of the transistor by converting it to the voltage value of the battery
And the output transistor is the converted battery voltage.
When the pressure value exceeds the specified limit value, the energizing cycle is controlled.
The method according to any one of claims 1 to 5, which is limited
Engine electronic control unit.