JP2591008B2 - Electronic distribution ignition system with fail-safe function - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic distribution (or low-pressure distribution) ignition device suitable for use in a multi-cylinder gasoline engine, and particularly to a case where cylinder identification information is not detected. The present invention also relates to an electronic distribution type ignition device having a fail-safe function that enables starting of an engine.

2. Description of the Related Art Conventionally, an ignition timing is calculated based on cylinder identification information and crank angle information from a crank angle sensor, and an ignition timing control signal is output to an ignition coil based on the calculation result. An electronic distribution ignition system for a multi-cylinder engine that sequentially ignites the ignition plug has been proposed and put into practical use.

In such an ignition device, the ignition timing is calculated by a computer, and a control signal is output to a power transistor for driving an ignition coil at a required timing, thereby performing ignition in a spark plug in a required sequence. No distributor is required.

[Problems to be Solved by the Invention] However, in such a conventional electronic distribution type ignition device, if the cylinder identification signal cannot be obtained due to disconnection of the crank angle sensor or the like, the disconnection occurs during engine rotation. If there is, the ignition can be continued by the program for distributing power in the same order, but if the wire is disconnected before the engine is started, the power distribution destination is unknown and the ignition cannot be performed, so that the engine cannot be started.

The present invention has been made in view of such a problem, and by providing a fail-safe function that enables the engine to be started even when cylinder identification information is not detected due to disconnection or the like, before starting the engine. It is an object of the present invention to provide an electronic distribution ignition device with a fail-safe function, which enables the engine to be started even when a disconnection occurs.

[Means for Solving the Problems] In order to achieve the above object, an electronic distribution ignition device with a fail-safe function of the present invention calculates an ignition timing based on cylinder identification information and crank angle information, and calculates the calculation result. By outputting an ignition timing control signal to the ignition coil side based on the above, in an electronic distribution type ignition device of a multi-cylinder engine that sequentially ignites a spark plug of each cylinder, ignition is started when the above-described cylinder identification information is not input. Cylinder assumption means for assuming a certain cylinder to be provided, and ignition test means for starting ignition from the cylinder assumed by the cylinder assumption means are provided, and when the engine is not started by the ignition test by the ignition test means, A hypothetical cylinder changing means for changing a cylinder assumption by the above-mentioned cylinder hypothesis means is provided.

[Operation] In the above-described electronic distribution ignition device with the fail-safe function of the present invention, when the cylinder identification information is not input, the cylinder assuming means assumes a certain cylinder to start ignition. The ignition test means starts ignition from the cylinder assumed by the cylinder assumption means.

When the engine is started by the ignition test, the ignition is continued in this order, but if the engine is not started by the ignition test by the ignition test means, the assumption of the cylinder by the cylinder assumption means is made by the assumed cylinder changing means by the assumed cylinder changing means. Then, the ignition test means starts ignition from the cylinder re-assumed by the cylinder assumption means.

Thereafter, until the engine starts, the change of the assumed cylinder by the assumed cylinder changing means and the ignition test by the ignition test means are repeated.

[Embodiment] Hereinafter, an electronic distribution type ignition device with a fail-safe function according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a control block diagram of a main part thereof, FIG. FIG. 3 is an overall configuration diagram showing an engine system having the present apparatus, FIG. 4 is a control block diagram of the engine system, FIG. 4 is a fuel control block diagram of the engine system, and FIG. FIG. 6 is a graph for explaining the operation.

Now, the vehicle-mounted gasoline engine system controlled by the present apparatus is as shown in FIG. 3. In FIG. 3, a gasoline engine E (hereinafter simply referred to as engine E) has an intake passage leading to a combustion chamber 1 thereof. 2 and an exhaust passage 3, and the intake passage 2 and the combustion chamber 1
The communication between the exhaust passage 3 and the combustion chamber 1 is controlled by an exhaust valve 5.

In addition, an air cleaner is provided in the intake passage 2 in order from the upstream side.
6, a throttle valve 7 and an electromagnetic fuel injection valve (injector) 8 are provided. In the non-air passage 3, a catalytic converter (three-way catalyst) 9 for purifying exhaust gas is sequentially provided from the upstream side.
A muffler (muffler) not shown is provided.

Note that the injectors 8 are provided in the intake manifold portion by the number of cylinders. Now, assuming that the engine E of the present embodiment is an in-line four-cylinder engine, four injectors 8 are provided. That is, it can be said that the engine is a so-called multipoint fuel injection (MPI) type engine.

The throttle valve 7 is connected to an accelerator pedal via a wire cable so that the opening varies according to the amount of depression of the accelerator pedal.
The motor 10 is also driven to open and close, so that the opening of the throttle valve 7 can be changed without depressing the accelerator pedal during idling.

Further, as shown in FIG. 4, each cylinder is provided with a spark plug 18-1, 18-2, 18-3, 18-4 toward the combustion chamber 1.

Here, the ignition plugs 18-1 and 18-4 for the first and fourth cylinders are connected to the ignition coil 51A in series with each other, and the ignition plugs 18-2 and 18- for the second and third cylinders are connected. Numerals 3 are connected to the ignition coil 51B in series with each other.

A power transistor 52A, 52B is connected to each of the ignition coils 51A, 51B, and a high voltage is generated in the ignition coils 51A, 51B by the OFF operation of the corresponding power transistors 52A, 52B. Plug group 18-1, 18-4;
Either of 18-2 and 18-4 sparks (ignites). Note that the corresponding ignition coils 51A, 51B start charging by turning on the power transistors 52A, 52B.

Therefore, this engine system is equipped with a two-ignition coil type electronic distribution ignition system.

With this configuration, the air sucked through the air cleaner 6 according to the opening of the throttle valve 7 is mixed with the fuel from the injector 8 at the intake manifold so as to have an appropriate air-fuel ratio, and the ignition is performed in the combustion chamber 1. Plug 18-1, 18
By igniting −2, 18-3, 18-4 at an appropriate timing, the fuel is burned to generate engine torque, and then the air-fuel mixture is discharged as exhaust gas to the exhaust passage 3, CO in the exhaust gas, HC, since the purifying three harmful components NO _X, are muted in the muffler so as to be discharged to the atmosphere side.

Further, various sensors are provided to control the engine E. First, as shown in Figs.
On the side of the intake passage 2, an air flow sensor 11 as a volume flow meter for detecting the amount of intake air from Karman vortex information, an intake air temperature sensor 12 for detecting the intake air temperature, and a large air pressure sensor for detecting the atmospheric pressure are provided in the air cleaner portion. An air pressure sensor 13 is provided, and a potentiometer type throttle sensor 14 for detecting an opening degree of the throttle valve 7, an idle switch 15 for detecting an idling state, and a position of the ISC motor 10 are provided in a portion where the throttle valve is provided. A motor position sensor 16 is provided.

On the exhaust passage 3 side, an oxygen concentration sensor (O ₂ sensor) 17 for detecting the oxygen concentration (O ₂ concentration) in the exhaust gas is provided in a portion upstream of the catalytic converter 9 and near the combustion chamber 1. I have. Here, the O ₂ sensor 17 is based on the principle of a solid electrolyte oxygen concentration cell, and its output voltage has a characteristic that changes abruptly near the logical air-fuel ratio, and the voltage on the lean side is lower than the stoichiometric air-fuel ratio. , The voltage on the rich side is higher than the logical air-fuel ratio.

Further, as other sensors, a water temperature sensor 19 for detecting an engine cooling water temperature is provided, and a crank angle sensor 21 for detecting a crank angle (this crank angle sensor 21 is also an engine speed sensor for detecting an engine speed N). The crank angle sensor 21 may be hereinafter referred to as an engine speed sensor if necessary, and a TD for detecting the top dead center of the first cylinder (reference cylinder).
Each of the C sensors 22 is provided.

The detection signals from the sensors 11 to 17, 19, 21, and 22 are input to an electronic control unit (ECU) 23.

The ECU 23 receives a voltage signal from a battery sensor 25 for detecting the voltage of a battery 24 (see FIG. 4) and a signal from an ignition switch (key switch) 26.

The hardware configuration of the ECU 23 is as shown in FIG. 4. The ECU 23 has a CPU 27 as its main part. The CPU 27 has an intake air temperature sensor 12, an atmospheric pressure sensor 13,
Throttle sensor 14, O ₂ sensor 17, water temperature sensor 19 and the input detection signal from the battery sensor 25 Interface 28
And the detection signal from the idle sensor 15 and the ignition switch 26 is input through the input interface 29, and the detection signal from the air flow sensor 11, the crank angle sensor 21 and the TDC sensor 22. Is directly input to the input port.

Further, the CPU 27 has a ROM 31 for storing program data and fixed value data, a RAM 32 that is updated and sequentially rewritten, and a battery 24 via a battery 24 via a bus line.
4 is connected to the battery-up RAM (BURA
M) Data is exchanged with 33.

The data in the RAM 32 is erased and reset when the ignition switch 26 is turned off.

In addition, an ignition timing control signal is sent from the CPU 27 to the ignition driver 5.
3 to the power transistors 52A and 52B, and further from the ignition coils 51A and 51B to the four ignition plugs 18-1 and 18-.
2,18-3,18-4 are sequentially sparked.

FIG. 2 shows a more detailed basic block diagram for ignition timing control. That is,
As shown in FIG. 2, the ignition timing map stores two-dimensional basic ignition timing data (advance angle data) θ _0.
Ignition timing setting means with MP3 (ignition timing calculation means) 58
In addition to the above, a water temperature correction means 59 having a water temperature correction map MP5,
Acceleration correction means 60 having an acceleration correction map MP6, intake temperature correction means (ignition timing correction amount setting means) 61 having an intake temperature correction map MP7, idle stabilization correction means having an idle stabilization correction map MP8 It is configured with 62.

Here, in the ignition timing map MP3, if the intake air amount / engine speed, that is, the volumetric efficiency and the engine speed Ne are known, the basic ignition timing θ ₀ is determined from the map value. In this case, For this value of volumetric efficiency,
Atmospheric pressure correction has been performed in advance.

In order to perform the atmospheric pressure correction on the volume efficiency in advance (the obtained volume efficiency is referred to as Ev _P by performing the atmospheric pressure correction in this way), first, the intake air amount A and the engine speed Ne are required. , Atmospheric pressure P is input, and A × (P / 760) is A ′
By normalizing the intake air amount A to 1 atm,
A '/ Ne is set as Ev _P. In this manner, the atmospheric pressure was corrected in advance for the volumetric efficiency of the ignition timing map MP3. After that, basic ignition timing data (advance angle data) θ ₀ is set based on the Ev _P and Ne. These relationships are stored in the ignition timing map MP3.

It should be noted that the volume efficiency of the ignition timing map MP3 does not need to be corrected in advance for the atmospheric pressure.

Water temperature correction map MP5 stores a relationship between the cooling water temperature WT and the advance angle theta _WT, the relationship is as the water temperature is high, so that the advance value theta _WT is reduced.

The acceleration correction map MP6 stores the relationship between the time t from the start of acceleration and the retard amount θ _AC, and the relationship is that the retard is greatly retarded at the start of acceleration, and then the retard amount θ _AC is gradually reduced. It is designed to be smaller.

The acceleration correction means 60 having the acceleration correction map MP6 uses a change in throttle opening as information for determining acceleration.

That is, the throttle opening value Θ detected by the throttle sensor 14 is time-differentiated by the throttle opening change calculating means 71 to calculate a throttle opening change value (dΘ / dt = ΔΘ). Then, the acceleration determining means 72 compares the value ΔΘ of the throttle opening change with the reference value α ₁ (α ₁ > 0),
.DELTA..theta sometimes is greater than the reference value _{α 1 (ΔΘ> α 1)} , it determines that the engine is in an acceleration state.

Intake air temperature correction map MP7 is the intake air temperature AT and the retard stores a relationship between the advance amount theta _AT, in its relationship with the place is low intake air temperature AT, high place and, is retarded, the intake It is 0 when the temperature AT is medium.

As the idle stabilization correction map MP8, for example, there are a map for proportional control (P control) and a map for differential control (D control).
For the P control, the relationship between the engine speed Ne and the ignition timing information θ _IDP is stored.
Is the ISC target engine speed N set by the ISC (idle speed control) target engine speed setting means 73
If it is higher than e _0, it is retarded, and if the engine speed Ne is lower than the ISC target engine speed Ne _0, it is advanced. For D control, the engine speed conversion Δ
The relationship between Ne and the ignition timing information θ _IDD is stored, and the relationship is such that when the engine speed is high, the angle is retarded, and when the engine speed is low, the angle is advanced. . In each case, a dead zone is provided to prevent hunting.

Also, the ignition timing data θ ₀ from the ignition timing setting means 58
And the water temperature correction data θ _WT from the water temperature correction means 59
The acceleration correction data θ _AC from the acceleration correction means 60 and the intake air temperature data θ _AT from the intake air temperature correction means 61 are accelerated by the acceleration means 64, and the data (θ
_AC + θ _AT ) is appropriately corrected by the operating state correcting means 69 according to the engine operating state.

Further, the data from the operating state correcting means 69 is added to the data (θ ₀ + θ _WT ) from the adding means 63 by the adding means 65.
Is to be added.

The data from the adding means 65 is added to the idling stabilization data θ _IDP and θ _IDD from the idling stabilizing correcting means 62 by the adding means 66, and the timing control unit 6
To be sent to 8.

Further, a switch 76 is interposed between the intake air temperature correcting means 61 and the adding means 64, and the switch 76 is controlled to be opened and closed by a switch control means 75 as ignition timing correction prohibiting means. ing. The switch control means 75 operates based on a detection signal from the engine operation zone detection means 74.

Here, the engine operating zone detecting means 74 is a specific operating zone of the engine in which ignition timing correction using the intake air temperature correction data θ _AT from the intake air temperature correcting means 61 is to be prohibited (a normal driving zone is considered as this operating zone). When the specific operation zone is detected by the engine operation zone detection means 74, a switch open signal is output from the switch control means 75, and the switch 76 is turned off. The ignition timing correction using the intake air temperature correction data θ _AT from the correction means 61 is prohibited.

Further, when the specific operation zone is not detected by the engine operation zone detection means 74 and a non-specific zone is detected, a switch close signal is output from the switch control means 75, and the switch 76 is turned on. Intake temperature correction means
The ignition timing correction using the intake air temperature correction data θ _AT from 61 is performed.

It should be noted that the engine operating zone detecting means 74 determines whether the zone is a specific operating zone or a non-specific zone based on a two-dimensional map.

Also, a switch 67 is interposed between the idle stabilization correcting means 62 and the adding means 66.
Is closed when the idle switch 15 is turned on when the engine is idle, and is open otherwise.

Further, the timing controller 68, various correction data (theta _WT to the base ignition timing data theta ₀ above, theta _AC, theta _AT,
θ _IDP , θ _IDD ) is used to determine the ignition timing from the data. Then, the signal from the timing control unit 68 is output to the power transistors 52A and 52B.

Further, in addition to the basic configuration or function of the electronic distribution ignition device as described above, the present device can also be used when the cylinder identification information is not detected through the crank angle sensor 21.
It has a fail-safe function that makes it possible to start the vehicle.
That is, as shown in FIG. 1, a cylinder assumption means 100 for assuming a certain cylinder to start ignition when cylinder identification information is not input from the crank angle sensor 21;
And ignition test means 101 for starting ignition from the cylinder assumed by 00.
A hypothetical cylinder changing means 102 for changing the cylinder assumption by the cylinder presuming means 100 when the engine E does not start according to the ignition test by 01 is provided.

In FIG. 1, reference numeral 103 denotes a calculating means for calculating the ignition timing based on the cylinder identification information and the crank angle information. The calculating means 103 includes the aforementioned ignition timing setting means (ignition timing calculating means) 58, It has functions of a means 59, an acceleration correction means 60, an intake air temperature correction means 61, an idling stabilization correction means 62 and the like.

Next, a fail-safe function that enables the engine E to start even when the cylinder identification information is not detected through the crank angle sensor 21 will be described with reference to FIG.

First, in step a1, it is determined whether or not the engine has been rotated twice, that is, whether or not the engine has been rotated for one cycle. If the engine has rotated twice, it is determined in step a2 whether the cylinder has not been determined. If the cylinder identification information is not input, the cylinder that takes the ignition timing is not determined, so the YES route is taken in step a2, and the cylinder assuming means 100 assumes a certain cylinder to start the ignition. (Step a3). Thereafter, in step a4, the ignition test unit 101 starts ignition from the cylinder assumed by the cylinder assumption unit 100. In this case, ignition is performed a number of times n (see FIG. 6) determined according to the cooling water temperature. The number of rotations n is set higher as the cooling water temperature is lower. This is because the lower the temperature, the poorer the startability of the engine.

When the engine E is started by the ignition test, that is, when the engine completely explodes, the alarm lamp 70 (see FIG. 4) is turned on in step a6 (engine check lighting), and the ignition is performed in this order. (Step a8).

Whether or not the engine has completely exploded is determined based on whether or not the engine speed has become, for example, 450 rpm or more (this value cannot be obtained by the starter).

However, if the engine E does not start due to the ignition test by the ignition test means 101 as described above, the NO route is taken in step a5, and the assumption of the cylinder by the cylinder assumption means 100 is changed by the assumption cylinder changing means 102. (Step a7), and the ignition test means 101 further sets the cylinder assumption means 1
Starting ignition from the cylinder reassured by 00 is performed.

Thereafter, the change of the assumed cylinder by the assumed cylinder changing means 102 and the ignition test by the ignition test means 101 are repeated until the engine E starts, that is, until the YES route is taken in step a5. That is, the processing of steps a4 to a7 is repeated.

As described above, even when the cylinder identification information is not detected due to a disconnection or the like, the fail-safe function that enables the engine E to be started is provided. It becomes possible.

As shown in FIG. 4, a control signal for fuel injection is output from the CPU 27 through an injector driver 34, whereby the four injectors 8 can be driven sequentially. ing.

In addition, the present device is provided with each of the spark plugs 18-1, 18-2, 18-3, 18
The present invention can be similarly applied to a four-coil type electronic distribution igniter in which an ignition coil is provided for every -4. In this case, the probability that the engine E starts in the initially assumed cylinder is 1/4 smaller than that of the above-described two-coil type electronic distribution ignition system, but the high tension cord (ignition plug) Has the advantage of being shorter.

[Effects of the Invention] As described above in detail, according to the electronic distribution ignition device with a fail-safe function of the present invention, even if the cylinder identification information is not detected due to a disconnection or the like, the fail-safe that enables the engine to be started. By providing the function, there is an advantage that the engine can be started while cranking, even if a disconnection occurs before the engine is started.

[Brief description of the drawings]

1 to 6 show an electronic distribution type ignition device with a fail-safe function as one embodiment of the present invention. FIG. 1 is a main part control block diagram, FIG. 2 is a control block diagram thereof,
FIG. 3 is an overall configuration diagram showing an engine system having this device, FIG. 4 is a control block diagram of the engine system, FIG. 5 is a flowchart for explaining its operation, and FIG. 6 is an explanation of the operation. It is a graph for. 1 ... combustion chamber, 2 ... intake passage, 3 ... exhaust passage, 4 ...
... intake valve, 5 ... exhaust valve, 6 ... air cleaner, 7 ...
Throttle valve, 8 ... Solenoid valve (injector), 9 ...
Catalytic converter, 10 ISC motor, 11 Air flow sensor (volume flow meter), 12 Inlet air temperature sensor, 13 Atmospheric pressure sensor, 14 Throttle sensor, 15 Idle switch, 16 Motor Position sensor, 17: O ₂ sensor as oxygen concentration sensor, 18-1 to 18-4: Spark plug, 19: Water temperature sensor, 20: Starter switch,
21 …… Crank angle sensor (engine speed sensor), 22
…… TDC sensor, 23 …… Electronic control unit (ECU), 24…
... Battery, 25 ... Battery sensor, 26 ... Ignition switch (key switch), 27 ... CPU, 28,29 ...
Input interface, 30 A / D converter, 31 RO
M, 32… RAM, 33 …… Battery backup RAM (BURA
M), 34: injector driver, 51A, 51B: ignition coil, 52A, 52B: power transistor for controlling ignition timing, 53: ignition driver, 58: ignition timing setting means (ignition timing calculation means), 59 ... water temperature correction means, 60 ... acceleration time correction means, 61 ... intake air temperature correction means, 62 ... idle stabilization correction means, 63-66 ... addition means, 67 ... switch, 68
…… Timing control section, 69 …… Operation state correction means, 70…
... Alarm lamp, 71 ... Throttle opening degree change calculating means, 72 ... Acceleration determining means, 73 ... ISC target engine speed setting means, 74 ... Engine operating zone detecting means, 75 ...
... switch control means, 76 ... switch, 100 ... cylinder assumption means, 101 ... ignition test means, 102 ... assumed cylinder change means, 103 ... calculation means, E ... engine, MP1 ... basic drive time map , MP2 ... air-fuel ratio map, MP3 ... basic ignition timing map, MP4 ... closing angle map, MP5 ... water temperature correction map, MP6 ... acceleration correction map, MP7 ... intake air temperature correction map, MP8 ... idle Stabilization correction map.

Claims (1)

(57) [Claims] An ignition timing is calculated based on cylinder identification information and crank angle information, and an ignition timing control signal is output to an ignition coil based on the calculation result, so that ignition plugs of each cylinder are sequentially ignited. In an electronic ignition system of a multi-cylinder engine, a cylinder presumption means for presuming a certain cylinder to start ignition when the above-mentioned cylinder identification information is not inputted, and ignition is started from a cylinder presumed by the cylinder presumption means. An ignition test means; and a failure cylinder changing means for changing a cylinder assumption by the cylinder assumption means when the engine is not started by the ignition test by the ignition test means. Electronic distribution ignition system with safe function.