JPH0689703B2 - Engine idle determination device - Google Patents

Description

The present invention relates to an engine idle determination device for determining an idle state from an output signal of a throttle sensor.

[Problems to be Solved by Conventional Techniques and Inventions] Generally, in idle operation, the idle speed control valve (ISCV) is controlled to adjust the bypass passage area, and the engine speed is adjusted to a set idle speed. , The ignition timing is fixed to a preset ignition advance angle.

Conventionally, this idle determination is mechanically performed by an idle switch, and when the idle switch is turned on, the throttle valve is fully closed, that is, the idle state is uniquely determined and the engine is idle-controlled.

By the way, the above idle switch needs to be surely turned on when the throttle is fully closed, so it is actually necessary to turn it on (mechanically determine that the throttle is fully closed) before the throttle valve is fully closed. Is set to.

As a result, even when the accelerator pedal is depressed to open the throttle valve when the vehicle starts, the engine speed increases but the idle control is not released until the throttle valve reaches the specified opening, and the vehicle is decelerated. If the accelerator pedal is released while the throttle valve is open, the idle switch turns on and the idle control is entered.

Conventionally, the idle switch does not turn off (judged that the throttle is fully closed) despite the throttle valve being slightly open, or even if the idle switch is turned on before the throttle valve is fully closed, Since the area variation of the throttle bore is small and the range of variation of the intake air amount is small, there was no great influence on the starting acceleration performance or deceleration running.

However, in recent engines with a large throttle bore diameter to obtain high performance and high output, even a slight change in throttle opening greatly changes the intake air amount, so open the throttle valve from the fully closed state. If the idle control is not released (idle switch OFF) even if the engine speed is increased, or if the idle switch is turned on before the throttle valve is fully closed during deceleration, the output signal of this idle switch will be output. Since the idle control is canceled or the idle control is performed based on this, not only the start acceleration performance and deceleration running performance are deteriorated due to insufficient output, but also proper air-fuel ratio control cannot be performed, which causes exhaust emission and fuel consumption to deteriorate. There is also a great influence on the idle controllability.

To deal with this, it is possible to set the idle switch near the fully closed slot, but there is a limit to the proximity distance to ensure ON / OFF of this idle switch, and the setting is Difficult to achieve because it is difficult and non-mass production.

On the other hand, for example, in Japanese Patent Publication No. 63-15467, in order to detect the case where the throttle valve is closed to the minimum feasible opening, when the output signal of the throttle sensor becomes smaller than the stored value, the above-mentioned throttle sensor There is disclosed a so-called soft idle switch that sequentially updates the stored value with the output value of, and at this time, determines that the throttle is fully closed (idle state) by software. This soft idle switch determines that the throttle is fully closed. If so, idle control is performed.

However, this soft idle switch only updates the memory value with the throttle sensor output value when the throttle sensor output value becomes smaller than the memory value, and the memory value is updated only to the smaller side (throttle closing side). No
In addition, since the stored value is used as it is as the idle reference comparison reference value and the idle reference comparison reference value is compared with the throttle sensor output value to determine the throttle fully closed state, the potentiometer of the throttle sensor is used. The throttle sensor output value when the throttle is fully closed has changed to the throttle open side due to the distortion of the throttle shaft that connects the throttles, the deflection due to negative pressure when the throttle is fully closed, or the effect of drift of the output signal of the throttle sensor. In this case, although the unit is actually fully closed, the throttle sensor output value shifts from the idle determination comparison reference value to the open side, and there is a problem in that the throttle fully closed state is not detected by software.

Further, for example, if the noise is stored as the minimum value of the throttle sensor output, there is a disadvantage that the idle state is not detected thereafter even though the throttle is fully closed.

Therefore, the applicant has detected the minimum output value THV _MIN from the throttle sensor signal output value THV in the earlier application (Japanese Patent Application Laid-Open No. 2-196142) related to the same applicant, and has a predetermined offset to this minimum output value THV _MIN. Add the value α to set the idle reference comparison reference value TVH _ISW (= THV _MIN + α) and compare the idle determination comparison reference value THV _ISW with the throttle signal output value THV to determine the fully closed throttle state. I proposed a soft idle switch that does.

That is, as shown in FIG. 9, the idle switch is turned on.
When soft idle is OFF in (THV> THV _ISW , elapsed time
t2 to t4), the output minimum value THV _MIN is slightly increased for each predetermined time TIME, and the idle determination comparison reference value THV _ISW is increased,
The idle reference comparison reference value THV _ISW is corrected by following the change in the throttle signal output value THV when the throttle is fully closed.

Immediately after the engine has exploded, the negative pressure on the throttle valve causes the throttle shaft to flex slightly. Further, in the case of cold start, after the complete explosion of the engine, the throttle shaft and the shaft portion that supports the throttle shaft thermally expand until the engine temperature rises to a predetermined temperature.

As a result, as shown after the elapsed time t in FIG. 9, the engine complete explosion occurs even though the indication value (throttle signal output value THV) of the potentiometer of the throttle sensor connected to the throttle shaft is fully closed. After that, the throttle signal output value THV fluctuates greatly until the temperature reaches a temperature at which thermal expansion is almost in equilibrium (for example, cooling water temperature Tw0 at the end of warm-up, elapsed time t3).

When the throttle signal output value THV fluctuates greatly toward the open side, the slight increase of the idle judgment comparison reference THV _ISW cannot follow the fluctuation amount, and the predetermined time t4 is reached even after the thermal expansion is balanced. Even though the throttle valve is fully closed, it is determined to be idle OFF (idle release state), and the idle controllability and the air-fuel ratio controllability deteriorate.

[Object of the Invention] The present invention has been made in view of the above circumstances, without straining the setting of the idle switch, distortion of the throttle shaft connecting the potentiometer of the throttle sensor, deflection due to negative pressure, or It is possible to accurately detect the throttle fully closed state without misjudgment without being affected by fluctuations in the throttle signal output value due to thermal expansion of components, and not only improve idle controllability and air-fuel ratio controllability. It is an object of the present invention to provide an engine idle determination device capable of improving fuel efficiency and exhaust emission.

[Means for Solving the Problems] An engine idle determination device according to the present invention is an idle switch state determination means for determining a mechanical idle state from an output signal of an idle switch, and a mechanical idle state by the idle switch state determination means. If it is determined that
Minimum value detecting means for taking in the throttle signal output value of the throttle sensor indicating the throttle opening and comparing the above-mentioned throttle signal output value with the minimum output value of the throttle signal output value stored in the storing means, and the throttle signal output value and storing The minimum value detecting means for comparing the minimum value of the throttle signal output value stored in the means, and the throttle signal output value by the minimum value detecting means is on the throttle valve opening side from the idle reference comparison reference value and this state is predetermined. If it continues for a time, the output minimum value is updated with a value obtained by adding a predetermined value to the output minimum value, and if it is determined that the throttle signal output value is on the closing side of the output minimum value, A minimum value updating means for updating the minimum output value with the above-mentioned throttle signal output value, and an offset value set to the minimum output value stored in the storage means. Comparison reference value setting means for adding and setting a comparison reference value for idle determination, start preparation determination means for determining start preparation from the engine state, complete explosion determination means for determining complete explosion at startup from the engine state, At least one of warm-up completion determining means for determining the completion of warm-up from the engine state, and at least one of the complete explosion determining means and the warm-up completion determining means based on the determination result of the start preparation determining means Based on the result, in the case of at least one of immediately after the start preparation, immediately after the complete explosion and immediately after the completion of warm-up, the minimum output value and the idle reference comparison reference value stored in the storage means are initialized with preset initial values. The idle state for determining the idle state by comparing the throttle signal output value with the idle reference comparison reference value set by the initialization means and the comparison reference value setting means It is obtained by including a determination unit.

[Operation] In the above configuration, first, the mechanical idle state is determined from the output signal of the idle switch, and when the mechanical idle state is determined, the throttle signal output value of the throttle sensor indicating the throttle opening is taken in The signal output value is compared with the minimum output value of the throttle signal output value stored in the storage means, and the throttle signal output value is on the throttle valve opening side from the idle reference comparison reference value and this state continues for a predetermined time. In this case, the output minimum value is updated with a value obtained by adding a predetermined value to the output minimum value, and when it is determined that the throttle signal output value is on the closing side of the output minimum value, the output minimum value is set to the above-mentioned value. Update with the throttle signal output value.

Then, the set offset value is added to the output minimum value to set the idle determination comparison reference value.

Further, the engine preparation state is determined from the engine state, the complete explosion at the start is determined from the engine state, and the warm-up completion is determined from the engine state.

Then, immediately after the preparation for starting, or at least one of immediately after the complete explosion and immediately after the completion of warm-up, the output minimum value and the idle reference comparison reference value are initialized with preset initial values.

Further, the comparison reference value for idle determination and the throttle signal output value are compared to determine whether the current operating state is the idle state or the idle release state.

Embodiments of the Invention Embodiments of the present invention will be described below with reference to the drawings.

1 to 8 show an embodiment of the present invention, FIG. 1 is a functional block diagram of an idle determination means, FIG. 2 is a schematic diagram of an engine control system, and FIG. 3 is a minimum output value and idle determination. 4 is a flow chart showing a procedure for initializing the reference value for comparison, FIG. 4 is a flow chart showing a procedure for updating the minimum value of the throttle signal output value, FIG. 5 is a flow chart showing a procedure for determining an idle state, and FIG. 6 is cooling after starting. Water temperature, engine speed, idle discrimination signal and soft idle time chart, Fig. 7 is throttle signal output value during normal operation, idle switch output, idle determination signal and soft idle time chart, Fig. 8 is accelerator pedal It is a time chart when it is started by stepping on.

(Structure) Reference numeral 1 in the drawing is an engine main body, and a cylinder head 1a of the engine main body 1 has an intake port 1c opening to a combustion chamber 1b.
And an exhaust port 1d are formed, the intake pipe 2 communicates with the intake port 1c, and the exhaust pipe 3 communicates with the exhaust port 1d. Further, an air cleaner 4 is attached upstream of the intake pipe 2, a throttle valve 5 is provided in the middle of the intake pipe 2, and an air chamber 2a is formed immediately downstream thereof.

An air bypass passage 6 is connected to the intake pipe 2 across the throttle valve 5, and an idle speed control valve (IS
CV) 7 is installed.

An intake air amount sensor (a hot wire type air flow meter in the figure) 8 is provided on the intake pipe 2 immediately downstream of the air cleaner 4.

Further, the throttle shaft of the throttle valve 5 described above.
A throttle sensor 9 and an idle switch 10 are connected to 5a. The idle switch 10 is set to be turned on / off at the opening point θ0 slightly opened from the fully closed state of the throttle valve 5 in order to ensure the operation thereof.

An injector 11 is attached to the intake pipe 2 immediately upstream of the intake port 1c.

Further, the crankshaft 1e of the engine body 1 is provided with a crank rotor 12 having protrusions or slits at predetermined crank angles on its outer periphery, and the crank angle is detected on the outer periphery of the crank rotor 12. A crank angle sensor 13 composed of an electromagnetic pickup or the like is installed oppositely. Further, the cooling water temperature sensor 14 is exposed to the cooling water passage 1f of the engine body 1.

Further, the O2 sensor 15 is exposed to the exhaust pipe 30, and the catalytic converter 16 is attached to the downstream side thereof.

(Circuit Configuration of Control Unit) On the other hand, reference numeral 17 is a control unit including a microcomputer and the like.
A CPU (Central Processing Unit) 18, ROM 19, RAM 20, input interface 21, and output interface 22 are connected to each other via a bus line 23.

Further, the idle switch 10 and the crank angle sensor 13 are connected to the input interface 21, and the intake air amount sensor 8, the throttle sensor 9, the cooling water temperature sensor 14, the O2 sensor 15 are connected to the A / D converter 24. Connected through.

Further, the injector 11 and the coil 7a of the ISCV7 are connected to the output interface 22 through the drive circuit 25, respectively, and the spark plug 26 is connected to the distributor.
27, connected via an igniter 28.

The ROM 19 stores fixed data and control programs, and the RAM 20 stores data after processing the signal input to the input interface 21 and data processed by the CPU 18. It Further, the CPU 18 performs air-fuel ratio control, ignition timing control, and idling speed control based on various data stored in the RAM 20 in accordance with a control program stored in the ROM 19.

(Functional Configuration of Idle Judgment Means) As shown in FIG. 1, the idle judgment means 29 provided in the control unit 17 is an idle state judgment means.
30, minimum value detection means 31, minimum value storage means 32, minimum value increase update condition determination means 33, counter means 34, minimum value update means
35, comparison reference value setting means 36, idle state determination means 37,
Idle data storage means 38, engine speed calculation means 3
9, cooling water temperature calculation means 40, start preparation determination means 41, complete explosion determination means 42, warm-up end determination means 43, initialization means 44, initialization data storage means 45.

The idle switch state determination means 30 determines from the output signal of the idle switch 10 whether or not it is in a mechanical idle state. That is, when the idle switch 10 is ON, the mechanical idle state is determined, and when the idle switch 10 is OFF, the idle release state is determined. When it is determined that the engine is in the idle state (the idle switch 10 is in the ON state), the trigger signal is output to the minimum value detecting means 31.

The idle switch 10 is turned off when the throttle opening θ is a predetermined opening θ0 or more, and is turned on when the throttle opening θ is less than the predetermined opening θ0.
At the time of assembly, the throttle valve 5 is set so as to be turned on / off at a slightly open position in consideration of certainty of ON / OFF operation and detection error.

In the minimum value detecting means 31, when the trigger signal is output from the idle switch state determining means 30, the throttle signal output value (output voltage) THV indicating the throttle valve opening from the throttle sensor 9 is read and this output value THV When,
The above throttle signal output value THV stored in the minimum value storage means 32 composed of a predetermined address area of the RAM 20.
Output minimum value THV _MIN of is compared.

In the minimum value increase update condition determining means 33, the determination result in the idle switch state determining means 30 is read and stored in the idle data storage means 38 formed in an address area different from the minimum value storage means 32 of the RAM 20. Read the idle data AI _DATA described later, the idle switch 10 is ON, and the idle data AI _DATA is AI
_In the case of idle OFF of _DATA = 1, it is determined that the output minimum value increase update condition is satisfied, and a trigger signal is output to the counter means 34.

The counter means 34 is the minimum value increase update condition determination means 33.
When the trigger signal is output from, the count starts, and the output minimum value increase update condition is for a predetermined time TIME (for example, TIME = 1s
ec) When continued, it outputs a trigger signal to the minimum value updating means 35.

In the minimum value updating means 35, the output value THV of the throttle sensor 9 is less than the output minimum value THV _MIN (T
HV <THV _MIN ), the output minimum value THV _MIN stored in the minimum value storage means 32 is used as the minimum value detection means 31.
Update with the throttle signal output value THV detected in (THV
_MIN ← THV).

The minimum value updating means 35 is an initialization means described later.
When the initialization signal from 44 is input, the minimum value storage means 32
The output minimum value THV _MIN stored in memory is initialized with the initial value THV _INI (THV _MIN ← THV _INI ).

Further, in the minimum value updating means 35, when the trigger signal is input from the counter means 34, that is, the idle switch 10 is ON, and the idle data AI _DATA is AI _DATA =
If the output minimum value update condition of 1 continues for a predetermined time TIME,
Setpoint THVs the output minimum value THV _MIN which in each case is a memory in the minimum value storage means 32 (e.g., 1bit; 5 mv) by adding, to update the output minimum value THV _MIN (THV _MIN ← THV
_MIN + THVs).

In the comparison reference value setting means 36, the output minimum value THV _MIN stored in the minimum value storage means 32 and the idle data AI stored in the idle data storage means 38 are stored.
Reads the _DATA, when the idle OFF of AI _DATA = 1, to the output minimum value THV _MIN first offset value A (e.g., 2
〜3bit; 10〜15mv) is added and this is set as idle comparison comparison reference value THV _ISW (THV _ISW ← THV _MIN +
A).

On the other hand, when the idle data AI _DATA is idle ON with AI _DATA = 0, the output minimum value THV _{MIN is set} to the first offset value A and the second offset value B (for example, 1 to 2b).
it; 5 to 10 mv) is added, and this is set as the idle determination comparison reference value THV _ISW (THV _ISW ← THV _MIN + A + B).

Further, when the initialization signal from the initialization means 44 is input, the comparison reference value setting means 36 sets the initialization THV _INI as the idle determination comparison reference value THV _ISW (THV _ISW ← THV
_INI ).

In the idle state determination means 37, the comparison reference value setting means
The comparison reference value THV _ISW for idle determination set in 36 is read, the comparison reference value THV _ISW for idle determination is compared with the output value THV of the throttle sensor 9, and if THV ≤ THV _ISW , the current operation is performed. When the state is the idle state, the idle data AI _DATA is stored in the idle data storage means 38 as AI _DATA = 0 and the idle ON signal is output.

When THV> THV _ISW , it is determined that the current operation state is the idle release state, the idle data AI _DATA is stored in the idle data storage means 38 as AI _DATA = 1, and the idle OFF signal is output.

Further, the engine speed calculation means 39 calculates the engine speed N from the output signal of the crank angle sensor 13, and the cooling water temperature calculation means 40 calculates the cooling water temperature Tw from the output signal of the cooling water temperature sensor 14.

The starting reference determination means 41 reads the engine speed N calculated by the engine speed calculation means 39 when the control unit 29 is powered on, and the engine speed N =
In the case of 0, it is determined that the engine is ready for starting and a trigger signal is output to the initialization means 44.

This start preparation is done by turning the ignition switch ON / O.
It may be determined by FF.

The complete explosion determination means 42 reads the engine speed N calculated by the engine speed calculation means 39 and compares it with a preset complete explosion determination reference speed N _EX (for example, 400 rpm) to determine that the engine speed N is When the reference engine speed N _EX for complete explosion determination is exceeded (N ≧ N _EX ), it is determined that the engine is complete explosion, and a trigger signal is output to the initialization means 44.

The complete explosion of the engine may be determined by turning the starter ON / OFF.

In the warm-up end judging means 43, the cooling water temperature Tw calculated by the cooling water temperature calculating means 40 is read and compared with a preset warm-up end judging reference cooling water temperature Tw0 (for example, Tw0 = 60 ° C.), When the cooling water temperature Tw exceeds the warm-up end determination reference cooling water temperature Tw0 (Tw ≧ Tw0), it is determined that the warm-up has ended,
A trigger signal is output to the initialization means 44.

The complete explosion determination reference rotation speed N _EX and the warm-up completion determination reference cooling water temperature Tw0 are obtained in advance from experiments or the like and are stored in the ROM 19.

With the initialization means 44, when the ignition is turned on, RA
Starting preparation data ST stored in a storage means 45 composed of an address area different from the constituent address areas of the minimum value storage means 32 and idle data storage means 38 of M20.
_DATA , complete explosion data EX _DATA , and warm-up end data HX _DATA
Are set to ST _DATA = 0, EX _DATA = 0, HT _DATA = 0 respectively, and the start preparation discriminating means 41 discriminates the start preparation, and when the trigger signal is inputted from the start preparation discriminating means 41, the initialization data is set. Start preparation data ST _DATA is read from storage means 45 and ST
Only when _DATA = 0, an initialization signal is output to the minimum value updating means 35 and the comparison reference value setting means 36, and the start reference data ST _DATA in the initialization data storage means 45 is ST _DATA =
Update to 1.

Further, the initialization means 44 reads the complete explosion data EX _DATA from the initialization data storage means 45 when the complete explosion determination means 42 determines that the complete explosion has occurred and a trigger signal is output from the complete explosion determination means 42. , EX _DATA = 0 only, the above minimum value updating means 35
And an initialization signal is output to the comparison reference value setting means 36, and the complete explosion data EX _DATA in the initialization data storage means 45 is EX.
Update to _DATA = 1.

Further, the initialization means 44 includes the warm-up completion determination means 43.
When it is determined that the warm-up has ended and the warm-up end determination means 43 outputs a trigger signal, the warm-up end data HT _DATA is read from the initialization data storage means 45, and only when HT _DATA = 0, the above minimum value is updated. An initialization signal is output to the means 35 and the comparison reference value setting means 36, and the warm-up end data HT _DATA in the initialization data storage means 45 is updated to HT _DATA = 1.

That is, the initialization means 44 initializes the minimum output value THV _MIN and the idle determination comparison reference value THV _ISW to the initial value THV _INI immediately after the preparation for starting, immediately after the complete explosion, and only for the first routine after the completion of warming up. , Minimum value updating means 35
Learning of the minimum output value THV _MIN by is restarted from the beginning.

(Operation) Next, the operation of the idle discrimination means 29 having the above-described configuration
It will be described with reference to the flowcharts of FIGS.

(Initialization procedure of output minimum value and comparison reference value for idle determination) The program shown in FIG. 3 (a) turns on the ignition.
Only after the power supply of the control unit 17 is turned on for the first time, the control unit 17 is system-set in step S101 and stored in a predetermined address of the RAM 20: start preparation data ST _DATA , complete explosion data EX _DATA , warm-up end data HT
Set _DATA to 0 (ST _DATA = 0, EX _DATA = 0, HT
_DATA = 0).

Then, the program of the initialization procedure of the output minimum value and the idle reference comparison reference value shown in FIG. 3B is executed. It should be noted that this program is repeated every predetermined cycle or every predetermined time.

First, in step S102, the engine speed N calculated based on the output signal from the crank angle sensor 13 is compared with the complete explosion determination reference speed N _EX (for example, 400 rpm). If N <N0, the process proceeds to step S103. , N ≧ N0, the process proceeds to step S104.

When the process proceeds to step S103, it is determined whether the engine speed N is N = 0. If N = 0, it is determined to be the starting reference and the process proceeds to step S105. If N ≠ 0, it is determined that the engine is being started, and the routine is executed. Exit through.

It is determined and the process proceeds to step S105, whether the read ST _DATA = 1 or the start preparation data ST _DATA stored in the RAM 20, if the ST _DATA = 1, and terminates the routine, also,
ST _DATA = φ, that is, immediately after the ignition is turned on,
It proceeds to step S106.

That is, in the first routine immediately after the ignition is turned on, the engine has not been rotated yet and N = 0, so the process proceeds from step S102 to step S103 to step S105, and when the routine is the first time, the above step S101 is performed.
Since the start preparation data ST _DATA is set to ST _DATA = φ, the process proceeds to step S106.

Then, in step S106, the minimum output value THV _MIN of the throttle signal output value THV stored at the predetermined address of the RAM 20,
Also, the idle reference comparison reference value THV _ISW set based on this output minimum value THV _MIN is initialized with the initial value THV _INI (THV _MIN ← THV _INI , THV _ISW ← THV _INI ).

Then, in step S107, the start preparation data ST _DATA stored in the RAM 20 is set to ST _DATA = 1 and then the routine ends (elapsed time t0 in FIG. 6).

That is, in the first routine immediately after the ignition is turned on and the control unit 17 is powered on (immediately after starting preparation), the minimum output value THV _MIN and the idle determination comparison reference value THV _ISW are initialized to the initial value THV _INI. It Immediately after the control unit 17 is powered on, the throttle valve 5 may not be fully closed, the throttle signal output value THV of the throttle sensor 9 when the throttle is fully closed is unclear, and this throttle signal output value THV is the throttle value. It also changes with the deterioration of the sensor 9 over time. Therefore, the minimum output value is output immediately after the control unit 17 is powered on.
THV _MIN and comparison reference value for idle judgment THV _ISW are initial values
Clarify the first set value by initializing with THV _INI .

Then, in the second and subsequent routines, when the engine is not yet rotating and N = 0, the start preparation data ST _DATA is set to ST _DATA = 1 in the first routine, and therefore from step S102. The routine is terminated through steps S103 and S105, and N <N _EX even before the complete explosion even when the engine is started, and the routine is terminated through steps S102 and S103. t01 to t1
1) The update of the output minimum value THV _MIN is executed based on the output minimum value update procedure (see FIG. 4) described later.

After that, when the engine has completely exploded and the engine speed N becomes equal to or higher than the complete explosion determination reference speed N _EX (N ≧ N _EX ), step S1
The process proceeds from 02 to step S104.

In step S104, the cooling water temperature Tw is compared with the warm-up end determination reference cooling water temperature Tw0 (for example, about 70 ° C.), and Tw
<Tw0, that is, when warming up, the process proceeds to step S108. When Tw ≧ Tw0, that is, when warming up ends, the process proceeds to step S109.

If it is judged that it is warming up and the process proceeds to step S108, complete explosion data EX
_DATA it is determined whether or not the EX _DATA = 1, the case of the EX _DATA = 1, the routine is finished it is determined that the warm-up after the complete explosion. When EX _DATA = φ, it is determined that the initial explosion is complete and step S1
Go to 10.

That is, in the first routine immediately after the engine is started in the cold state and the engine has completely exploded, Tw <Tw0,
Moreover, in step S101, the complete explosion data EX _DATA is EX _DATA =
Since it is set to φ, steps S102 to S10
After 4, S108, the process proceeds to step S110.

Then, in step S110, the output minimum value THV _MIN of the throttle signal output value THV stored at the predetermined address of the RAM 20 and the idle determination comparison reference value THV _ISW set based on this output minimum value THV are set. Initial value THV _INI
Initialize with (THV _MIN ← THV _INI , THV _ISW ← THV _INI ).

Then, in step S111, the start preparation data ST _DATA and the complete explosion data EX _DATA are set to ST _DATA = 1 and ST _DATA = 1 respectively, and then the routine ends (elapsed time t1 in FIG. 6).
1).

In the above step S111, the start preparation data ST _DATA is ST _DATA =
To set it to 1, for example, turn off the ignition once during coasting and then turn it on again.
This is because the time when N was taken into consideration.

Note that the engine state is unstable before the complete explosion in the cold state of the engine, and the throttle of the throttle sensor 9 when the throttle is fully closed due to distortion of the throttle shaft 5a and bending of the throttle shaft 5a due to negative pressure when the throttle is fully closed. Since the fluctuation of the signal output value THV is large, as described above,
Output minimum value THV _MIN and idle reference comparison reference value THV _{ISW in} the first routine immediately after the complete explosion when the engine started cold
By initializing with the initial value THV _INI ,
The followability to the variability of the throttle signal output value THV when the throttle is fully closed thereafter is improved.

And in the routine after the second engine cold complete explosion, the complete explosion data is obtained in the first routine after the engine complete explosion.
Since EX _DATA is set to EX _DATA = 1, step S10
2, the routine is terminated through S104 and S108, and during this period (elapsed time t12 to t14 in FIG. 6), the minimum output value THV _MIN is updated by the minimum output value updating procedure (see FIG. 4) described later. It

After that, the cooling water temperature Tw is the reference cooling water temperature for determining the warm-up end
When Tw0 or more (Tw ≧ Tw0) and the engine warm-up is completed, the process proceeds from step S102 to step S104 and then to step S109.

When it is determined in step S104 that the warm-up has ended (Tw ≧ Tw0) and the process proceeds to step S109, the warm-up end data HT _DATA is HT _DATA =
It is determined whether or not 1, and if HT _DATA = 1 the routine is ended. If HT _DATA = φ, it is determined that the warm-up has just ended and the routine proceeds to step S112.

After the engine is warmed up, in the first routine, since the warm-up end data HT _DATA is set to HT _DATA = φ in the previous step S101, steps S102 to S104, S
After 109, the process proceeds to step S112.

In step S112, the output minimum value THV _MIN and the idle determination comparison reference value THV _ISW are initialized with an initial value THV _INI (THV _MIN ← THV _INI , THV _ISW ← THV _MIN ).

Then, in step S113, start preparation data ST _DATA , complete explosion data EX _DATA , warm-up end data HT stored in RAM 20.
_{DATA is set} to ST _DATA = 1 and EX _DATA = 1 and HT _DATA = 1 respectively, and the routine ends (elapsed time t14 in FIG. 6).

The complete explosion data EX _DATA is set to EX _DATA = 1 here, for example, in consideration of restarting after warming up.

In the second and subsequent routines after the engine warm-up is completed, each data is set in the first routine after the engine warm-up is completed.
Since ST _DATA = 1, EX _DATA = 1, and HT _DATA = 1, the minimum output value THV _MIN and the idle reference comparison reference value
The initialization of THV _ISW is stopped, and thereafter (after the elapsed time t15 in FIG. 6), the minimum output value THV _MIN is updated by the minimum value update procedure described later.

As described above, by initializing the output minimum value THV _MIN and the idle determination comparison reference value THV _ISW to the initial value THV _INI immediately after starting preparation, immediately after complete explosion, and immediately after warming up,
At the time of preparation for starting, clarify the first set value, and at the time of complete explosion and after warm-up, as shown in Fig. 6 (c), the throttle signal output value THV (when each component is negative The followability to fluctuations (due to the influence of deflection due to pressure, thermal expansion, etc.) is improved.

That is, conventionally, as shown in FIG. 9, the throttle signal output value of the throttle sensor 9 when the throttle valve is fully closed.
When THV fluctuates due to the thermal expansion of each component, the minimum output value THV _MIN stored in RAM20 is slightly increased for each predetermined time TIME and idles until the predetermined time t4 after the end of warm-up t3. Although the state cannot be properly judged, according to this embodiment, as shown in FIG. 6, the output minimum value THV _MIN and the idle judgment comparison reference value THV _ISW immediately after the complete explosion and immediately after the end of warming up are obtained. Is initialized, so the minimum output value TH after the complete explosion, which tends to fluctuate due to external factors, and during warm-up
V _MIN and the idle reference comparison reference value THV _ISW set based on this output minimum value THV _MIN can be set appropriately, and the idle state can be accurately determined.

By the way, FIG. 8 is a time chart when the engine is started by depressing the accelerator pedal. As shown in the figure, at the end of warm-up (elapsed time t15), the minimum output value THV
By initializing _MIN with the initial value THV _INI , the following output minimum value THV _MIN follows the throttle signal output value THV better, and the idle determination accuracy is greatly improved.

Note that N _{IDL in} FIGS. 6B and 8B is an idle rotation speed (for example, 600 rpm), and Nup is an idle-up rotation speed (for example, 1200 rpm) during warm-up.

(Minimum Output Value THV _MIN Update Procedure and Idle State Judging Means) The minimum output value THV _MIN update procedure and idle state determination procedure will be described with reference to FIGS. 4 and 5.

The program of the minimum output value updating procedure and the program of the idle state determining procedure are repeated every predetermined period or every predetermined time after the program of the initialization procedure.

: At the time of starting: First, the minimum value THV _MIN that serves as a reference when setting the idle reference comparison reference value THV _ISW used for idle determination
The update procedure of will be described.

As shown in FIG. 4, first, in step S201, it is determined whether or not the idle switch 10 is ON, and if the ON state, that is, the idle state is mechanically detected, the process proceeds to step S202, and OFF. If the state, that is, the idle release state is mechanically detected, step S209
Jump to.

For example, when the engine is started with the accelerator pedal released, the idle switch 10 is in the ON state, and thus the process proceeds to step S202.

On the other hand, when the accelerator pedal is depressed to start the engine, the idle switch 10 is in the OFF state, so that the step S209 is performed.
Then, the output minimum value THV _MIN is not updated, and the output minimum value THV _MIN is held at the initial value THV _INI set in step S106 of the aforementioned initialization procedure (elapsed time t0 to t120 in FIG. 8).

When the idle switch 10 is determined to be ON in step S201 and the process proceeds to step S202, the minimum output value THV of the RAM 20 is set.
_The idle data AI _DATA stored in an address area different from the address area in which _MIN is stored is read, the output value THV of the throttle sensor 9 is read, and the process proceeds to step S203.

The idle data AI _DATA is data representing the idle state determination result in the idle determination means 29, and is set in step S307 or S309 in the idle state determination procedure described later. When AI _DATA = 0, the idle determination means The idle determination result in 29 indicates that the idle state (idle ON), and when AI _DATA = 1, indicates that the idle release state (idle OFF).

In step S203, it is determined whether or not the idle data AI _DATA read in step S202 is AI _DATA = 0, and AI
_{If the DATA} = 0 idle state, proceed to step S204, and if the _AIDATA = 1 idle release state, step
Proceed to S206.

In the case of the first time, since the idle data AI _DATA is not set, step S203 is jumped to step S2.
Go to 04. In the case of the second and subsequent routines when the engine is started with the accelerator pedal released as described above, the idle data AI _DATA is AI _DATA = 0 (idle ON).
Since it is set to step S203 to step S204
Go to.

In step S204, the minimum output value THV _MIN stored in the RAM 20 is compared with the throttle signal output value THV of the throttle sensor 9 read in step S202, and THV ≥ THV
_{If MIN,} the process proceeds to step S209, and if THV <THV _MIN , the process proceeds to step S205.

When the accelerator pedal is released and the engine is started, the throttle signal output value THV of the throttle sensor 9 read in step S202 indicates the minimum value because the throttle valve is fully closed, and the output minimum value is initialized. It is lower than the minimum output value THV _MIN (= THV _INI ) initialized by the procedure, and therefore THV <THV _MIN , so the routine proceeds to step S205, and the minimum output value THV _MIN stored in RAM 20 is read in above step S202. Update with the throttle signal output value THV (THV _MIN ← THV), clear the count value T _COUNT of the counter in step S209 (T _COUNT ← φ), and end the program (elapsed time t01 in FIG. 6). .

As shown in FIG. 5, the idle state determination procedure at this time is as follows. First, in step S301, the throttle signal output value THV is read, and in step S302 the minimum output value THV _MIN of the throttle signal output value THV stored in the RAM 20, Also, the idle data AI _DATA is read and the process proceeds to step S303.

In step S303, the above idle data AI _DATA is AI _DATA =
It is determined whether or not 1. When the routine is the first time, since the idle data AI _DATA has not been set yet, the process jumps from step S302 to step S306.

In step S306, the throttle signal output value THV read in step S301 is compared with the idle determination comparison reference value THV _ISW . When the engine is started without depressing the accelerator pedal, the throttle signal output value THV is equal to or less than the initial set idle comparison reference value THV _ISW (= THV _INI ) (THV ≤ THV _ISW ) It is determined that the state (soft idle is ON), the process proceeds from step S306 to step S307, the idle data AI _DATA is set to AI _DATA = 0, and RA is set.
Store it at the specified address of M20 and proceed to step S308.
Output the idle ON signal (elapsed time t0 to t1 in Fig. 6)
1).

On the other hand, when the engine is started by depressing the accelerator pedal, the throttle signal output value THV is greater than the initial set idle comparison reference value THV _ISW (THV> THV
_ISW ), it is determined that the idle state is released (soft idle OFF), the process proceeds from step S306 to step S309, the idle data AI _DATA is set to AI _DATA = 1 and stored in a predetermined address of RAM 20, and then the process proceeds to step S310. Idol OF
The F signal is output (elapsed time t0 to t120 in FIG. 8).

During this period, the minimum output value TH
Both V _MIN and comparison reference value THV _ISW for idle judgment are initial values
Set in THV _INI (Elapsed time in Fig. 6 or 8)
t11).

: During idle operation: When the engine is started with the accelerator pedal open, the engine is completely detonated and the engine shifts to idle operation (when the accelerator pedal is open and the throttle is fully closed). The procedure for updating the minimum output value THV _MIN is step S201. The program described above is executed up to step S203. At this time, since the idle data AI _DATA read in step S202 is set to AI _DATA = 0 (idle ON), the process proceeds from step S203 to step S204, and the above step S202 is executed. Throttle signal output value THV and RAM read by
Compare the output minimum value THV _MIN stored in 20 and
If V ≧ THV _MIN, the process proceeds to step S209 without updating the minimum output value THV _MIN. If THV <THV _MIN , the process proceeds to step S205, and the minimum output value T stored in the ROM 20.
Throttle output value T read from HV _MIN in step S202 above
Update with HV and proceed to step S209 to clear the counter value T _COUNT and end the program (elapsed time t2 in FIG. 6).
~ T13).

In the idle state determination procedure at this time, in the case of the routine for the first engine complete explosion, the comparison reference value THV _ISW for idle determination is set to the initial value THV _INI in the initial value setting procedure described above. After reading the throttle sensor output THV from the throttle sensor 9 in S301, step S30
Jump to 6. At this time, the throttle signal output value THV read in step S301 is the minimum value for fully closing the throttle, and the idle determination reference value THV _ISW or less (THV ≤ THV _ISW ) is set as the initial value. The flow proceeds from step S306 to step S307 to set the idle data AI _DATA .
Set AI _DATA = φ and proceed to step S308 to turn on idle
A signal is output (elapsed time t11 to t12 in FIG. 6).

Then, in the second and subsequent routines after the complete explosion of the engine, as described above, the steps S301 and S302 are performed, and then the step S30.
Proceed to 3 and set idle data AI in the previous routine.
_{Since DATA} is set to AI _DATA = 0 (idle ON), the process proceeds from step S303 to step S305.

In step S305, the idle reference comparison reference value THV
_ISW is the minimum output value THV _MIN read in step S302 above.
It is calculated from the following formula based on

THV _ISW = THV _MIN + A + B (1) A; first offset value B; second offset value Then, the process proceeds to step S306, and the idle determination comparison reference value THV _ISW calculated by the above equation (1) and the above Step S301
Compare with the throttle signal output value THV read in.

Throttle signal output value when elapsed time t12 to t13 in Fig. 6
THV is set to the minimum output value THV _MIN stored in ROM20.
Since it is less than or equal to the idle reference comparison reference value THV _ISW (THV ≤ THV _ISW ) set by adding the first and second offset values A and B, it is determined to be in the idle state (soft idle ON), and steps S306 to S307 are performed. Go to and idle data AI _DATA
Is set to AI _DATA = 0 and then stored in a predetermined address of RAM 20, and the process proceeds to step S308, and an idle ON signal is output.

It should be noted that the first offset value A in the equation (1) above, and
The second offset value B is obtained in advance by experiments or the like and is stored in the ROM 19.

If the output minimum value THV _MIN is used as the idle determination comparison reference value THV _ISW without adding the offset values A and B, the throttle signal value THV may drift or the like.
If the output minimum value THV _MIN is increased by 1 bit (minimum resolution), it will be erroneously judged as idle OFF even though the throttle valve is fully closed. output minimum value is added to the THV _MIN THV _MIN
When the throttle valve is fully closed, the throttle signal output value THV becomes larger than the minimum output value THV _MIN by 1 bit (minimum resolution) by offsetting to the throttle valve opening side and using it as the idle reference comparison reference value THV _ISW . Even if the idle state is determined to be idle OFF
I try not to make a false decision.

Further, according to the experiment, the first offset value A is 2
~ 3bit (10 ~ 15mv), the second offset value B is 1-2b
It (5-10mv) is desirable.

Also, depress the accelerator pedal and the idle switch 10
When the engine is started in the OFF state and then the accelerator pedal is released to shift to idle operation, the opening of the throttle valve 5 decreases and the throttle signal output value TH
V shifts to the closing side, and the idle switch 10 shifts from OFF to ON.

The minimum output value updating procedure at this time is as follows:
Since the idle switch 10 is still OFF between t120 and t120, the program exits the routine from step S201 to step S209 as described above.
Update of V _MIN is canceled.

Then, when the idle switch 10 is turned on, step S2
The process proceeds from 01 to step S2, the throttle signal output value THV is read, the idle data AI _DATA is read from the RAM 20, and the process proceeds to step S203. At this time, in the previous idle state determination means routine, the idle data AI _DATA
Since AI _DATA is set to 1 (idle OFF), the flow advances to step S206 to increment the count value T _{COUNT of the} counter (T _COUNT ← T _COUNT +1).

Next, in step S207, the count value T _COUNT incremented in step S206 is compared with the set time TIME (for example, 1 sec), and when T _COUNT <TIME, the program ends, and when T _COUNT ≧ TIME the process proceeds to step S208, the set value to output a minimum value THV _MIN that is memory RAM20 THVs (e.g., 1bit; 5 mv) by adding, to update the output minimum value _{THV MIN (THV MIN ← THV MIN} + THVs), Step
In S209, the count value T _COUNT of the counter is cleared and the program ends (elapsed time t120 to t121 in FIG. 8).

Then, the idle data AI _DATA is set to AI _DATA = 0 (idle ON) at the elapsed time t121 in FIG. 8, that is, when the throttle signal output value THV becomes equal to or less than the idle determination comparison reference value THV _ISW. Then, the process proceeds from step S201 through steps S202 and S203 to step S204.

Throttle signal output value TH during the elapsed time t120 to t121
V is the minimum output value THV _MIN stored in RAM20 or more (TH
Since V ≧ THV _MIN ), the routine deviates from the step S204 and the output minimum value THV _MIN is not updated.

Then, after the elapsed time t121 in FIG. 8, when the throttle signal output value THV becomes less than the output minimum value THV _MIN (THV <THV _MIN ), the process proceeds to steps S205 through S201 to S204, and the throttle signal read to step S202. Update the minimum output value THV _MIN stored in ROM20 with the output value THV, and
It leaves the routine through S209.

On the other hand, the idle state determination procedure proceeds from step S303 to step S304 through steps S301 and S302 because the idle data AI _DATA is set to AI _DATA = 1 in the previous routine, and the output minimum read in step S302 above is set. Based on the value THV _MIN , the comparison reference value for idle judgment THV _ISW
Is calculated from the following formula.

THV _ISW = THV _MIN + A (2) A; First offset value Then, in step S306, the idle reference comparison reference value THV _ISW calculated by the above equation (2) and the throttle signal read in step S301. Compare with the output value THV.

Throttle signal output value THV up to elapsed time t121 in FIG.
Is larger than the idle reference comparison reference value THV _ISW (THV
> THV _ISW ), so it is determined that the idle state has been released, and step S3
From 06, proceed to step S309 and set the idle data AI _DATA to AI.
_DATA is set to 1 and stored in RAM 20, and the process proceeds to step S310 to output an idle OFF signal.

Then, at the time of elapsed time t121 in FIG. 8, THV ≦ THV _IW , and the process proceeds from step S306 to step S307, the idle data AI _DATA is updated to AI _DATA = 0, and the process proceeds to step S308 to output the idle ON signal. .

Furthermore, in the routine after the next time (elapsed time t121 to t13 in FIG. 8), the idle data in the previous routine will be
Since AI _DATA was set to AI _DATA = 0, step S303
From step S304, the comparison reference value THV _ISW for idle determination is set by the formula (1) THV _ISW = THV _MIN + A + B, and then the process proceeds to step S308 via steps S306 and S307 to output the idle ON signal.

By the way, the throttle signal output value THV decreases as the throttle valve 5 closes, and the idle determination reference value THV _ISW immediately after the transition from THV> THV _ISW to THV ≤THV _ISW. When THV _ISW is set,
The offset amount with respect to the minimum output value THV _{MIN is} increased by the second offset value B. With this, the throttle signal output value THV changes from THV> THV _ISW to THV ≦ THV _ISW.
The hunting for idle OFF / ON judgment immediately after shifting to is prevented.

Elapsed time in the time charts of FIGS. 6 and 8
After t13, the same change occurs regardless of the starting state of the engine. Therefore, description will be given based on the time charts of FIGS. 6 and 7.

As the engine temperature rises, the throttle shaft 5a connected to the throttle sensor 9 thermally expands, and the throttle sensor 9
Even though the throttle signal output value THV of (3) is fully closed, it fluctuates toward the throttle opening side (elapsed time t12 to t16 in FIG. 6).

The idle data AI _DATA becomes A when the elapsed time t13 in FIG. 6, that is, when the throttle signal output value THV becomes larger than the idle determination comparison reference value THV _ISW (THV> THV _ISW ).
Since I _DATA = 1 (idle OFF) is set, the output minimum value updating procedure at this time proceeds to step S206 via steps S201 to S203.

Then, in step S206, the count value T _COUNT of the counter is incremented (T _COUNT ← T _COUNT +1), and then in step S207, the count value T _COUNT incremented in step S206 and the set time TIME (for example, 1 sec) are calculated. Compare and terminate the program if T _COUNT <TIME,
If T _COUNT ≧ TIME, the process proceeds to step S208, and the set minimum value THV _MIN stored in the RAM 20 is set to the set value THVs (for example,
1bit; 5mv) is added and the minimum output value THV _MIN is updated (THV _MIN ← THV _MIN + THVs), the count value T _COUNT of the counter is cleared in step S209, and the program ends (the progress of FIG. 6). Time t13 ~ t14). On the other hand, the idle determination procedure at this time is the steps after the steps S301 to S303 since the idle data AI _DATA is set to AI _DATA = 1.
The process proceeds to S307, the comparison reference value THV _ISW for idle determination is set by the formula (2) THV _ISW = THV _MIN + A, the process proceeds to step S310 via steps S306 and S309, and the idle is turned off.
Output a signal.

That is, the throttle signal output value TH of the throttle sensor 9 is caused by thermal expansion of components such as the throttle shaft 5a.
When V fluctuates to the throttle opening side and becomes larger than the idle stability comparison reference THV _ISW , and the idle switch 9 is ON and the soft idle is OFF, the minimum output value THV _MIN is set at the specified time TIME and the set value THVs is set. Each time the throttle opening side is slightly increased and updated, the comparison reference value THV _ISW for idle determination is slightly increased, and the throttle output signal value THV when the throttle is fully closed
Following the change of the above, the comparison reference value for idle judgment above THV _ISW
The throttle signal output value TH
A slight increase in the idle reference comparison reference value THV _ISW cannot follow the V fluctuation amount.

Therefore, when the engine warming-up is completed (the elapsed time t14 in FIG. 6) when the temperature reaches the temperature Tw0 at which the thermal expansion almost reaches the equilibrium state, the output minimum value THV _MIN and the idle determination comparison are performed in step S112 of the initialization procedure. Since the reference value THV _ISW is set to the initial value THV _INI and largely updated to the throttle opening side at once, the erroneous determination of idle after engine warm-up is completely eliminated.

Immediately after the engine warms up, the comparison reference value THV for idle determination
_{When the ISW} is initialized to the initial value THV _INI , the first idle state determination procedure immediately after completion of engine warm-up jumps from step S301 to step S302 to step S306, at which time the idle value set to the initial value THV _INI is set. Since the throttle signal output value THV of the throttle sensor 9 when the thermal expansion is substantially balanced is smaller than the comparison reference value THV _ISW for determination, the process proceeds to step S307, and the idle data AI _{DATA is set} to AI.
_DATA is set to φ and stored in a predetermined address of RAM 20, and an idle ON signal is output in step S308 (sixth).
Elapsed time t14 to t15 in the figure).

In the minimum output value updating procedure after engine warm-up is completed, since the idle data AI _DATA is set to AI _DATA = φ, the process proceeds from step S201 through steps S202 and S203 to step S204, at which time the initial value is set. Since the throttle signal output value THV when the thermal expansion is approximately balanced is smaller than the minimum output value THV _MIN set in THV _INI (THV <THV _MIN ),
In step S205, the minimum output value THV _MIN is updated with this throttle signal output value THV (elapsed time t1 in FIG. 6).
Five).

In the second and subsequent idle state determination procedures after warm-up is completed, the idle data AI _{DATA in the} previous routine is AI _DATA =
Since it is set to φ, steps from step S301
After passing through S303 and S302, the routine proceeds to step S305, where the idle reference comparison reference value THV _ISW is set by the equation (1) THV _ISW = THV _MIN + A + B and the routine proceeds to step S306.

Between the elapsed time t15 in FIG. 6 and the elapsed time t3 in FIG.
The throttle signal output value THV is less than or equal to the idle determination comparison reference value THV _ISW set in step S305 (THV ≤ TH
Since it is V _ISW ), it is determined to be in an idle state (soft idle OFF), the process proceeds from step S306 to step S307, idle data AI _DATA is set to AI _DATA = φ, and an idle ON signal is output in step S308.

Therefore, the throttle signal output value THV when the throttle is fully closed due to thermal expansion of components such as the throttle shaft.
Even if fluctuates, the idle ON signal can be obtained immediately after the engine warms up, and the throttle fully closed can be accurately determined.

As described above, after the output minimum value THV _MIN and the idle reference comparison reference value THV _ISW are set to the initial values immediately after the completion of engine warm-up, the output minimum value TH according to the initialization procedure is set.
The initial values of V _MIN and comparison reference value THV _ISW for idle judgment are not set.

: Start acceleration: When the accelerator pedal is depressed to accelerate the vehicle from the idle state, the throttle signal output value THV gradually increases with the opening operation of the throttle valve 5.

In the minimum output value updating procedure, the elapsed time t2 in FIG.
During t3, the throttle signal output value THV is equal to or less than the idle determination comparison reference value THV _ISW (THV ≤ THV _ISW ), and the ROM20
The idle data AI _DATA stored in is AI _DATA = 0
Since (idle ON) is set, the process proceeds from step S201 to steps S202 and S203, and then to step S204.

At this time, the throttle signal output value THV gradually increases, so the minimum output value THV _MIN stored in the RAM 20
Since the above is (THV ≧ THV _MIN ), the program ends through step S204. Therefore, the updating of the minimum output value is stopped.

During the elapsed time t3 to t4 in FIG. 7, the throttle signal output value THV is larger than the idle determination comparison reference value THV _ISW (THV> THV _ISW ) and the idle data AI _DATA is AI.
Since it is set to _DATA = 1 (Idle OFF), the process proceeds from step S203 to step S206, increments the count value T _COUNT of counter compares the count value T _COUNT and the predetermined time TIME is incremented in step S209, When T _COUNT <TIME, the program ends. When T _COUNT ≧ TIME, the process proceeds to step S208, RAM2
The minimum output value THV _MIN stored in 0 is added with the set value THVs to update the minimum output value THV _MIN , and in step S209 the count value T _COUNT of the counter is cleared and the routine ends.

At the time of starting acceleration, the opening of the throttle valve 5 increases,
When the set opening θ0 is reached and the idle switch 10 is turned off, the process proceeds from step S201 to step S209 to clear the count value T _{COUNT of the} counter and terminate the routine. Therefore, the idle switch 10 after the elapsed time t4 in FIG.
Even when it is OFF, updating of the minimum output value THV _MIN is canceled.

On the other hand, in the idle state determination procedure at the time of starting acceleration, in the elapsed time t2 to t3 in FIG. 7, since the idle data AI _DATA is set to AI _DATA = 0 in the previous routine, steps S301 and S302 are executed. After that, the process proceeds from step S303 to step S305, and based on the output minimum value THV _MIN read in step S302, the idle reference comparison reference value THV _ISW
Is set by the equation (1) THV _ISW = THV _MIN + A + B, and the process proceeds to step S306.

During the elapsed time t2 to t3 in FIG. 7, the throttle signal output value THV is equal to or less than the idle determination comparison reference value THV _ISW set in step S305 (THV ≤ THV _ISW ), so it is determined to be in the idle state, and the step From S306 to step S307,
Idle data AI _DATA is set to AI _DATA = 0 and stored at a specified address in RAM20, and idle is turned on in step S308.
Output a signal.

Then, at the time of elapsed time t3 in FIG. 7, THV> THV _ISW , and it is determined that the idle state is released, the process proceeds from step S306 to step S309, and the idle data AI _DATA is AI _DATA = 1.
Is updated to step S310, and the idle OFF signal is output.

In the next and subsequent routines until THV ≤ THV _ISW again, the idle data is
Since AI _DATA is set to AI _DATA = 1, the process proceeds from step S303 to step S304, and the comparison reference value THV _ISW for idle determination is set by the equation (2) THV _ISW = THV _MIH + A, and step S306 , S309 and then to step S310, idle O
Output FF signal.

The throttle signal output value THV increases as the throttle valve opening increases, and the idle reference comparison reference value
For THV _ISW , when the idle reference comparison value THV _ISW is set immediately after the transition from THV ≤ THV _ISW to THV> THV _ISW , the offset amount for the minimum output value THV _{MIN is} decreased by the second offset value B. The throttle signal output value THV is THV ≤ THV _ISW to THV> T
Judgment hunting for idle ON / OFF immediately after shifting to HV _ISW is prevented.

: During deceleration: On the other hand, during deceleration operation, when the accelerator pedal is released, the throttle signal output value THV shifts toward the minimum value and the set opening θ
At 0, the idle switch 10 turns from OFF to ON.

In the updating procedure of the output minimum value at this time, the idle switch 10 has shifted to ON, so the process proceeds from step S201 to step S20, and the throttle signal output value THV is read and the idle data AI _DATA is read from a predetermined address of the RAM 20. , Go to step S203.

At this time, since the idle data AI _DATA was set to AI _DATA = 1 (idle OFF) in the previous idle state determination procedure, the process proceeds from step S203 to step S206.
Increment the count value T _COUNT of the count.

Next, in step S207, the count value T _COUNT incremented in step S206 is compared with the set time TIME, and T
_{If COUNT} <TIME, the program ends, and T
_{If COUNT} ≥ TIME, the process proceeds to step S208, and the set value THV _MIN is added to the output minimum value THV _MIN stored in the predetermined address of the RAM 20 to update the output minimum value THV _MIN (THV _MIN ←
THV _MIN + THVs), the count value of the counter in step S209
The T _COUNT is cleared and the program ends (elapsed time t5 to t7 in FIG. 7).

On the other hand, the idle state determination procedure at this time proceeds from step S303 to step S30 because the idle data AI _DATA is set to AI _DATA = 1 (idle OFF) in the previous routine, and the THV _ISW equation (2) is used. = THV _MIH + A is used to set the idle reference comparison reference value THV _ISW, and the flow proceeds to step S306.

In the elapsed time t5 to t7 in FIG. 7, the above step S304
Since the throttle signal output value THV is larger than the idle determination reference value THV _ISW set in (THV> THV _ISW ), it is determined to be the idle release state, and steps S306 to S3 are performed.
Go to 09, idle data AI stored in RAM 20
Set _DATA to AI _DATA = 1 and set OF to idle at step S310
Output F signal.

At this time, as shown by the elapsed time t6 to t8 in FIG. 7, due to the distortion of the throttle shaft 5a connecting the potentiometer of the throttle sensor 9 or the deflection of the throttle shaft 5a due to the negative pressure when the throttle is fully closed. The output value THV of the throttle sensor 9 when the throttle is fully closed lifts in the opening direction of the throttle valve, and the throttle signal output value THV is higher than the comparison reference value THV _ISW for idle determination, even though the throttle is actually closed. In this state, if the idle reference comparison reference value THV _ISW is left unchanged, the throttle fully closed state cannot be detected.

Therefore, in the present invention, the idle switch 10 is switched from OFF to O
When N is entered and a mechanical idle condition is detected,
The throttle signal output value THV is the comparison reference value T for idle judgment.
If it is higher than HV _ISW (software idle release state; idle OFF), steps S203, S206, S of the minimum value update procedure
After 207, in step S208, the minimum output value THV _MIN stored in the RAM 20 is updated by adding the set value THVs for each predetermined time TIME.
Idle judgment comparison reference value THV _ISW, which is set by adding the set offset value A to V _MIN , is also the set value for each predetermined time TIME
THVs are lifted up to the opening side of the throttle valve 5, and at the elapsed time t7 in FIG. 7, the idle determination comparison reference value THV _ISW becomes equal to or more than the throttle signal output value THV. Even if the signal output value THV is lifted, step S306-
Through S308, the idle state in which the throttle valve is fully closed can be detected by software.

The predetermined time TIME and the set value THVs are experimentally obtained in advance and are stored in the ROM 19, and in consideration of the influence of the idle determination when the throttle signal output value THV is normal, TIME = 1sec, THVs = 1bit (5mv) is desirable.

Further, in the present embodiment, the comparison reference value for idle determination THV _ISW
When setting up, the amount of offset added to the output minimum value THV _MIN, compared with the comparative reference value THV _ISW for the idle determination throttle signal output THV, in the case of THV> THV _ISW is only the first offset value A , If THV ≤ THV _ISW , then add the second offset value B to make it larger than when THV> THV _ISW , and when _changing the relationship between THV> THV _ISW and THV ≤ THV _ISW , change hysteresis. Is formed, which results in TH
Hunting for determination of soft idle ON / OFF at the time of mutual switching of the relationship of V> THV _ISW and THV ≦ THV _ISW is prevented.

As a result, the idle determination can be made more accurately than the determination using the output signal of the idle switch 10 as it is,
Also, the idle is turned on accurately by almost following the throttle fully closed.
You can get a signal.

On the other hand, the control unit 17 performs air-fuel ratio control, ignition timing control, and idling speed control according to an idle state and an idle release state according to the output signal of the idle determination means 29.

After the control unit 17 is energized, if the idle switch 10 has never been turned on, if the throttle sensor 9 output value is inaccurate, or if self-diagnosis is being performed, the idle switch 10 outputs the output signal according to the output signal. To determine the idle state and idle release state.

Further, although the present embodiment has described the case of using the throttle sensor of the type in which the output value decreases as the throttle valve opening decreases, the present invention is not limited to this, and the output value increases as the throttle valve opening decreases. It is also possible to use a throttle sensor of the type described in FIG.
The directions of the inequality signs in steps S204 and S306 in the flowchart in the figure are reversed, and the maximum output value is used instead of the minimum output value.

Further, in the present embodiment, an idle switch that is turned off when the throttle valve is open from the set opening θ0 and turned on when the throttle valve is closed from θ0 is used.
Instead of this, an idle switch may be used which is turned on on the throttle valve opening side with respect to the set opening θ0 and turned off on the throttle valve closing side with respect to θ0. In this case, the determination in step S102 is reversed.

[Effects of the Invention] As described above, according to the present invention, fluctuations in the throttle signal output value due to deterioration of the throttle sensor over time, thermal expansion of each component, etc., without strict setting of the idle switch. It is possible to accurately detect the fully closed state of the throttle without being affected by the above, and not only improve idle controllability and air-fuel ratio controllability, but also improve fuel consumption and exhaust emission. The effect is played.

[Brief description of drawings]

1 to 8 show an embodiment of the present invention, FIG. 1 is a functional block diagram of an idle determination means, FIG. 2 is a schematic diagram of an engine control system, and FIG. 3 is a minimum output value and idle determination. 4 is a flowchart showing a procedure for initializing a comparison reference value for use, FIG. 4 is a flowchart showing a procedure for updating the minimum throttle signal output value, FIG. 5 is a flowchart showing an idle state determination procedure, and FIGS. Cooling water temperature after starting, engine speed, idle discrimination signal, and soft idle time chart, Fig. 8 is a time chart when the engine is started by depressing the accelerator pedal, and Fig. 9 is a comparison reference value for conventional idle determination. It is a time chart which shows an update procedure. 9: Throttle sensor, 10: Idle switch, 20
...... Memory means, 30 …… Idle switch state determination means,
31 …… Minimum value detecting means, 35 …… Minimum value updating means, 36 ……
Comparison reference value setting means, 37 ... Idle state judging means, 41
...... Startup preparation determination means, 42 …… Complete explosion determination means, 43 …… Warm-up completion determination means, 44 …… Initialization means, A, B …… Set offset value, THV …… Throttle signal output value, THV _MIN ......
Output minimum value (of throttle signal output value), THV _ISW …… Comparison reference value for idle judgment, THVs …… predetermined value, THV _INI ……
Initial value, TIME ... predetermined time.

Claims (1)

[Claims] 1. An idle switch state determining means for determining a mechanical idle state from an output signal of an idle switch, and a throttle of a throttle sensor indicating a throttle opening when the idle switch state determining means determines a mechanical idle state. A minimum value detecting means for taking the signal output value and comparing the throttle signal output value with the minimum output value of the throttle signal output value stored in the storage means, and a comparison for comparing the throttle signal output value by the minimum value detecting means for idle determination. When the throttle valve is open from the reference value and this state continues for a predetermined time, the minimum output value is updated with a value obtained by adding a predetermined value to the minimum output value,
When it is determined that the throttle signal output value is on the closing side of the output minimum value, the output minimum value is updated by the minimum value updating means for updating the throttle signal output value with the output minimum value stored in the storage means. Comparison reference value setting means for adding a set offset value to set a comparison reference value for idle determination, start preparation determination means for determining start preparation from the engine state, and complete explosion for determining complete explosion at engine start from the engine state Based on the determination result of the determination means and at least one of the warm-up termination determination means for determining the warm-up termination from the engine state, and the start-up preparation determination means, the complete explosion determination means and the warm-up termination determination means In the case of at least one of after the preparation for start-up, immediately after the complete explosion and immediately after the completion of warm-up based on the judgment result of one of the judgment results, the minimum output value and the idle judgment stored in the storage means are Initializing means for initializing the constant comparison reference value with a preset initial value, and comparing the idle determination comparison reference value set by the comparison reference value setting means with the throttle signal output value to determine the idle state. And an idle state determining means for controlling the idle state of the engine.