JPH0238794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic control device for an engine, and particularly to an electronic control device for an engine that controls the ignition timing of an engine equipped with a gasoline injection device.

[Conventional technology]

Conventionally, the basic fuel injection amount is calculated from the amount of intake air taken into the engine and the engine speed, and the basic fuel injection amount is corrected depending on the engine condition such as when cold or accelerating. 2. Description of the Related Art Engines are known that include a fuel injection device that outputs a fuel injection signal from an electronic control circuit to the fuel injection device and injects a predetermined amount of fuel. In an engine equipped with such a fuel injection device, when the throttle valve is fully closed and the engine speed is above a predetermined speed, that is, during engine braking, fuel injection from the fuel injection device is stopped and the catalyst is turned off. Prevents the converter from overheating. Note that when stopping fuel injection, if you stop fuel injection immediately with the throttle valve fully closed, shock will be applied to the vehicle body. is provided.

In addition, when controlling the ignition timing of an engine equipped with such a fuel injection device, the basic ignition advance angle, which is determined from the engine speed and intake air amount that is stored in advance in the electronic control circuit, is adjusted based on the engine speed and the intake air amount. The optimum ignition advance angle for the engine is determined by adding a corrected ignition advance angle determined by intake air temperature, engine cooling water temperature, etc. to the basic ignition advance angle, which is selected according to the amount of intake air, and ignites the igniter from the electronic control circuit. It outputs a signal and controls the energization time and ignition timing.

[Problem to be solved by the invention]

However, when controlling the ignition timing of an engine equipped with a conventional fuel injection device, the ignition timing is determined based on the amount of intake air and the engine speed, even when the fuel injection is stopped and when waiting for the fuel injection to stop. Since it is controlled based on angle, if the throttle valve is suddenly closed during deceleration, the intake mixture will become too rich immediately after deceleration. As a result, incomplete combustion of the air-fuel mixture occurs and afterburn occurs, leading to increased heat loss and engine overheating. In order to solve this problem, it is possible to further advance the ignition timing in the afterburn region, but
If the angle is advanced immediately after the throttle valve is fully closed, knocking will occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic control device for an engine that is equipped with means for preventing the occurrence of knocking due to a delay in intake immediately after the throttle is fully closed, and also suppressing the occurrence of afterburn due to a supercharged mixture when the throttle is fully closed. It is.

[Means to solve the problem]

In order to achieve the above object, as shown in FIG. a throttle sensor that detects the opening degree of the throttle valve and outputs a throttle position signal; and a throttle sensor that detects the opening degree of the throttle valve and outputs a throttle position signal; Optimum ignition advance control means for controlling the ignition timing to the optimum ignition advance angle based on the signal; and ignition number counting means for detecting that a predetermined number of ignition times have elapsed since the throttle valve fully closed state was detected based on the throttle position signal. and ignition advance control means for controlling the ignition timing to a preset maximum ignition advance angle under a fully closed throttle state, regardless of the optimum ignition advance control means, when a predetermined number of ignitions have elapsed since the throttle was fully closed. This paper proposes an electronic control device for an engine equipped with the following.

[Effect]

In the present invention, when the throttle is fully closed and a predetermined number of ignitions have elapsed since the throttle is fully closed, the preset ignition advance angle is Since the ignition timing is controlled to the maximum ignition advance angle, it is possible to prevent the occurrence of knocking due to a delay in intake immediately after the throttle is fully closed, and to suppress the occurrence of afterburn due to an overly rich mixture when the throttle is fully closed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, this embodiment includes an air cleaner 2 and an air flow meter 4 as an intake air amount sensor provided downstream of the air cleaner 2. air flow meter 4
is composed of a compensation plate 4B rotatably provided within the chamber 4A, and a potentiometer 4C that detects the opening degree of the compensation plate 4B. Therefore, the amount of intake air is detected as the voltage output from the potentiometer 4C. Further, an intake air temperature sensor 6 is provided near the air flow meter 4 to detect the temperature of intake air.

A throttle valve 8 is arranged downstream of the air flow meter 4, and a throttle sensor 10 such as a throttle switch that detects the opening of the throttle valve and outputs a throttle position signal is arranged near the throttle valve 8. ing. A surge tank 12 is provided downstream of the throttle valve 8, and the surge tank 12 is provided with a detour 14 that bypasses the throttle valve 8. An air valve 18 controlled by a step motor 16 is provided on the detour 14. This air valve 18 is
When the engine is idling, intake air is passed through the surge tank 12 bypassing the throttle valve 8 to control the engine speed to a target.

An intake manifold 20 is connected to the surge tank 12, and a fuel injection device 22 is disposed protruding into the intake manifold 20. The intake manifold 20 is connected to a combustion chamber of an engine 24, and the combustion chamber of the engine is connected via an exhaust manifold 26 to a catalytic converter 28 filled with a three-way catalyst. Note that 29 is an O ₂ sensor for controlling the air-fuel mixture to near the stoichiometric air-fuel ratio, and 30 is a water temperature sensor that detects the engine cooling water temperature.

The spark plug 32 of the engine 24 is connected to a distributor 34, and the distributor 34 is connected to an igniter 36. Note that 38 is a transmission, 40 is a neutral start switch that detects the neutral position of the shift lever, and 42 is an ignition switch.

The distributor 34 is also provided with a pick-up as an engine rotation speed sensor and a signal rotor fixed to the distributor shaft. For example, a crank angle reference position signal is sent to the electronic control circuit 44 every 30 degrees of the crank angle. It has been entered. Therefore, the engine speed can be determined from the generation interval of the crank angle reference position signals and the number of crank angle reference position signals.

The electronic control circuit 44, as shown in FIG.
RAM46, ROM48, CPU50, input/output circuit I/O52, analog-digital converter
ADC54, RAM46,
The ROM 48, CPU 50, I/O 52, and ADC 54 are connected by a data bus 56. As shown in FIG. 3, the ROM 48 of the electronic control circuit 44 has a map of the basic ignition advance angle represented by the engine speed N and the ratio Q/N of the intake air amount Q and the engine speed N (the map contains information in the map). The unit of the number is the before-top-dead-center (BTDC) crank angle (℃A)) and the basic fuel injection amount. In I/O52,
A crank angle reference signal outputted from the distributor 34, a throttle position signal outputted from the throttle sensor 10, a neutral switch signal outputted from the neutral switch 40, and an air conditioner output signal outputted from the air conditioner. Yona signal and ignition switch 42
The ignition switch signal output from the
An ignition confirmation signal output from the igniter 36,
The air-fuel ratio signal output from the O ₂ sensor 29 and the like are input, and an air valve signal for controlling the air valve 16, a fuel injection signal for controlling the fuel injection device 22, an ignition signal for controlling the igniter 36, etc. are output. In addition, the ADC 54 receives an intake air amount signal output from the air flow meter 4, an intake air temperature signal output from the intake air temperature sensor 6, and a cooling water temperature signal output from the water temperature sensor 30. The signal is converted into a digital signal by ADC54. In this way, data is read from the map written in the ROM 48 according to the control state of the engine, and is sent to the I/O 52 and ADC 54.
, various signals are input or output.

Next, the operation of this embodiment will be explained with reference to FIG. In the following description, the case where the ignition timing is controlled to the maximum ignition advance angle when a predetermined number of ignitions have elapsed after the throttle valve fully closed state is detected, which is a characteristic part of the present invention, will be mainly explained. The control of the fuel injection amount and the intake air amount by the electronic control circuit is the same as in the prior art, so a description thereof will be omitted. Further, the operation shown in FIG. 4 is performed, for example, by interrupt processing every 30 degrees of crankshaft.

First, an effective ignition advance angle SBUF that actually controls the igniter 36 is stored in a register tSBUF, and a basic ignition advance angle SBSE corresponding to the engine state shown in FIG. 3 is stored in a register tΘ. continue,
It is determined whether a throttle valve fully closed signal is input from the throttle sensor 10. When the throttle valve fully closed signal is not input, that is, when the engine is not in an idling state, the igniter 36 is set to the basic ignition advance angle (value in the map in Fig. 3) stored in the register tΘ as the execution ignition advance angle SBUF. Control.

In the next interrupt processing, the executed ignition advance angle SBUF is set in the register tSBUF as in the previous interrupt processing.
At the same time, the basic ignition advance angle SBSE is stored in the register tΘ, and if the throttle valve is fully closed, it is determined in the next step whether a predetermined number of ignitions (for example, 5 ignitions) has elapsed. In addition,
The number of ignitions is counted by a counter using an ignition confirmation signal or the like. Here, if five ignitions have not elapsed, the ignition timing is controlled in the same way as described above, but if five ignitions have elapsed, it is determined in the next step whether or not the throttle valve was fully closed last time. If the throttle valve was not fully closed last time, that is, if the throttle valve is detected for the first time, the fully closed throttle valve is stored in the RAM 46, and the maximum ignition advance (e.g.
BTDC47℃A) is stored in register tΘ. Then, the value of the register tΘ, that is, BTDC47°CA is set as the effective ignition advance angle SBUF, and an ignition signal is output to the igniter 36. Therefore, if the throttle valve becomes fully closed for the first time, such as during deceleration, the ignition timing will be changed to 47°C BTDC immediately after the predetermined number of ignitions have elapsed.
Control to A.

In addition, in the next interrupt processing, the executed ignition advance angle SBUF is registered in the same way as the previous interrupt processing.
In addition to storing it in tSBUF, the basic ignition advance angle SBSE
is stored in register tΘ. Here, the value of the executed ignition advance angle SBUF is
It has been changed to BTDC47℃A. Note that the value of the basic ignition advance angle SBSF is the value shown in the map shown in FIG. 3, which is the same as the previous time and the time before the previous time. Subsequently, it is determined whether the throttle valve is fully closed or not, and if the throttle valve is fully closed, it is determined whether five more ignitions have elapsed and whether or not the throttle valve was fully closed last time. If 5 ignitions have elapsed and the throttle valve was fully closed last time, that is, if 5 ignitions have elapsed after the throttle valve was in a fully closed state (idling state), it is possible to determine whether fuel injection is stopped or not. Determine whether or not it is waiting for a stop. If fuel injection is stopped or waiting for fuel injection to stop, register
Shift the value stored in tSBUF to register tΘ. Since BTDC47°CA is stored in register tSBUF, BTDC47°CA is stored in register tΘ. Next, the value of register tΘ (BTDC47
℃A) Execute ignition advance angle SBUF as igniter 3
6 and control the igniter 36 to 47°C BTDC.

Then, in the next interrupt processing, as in the previous interrupt processing, the executed ignition advance angle SBUF is stored in the register tSBUF, and the basic ignition advance angle is stored in the register tSBUF.
Store SBSE in register tΘ. Here, since the previous executed ignition advance angle SBUF was BTDC47℃A,
Register tSBUF stores BTDC47°C. Note that the basic ignition advance angle SBSE is the value shown in the map in Figure 3, as in the previous case. Subsequently, it is determined whether the fully closed state of the throttle valve continues and whether five ignitions have elapsed. If it continues, it is determined whether fuel injection is being stopped or whether fuel injection is being stopped. If the fuel injection is neither stopped nor waiting for the fuel injection to stop, that is, if the fuel injection is restored, it is determined whether the value of the register tΘ is greater than or equal to the value of the register tSBUF. The value of register tΘ is
If the value is greater than or equal to the value of tSBUF, that is, if the value of the basic ignition advance angle is greater than or equal to BTDC47°C, the igniter 36 is controlled using the value of the register tΘ (the value of the map in FIG. 3) as the actual ignition advance angle.

On the other hand, if the value stored in the register tSBUF is larger than the value stored in the register tΘ, the engine speed N is set to a predetermined value (e.g.
1000rpm) or more. Here, if the engine speed N is 1000 rpm or more, the value of register tSBUF (BTDC47℃A)
Subtract BTDC1℃A to obtain the value of register tSBUF. After that, it is determined whether the value stored in register tΘ is greater than or equal to the value stored in register tSBUF, and the value stored in register tΘ is
If the value is greater than or equal to the value of tSBUF, the igniter 36 is controlled using the basic ignition advance angle shown in the map shown in FIG. On the other hand, if the value stored in register tSBUF is larger than the value stored in register tΘ, the value of register tSBUF is shifted to register tΘ, and the value of register tΘ is set as the actual ignition advance angle SBUF. That is, the igniter 36 is controlled with BTDC46°C A as the effective ignition advance angle.

On the other hand, if the engine speed N is 1000 rpm or less, the value of register tSBUF (BTDC47
Subtract BTDC5℃A from ℃A) and register
The value shall be tSBUF. After that, it is determined whether the value stored in register tΘ is greater than or equal to the value stored in register tSBUF, and if the value stored in register tΘ is greater than or equal to the value of register tSBUF, the map shown in Figure 3 is The igniter 36 is controlled by the basic ignition advance angle. Also, if the value stored in register tSBUF is larger than the value stored in register tΘ, the value of register tSBUF is shifted to register tΘ, and the value of register tΘ is set as the actual ignition advance angle SBUF, that is, BTDC42 The igniter 36 is controlled using °CA as the effective ignition advance angle.

In addition, in the above operation, when controlling the ignition timing using the value of the map shown in Fig. 3, if there is an ignition correction based on the water temperature signal and the air conditioner signal, etc., the correction is made at the same time, and the corrected effective ignition advance angle is used. Controls the igniter 36.

By controlling as described above, the ignition timing is controlled from the time when the throttle valve is fully closed for the first time and the 5th ignition passes until the fuel injection stop is restored.
BTDC is controlled at 47℃A, and after returning from fuel injection stop, the ignition timing changes according to the engine speed.
It is controlled to a value subtracted by BTDC1 or 5℃A. Further, if the value of the forced advance angle is smaller than the advance angle required by the map, the ignition timing is controlled by the value of the map. The reason for increasing the rate at which the engine speed approaches the basic ignition advance angle when the engine speed is below a predetermined value is to quickly lower the engine speed to an idling state.

〔Effect of the invention〕

In the present invention, when the throttle is fully closed and a predetermined number of ignitions have elapsed since the throttle is fully closed, the preset ignition advance angle is By controlling the ignition timing to the maximum ignition advance angle, the engine's electronic control system prevents knocking caused by delayed intake immediately after the throttle is fully closed, and also suppresses afterburn caused by an overly rich mixture when the throttle is fully closed. can get.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the electronic control device for an engine according to the present invention, Fig. 2 is a block diagram showing the electronic control circuit of the embodiment shown in Fig. 1, and Fig. 3 shows the rotational speed and intake air amount. Figure 4 is a diagram showing an example of a map of the basic ignition advance angle determined by the ratio to the rotation speed.
FIG. 5 is a flowchart showing the operation of the embodiment, and FIG. 5 is a block diagram showing an outline of the system configuration of the engine electronic control device according to the present invention. 2... Air cleaner, 4... Air flow meter, 6... Adsorption temperature sensor, 10... Throttle sensor, 22... Fuel injection device, 34... Distributor, 36... Igniter, 44... Electronic control circuit.

Claims (1)

[Claims] 1. An intake air amount sensor that detects the intake air amount of the engine on the upstream side of the throttle valve and outputs an intake air amount signal; and an intake air amount sensor that detects the engine rotation speed and outputs an engine rotation speed signal. an engine rotation speed sensor; a throttle sensor that detects the opening degree of the throttle valve and outputs a throttle position signal; and controls ignition timing to an optimal ignition advance angle based on the intake air amount signal and the engine rotation speed signal. optimum ignition advance control means; ignition number counting means for detecting that a predetermined number of ignitions have elapsed since the throttle valve fully closed state was detected by the throttle position signal; An electronic control device for an engine, comprising ignition advance control means for controlling ignition timing to a preset maximum ignition advance angle under a fully closed throttle state, regardless of the optimum ignition advance control means.