JPH01232168A - Starting control device for engine - Google Patents

Abstract

PURPOSE:To prevent generation of an engine stall by providing an ignition inhibiting means, which inhibits ignition action of an engine, so as to inhibit the ignition action of the engine for a predetermined period after a start is detected when the start of the engine is detected further when the engine is in a temperature of predetermined value or less. CONSTITUTION:An engine E, when it is in a cold start, controls a supply fuel amount of predetermined value by a fuel supply amount control means A in accordance with a temperature of the engine E. In the time of this cold start, in case of detecting the start of the engine E by a start detecting means F, the engine E is inhibited in its ignition action by an ignition inhibiting means C for a predetermined period after the start is detected, preventing early initial explosion while supplying an increase amount of fuel so as to dilute engine oil in a cylinder. Accordingly, since the engine performs its ignition and complete explosion after the engine oil decreases its viscosity, the engine is prevented from easily generating its engine stall.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine starting control device.

(Prior art) In general, in an engine that employs an electronically controlled fuel injection system, the basic fuel injection m is first determined based on the intake air amount during the engine operation, and the basic fuel injection amount is determined based on the operating conditions during the operation. The optimal fuel injection amount is obtained by appropriately increasing or decreasing the amount of fuel (during startup or non-starting, high or low cooling water temperature, during acceleration or non-acceleration, etc.).

Then, when the engine is started when the engine cooling water temperature is cold, for example, by about 10 degrees Celsius, a predetermined fuel injection amount is injected in accordance with the ignition timing in accordance with the cooling water temperature. (See, for example, Japanese Unexamined Patent Publication No. 55-49538).

(Problems to be Solved by the Invention) However, as described above, during a cold start, the temperature inside the combustion chamber is low and the viscosity of the engine oil is high, so the driving resistance of the engine is also high. Therefore, if the first explosion occurs too early, as shown by the broken line in Figure 6, for example, the viscosity of the oil has not become sufficiently low and the torque generated by the explosion is smaller than the engine's driving resistance. A problem arises in that the engine stalls without reaching a complete explosion.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems. An engine start control device comprising: a fuel supply means for supplying a predetermined amount of fuel to the engine when the start of the engine is detected by the start detection means; and an engine temperature detection means for detecting the temperature of the engine. An ignition prohibition means for prohibiting the ignition operation of the engine is provided, and when the start detection means detects the start of the engine and the engine temperature detection means detects that the engine temperature is below a predetermined value, After the startup is detected, the ignition operation of the engine is prohibited for a predetermined period of time.

(Function) According to the problem-solving means of the present invention, when the engine is cold started, the amount of fuel supplied is controlled to increase by a predetermined value in accordance with the temperature of the engine.

If an engine start is detected during the cold start, engine ignition is prohibited during the start detection period to prevent an early initial explosion, and the engine in the cylinder is supplied with increased fuel. It is designed to dilute the oil.

(Example) First, Figs. 2 to 5 show a starting control device for an automobile engine when the present invention is applied to the engine, and Fig. 2 shows a control system of the above-mentioned embodiment device. The schematic diagrams and FIGS. 3 to 5 are flowcharts each showing the start control operation of the engine control unit in the same control system.

First, the outline of the control system according to the embodiment of the present invention will be explained with reference to FIG. 2, and then the control of the main parts will be explained.

In FIG. 2, reference numeral l is the engine body, and intake air is taken in from the outside via an air cleaner 30.
Thereafter, the air is supplied to each cylinder via an air flow meter 2, a throttle chamber 3, etc. Also fuel (gasoline)
is the fuel tank (gasoline tank) by the fuel pump 13.
12 to the engine side, and is injected by the fuel injector 5 into the intake boat of the engine main body 1 in synchronization with the ignition timing. The amount of intake air into the cylinder during running is determined by the throttle valve provided in the throttle chamber 3.
controlled by The throttle valve 6 is operated in conjunction with the accelerator pedal, and is maintained at the minimum opening state in the idling state.

The throttle chamber 3 is provided with a bypass intake passage 7 that bypasses the throttle valve 6, and the bypass intake passage 7 is provided with intake air for highly accurate feedback control of the engine speed during idling operation. A current-controlled solenoid valve (so-called ISO valve) 8 is provided as an adjustment means. Therefore, in the idling operating state, the intake air measured through the air flow meter 2 is supplied to the combustion chamber in each cylinder on the engine body side via the bypass intake passage 7, and the amount of intake air is It is regulated by the current controlled solenoid valve 8.

The opening/closing state (valve opening degree) of this current-controlled solenoid valve 8 is controlled according to the duty ratio of an intake air amount control signal G supplied from an engine control unit (hereinafter referred to as ECU) 9, which will be described later. Ru.

Further, the reference symbol 10 indicates an exhaust pipe that includes, for example, a three-way catalytic converter (catalyst converter) II in the middle of the exhaust passage and has an exhaust gas purifying function. The upstream portion of the three-way catalytic converter 11 of the exhaust pipe 10 is provided with a 0.00.degree.
A sensor 21 is provided.

On the other hand, reference numeral 14 denotes an ignition plug provided in the cylinder head of the engine body 1, and the ignition plug 14
A predetermined ignition voltage is applied to the EC via the distributor 17 and the igniter 18, and the application timing of this ignition voltage, that is, the ignition timing is determined by the above-mentioned EC.
It is controlled by the ignition timing control signal (gc) supplied from U9 to the igniter 18. Furthermore, reference numeral 20 denotes a boost pressure sensor 20, which detects an engine boost pressure B corresponding to the engine load and inputs it to the ECU 9. Further, I'G-SW is an ignition key switch of the engine and is turned ON when the engine is started, and its ON signal is input to the ECU 9 as an ECU trigger and an engine start state detection signal.

The E CU 9 is, for example, a microprocessor (C
It is structured around a memory (ROM and RAM) and an interface (I10') circuit. The interface circuit of this ECU 9 includes, for example, the ignition key switch IG.
- Engine starting state detection signal from SW (ECU trigger), engine speed sensor (and crank angle sensor)
engine rotation speed (and crank angle) detection signal Nε (θNE) from 15, detection signal Tw of the cooling water temperature of the engine body l detected by the water temperature thermistor 16, and exhaust gas detected by the Ox sensor (oxygen sensor) 21. Various detection signals such as an oxygen concentration (A/F) detection signal Vo, an intake air amount detection signal Q detected by an air flow meter, and an ignition timing detection signal 1gc from the distributor 17 are inputted. For example, the ECU 9 sets the actual air-fuel ratio A/F of the engine to 0 in the low load/low rotation region, and sets the actual air-fuel ratio A/F of the engine indicated by the detected value Vo of the sensor 21 to a predetermined target air-fuel ratio centered on the stoichiometric air-fuel ratio (14, 7). The above-mentioned 0.0. Based on the oxygen concentration detection signal vO of the sensor 19, the rich state of the oxygen concentration in the exhaust gas (
The basic fuel supply amount Tp from the fuel injector 5 is determined based on the intake air amount Q measured by the air flow meter 2 according to the determined value. is configured to perform feedback correction control with high precision. On the other hand, when the operating state of the engine is in a predetermined high load/high rotation range, for example, the feedback correction control is stopped and oven loop control is performed to an air fuel ratio richer than the stoichiometric air fuel ratio. .

On the other hand, the above engine is connected to the ignition key switch IG.
- In the case of a starting state of 9WON, the fuel supply amount is fixedly increased by the oven loop according to the value of the engine cooling water temperature Tw at that time (starting amount increase correction)
. That is, when the engine cooling water temperature value Tw is low, the temperature of the fuel adhering portion is also low and the vaporization of the fuel is poor.

Therefore, with only the basic fuel supply amount based on the intake air IQ, the air-fuel ratio A/F that can actually contribute to engine combustion will be considerably leaner than the target air-fuel ratio.

As a result, if no increase correction is performed, even if the engine is started, engine malfunctions such as unstable idle rotation, surging, and engine stalling will occur. Therefore, the fuel increase correction value (K T W) at the time of engine startup is determined according to the cooling water temperature value Tw as described above, and the lower the cooling water temperature Tw, the more the fuel increase correction value (K T W) (initial value up to) KTW becomes larger.

The fuel whose amount has been increased in this manner is injected into the intake port of the engine from the fuel injector 5 of each cylinder in synchronization with the ignition timing indicated by the ignition timing control signal 1gc.

Next, the engine control unit (ECU) 9
The control operation of the ignition timing at the time of starting the engine will be explained in detail with reference to the flowcharts shown in FIGS. 3 to 5.

Now, when the ECU 9 is triggered by turning on the ignition key switches IC-9 to IC-V, the control operations shown in the flowcharts of FIGS. 3, 4, and 5 are started.

First, the flowchart in FIG. 3 shows an ignition execution routine that is the basis of ignition timing control in this embodiment.
First, in step S1, the timing on the current control cycle (
It is determined whether the crank angle θNε) is the ignition timing. If the determination is YE or S, the process proceeds to step S2, where it is determined whether the value of the ignition prohibition flag F++ (+y (described later)) for canceling the ignition execution is 0 (ignition possible). , YES (FNOT=0), the engine mixture is ignited as usual (step S
3).

On the other hand, the step S1. If the determination in St is NO, the process directly returns to the initial step of the next cycle. The above-mentioned ignition prohibition flag FNOT is a control flag for prohibiting ignition of the engine within a predetermined period of waiting for oil viscosity to decrease during a cold start of the engine, and is a control flag for prohibiting ignition of the engine within a predetermined period of time during which the engine is cold-started. Set in the determination routine. It looks like this.

Next, the flowchart shown in FIG. 4 will be explained.

First, in step S1, it is sequentially determined whether or not the operating state of the engine is at the time of starting (during cranking) in the current control cycle, and then in step S, it is sequentially determined whether or not the operating state of the engine is at the time of starting and at the ignition timing. .

If both of the determinations are YES, the process proceeds to step S3, where the number N of arrivals of the ignition timing is incremented (N+1) every number of arrivals and is integrated. Then, the process further advances to step S4, and the integrated value N is determined to be the fifth
As shown in the flowchart in the figure, it is determined whether the set number of times (set ignition inhibition number) Nl preset in the map state has been reached in accordance with the initial detected value of the cooling water temperature Tw during the relevant operation. Here, the set map is such that when the cooling water temperature Tw is relatively high, for example, 0°C or higher, the number of times ignition is prohibited is set to O, and ignition is prohibited only when the actual cooling water temperature Tw is low. It has become so.

As a result of this determination, N=N, and in the case of YES that the number of times the ignition timing has arrived has reached the set number of ignition inhibition times N, the viscosity of the engine oil is sufficiently reduced, and the driving resistance is reduced. First, in step S5, the value of the above-mentioned ignition prohibition flag FNOT is reset to 0, and at the same time, in step S, the integrated value N of the number of times the ignition timing has arrived is also reset to N=0. . As a result, in the next control cycle, the determination result of step S in the flowchart of FIG. 3 above becomes YES, so step S
3, the engine will be ignited. In this state, as described above, the engine oil is sufficiently diluted by the total amount of increased fuel during cold operation, and its viscosity is greatly reduced, resulting in a considerable reduction in driving resistance.

Therefore, if the engine is ignited in this state, the engine will almost certainly reach a complete explosion as shown by the solid line in FIG. 6, making it possible to realize stable starting.

Note that if the number N of arrivals of the ignition timing determined as No in step S4 does not reach the set number N of ignition prohibitions, the process moves to step S7 and the ignition prohibition flag F NOT is set until N=N. The value of F_N0T-1 is set or maintained in the set state to continue the ignition inhibited state.

(Effects of the Invention) As described above, the present invention includes a start detection means for detecting the start state of the engine, and a predetermined amount of fuel that is supplied to the engine when the start detection means detects the start of the engine. An engine starting control device comprising a fuel supply means and an engine temperature detecting means for detecting the temperature of the engine, wherein an ignition inhibiting means for prohibiting the ignition operation of the engine is provided, and the starting detecting means prevents the engine from starting. If the engine temperature is detected and the engine temperature detection means detects that the engine temperature is below a predetermined value, the ignition operation of the engine is prohibited for a predetermined period after the start detection. It is something.

That is, in the configuration of the present invention, when the engine is cold started, the amount of fuel to be supplied is controlled to increase by a predetermined value in accordance with the temperature of the engine.

If engine start is detected during the cold start, engine ignition is prohibited during the start detection period to prevent early initial explosion.

Therefore, according to the above configuration of the present invention, the viscosity of the engine oil is reduced by supplying a predetermined amount of fuel, and then the engine is ignited and completely exploded, and the engine stall as in the conventional case is less likely to occur. .

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to claims of the present invention, Fig. 2 is a system system diagram showing the overall configuration of an engine starting control device according to an embodiment of the present invention, and Figs. FIG. 6, a flowchart showing the control operation of the example device, is a graph showing the operating characteristics of the example device in comparison with the conventional characteristics. l...Engine body 2...Air flow meter 5...Fuel injector 9...Engine control unit 14...
・Spark plug 16...Water temperature thermistor 17...Distributor Fig. 6

Claims (1)

[Claims] 1. Start detection means for detecting the start state of the engine; fuel supply means for supplying a predetermined amount of fuel to the engine when the start detection means detects the start of the engine; and engine temperature detection for detecting the temperature of the engine. an ignition inhibiting means for inhibiting ignition operation of the engine, wherein the start detecting means detects the start of the engine, and the engine temperature detecting means sets the engine temperature to a predetermined value. 1. An engine starting control device, characterized in that, if it is detected that the starting value is below a value, the ignition operation of the engine is prohibited for a predetermined period after the starting detection.