JPH0441947A - Starting controller of engine - Google Patents

Abstract

PURPOSE:To prevent overrich of air-mixture at the time of restarting after engine stall so as to secure proper startability by calculating a residual fuel quantity in the case of controlling starting fuel of an engine, and controlling an actually supplied starting fuel quantity by taking this condition into account. CONSTITUTION:In a starting controller, a fuel quantity Q1 which is supplied at the starting time is calculated by a calculation means 4 based on the starting condition of an engine 2. The engine 2 is started by supplying the calculated fuel quantity by a supply means 12 to the engine 2. In this case, a means 6 which monitors generation of misfire phenomenon which causes stop of the engine 2 is provided so that difference between a fuel supply quantity and a fuel discharge quantity after generation of the misfire is calculated so as to calculate a fuel quantity Q2 which remains inside the engine 2 by a calculation means 10. The calculated starting fuel supply Q1 is corrected based on the residual fuel quantity Q2, an actually supplied starting fuel quantity Q is calculated by a calculation means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling the amount of fuel supplied to an engine during engine starting, and in particular to control for improving startability when restarting the engine after an engine stall. Regarding equipment.

[Prior Art] As a technique for controlling the amount of fuel supplied during engine startup, the technique described in Japanese Patent Application Laid-Open No. 126239/1983 is known. In this technology, the amount of fuel during starting is reduced as the cranking rotation speed increases, thereby achieving good starting performance.

The technique described in Japanese Patent Publication No. 63-21816 is also known. This technology learns whether the starting fuel amount is appropriate each time the engine is started, and thereby the starting fuel amount is always adjusted to the optimum value.

[Problems to be Solved by the Invention] However, none of the conventional techniques considers the case where the engine is restarted after it has stalled. Here, engine stalling means that the engine ignition switch is on and the electrical equipment controlling the engine, such as the ECU,
(engine control unit), injector (
This refers to a situation where the engine rotation stops while the electromagnetic fuel injection valve (electromagnetic fuel injection valve) etc. are operating normally, and refers to a situation that occurs due to, for example, a clutch operation error.

When the engine rotation is stopped by turning off the engine ignition switch, that is, when the engine rotation is stopped normally, the engine rotates due to inertia for a while after the ECU or injector stops operating. , then completely stops. Therefore, the engine continues to rotate for a while after the fuel supply is stopped, and during this time the air-fuel mixture in the cylinder is scavenged. Therefore, when the engine stops normally, no fuel remains in the cylinder. A conventional starting control device plans to start the engine in this state. The technique of the above-mentioned Japanese Patent Application Laid-Open No. 126239/1983 or the Japanese Patent Publication No. 1983
The technique disclosed in Japanese Patent No. 21816 also plans to start the engine in this state.

On the other hand, if the engine rotation stops due to engine stalling, even if the fuel is supplied in synchronization with the engine rotation, fuel will continue to be supplied until the engine completely stops, so as mentioned above, No scavenging phenomenon occurs. Therefore, when the engine stops due to engine stalling, fuel remains in the cylinder.

When restarting an engine after an engine stall, a conventional engine start control device restarts the engine using the same control as when the engine is stopped normally.

Therefore, when restarting the engine after stalling, the air-fuel ratio of the air-fuel mixture becomes overrich by the amount of fuel remaining in the cylinder, making it difficult to start the engine.

Furthermore, if learning is performed without distinguishing between restarting after a normal stop and restarting after an engine stall, as in the technique described in Japanese Patent Publication No. 63-21816, erroneous learning will occur.

When restarting the engine after stalling, the engine learns that it has become overrich due to the residual amount of fuel, so the fuel amount at startup is corrected to the lower side, but the next time the engine restarts after a normal stop, the remaining amount will be reduced. Because there is no such thing, over-leaning occurs due to the amount learned on the decreasing side.

Therefore, the present invention aims to develop a starting control device that can improve restartability after an engine stall. It is also intended to make it easier to adapt to a system that learns the amount of fuel at startup and maintains it at an optimal value.

[Means for Solving the Problem] The above problem is solved by an apparatus whose schematic configuration is shown in FIG. In the apparatus for starting the engine 2 by supplying a quantity of fuel (by the means 12), the means 6 monitors the occurrence of a misfire phenomenon leading to the engine stop of the engine 2, and the supply fuel after the occurrence of the misfire phenomenon. means IO for calculating the amount of fuel Q2 remaining in the engine by integrating the difference between the amount of fuel and the amount of discharged fuel; This problem is solved by an engine starting control device characterized by adding means 8 for calculating the starting fuel ftQ to be supplied to the engine.

"Function" Now, according to the start control device having the above means, while the engine 2 is operating, the occurrence of a misfire phenomenon that leads to engine stop is monitored.Here, the misfire phenomenon that leads to engine stop is a continuous misfire phenomenon. This misfire phenomenon is caused by a clutch operation error or a sudden increase in engine load.This misfire phenomenon can be detected by installing a vibration sensor on the engine 2, for example, and detecting the vibrations associated with the explosion stroke. It can also be detected by detecting the presence or absence of the engine speed.Alternatively, since the engine speed drops abnormally when a misfire phenomenon that leads to engine stop occurs, it can also be monitored by detecting this abnormal drop in engine speed. Ru.

When the occurrence of a misfire phenomenon is detected by some means in this way, the difference between the amount of supplied fuel and the amount of discharged fuel begins to be integrated. Since misfire has already occurred here, the supplied fuel is not combusted. While the engine continues to rotate due to inertia, unburned fuel is discharged from the engine, but some of it adheres to the inner walls of the cylinders and remains without being discharged. In other words, the difference between the supplied fuel amount and the discharged fuel amount corresponds to an increase in the residual fuel amount. Therefore, the residual fuel amount Q2 is calculated by integrating the difference in synchronization with the fuel supply timing or exhaust timing.

Means 8 calculates the basic starting fuel amount Q1 obtained by means 4.
is corrected based on the residual fuel amount Q2 determined as described above. Here, the basic starting fuel amount Q1 is the optimal value when the residual fuel amount Q2 is zero, but since it is corrected based on the residual fuel amount Q2, the corrected value is Q2.
This is the optimal supply amount when only 50% of fuel remains. Therefore, the fuel supplied from the means 12 has an optimum value when restarting the engine after stalling, and good engine startability is maintained.

Note that when a misfire phenomenon does not occur, the basic fuel amount Ql calculated by the means 4 is not corrected, but this can be realized either by starting the means 8 only when a misfire phenomenon occurs or by always starting it. In the latter case, when the engine stops normally, the residual fuel amount Q2 is zero, so even if the means 8 is activated, the basic iQl is not corrected.

It should be noted that the techniques explained in the column of prior art are all related to means 4, and the system to which means 6, 8, and 10 are added is unique to the present application.

[Example] Next, an example embodying the present invention will be described with reference to the drawings.

FIG. 2 shows an outline of an engine system implementing the starting control device of the present invention. In the figure, 30 is the engine body, 2
4 is an intake pipe, 22 is a throttle valve, 28 is a pressure sensor that detects the pressure inside the intake pipe 22, and 32 is a crank angle that outputs a pulse every time the crank of the engine 30 rotates by a predetermined angle through the rotation of the camshaft. sensor, 34 is engine 30
26 is an injector that supplies fuel to the engine 30; 36 is the engine 3;
A starter motor that forcibly rotates the
38 is an ignition switch, 40 is a battery, 42
1 is a starter switch, and 100 is an engine control unit (ECU).

This engine system has a control system roughly shown in FIG. ECU 100 is multiplexer 110
The pressure sensor 28 and the water temperature sensor 34 are connected to the multiplexer 110, and the signal from either one is connected to the A/
The information is sent to a D converter 112 and A/D converted, and the digitized information can be input to a CPU (central processing unit) 150. Also, the starter switch 42 is turned on.
Different signals can be input to the CPU 150 via the level correction circuit 113 depending on whether N is set or not. Further, the pulse wave from the crank angle sensor 32 can be input to the CPU 150 after being waveform-shaped by a waveform shaping circuit 114 . Based on the program stored in the ROM 120, the CPU 150 inputs signals from each signal source in a predetermined procedure and timing, processes them based on the program, and sends a drive pulse signal to the injector drive circuit 116 according to the processing result. Output. The injector drive circuit 116 turns on and off the current flowing through the injector 26 based on a pulse signal sent from the CPU 150. Note that 122 is a RAM, which is used in processing by the CPU 150. Note that a portion 122a of the storage capacity of the RAM 122 is backed up by a power source 122b, so that the memory can be retained even when the ignition switch 38 is turned off.

, :: (7) The ECU 100 is configured to operate by being supplied with drive power from the battery 4o while the ignition switch 38 is turned on.

FIG. 4 shows a control procedure when the CPU 150 performs calculations and processes according to the program stored in the ROM 120. This control procedure is performed using the ignition switch 38.
While on, it is executed repeatedly in synchronization with the engine rotation. That is, the number of pulses from the crank angle sensor 13 is
It is executed every time the number of pulses corresponds to the fuel supply timing of the engine 3 degrees.

In step S1, the engine rotation speed Ne is calculated from the time interval of the pulse waves from the crank angle sensor 32, and is compared with a predetermined value. Here, the predetermined rotation speed is set to a low rotation speed that cannot occur if the engine is rotating normally, and when the engine speed drops to this predetermined rotation speed while the ECUI 00 is energized, the engine The rotation speed is set to correspond to a state in which a misfire phenomenon that leads to a stop occurs and the engine stalls.

Note that when the engine is stopped normally, the ignition switch 38 is turned off and the operation of the ECUloo is stopped when the engine speed is above this predetermined value, so the answer in step S1 is YES and steps S4 and subsequent steps are performed. It will never be executed.

During normal engine rotation, step S2. S3 is repeatedly executed, and when engine stalling starts to occur, the process from step S4 onwards is executed.

Note that during engine starting, the engine speed may fall below a predetermined value even though no misfire phenomenon has occurred, so the program is programmed so that the process shown in FIG. 4 is not executed while the starter switch 42 is on.

Now, in the process shown in Fig. 4, CINJ is a counter that calculates the number of times fuel is supplied after the engine stalls, and 5I
NJ indicates a variable name for calculating the amount of residual fuel.

While the engine is rotating normally, step S2.3 is repeatedly executed and CINJ and 5INJ are cleared to zero. When the engine is stopped normally, the process shown in FIG. 4 is also stopped at the same time as the fuel supply is stopped.

In this case, it is reasonable to stop the process when 5INJ is cleared to zero, so that the fuel will not remain in the engine due to scavenging while the engine is rotating due to inertia after the fuel supply is stopped. It is.

Now, when a misfire phenomenon starts to occur for some reason while the ignition switch is on and the engine speed becomes less than a predetermined value, the process of step S4 is executed.

Here, the signal THW of the cooling water temperature sensor 34 is input,
A correction coefficient KTHW, which is set in advance in the relationship shown in FIG. 5(,a), is determined for the signal THW. This correction coefficient KTHW is mapped to the signal THW and stored in the ROM 120 in advance. This correction coefficient K
THW corresponds to the rate at which the supplied fuel remains in the cylinder when it is not combusted, and it increases at low temperatures because the lower the engine cooling water temperature, the more the fuel adheres to the inner wall of the cylinder and is less likely to be scavenged. It becomes. Note that this function can be determined in advance through experiments for each engine.

Step S5 is a process for counting the number of times fuel is supplied after the engine stall starts, and as described above, the process in FIG. The number of times of supply is calculated by adding 1 to .

Step S6 is a correction coefficient KCIN for the number of fuel supplies.
This is a process to obtain J, and this correction coefficient KCINJ corrects the phenomenon that the residual rate changes with the number of fuel supplies. Immediately after the engine starts stalling, a large amount of fuel remains on the inner wall of the cylinder because it has not yet adhered, but as more fuel is supplied from the start of the engine stalling, it gradually becomes difficult to adhere and is scavenged. The relationship is set as shown in FIG. 5(b). This KCINJ is also determined experimentally for each engine in advance and is mapped and stored in the ROMI 20.

Step S7 is the fuel supply amount TI at the timing.
NJ, residual correction coefficient KTH affected by temperature
Residual correction coefficient KCI affected by W and number of supplies
This process calculates the remaining fuel amount A at the timing by multiplying by NJ.

This residual amount A is actually calculated to be equal to the value obtained by subtracting the discharged fuel amount from the supplied fuel amount TINJ.

Note that instead of the above process, it is also possible to adopt a process of estimating the exhaust amount from the exhaust gas pressure, exhaust gas temperature, etc., and subtracting this from the supply amount.

Step S8 is a process for calculating the remaining amount 1isINJ by integrating the remaining amount at each supply timing.

As mentioned above, the process shown in Fig. 4 is executed at each fuel supply timing, so when the engine rotation completely stops due to engine stalling, 5INJ stores the remaining amount from the time the engine starts stalling until it completely stops. The summation will be required.

Since this 5INJ is stored in the backup RAM 122a, the value is retained even if the ignition switch is turned off after the engine stalls and stops.

Now, FIG. 6 shows a process that is repeatedly executed every time the engine 2 is supplied with fuel while the starter switch 42 is on.

Step 311 is the residual amount 5I determined by the process shown in FIG.
This is a process of determining whether NJ is zero or not, and if the engine is normally stopped, steps 812 to 14 are omitted and step S16 is executed. Here T.I.
NJ is the basic starting fuel supply amount determined by a process not shown based on the state of the engine at starting;
When steps SI2 to I4 are not executed, the basic amount is not modified and the same amount of fuel is supplied to the engine 2. Note that this TINJ is determined by the technique described in Japanese Patent Application Laid-Open No. 126239/1982 or Japanese Patent Publication No. 21816/1983, which was explained in the section of the prior art.

Now, while the residual fuel amount 5INJ is not zero in step Sll, step S12 is executed. In step S12, the residual fuel amount S I N , J and the current basic fuel amount TI
The magnitude of NJ is compared, and if the residual fuel amount is smaller, the residual fuel amount 5INJ is subtracted from the basic fuel amount TINJ in step SI3, and the reduced amount is supplied in step 316.

As a result, the amount obtained by adding the residual amount to the actual supply amount becomes equal to the basic amount, and over-richness is prevented when the engine is restarted after the engine stalls. In this case, since the next residual amount is zeroed, 5INJ is cleared to zero in step SI4.

Now, if the remaining amount is large and the basic injection amount or more remains, step S15 is executed, and further step S1
．． 6 is omitted. Since step S16 is omitted, fuel is not supplied and only scavenging is performed. Here-
Since the scavenging amount per exhaust stroke is considered to be approximately equal to the basic supply amount TINJ, the process of step S15 is executed to correct the next residual amount. Then, this process is repeated to achieve scavenging, and after the residual amount becomes less than the basic fuel amount, the processes of steps 813 to 16 are executed.

Now, FIG. 7 shows another embodiment for controlling the amount of fuel at the time of starting, in which processes in steps 817 to 19 are added following step 315 in the process in FIG. 6. Here, C3lNG is a counter that counts the number of fuel supply timings after the engine is forced to rotate for starting, and is programmed to be cleared to zero when the engine starter switch is turned on. Then, in step S17, it advances every time the fuel supply timing comes. In step S18, the coefficient KC is calculated based on the number of times.
This is a process to obtain 8INJ, which is in a relationship that decreases as C31NJ increases. Then, in step SI9, processing is executed to reduce the amount of residual fuel as well as the number of times.

As a result, the amount of reduction in residual content due to engine scavenging can be estimated more accurately than in the case of the process shown in FIG. 6.

[Effects of the Invention] As detailed above, according to the present invention, the amount of residual fuel is determined when controlling the fuel at the time of starting the engine, and the amount of fuel actually supplied at the time of starting is determined by taking this into consideration. controlled. Therefore, when restarting the engine after stalling, the air-fuel mixture does not become overrich, and good startability is ensured.

In addition, since the actual supply amount is controlled after considering the residual amount, there will be no erroneous learning even if the supply amount is controlled by learning, and the system will not adapt to the system that learns the fuel amount at startup and maintains it at the optimal value. It's easy.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the concept of the present invention, Fig. 2 is a diagram showing an example of an engine system embodying the present invention, Fig. 3 is a system diagram centered on the engine control unit, and Fig. 4 is a diagram showing an example of an engine system embodying the present invention.
The figure shows the processing procedure for determining the residual amount executed by the engine control unit, Fig. 5 (a)
(b) is a diagram showing the characteristics of the correction coefficient used in the process of FIG. 4, and FIG. 6 is a diagram showing the process procedure for controlling the actual amount of fuel supplied at the time of starting, which is executed by the engine control unit. FIG. 7 is a diagram corresponding to FIG. 6 relating to another embodiment.

Claims (1)

[Scope of Claims] In a device that calculates the amount of fuel Q1 to be supplied at the time of starting based on the starting state of the engine and starts the engine by supplying the calculated amount of fuel, a misfire phenomenon that leads to engine stop of the engine is provided. means for monitoring the occurrence of the misfire phenomenon; means for calculating the amount of fuel Q2 remaining in the engine by integrating the difference between the amount of fuel supplied and the amount of discharged fuel after the occurrence of the misfire phenomenon; 1. A starting control device for an engine, further comprising a means for correcting a starting fuel amount Q1 based on a residual fuel amount Q2 and calculating an actually supplied starting fuel amount Q.