JPS6187934A - Fuel injection controller - Google Patents

Abstract

PURPOSE:To prevent output shortage from occurring, by calculating a recovery injection quantity according to the decelerating state of an engine in time of releasing a fuel cut, while making a controller perform the recovery injection asynchronously with the injection timing usually. CONSTITUTION:There is provided with a driving state detecting device (a) which detects those of suction quantity, engine speed, throttle valve opening, etc., each, and when is is judged that an engine is within the specified deceleration driving range from the output signal, a fuel cut signal is outputted out of a fuel cut signal generating device (b). An on the basis of the output signal of the driving state detecting device (a), a fuel injection quantity is calculated at an injection quantity operational device (c), and in time of the said fuel cut signal being inputted, outputting an injection signal is stopped. At the abovementioned, when the output of the fuel cut signal is stopped, a recovery injection quantity is calculated at a recovery value operational device (d) according to the decelerating state, whereby a recovery injection signal is outputted without synchronizing with the injection timing usually.

Description

[Detailed description of the invention] (Technical field) The present invention relates to an engine fuel injection control device.

(Prior art) In general, in engines that perform fuel cut, when releasing the fuel cut (hereinafter referred to as recovery), it is necessary to supply an appropriate amount of fuel according to the operating condition so as not to impair drivability. is necessary.

As a conventional fuel injection control device for an engine, there is one described, for example, in Japanese Utility Model Publication No. 1937-1983. This device detects the amount of intake air per rotation as the engine load, calculates the basic injection amount according to the air amount, and injects the basic injection amount of fuel into the intake boat at a predetermined normal injection timing that is synchronized with the rotation. It is spraying nearby.

Also, when decelerating from high rotation, the fuel supply is stopped (
The engine is operated with negative torque due to the vehicle's running inertia to prevent the generation of unburned gas and save fuel.

When the speed is reduced to a predetermined recovery rotation speed (the rotation speed at which re-injection is performed by dividing the fuel cut by M; the same applies hereinafter), fuel is immediately re-injected regardless of the normal injection timing. (recovered) and generated positive torque in the engine again. In this case, the fuel injection amount during recovery (hereinafter referred to as recovery injection amount) Tr is set in advance to a constant amount regardless of the degree of deceleration. In addition,
The recovery rotation speed is not necessarily constant, and different values are adopted depending on the operating conditions.

However, in such conventional fuel injection control devices, the recovery injection MtTr is set to a constant amount regardless of the degree of deceleration, so the combustion state during recovery is not necessarily optimal and driveability is affected. The problem was that it worsened.

For example, when the recovery rotation speed is high, the amount of fuel is less than the optimum value, the air-fuel ratio of the air-fuel mixture becomes lean, and the combustion state deteriorates. As a result, the rotational speed after recovery becomes unstable, making it impossible to smoothly shift to idling operation, or, in extreme cases, causing a misfire and stalling the engine. On the other hand, when the recovery rotational speed is low, the amount of fuel increases, resulting in high output, and even though the engine is decelerating, it is accelerated, resulting in torque fluctuations and so-called engine shock.

(Purpose of the Invention) Therefore, the present invention sets the recovery injection amount according to the deceleration state (for example, rotation speed) during recovery, so that the engine output during recovery can be optimally adjusted according to the operating state, and torque fluctuations are achieved. The purpose is to prevent engine failure and power shortages and improve engine drivability.

(Configuration of the Invention) FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention.

The operating state detecting means a detects the operating state of the engine, and the fuel cut signal generating means outputs a fuel cut signal when the engine is within a predetermined deceleration operating range. The injection amount calculation means C calculates a basic injection amount based on the operating state, outputs an injection signal at a predetermined normal injection timing synchronized with engine rotation, and stops outputting the injection signal when a fuel cut signal is input. do. On the other hand, the recovery abrasive calculation means d calculates the recovery injection amount according to the deceleration state of the engine when the output of the fuel cut signal is stopped, and outputs the recovery injection signal without synchronizing with the normal injection timing. The fuel injection means e injects fuel based on the injection signal and the recovery injection signal, thereby optimally controlling the engine output during recovery.

(Example) The present invention will be explained below based on the drawings.

2 to 6 are diagrams showing an embodiment of the present invention.

First, the configuration will be explained. In FIG. 2, 1 is an engine, intake air is supplied from an air cleaner 2 to each cylinder through an intake pipe 3, and fuel is supplied to an injector (fuel injection means) based on an injection signal Si and a recovered injection signal Sir.
4 is injected. The flow rate Qa of the intake air amount is detected by an air flow meter 5 and controlled by a throttle valve 6 in the intake pipe 3. The opening Cv of the throttle valve 6 is detected by a throttle valve opening sensor 7, and the rotation speed N of the engine 1 is detected by a crank angle sensor 8. Further, the temperature Tw of the cooling water flowing through the water jacket is detected by a water temperature sensor 9. The air flow meter 5, throttle valve opening sensor 7, crank angle sensor 8, and water temperature sensor 9 constitute an operating state detecting means 10, and a signal from the operating state detecting means IO is input to a control unit 11.

The control unit 11 has the following functions: an injection amount calculation means, a fuel cut signal generation means, and a recovery image calculation means.
It consists of 23 and 24 I10 boats. CPU
21 reads necessary external data from the I10 boat 29 according to the program written in the ROM 22, performs arithmetic processing while exchanging data with the RAM 23, and transfers the processed data to the I10 as necessary. Output to boat 24. A signal from the operating state detection means 10 is input to the I10 boat 24, and
The I10 boat 24 outputs an injection signal Si and a recovery injection signal Sir. The ROM 22 stores calculation programs for the CPU 21, and the RAM 23 stores data used in calculations in the form of a map or the like.

Next, the effect will be explained.

In general, fuel injection in an engine is performed in synchronization with engine rotation, and normally, fuel necessary for combustion is injected simultaneously in all cylinders for each combustion stroke of the engine. For example, in a four-stroke engine, two rotations of the crankshaft constitute one stroke, so all the fuel required for combustion is often injected in two rotations, and 1/2 of the fuel is injected in each rotation.

That is, fuel is injected not continuously but intermittently in synchronization with rotation. However, the engine recovery request occurs not at a timing synchronized with the rotation, but at an arbitrary timing. In this case, only intermittent normal injection may cause a delay in response to a recovery request, resulting in degraded operating performance. Therefore, when a recovery request is received, recovery is immediately performed and a certain amount of fuel is injected.

On the other hand, different values are adopted for the recovery rotation speed depending on various operating conditions including cooling water temperature, etc., with the intention of improving driveability. Conventionally, the recovery injection amount was set to the above-mentioned constant amount, and although it was possible to avoid the delay in response to the recovery request, it was not possible to appropriately respond to various recovery rotation speeds, and it was still difficult to optimize the combustion state during recovery. It was insufficient.

Therefore, in this embodiment, when there is a recovery request, recovery is performed by interrupting the intermittent normal injection timing in response to the recovery request, and the recovery injection amount Tr is set to an appropriate value according to the operating conditions at that time. By doing so, the combustion state is optimized while avoiding response delays.

3 to 5 are flowcharts showing the injection amount control program written in the ROM 22, and in the figure, P1 to
P4s indicates each step of the program 6 Figure 3 is a flowchart showing the program for normal injection amount calculation.
For example, it is executed once every 180 degrees of crank angle.

First, the data required for P work, namely the intake air amount Qa,
Read the rotation speed N, throttle valve opening Cv, and cooling water temperature TW, and set P
2, various correction coefficients C0 are calculated.

These various correction coefficients C0 are used to perform various increase corrections on the basic injection amount Tp, which will be described later, based on, for example, the cooling water temperature Tw, acceleration increase, and the like. Next, in P3, it is determined whether or not it is in a deceleration state based on the throttle valve opening degree Cv, and if it is not in a deceleration state, it is determined in P4.
Reset the fuel cut flag FcF with and proceed to P. The fuel cut flag FCF indicates whether or not to perform a fuel cut. It is set (FC, F = 1) when a fuel cut is performed, and reset (FC, F = 1) when a fuel cut is not performed.
FCF=O). On the other hand, in the deceleration state, the rotation speed N is compared with the recovery rotation speed Nr in P6, and when N≧Nr, it is determined that the fuel cut condition is satisfied, and the fuel cut flag FCF is set in P7, and the fuel cut flag FCF is set in P8. Then, set the various correction coefficients C8 to C,=O and proceed to P. Also, N <
When N'r, it is determined that the fuel cut condition is not satisfied even though the vehicle is in a deceleration state, and the process proceeds to P. Therefore, when N≧Nr, fuel cut is performed, and when N<Nr, fuel cut is not performed.

P, then let R be the value of the various correction coefficients CI for this routine.
Store at a predetermined address of AM23. Next, basic injection jtTp is calculated at P according to the following equation (2).

T p = K-Q a / N・・・・・・・・・■
However, K: constant This basic injection amount Tp is the intake air amount Qa per engine revolution
This is because this device injects fuel into the front cylinders at the same time, for example, every rotation, in synchronization with the rotation of the engine.

Next, P-engineering. The final injection amount Ti is calculated according to the following equation (2).

T i = T p X Co + T s --- ■
■In the formula, Ts is the response delay (dead time) of injector 4
This is a coefficient for correcting. therefore.

When the fuel cut flag FCF is reset, the injection signal Si is output at a predetermined normal injection timing synchronized with the engine rotation, and the final injection amount Ti of fuel is injected from the injector 4 into the intake pipe 3. On the other hand, when the fuel cut flag FCF is set, the various correction coefficients 00 become 0020 and T i = T s, and Ti is only a dead time correction and no fuel is actually injected. That is, a fuel cut is performed.

FIG. 4 is a flowchart showing a recovery injection amount calculation program, and this program is executed once every 10 m5. This is because it is taken into consideration that recovery is performed at any timing unrelated to engine rotation.

First, p zt determines whether the value of various correction coefficients C6 is zero, that is, whether fuel cut is being performed or not. If co≠O, fuel cut is not being performed and recovery is necessary. It is determined that there is no error, the recovery flag RFG is reset at P22, and the current routine is ended. The recovery flag RFG indicates whether or not the recovery has been completed, and is set (RFG=1) when the recovery is completed, and reset (RFG=O) when the recovery is not completed.

On the other hand, when Cl1=O, it is determined that fuel cut is being performed, and P2. The rotation speed N is compared with the recovery rotation speed Nr. When N>Nr, it is determined that the deceleration has not reached the recovery state yet, and the current routine is terminated and fuel cut is continued), and when N≦Nr, P2. It is determined whether the recovery flag RFG is set or not. When RFG=1, it is determined that recovery has already been completed (for example, when recovery was performed in the previous routine), and the current routine is ended. In addition, when RFG=O, it is determined that the recovery is not completed and the recovery flow R
Move to F.

In Recover Flow RF, first P2. Read the value of the deceleration rotation difference ΔN from the RAM23, and read the deceleration rotation difference ΔN at P2s.
is compared with the discrimination reference value N, . The deceleration rotation difference ΔN is calculated in a subroutine to be described later and stored in the RAM 23, and represents the degree of deceleration per predetermined time (100 m5 in this embodiment).

Next, the basic recovery injection amount Tr0 is adjusted according to the degree of deceleration.
is set in two stages. In other words, when ΔN≦N in P2G, it is determined that the degree of deceleration is small, and in P27, '17r,
= 1 ms, and when ΔN>N, it is determined that the degree of deceleration is large and P2. Set Tr to 2 ms. And basic recovery injection iTr at 22g. is corrected according to the cooling water temperature Tw to determine the final recovery injection TITr.

Next, P. Then, at p3t, the recovery flag RFG is set to indicate the completion of recovery.

In this way, during recovery, the final recovery injection amount Tr is calculated according to the degree of deceleration and the cooling water temperature Tw at that time, and is independent of the normal injection timing that is synchronized with the engine rotation (in other words, it waits for the normal injection timing). Immediately (strictly speaking, in the next routine every 10 m5 after the recovery request), the recovery injection signal Sir is output and recovery is performed when there is a recovery request. Therefore, during recovery, an optimal amount of fuel is always supplied, and the engine output corresponds to the operating state. As a result, it is possible to prevent torque fluctuations and output shortages during recovery, thereby improving drivability.

Note that when the recovery is completed, the recovery flag RFG is set, so recovery is not performed in the first and subsequent routines. Then, when the fuel cut is started again, the recovery flag RFG is reset and the system waits in preparation for the next recovery request. In other words, when there is a recovery request,
Perform recovery once and then shift to normal injection.

FIG. 5 is a flowchart showing a subroutine for calculating the deceleration rotation difference ΔN, and this routine is performed once every LOQms.
Executed once.

First, read the rotation speed N with P,1, and set it to N with P42.
Leave it as new. Next, in P43, the deceleration rotation difference ΔN is calculated according to the following equation (2).

ΔN=No l d-Nne w-■ However, No1
d: N of the previous routine (100mS ago) Then, in P44, the deceleration rotation difference ΔN is stored in the specified address of the RAM 23, and in P45, the current Nnew is NoLd.
The same < is stored in the RAM 23. Therefore, 1
The deceleration rotation difference ΔN is calculated every 00m5.

The degree of deceleration is required.

(Effects) According to the present invention, when the fuel cut is released, an appropriate amount of fuel can be supplied to optimize the engine output corresponding to the operating condition, and torque fluctuations and insufficient output can be prevented and the engine can be improved. Drivability can be improved.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the present invention, FIGS. 2 to 5 are diagrams showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram thereof, and FIG.
FIG. 4 is a flowchart showing a program for calculating the normal injection amount, FIG. 4 is a flowchart showing a program for calculating the recovery injection amount, and FIG. 5 is a flowchart showing a subroutine for calculating the deceleration rotation difference. 1...engine, 4...fuel injection means. 10... Operating state detection means, 11... Control unit (fuel signal generation means, injection amount calculation means, recovery amount calculation means).

Claims (1)

[Scope of Claims] a) Operating state detection means for detecting the operating state of the engine; b) Fuel cut signal generating means for outputting a fuel cut signal when the engine is within a predetermined deceleration operating range; and c) Operation. Injection amount calculation means that calculates a basic injection amount based on the state, outputs an injection signal at a predetermined normal injection timing synchronized with engine rotation, and stops outputting the injection signal when a fuel cut signal is input; d) a recovery amount calculation means that calculates a recovery injection amount according to the deceleration state of the engine when the output of the fuel cut signal is stopped, and outputs the recovery injection signal without synchronizing with the normal injection timing, and c) injection. A fuel injection control device comprising: fuel injection means for injecting fuel based on a signal and a recovery injection signal.