JP2896411B2 - Engine fuel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel control apparatus for an engine that injects fuel asynchronously regardless of crank angle when a change in intake air amount is large during acceleration or the like.

[0002]

2. Description of the Related Art In a fuel injection type engine, an optimum fuel injection amount is calculated in accordance with the operating state of the engine, and an injection pulse having a pulse width corresponding to the calculated injection amount is output to an injector, and a crankshaft is driven. It is common to supply fuel by so-called synchronous injection of angular synchronization. Also, as described in, for example, Japanese Patent Application Laid-Open No. Sho 60-132033, at the time of acceleration, at the time of starting, at the time of returning from deceleration fuel cut, and the like, in addition to the above-described synchronous injection, the crank angle and Regardless, the injection of fuel is performed asynchronously.

Further, as described in Japanese Patent Application Laid-Open No. 1-116268, a shift is detected because the effect of the actual increase in acceleration cannot be expected even if the fuel is increased during acceleration accompanied by upshifting. Attempts are sometimes made to limit the increase in acceleration, but especially in the case of a manual transmission type vehicle, an overshoot or undershoot occurs in the air flow meter due to the driver's accelerator operation at the time of gear change. For this reason, there is a possibility that the traveling performance may be deteriorated due to an over-rich tendency. Therefore, in order to prevent the over-rich tendency from being promoted, it is necessary to cancel the increase in acceleration or the like at the time of shifting.
Therefore, as described above, when increasing the acceleration by the asynchronous injection, the asynchronous injection is canceled at the time of shifting, and
A control method has been proposed in which asynchronous injection is executed after overshoot of the air flow meter or the like has subsided.

[0004]

In an engine in which the amount of acceleration is increased by asynchronous injection or the like, the asynchronous injection is canceled at the time of shifting as described above, thereby suppressing the over-rich tendency of the air-fuel ratio due to overshoot of the air flow meter or the like. However, in the conventional proposal, the asynchronous injection is canceled simply by detecting the shift, so that the asynchronous injection is canceled even in the case of a gear change that requires running such as full-open acceleration. As a result, even if the air-fuel ratio required for the running request cannot be obtained, the running performance may be adversely affected, such as occurrence of backlash.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to prevent an adverse effect on traveling performance when a driving request is made by canceling asynchronous injection at the time of shifting.

[0006]

As shown in FIG. 1, an engine fuel control apparatus according to the present invention comprises an intake air amount detecting means for detecting an intake air amount of an engine, and an intake air amount detecting means. Means for calculating the change in the amount of intake air, receiving the output of the control unit, and determining the asynchronous injection request state when the calculated change in the amount of intake air is greater than or equal to the first threshold value, and sending an asynchronous injection signal to the injector. An asynchronous injection signal generating means for outputting, a shift signal of the transmission, an asynchronous injection canceling means for canceling the asynchronous injection signal at the time of shifting, and a second change in the intake air amount larger than the first threshold value. A cancel canceling means for canceling cancellation of the asynchronous injection signal by the asynchronous injection canceling means when the threshold value is equal to or more than the threshold value is provided.

[0007]

The intake air amount is detected by the intake air amount detection means, and the change in the intake air amount is calculated by the intake air amount change calculation means. When the change is equal to or greater than a preset first threshold value, the asynchronous injection request is made. When the state is determined, the asynchronous injection signal is output to the injector by the asynchronous injection signal generating means, and the increased fuel is supplied to the engine by the asynchronous injection. However, during shifting, the asynchronous injection signal is canceled by the asynchronous injection canceling means, and the asynchronous injection is prohibited. If the change in the intake air amount is equal to or greater than a second threshold value larger than the first threshold value, the cancellation of the asynchronous injection signal is canceled by the cancel canceling means, and the asynchronous injection is executed.

[0008]

Embodiments will be described below with reference to the drawings.

FIG. 2 is an overall system diagram of one embodiment of the present invention. In this embodiment, an injector 4 is disposed downstream of an intake passage 3 communicating with an intake port 2 of an engine 1. A surge tank 5 is formed in the intake passage 3 upstream of the injector 4. A throttle valve 6 is provided upstream of the surge tank 5, and an air flow meter 7 is provided upstream of the surge tank 5. Is connected to an air cleaner 8. In addition, a bypass passage 9 that bypasses the throttle valve 6 is formed in the intake passage 3, and an idle speed control valve (ISC valve) 10 is provided in the middle of the bypass passage 9.

An O ₂ sensor 13 for detecting oxygen concentration in exhaust gas is provided in an exhaust passage 12 communicating with an exhaust port 11 of the engine 1, and a catalytic converter 14 is connected downstream of the O ₂ sensor 13.

In order to control the injector 4, the ISC valve 10, etc., the engine 1 is equipped with a control unit 15 composed of a microcomputer.
The control unit 15 receives an engine rotation signal from a rotation sensor (not shown), an intake air amount signal from the air flow meter 7, an idle switch signal from an idle switch 16 attached to the throttle valve 6, and a signal from the throttle sensor 17. Throttle opening signal,
Engine coolant temperature signal from the water temperature sensor 18, the air-fuel ratio signal from the O ₂ sensor 13, the shift signal or the like representing the gear change of a transmission (not shown) is input as information. In the control unit 15, the fuel injection amount is set by a well-known calculation based on the various kinds of input information as described above, or the control amount of the ISC valve is set.

Under the control of the injector 4 by the control unit 15, during normal operation, fuel is injected into the intake passage 3 of the engine 1 in synchronization with the crank angle. Then, when the intake air amount change (dVS) becomes equal to or more than the first threshold value (KGTAVM), in addition to synchronous injection, asynchronous injection irrespective of the crank angle is performed. Further, as shown in FIG. 3A, the shift signal (Xgr)
in) changes from on (gear-in) to off (gear-off), a cancel time (VS asynchronous inhibition time after change: Cgrind) is set. During this cancel time, asynchronous injection is performed even if dVS is equal to or greater than the above KGT AVM. The pulse is canceled. However, when dVS becomes equal to or more than a second threshold value (KGTAVMH) larger than KGTAVM even during the cancel time, the Cgrind is reset (RESET),
Asynchronous injection is executed by canceling the cancellation of the asynchronous injection pulse. FIG. 3B shows the RESET for comparison.
3 shows the control characteristics when the control is not performed. In this case, during the cancellation time, dVS may be KGTAVMH
Even with the above, the asynchronous injection pulse (shown by a broken line) is canceled.

FIG. 4 is a flowchart for executing the above control of this embodiment. In addition, S1 to S10 indicate each step.

In the flow of FIG. 4, when started, S
1, the feedback zone (XZf
b) Set the zone of the high load increase zone (XZer) or the deceleration fuel cut return increase zone (XZdec) and set a flag. Then, in S2, it is checked whether or not it is idle (Idle SW = 0), and if it is not idle, it goes to S3.

In S3, the current value of the change in the intake air amount (dV
S [i]) is equal to or greater than a first threshold value (KGTAVM). If YES, then in S4,
Further, the previous value of the change in the amount of intake air (dVS [i-1])
Is greater than or equal to KGTAVM. If this time and the previous time are KGTAVM or more, the process goes to S5 to check whether the prohibition time (the prohibition time after VS asynchronous execution: Catinh) set when the previous non-synchronous injection was performed is over, and the process is over. If so, go to S6.

In S6, it is determined whether or not the cancel time of the asynchronous injection has expired (Cgrind = 0). If it has been completed, the process proceeds to S7 to execute asynchronous injection (VS asynchronous).

If NO in S6, that is, if it is during the cancel time, the process goes to S8, where the current value (dVS [i]) of the change in the intake air amount is changed to the second threshold value (KGTAV).
MH) or not, and if YES,
Next, in S9, the previous value (dV
S [i-1]) is checked to see if it is greater than or equal to KGTAVMH.
Then, if this time and the previous time are KGTAVMH or more, S
At 10, Cgrind is reset, and the process proceeds to S7 to execute asynchronous injection.

If NO is determined in any of the steps S2 to S5 and S8, S9, the flow ends.

[0019]

Since the present invention is configured as described above, when canceling the asynchronous injection at the time of shifting, the air-fuel ratio required for the running request cannot be obtained, and the running performance is adversely affected, such as occurrence of backlash. Can be prevented from reaching.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is an overall system diagram of an embodiment of the present invention.

FIG. 3 is a time chart illustrating control characteristics of the embodiment.

FIG. 4 is a flowchart for executing control of the embodiment.

[Explanation of symbols]

 1 engine 4 injector 7 air flow meter 15 control unit

Continuation of front page (56) References JP-A-58-57035 (JP, A) JP-A-59-90768 (JP, A) JP-A-2-201049 (JP, A) JP-A-2-271043 (JP) , A) Japanese Utility Model Showa 62-162361 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 41/34 F02D 41/04

Claims (1)

(57) [Claims] 1. An intake air amount detecting means for detecting an intake air amount of an engine, an intake air amount change calculating means for receiving an output of the intake air amount detecting means and calculating a change in an intake air amount, and a calculated intake air. An asynchronous injection signal generating means for determining an asynchronous injection request state and outputting an asynchronous injection signal to an injector when the amount change is equal to or more than a first threshold value; receiving a shift signal of a transmission; Canceling canceling the asynchronous injection signal by the asynchronous injection canceling means when the change in the amount of intake air is equal to or greater than a second threshold greater than the first threshold. A fuel control device for an engine, characterized by comprising means.