JPH0792007B2 - Electronically controlled fuel injection type internal combustion engine interrupt injection control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interrupt injection control device for an electronically controlled fuel injection type internal combustion engine, and more specifically, to an interrupt injection amount based on a rate of opening change of a throttle valve. Relates to an interrupt injection control device.

<Prior Art> As an electronically controlled fuel injection internal combustion engine, there are the following conventional ones.

That is, the basic fuel injection amount Tp (= K × Q / N; K is a constant) is calculated from the intake air flow rate Q detected by the air flow meter and the engine rotation speed N detected by the crank angle sensor, and the cooling is performed. Various correction factors COEF and air-fuel ratio feedback correction factor α depending on engine operating conditions such as water temperature Tw
After calculating the correction amount Ts from the battery voltage and the battery voltage, the final fuel injection amount Ti (= Tp × COEF × α + Ts) is calculated. Then, an injection pulse signal having a pulse width corresponding to the fuel injection amount Ti is output at a predetermined timing to an electromagnetic fuel injection valve provided for each cylinder to inject and supply a predetermined amount of fuel to the engine. ing.

By the way, although the various correction coefficients COEF include those that include an increase correction coefficient during acceleration, in order to compensate for the response delay of the fuel injection amount control during acceleration, so-called interrupt injection is performed to improve the response during acceleration. (Japanese Patent Application No. 61-0811)
See No. 87).

Specifically, the opening degree θ of the throttle valve is detected for a predetermined sampling time (for example, 10 ms), and when the opening degree changes more than a predetermined value from the idle state (throttle valve fully closed state), the engine is in the acceleration state. It is determined that there is an injection pulse signal with a pulse width corresponding to the change rate Δθ of the throttle valve opening θ detected at the first time of this acceleration determination (the interrupt injection amount is set in advance in correspondence with the change rate Δθ. The fuel injection amount Ti
The output is made by interrupting the injection pulse signal corresponding to.

<Problems to be Solved by the Invention> However, in such a conventional interrupt injection control,
Since simultaneous interrupt injection was performed for all cylinders when the engine acceleration condition was detected, the intake valve actually opened and the fuel injected by interrupt injection into the cylinders, especially when the engine speed was low. A cylinder that takes a long time to appear appears, and the optimal amount of interrupt injection cannot be performed.

That is, in the cylinder that is in the intake stroke during the interrupt injection, the interrupt injection fuel corresponding to the engine acceleration state (specifically, the throttle valve opening change rate Δθ) at that time is immediately supplied to the cylinder. However, in a cylinder in which the intake stroke is delayed after the interrupt injection is performed, the interrupt injection amount is the current engine acceleration state when the interrupt injection fuel is actually supplied into the cylinder. The fuel injection amount is not the fuel amount required by the engine but the interrupt injection amount based on the old acceleration state data.
Therefore, if the engine-requested interrupt injection amount increases after the acceleration is determined and the interrupt injection is performed (when the engine gradually changes from the slow acceleration state to the rapid acceleration state), it is possible to follow this. It is not possible to do so, the air-fuel ratio becomes over lean, and the acceleration shock due to misfire and deterioration of exhaust properties (increase of NOx in nitrogen oxides)
There was a problem that there was a fear of causing problems such as.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the accelerating performance of an engine by enabling an interrupt injection at the time of acceleration corresponding to a required amount of the engine.

<Means for Solving Problems> Therefore, in the present invention, as shown in FIG. 1, engine operating state detecting means for detecting the operating state of the engine, and fuel injection based on the engine operating state detected thereby An electronic device including a fuel injection amount setting means for setting an amount and an injection pulse signal output means for outputting an injection pulse signal corresponding to the fuel injection amount set by the fuel injection valve to a fuel injection valve provided for each cylinder. In a controlled fuel injection type internal combustion engine, a throttle valve opening change rate detecting means for detecting an opening change rate of an opening side of a throttle valve interposed in an intake passage of the engine at predetermined time intervals, and intake air of each cylinder. Intake-stroke cylinder detecting means for detecting a predetermined crank angle during a stroke, and the throttle valve opening change rate detection when the predetermined crank angle during an intake stroke of a predetermined cylinder is detected by the intake-stroke cylinder detecting means An interrupt injection amount setting means for setting an interrupt injection amount for the predetermined cylinder based on the latest throttle valve opening change rate detected by the means, and an interrupt injection pulse corresponding to the interrupt injection amount set by the interrupt injection amount setting means. And an interrupt injection pulse signal output means for outputting a signal to the fuel injection valve of the predetermined cylinder.

<Operation> According to the interrupt injection control device having such a configuration, interrupt injection is not performed simultaneously for all cylinders, but the latest throttle valve opening degree at that time at a predetermined crank angle during the intake stroke in each cylinder. Interrupt injection is performed according to the rate of change. That is, since the interrupt injection amount for the cylinder is set according to the engine acceleration state when the fuel injected by the interrupt injection is sucked into the cylinder, it is possible to perform the interrupt injection corresponding to the required amount of the engine. Is.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 2 is a system diagram of the electronically controlled fuel injection type internal combustion engine according to the present embodiment.

The distributor 2 attached to the internal combustion engine 1 has a photoelectric crank angle sensor 3 built therein. The crank angle sensor 3 includes a signal plate 5 that rotates integrally with the distributor shaft 4 and a detection unit 6. The signal plate 5 has 360 at equal intervals.
Slits 7 for position signals Pos (unit angle pulse signal for each 1 °) and four reference signals Ref for four cylinders (reference angle pulse signals for every 180 ° for four cylinders, and compression for each cylinder) The slit 8 is formed so as to emit a pulse 70 ° before the top dead center). The detection unit 6 detects these slits 7 and 8 and outputs a position signal Pos and a reference signal Ref, which are pulse signals having a pulse width corresponding to a predetermined crank angle.

The output of the crank angle sensor 3 is input to a control unit 9 having a built-in microcomputer, and the control unit 9 measures the number of times the position signal Pos is input per unit time or the cycle of the reference signal Ref to determine the engine rotation speed N. And the basic fuel injection amount Tp (= K × Q / N; K) based on the engine speed N and the intake air flow rate Q detected by the air flow meter 10.
Is a constant). And this basic fuel injection amount Tp
Is corrected based on the engine operating state such as the engine cooling water temperature to set the final fuel injection amount Ti, and the injection pulse signal of the pulse width corresponding to this fuel injection amount Ti is set to the electromagnetic fuel of each cylinder. The fuel is output to the injection valve 12 at a predetermined timing to inject and supply a predetermined amount of fuel to the engine.

That is, the engine operating state detecting means in this embodiment corresponds to the crank angle sensor 3 and the air flow meter 10, and the control unit 9 also serves as the fuel injection amount setting means and the injection pulse signal output means.

Further, the control unit 9 controls the basic fuel injection amount.
In order to cause spark ignition by the spark plug 12 at a predetermined ignition timing set based on Tp and the engine speed N, the position signal Pos is counted from the ignition reference signal set based on the reference signal Ref, and the count number is When the number of times corresponding to the predetermined time is reached, the power transistor 14 attached to the ignition coil 13 is controlled to control the high voltage generation time of the ignition coil 13.

Further, the control unit 9 controls the reference signal R
Every time ef is input, the interrupt injection for the cylinder in the intake stroke at that time is controlled based on the throttle valve opening change rate Δθ. The interrupt injection control will be described with reference to the flowcharts of FIGS. 3 and 4. Here, the control unit 9 constitutes the throttle valve opening change rate detecting means by the throttle valve opening sensor 16 and the intake stroke cylinder detecting means by the crank angle sensor 3, and the interrupt injection amount. It also serves as setting means and interrupt injection pulse signal output means.

The flowchart of FIG. 3 is executed each time the reference signal Ref from the crank angle sensor 3 is input to the control unit 9.

When the reference signal Ref is input, in step (“S” in the figure, the same applies hereinafter) 1, during the intake stroke from the cylinder 70 ° before the compression top dead center position indicated by the reference signal Ref. Identify a cylinder. As shown in FIG. 5, in the case of four cylinders (# 1 to # 4), for example, #
If 2 is 70 ° before the compression top dead center position, # 1 is during the intake stroke (the intake valve is open).

When it is determined in step 1 which cylinder is in the intake stroke, in step 2, the throttle valve opening change rate Δθ calculated every predetermined minute time (5 ms) as shown in the flowchart of FIG.
Enter the latest data for.

The Δθ calculation routine of FIG. 4 is executed every predetermined minute time (5 ms) as described above, and when the throttle valve opening θ detected by the throttle valve opening sensor 16 in step 10 is input, In the next step 11, the opening change rate Δθ of the throttle valve 15 per unit time is calculated from this opening θ and the previously input opening θ.

When the throttle valve opening change rate Δθ is input in step 2, it is determined in step 3 whether the engine 1 is in an accelerating state based on this Δθ. That is, when Δθ indicates that the throttle valve 15 is changing to the open side at a rate higher than the predetermined value, it is determined that the engine 1 is in the acceleration state.

If it is determined that the engine 1 is in the accelerating state, the routine proceeds to step 4 to search for the interrupt injection amount Tinj. The microcomputer incorporated in the control unit 9 stores the interrupt injection amount Tinj in advance in association with the throttle valve opening change rate Δθ, and interrupts as the throttle valve opening change rate Δθ increases and during rapid acceleration. Injection amount Tin
The j is set to be large.

When the interrupt injection amount Tinj is set, the fuel injection valve 12 provided in the corresponding cylinder (the cylinder in the intake stroke determined in step 1) is set in step 5 for interrupt injection.

On the other hand, when it is determined in step 3 that the engine 1 is not in the acceleration state, the interrupt injection is not performed and the engine is directly returned.

By the above interrupt injection control, the injection pulse signal as shown in FIG. 5 is output to the fuel injection valve 12 of each cylinder. That is, for example, when the injection timing is controlled such that the injection pulse signal corresponding to the normal fuel injection amount Ti ends at the beginning of opening the intake valve, the intake valve is opened and 70 ° before the bottom dead center of the intake stroke ( When the reference signal Ref is input), the acceleration judgment is made based on the latest data of the throttle valve opening change rate Δθ, and when the acceleration judgment is made, the interrupt injection amount Tinj is set according to the Δθ and the interruption is performed. A jet is made.

Therefore, even though the interrupt injection is performed for each cylinder, the interrupt injection amount Tinj is set for each cylinder based on the latest data of the throttle valve opening change rate Δθ. That is, as shown in FIG. 5, after the interrupt injection is performed on # 1 according to Δθ (# 1) in the first acceleration determination, the latest injection is performed when the interrupt injections on # 3 and # 4 are performed. Based on the data Δθ (# 3) and Δθ (# 4), the interrupt injection amount Tinj of the cylinder in the intake stroke at that time is set, so that, for example, Δθ (# 1)
Therefore, even if Δθ largely changes, the interrupt injection is executed corresponding to the change in the acceleration state.

As a result, it is possible to perform the interrupt injection corresponding to the required amount of the engine 1 at the time of acceleration, avoid over-leaning of the air-fuel ratio, and prevent acceleration shock, deterioration of exhaust characteristics, and the like.

<Advantages of the Invention> As described above, according to the present invention, the air-fuel ratio can be controlled to a desired value by securing the interrupt injection amount commensurate with the required amount of the engine in the accelerating state of the engine. There is an effect that it is possible to prevent the occurrence of troubles such as acceleration shock and deterioration of exhaust property by avoiding the change.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a system diagram showing an embodiment of the present invention, FIG. 3 is a flowchart showing an interrupt injection control routine in the same embodiment, and FIG. 4 is in the same embodiment. FIG. 5 is a flowchart showing a calculation routine of the throttle valve opening change rate, and FIG. 5 is a time chart showing the generation timing of the injection pulse signal in the above embodiment. 1 ... Engine, 3 ... Crank angle sensor, 9 ... Control unit, 10 ... Air flow meter, 11 ... Fuel injection valve, 15 ... Throttle valve, 16 ... Throttle valve opening sensor

Claims (1)

[Claims] 1. An engine operating state detecting means for detecting an operating state of the engine, a fuel injection amount setting means for setting a fuel injection amount based on the detected engine operating state, and a fuel injection amount corresponding to the set fuel injection amount. In an electronically controlled fuel injection internal combustion engine equipped with an injection pulse signal output means for outputting an injection pulse signal to a fuel injection valve provided for each cylinder, the injection pulse signal output means is provided in an intake passage of the engine at predetermined predetermined time intervals. Throttle valve opening change rate detecting means for detecting the opening change rate of the throttle valve, intake stroke cylinder detecting means for detecting a predetermined crank angle during the intake stroke of each cylinder, and intake stroke of the predetermined cylinder The interrupt injection amount for the predetermined cylinder is set based on the latest throttle valve opening change rate detected by the throttle valve opening change rate detecting means when the predetermined crank angle is detected. And an interrupt injection pulse signal output means for outputting an interrupt injection pulse signal corresponding to the set interrupt injection amount to the fuel injection valve of the predetermined cylinder. An interrupt control device for an electronically controlled fuel injection type internal combustion engine.