JPS6338632A - Electronically controlled fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To decrease an acceleration shock and/or surge, by holding a fuel arithmetic coefficient to a fixed value and calculating a fuel injection amount so as to suppress a change of the injection amount due to the change of a speed of an engine when it is in transient operation. CONSTITUTION:From signals of a throttle valve opening sensor A and an engine speed sensor, B, an arithmetic coefficient setting means C reads a fuel arithmetic coefficient, for calculating a fuel injection amount, from a ROM to be set. And if a transient operation condition is detected by a transient operation condition detecting means D, device, which reads a fuel arithmetic coefficient in the initial time of transient operation to be held to that value by a holding means E, calculates the injection amount in a fuel injection amount means F by using the held coefficient. In this way, an engine, when it is in transient operation, enables an acceleration shock or the like to be suppressed by preventing the injection amount from changing in accordance with the change of an engine speed even if it is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronically controlled fuel injection device for an internal combustion engine, and particularly to one that calculates a fuel injection amount based on a throttle valve opening and an engine rotational speed.

<Prior Art> Conventional examples of this type of electronically controlled fuel injection device include the following.

That is, data on intake air flow IQ or basic fuel injection amount 'rp corresponding to each operating range is stored in ROM (or RAM) in advance for each of a plurality of operating ranges with throttle valve opening α and engine rotational speed N as parameters. The configuration is such that the data in the corresponding operating range is retrieved from the ROM based on the detected values of the throttle valve opening α and the engine rotational speed N.

When searching for the intake air flow rate IQ, basic injection 1Tp (= to -Q/N;
After calculating the constant), the fuel injection ITi = Tp
Calculate C0EFxα+Ts.

Then, an injection pulse signal corresponding to the calculated fuel injection lTi is output to the fuel injection valve, so that fuel injection 1 is supplied to the engine.

Moreover, when storing the basic injection amount Tp in the ROM,
The basic injection ITp retrieved based on the throttle valve opening α and the engine speed N is substituted into the equation for the fuel injection 1'ri to calculate the fuel injection iTi.

<Problems to be Solved by the Invention> Incidentally, since fuel injection control is performed with good responsiveness depending on the operating state of the engine, for example, when the operation shifts from deceleration to acceleration, the combustion chamber pressure is lowered by the throttle valve [7]. It follows the change of 18 degrees (shown by the solid line in FIG. 4) with good responsiveness and rises rapidly.

As a result, the engine output tries to increase rapidly, but the vehicle is unable to respond to the increase and the vehicle torsional vibration (
Jittery vibrations occur between the direction the vehicle is traveling and the direction it is reversing.
Along with this, the engine rotational speed also fluctuates greatly for a short period of time as shown in Figure 4 (during the maximum fluctuation, it is approximately 40 Or, p, m).
,).

Therefore, when the intake air flow IQ is retrieved from the ROM based on the detected throttle valve opening and the interstage rotation speed, the retrieved intake air flow 1iQ also changes approximately in synchronization with the engine rotation speed, as shown in FIG. do.

For this reason, there is a problem in that the fuel injection iTi also fluctuates substantially in synchronization with the engine rotational speed as shown in FIG. 4, which aggravates acceleration shock and surge.

Also, when the engine shifts to deceleration operation immediately after acceleration operation, the engine rotational speed changes to 1? for a short period of time, as shown in FIG. n fluctuates greatly, and there is a problem similar to that during accelerated driving.

Furthermore, the intake air flow I
Q or basic injection ff1Tp in ROM (or RAM)
Therefore, it is necessary to perform interpolation calculations so that the data near the boundaries of adjacent operating regions are accurate. However, if the above interpolation calculation is omitted in order to increase the calculation speed of the fuel injection amount, the throttle valve opening or engine speed detected during acceleration operation as shown in the middle part of Fig. 6 may fall within the operating range of the ROM. If the intake air flow iQ or the basic injection ff1Tp is held near the boundary for a predetermined time, the intake air flow iQ or the basic injection ff1Tp that is searched at this time fluctuates between the two speed ranges, causing the same problem as above.

The present invention has been made in view of the above circumstances, and provides an electronically controlled fuel injection device that can suppress fluctuations in fuel injection amount and suppress acceleration shock, etc. even when engine rotational fluctuations occur during transient operation. The purpose is to

Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention includes a throttle valve opening detection means A for detecting the throttle valve opening of an engine;
A rotational speed detection means B that detects the rotational speed of the engine, and a calculation coefficient setting means C that sets a fuel calculation coefficient for calculating the fuel injection amount according to the detected throttle valve opening and the detected engine rotational speed. and a transient operating state detection means for detecting a transient operating state of the engine; when a transient operating state is detected, a predetermined value at the initial stage of the transient operation of the fuel calculation coefficient that changes during the transient operation is read and the predetermined value is determined. The fuel is injected according to the fuel calculation coefficient held by the holding means E which is held at Fuel injection amount calculation means F that calculates the amount
and a drive control means H for driving and controlling the fuel injection valve G in accordance with the calculated fuel injection amount.

In this way, during transient operation, the fuel injection amount is calculated according to the held fuel calculation coefficient, and even if the actual engine speed changes, fluctuations in the fuel injection amount are suppressed11. .

<Example> An example of the present invention will be described below with reference to FIGS. 2 and 3.

In the figure, a control device 1 consisting of a microcomputer, etc. includes a rotation speed sensor 2 as a rotation speed detection means for detecting the engine rotation speed, and a throttle valve opening detection means for detecting the opening of a throttle valve (not shown). Detection signals are inputted from a throttle valve opening sensor 3 as means for detecting a transient operating state, and a water temperature sensor 4 for detecting engine cooling water temperature.

The control device 1 operates according to the flowchart shown in FIG. 3 and outputs a drive pulse signal to the fuel injection valve 5 via the drive circuit 6.

Here, the control device 1 constitutes a holding means, a calculation coefficient setting means, and a fuel injection amount calculation means, and the control device 1 and the drive circuit 6 constitute a drive control means.

Next, the operation will be explained according to the flowchart shown in FIG.

At Sl, various signals such as the throttle valve opening α2 detected by the throttle valve opening sensor 3 and the engine rotational speed N detected by the rotational speed sensor 2 are read.

In S2, 1. is written in the ROM based on the detected throttle valve opening α and engine rotational speed N. Intake airflow made -
Data on the intake air flow-IQ as a fuel calculation coefficient corresponding to the relevant operating region is retrieved from the IQ three-dimensional map table.

In S3, it is determined from the opening speed of the throttle valve whether or not the accelerating operation is in progress. If YES, the process proceeds to S4; if NO, the process proceeds to S6.

Incidentally, the acceleration driving state may be detected by the rate of change of basic injection ff1Tp, the rate of change of intake air flow rate, the rate of change of boost pressure, etc., which will be described later.

In S4, it is determined whether or not the intake air flow IQ retrieved at the beginning of the acceleration operation has reached the maximum intake air flow QMAX for the first time. If YES, the process advances to S5 and N.

When this happens, the process advances to S6.

Here, the maximum intake air flow rate Q14AX is determined by, for example, the previous intake air flow rate FJQ, which is searched at each predetermined timing.
Let the previous intake air flow IQ when the difference between the current intake air flow rate Q and the current intake air flow rate Q become negative be the maximum intake air flow ffiQMAX. For example, in FIG. 4, point B is the maximum intake air flow rate QMAx.

In S5, the set maximum intake airflow ff(Q, Ax
is stored in RAM or the like.

In S6, the intake air flow IQ or S retrieved in S2 is
Maximum intake air flow memorized in 5 FI Q s A x
Based on the detected engine rotational speed N, the basic injection amount 'rp is calculated and set using the following equation.

Tp=to-Q(QA)/N (K is a constant) In S7,
Various correction coefficients C0FF to be multiplied by the 'rp are calculated based on the engine cooling water temperature and the like.

In S8, the voltage correction numerator s is calculated based on the voltage value of the battery.
Set.

In S9, the final fuel injection fiTi is calculated using the following equation.

T i =Tp xCOEF+Ts In S10, a drive pulse signal having a pulse width corresponding to Ti calculated in S9 is output to the fuel injection valve 5 via the drive circuit 6.

As a result, the fuel injection valve 5 is energized for a predetermined period of time, and fuel in an amount corresponding to Ti is injected and supplied to the engine.

Therefore, during acceleration operation after the intake air flow rate reaches the maximum value, the memorized maximum intake air flow rate Q1. IA
Fuel injection lTi is calculated based on K, and during other operations, fuel injection amount Ti is calculated based on intake air flow jlQ retrieved from throttle valve opening and engine rotational speed.

As explained above, during acceleration operation, the fuel injection amount T
Since i is calculated, it is possible to suppress fluctuations in the fuel injection amount when the actual engine rotational speed fluctuates or when interpolation calculations are not performed, reducing acceleration shocks and surges, as well as reducing acceleration response delays and breathing. can be suppressed.

Although the present embodiment describes the case where the intake air flow rate is searched, the present invention can also be applied to the case where the basic injection amount is searched. Further, although the maximum intake air flow rate is held at QMAX, it may be held at a value other than the maximum value. Also,
The present invention can also be applied during deceleration operation.

<Effects of the Invention> As explained above, the present invention calculates the fuel injection amount according to the fuel calculation coefficient that is held constant during transient operation, so that the actual engine speed does not fluctuate during transient operation. Therefore, it is possible to suppress fluctuations in the fuel injection amount even when the engine is in use, thereby suppressing acceleration shocks, surges, etc.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is a diagram corresponding to the claims of the same,
FIG. 4 is a diagram for explaining the operation of the embodiment and the conventional drawbacks, and FIGS. 5 and 6 are diagrams for explaining the conventional drawbacks, respectively. 1...Control device 2...Rotation speed sensor 3.
... Throttle valve opening sensor 5 ... Fuel injection valve 6
... Drive circuit patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima N Yen

Claims (1)

[Claims] A throttle valve opening detection means for detecting the throttle valve opening of the engine, a rotation speed detection means for detecting the rotational speed of the engine, and a fuel injection amount according to the detected throttle valve opening and the detected engine rotational speed. a calculation coefficient setting means for setting a fuel calculation coefficient for calculating the engine; a transient operation state detection means for detecting a transient operation state of the engine; holding means for reading a predetermined value of the coefficient at the initial stage of the transient operation and holding it at the predetermined value; and a holding means for reading the predetermined value of the coefficient at the initial stage of the transient operation, and the arithmetic coefficient setting means according to the held fuel calculation coefficient during the transient operation except for the initial stage, and according to the calculation coefficient setting means during other operating conditions. A fuel injection amount calculating means for calculating a fuel injection amount according to a set fuel calculation coefficient, and a drive control means for driving and controlling a fuel injection valve according to the calculated fuel injection amount. Electronically controlled fuel injection system for internal combustion engines.