JPS6338633A - Electronically controlled fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To suppress an acceleration shock or the like, by holding a detection engine speed to a fixed value while using a value of this detection engine speed, held to the fixed value, and calculating a fuel injection amount so as to suppress a change of the injection amount in accordance with the change of the engine speed when an engine is in transient operation. CONSTITUTION:An injection amount is calculated by a fuel injection amount arithmetic means E from signals of a throttle valve opening sensor A and an engine speed sensor B. And if a condition of acceleration and deceleration is detected by an acceleration and deceleration detecting means C, a device, in which an engine speed holding means D holds a detection engine speed to the initial time value when an engine is accelerated and decelerated, calculates the injection amount of fuel by using a value of this detection engine speed held to the initial time value. In this way, an acceleration shock or the like is suppressed by preventing the injection amount from changing in accordance with the change of the speed of the engine when it is accelerated and decelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> 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 rotation speed.

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

That is, data on the intake air flow rate Q or the basic fuel injection amount 'rp corresponding to each operating range is stored in the ROM (or RAM) in advance for each of a plurality of operating ranges using the throttle valve opening α and the 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 iQ, the basic injection ff1Tp (=to -Q/
After calculating N; is a constant), fuel injection possible 1 = TpX
Calculate cOEFXα+Ts.

Then, an injection pulse signal corresponding to the calculated fuel injection amount Ti is output to the fuel injection valve to inject and supply fuel 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 rotational speed N is substituted into the formula for the fuel injection amount Ti to calculate the fuel injection amount Ti.

<Problems to be Solved by the Invention> By the way, fuel injection control is performed with good responsiveness depending on the operating state of the engine. For example, when transitioning from deceleration to acceleration, the combustion chamber pressure changes depending on the throttle valve opening (the first It follows the change in the curve (shown by the solid line in Figure 4) with good responsiveness and rises rapidly. As a result, the engine output attempts to increase rapidly, but the vehicle is unable to respond to this increase with good response, resulting in vehicle torsional vibration (jerky vibration between the forward and backward directions of the vehicle), which causes the engine to rotate. The speed also fluctuates greatly over a short period of time as shown in Figure 4 (approximately 40 Or, p, m, during maximum fluctuation).
.

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

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

Furthermore, when the engine is shifted to deceleration immediately after acceleration, the engine rotational speed fluctuates greatly for a short period of time as shown in FIG. 5, causing the same problem as during acceleration.

Furthermore, since the intake air flow rate Q or the basic injection amount Tp is stored in the ROM (or RAM) for each operating region in which parameters are a throttle valve opening of a predetermined width and an engine speed of a predetermined width, 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 speed up the calculation speed of the fuel injection amount,
When the detected throttle valve opening or engine rotational speed is maintained near the boundary of the ROM operating range for a predetermined period of time as shown in FIG. It varies between regions and has the same problems 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 rotation speed detection means B detects the rotation speed of the engine, an acceleration/deceleration operation state detection means C detects the acceleration/deceleration operation state of the engine, and an engine rotation detected when the acceleration/deceleration operation state is detected. A rotational speed holding means for setting and maintaining a predetermined engine rotational speed constant in a period from immediately before the start of acceleration/deceleration operation to immediately after the start of acceleration/deceleration operation based on the speed, Fuel injection is calculated according to the detected engine rotational speed and the detected throttle valve opening, and in other operating conditions, fuel injection is calculated according to the detected engine rotational speed and the detected throttle valve opening. The fuel injection amount calculation means E which calculates the injection amount and the drive control means G which drives and controls the fuel injection valve F according to the calculated fuel injection amount are provided.

<Operation> In this way, during acceleration/deceleration operation, the fuel injection amount is calculated at least initially based on the constant engine rotation speed and the detected throttle valve opening, and even if the actual engine rotation speed fluctuates, the fuel injection amount is calculated. Fluctuations in injection amount were suppressed.

<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). a throttle valve opening sensor 3 as means and means for detecting acceleration/deceleration operating conditions;
Detection signals are input from a neutral switch 4 that detects the presence or absence of a neutral state, and a water temperature sensor 5 that detects 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 6 via the drive circuit 7.

Here, the control device 1 constitutes a rotational speed holding means and a fuel injection amount calculation means, and the control device 1 and the drive circuit 7 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 α1 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, it is determined whether the neutral switch 4 is ON or not. If YES, the process proceeds to S3, and if NO, the process proceeds to S4. At this point, neutral switch 4 is turned on (YE
S), it is determined that the engine side and the driving wheel side are disconnected in the neutral state, and no external load (driving force) is acting on the engine, and the neutral switch 4 is OFF.
When the result is (No), it is determined that the engine side and the driving wheel side are connected and that an external load is acting on the engine. Note that the external load may be detected from the on/off state of the clutch and the presence or absence of the neutral state.

In S3, 3 of the intake air flow rate Q stored in the ROM is calculated based on the detected throttle valve opening α and engine rotational speed N.
Data on the intake air flow rate Q corresponding to the relevant operating region is retrieved from the dimensional map table.

In S4, it is determined from the opening speed of the throttle valve whether or not the acceleration/deceleration operation is in progress. If YES, the process proceeds to S5; if NO, the process proceeds to S3.

Incidentally, the acceleration/deceleration operating state may be detected by the rate of change in the basic injection amount 'rp, the rate of change in the intake air flow rate, the rate of change in the boost pressure, etc., which will be described later.

In S5, it is determined whether or not the engine rotational speed is read for the first time after the start of acceleration/deceleration operation. If YES, the process proceeds to S6, and if NO, the process proceeds to S7.

In S6, the engine rotation speed N read first after the start of acceleration/deceleration operation (the engine rotation speed immediately after the start of acceleration/deceleration operation) is stored in the RAM.

In S9, a predetermined period of time (for example, 0.
5 seconds) (first jIA of acceleration/deceleration operation), and if YES, proceed to S8; if NO, proceed to S3.

In S8, the intake air flow rate Q is retrieved from the three-dimensional map table based on the memorized engine rotation speed N1 and the detected engine rotation speed.

In S9, the basic injection ITp is calculated and set based on the following equation based on the intake air flow IQ retrieved in S3 or S8 and the detected engine rotational speed N.

TI)=-Q(QA)/N (K is a constant) In S10, various correction coefficients C0EF to be multiplied by the 'rp are calculated based on the engine cooling water temperature and the like.

In Sll, the voltage correction numerator 3 is set based on the voltage value of the battery.

In S12, the final fuel injection lTj is calculated using the following equation.

T i =Tp

As explained above, within a predetermined period of time after the start of acceleration/deceleration operation, the intake air flow rate is determined based on the engine rotational speed, which is stored and held constant immediately after the start of acceleration/deceleration operation, and the detected throttle valve opening. Since the search is performed, even if the actual engine speed changes, fluctuations in the retrieved intake air flow rate can be suppressed. As a result, fluctuations in the fuel injection amount can be suppressed, shocks and surges during acceleration and deceleration operations can be suppressed, and acceleration response delay or breathing can be suppressed.

Here, since the engine rotation speed during acceleration/deceleration operation does not immediately increase, even if the engine rotation speed is maintained at a substantially constant value, the acceleration/deceleration operation characteristics are not affected.

Note that the intake air flow rate may be searched from the engine rotational speed immediately before the start of acceleration/deceleration operation. Further, the control may be performed on only one of acceleration and deceleration.

<Effects of the Invention> As explained above, the present invention calculates the fuel injection amount based on the engine rotational speed, which is held constant at least at the initial stage of the acceleration/deceleration operation state, and the detected throttle valve opening. As a result, even if the actual engine speed changes during acceleration/deceleration operation, fluctuations in fuel injection amount can be suppressed, thereby reducing acceleration shock.

Surges, etc. can be suppressed.

[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,
FIGS. 4 to 6 are diagrams for explaining the drawbacks of the conventional technology. 1...Control device 2...Rotation speed sensor 3.
...Throttle valve opening sensor 6...Fuel injection valve 7
... Drive circuit patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima NCv>,, around t

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 rotation speed of the engine, an acceleration/deceleration operation state detection means for detecting the acceleration/deceleration operation state of the engine,・Rotational speed holding means that sets and maintains a predetermined engine rotational speed constant during a period from immediately before the start of acceleration/deceleration operation to immediately after the start of acceleration/deceleration operation based on the engine rotational speed detected when the deceleration operation state is detected; At least in the initial stage of the acceleration/deceleration operating state, fuel injection is calculated according to the maintained engine rotational speed and the detected throttle valve opening, and in other operating states, the fuel injection is calculated according to the detected engine rotational speed. A fuel injection amount calculation means for calculating a fuel injection amount according to a detected throttle valve opening degree, 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.