JPH0596449U - Electronically controlled fuel injection device - Google Patents

Abstract

(57) [Summary] [Purpose] High-precision fuel injection control is performed over the entire engine range without abrupt changes in engine torque. The electronic control unit determines a basic injection time PW1 based on a map having the engine speed N and the manifold pressure P as parameters. Throttle opening T
When HP is equal to or less than a predetermined value, this basic injection time PW1
The fuel injection valve is controlled based on. Also, the throttle opening T
When HP is larger than the predetermined value, at the basic injection time PW1,
The correction basic injection time PW2 is calculated by performing correction based on the map using the engine speed N and the throttle opening THP as parameters. And this corrected basic injection time PW
The fuel injection valve is controlled based on 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electronically controlled fuel injection device that supplies a required amount of fuel to an engine.

[0002]

[Prior Art]

 As a conventional electronically controlled fuel injection device, a basic injection time with parameters of engine speed and suction negative pressure and a basic injection time with parameters of engine speed and throttle opening as parameters are stored in a microcomputer as a three-dimensional map. There is one that determines the basic injection time by properly using these maps according to the load condition of the engine (see Japanese Patent Laid-Open No. 57-52121). In such an electronically controlled fuel injection device, when the throttle opening is below a predetermined value, a map using the engine speed and the suction negative pressure as parameters is used, and when the throttle opening becomes larger than the predetermined value, The basic injection time is determined by switching to a map that uses engine speed and throttle opening as parameters. This makes it possible to deal with the lack of resolution of the manifold pressure sensor when the engine is under high load and the lack of resolution of the throttle position sensor under low load.

[0003]

[Problems to be solved by the device]

 However, in the above-described conventional electronically controlled fuel injection device, two maps are used by switching depending on the size of the throttle opening. Therefore, how much the throttle opening for switching the map is set, and the engine accompanying switching There is a problem to be solved such as how to make the torque fluctuation smooth. An object of the present invention is to provide an electronically controlled fuel injection device that can perform highly accurate fuel injection control in the entire operating region of an engine and that is not accompanied by sudden changes in engine torque.

[0004]

[Means for Solving the Problems]

 The electronically controlled fuel injection device according to the present invention is based on a fuel injection valve, a means for detecting an engine speed, a means for detecting a throttle opening, a means for detecting a manifold pressure, and the detection of each means. A control means for controlling the fuel injection by the fuel injection valve, the control means controls the fuel injection based on the engine speed and the manifold pressure when the throttle opening is within a predetermined range, and When the throttle opening is out of a predetermined range, the fuel injection is controlled based on the engine speed, the manifold pressure and the throttle opening.

[0005]

【Example】

 The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a schematic diagram showing an engine control system to which an electronically controlled fuel injection device according to an embodiment of the present invention is applied. In this figure, an electronic control unit (ECU) 20 determines a basic injection time by a map using various information of an engine operating state as a parameter, and based on this basic injection time, a valve opening time of the fuel injection valve 10 is determined. It is controlled and a required amount of fuel is injected into the intake manifold 11. The fuel injected from the fuel injection valve 10 is sucked into the cylinder 13 together with the air sucked through the air cleaner 12, and after combustion, is discharged to the atmosphere as exhaust gas from the exhaust manifold 14 via a catalytic converter and a muffler not shown. Be done.

The electronic control unit 20 determines the basic injection time PW1 based on a map having the engine speed N and the pressure P in the intake manifold 11 (hereinafter simply referred to as manifold pressure P) as parameters. When the throttle opening THP is equal to or less than the predetermined value, the electronic control unit 20 controls the fuel injection valve 10 based on this basic injection time PW1. When the throttle opening THP is larger than the predetermined value, the basic injection time PW1 is corrected based on the map using the engine speed N and the throttle opening THP as parameters, and the corrected basic injection time PW2 is calculated. Then, the fuel injection valve 10 is controlled based on the corrected basic injection time PW2.

Of the various pieces of information on the operating state of the engine sent to the electronic control unit 20, the engine speed N is calculated from the signal sent from the crank angle sensor 15. The manifold pressure P is detected by the manifold pressure sensor 16. The throttle opening THP is detected by a throttle position sensor 18 provided near the throttle valve 17.

The control by the electronic control unit 20 will be described with reference to FIG. The program shown in this figure is executed at a predetermined time (for example, every 10 ms).

In step S1, the basic injection time PW1 is determined based on a map having the engine speed N and the manifold pressure P as parameters. Next, in step S2, it is determined whether or not the throttle opening THP is less than or equal to a predetermined value. In step S2, when the throttle opening THP is less than or equal to the predetermined value, the valve opening time of the fuel injection valve 10 is controlled based on this basic injection time PW1 and the required amount of fuel is injected. (Step S3).

When the throttle opening THP is larger than the predetermined value in step S2, the correction value CT is obtained based on a map using the engine speed N and the throttle opening THP as parameters (step S4). The corrected basic injection time PW2 is calculated by multiplying the basic injection time PW1 by a value obtained by dividing the correction value CT by 128 (step S5). Then, the valve opening time of the fuel injection valve 10 is controlled based on the corrected basic injection time PW2, and the required amount of fuel is injected (step S6).

FIG. 3 is a diagram showing a relationship between the manifold pressure P and the basic injection time PW1. In this figure, the solid line shows the basic injection time PW1 based on the map using the engine speed N and the manifold pressure P as parameters, and the dashed line shows the basic injection time required by the engine. From this figure, the basic injection time PW1 based only on the map with the engine speed N and the manifold pressure P as parameters is the lattice point A on the map of the manifold pressure, and matches the basic injection time required by the engine. It is understood that there is a region that does not exist (hatched portion in the figure). However, in the electronically controlled fuel injection device of this embodiment, the basic injection time PW1 is corrected by the correction value CT based on the map having the engine speed N and the throttle opening THP as parameters to obtain the basic injection time required by the engine. The corrected basic injection time PW2 that substantially matches is calculated. Therefore, the amount of fuel injected from the fuel injection valve 10 can be matched with the required amount of the engine with high accuracy.

As described above, according to the above-described embodiment, when the throttle opening THP is larger than the predetermined value, the engine speed is changed to the basic injection time PW1 obtained from the map using the engine speed N and the manifold pressure P as parameters. Correction is performed based on the correction value CT obtained from the map using the number N and the throttle opening TH P as parameters, and the corrected basic injection time PW2 is calculated to perform fuel control. Therefore, the lack of resolution of the manifold pressure sensor 16 at the time of high load of the engine and the lack of resolution of the throttle position sensor 18 at the time of low load can be compensated for each other. Injection control can be performed. Moreover, since the map is not switched and used, only the correction based on the correction value CT is performed with the basic injection time PW1 as a reference, so that the engine torque is not suddenly changed due to the map switching.

Further, an engine control system to which a conventional electronically controlled fuel injection device is applied, in which a basic injection time is determined by using a map having an engine speed N and a manifold pressure P as parameters, is a throttle control for acceleration determination or the like. Since a position sensor is already provided, therefore, when the electronically controlled fuel injection device according to the present embodiment is applied to such a system, it is not necessary to add additional parts and the cost is low.

In the above embodiment, the basic injection time, that is, the pulse width for controlling the valve opening time of the fuel injection valve 10 is configured to be corrected. However, the fuel injection amount from the fuel injection valve 10 is corrected. For example, when a plurality of fuel injection valves 10 are provided, the fuel injection amount can be corrected by changing the number of fuel injection valves 10 to be operated without changing the basic injection time.

[0015]

[Effect of the device]

 As described above, according to the present invention, it is possible to perform highly accurate fuel injection control in the entire operating region of the engine, and further, there is no sudden change in engine torque.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an engine control system to which an electronically controlled fuel injection device according to an embodiment of the present invention is applied.

FIG. 2 is a flowchart showing the operation of the electronic control unit.

FIG. 3 is a diagram showing a relationship between a manifold pressure P and a basic injection time PW1.

[Explanation of symbols]

 10 Fuel Injection Valve 15 Crank Angle Sensor 16 Manifold Pressure Sensor 20 Electronic Control Unit (Control Means) N Engine Speed THP Throttle Opening P Manifold Pressure

Claims (1)

[Scope of utility model registration request] 1. A fuel injection valve, a means for detecting an engine speed, a means for detecting a throttle opening, a means for detecting a manifold pressure, and fuel injection by the fuel injection valve based on the detection of each means. And a control means for controlling,
The control means controls the fuel injection based on the engine speed and the manifold pressure when the throttle opening is within a predetermined range, and when the throttle opening is outside the predetermined range, An electronically controlled fuel injection device, characterized in that fuel injection is controlled based on a rotational speed, a manifold pressure and a throttle opening.