JPS61138853A - Engine controller - Google Patents

Abstract

PURPOSE:To restrain change of air fuel ratio sods to improve driving performance by providing a sensor to detect a combustion state of an engine, and regulating fuel amount to be supplied to the engine by output of this sensor. CONSTITUTION:A throttle chamber 17 provided with a throttle valve 3 is fixed to the intake pipe 2 of an engine 1. Intake air amount is regulatingly controlled by the throttle valve 3. An injector 3 supplies fuel. A combustion state of the engine is detected by a pressure sensor 151 mounted on the edge of a spark plug. A signal of the pressure sensor 151 is input to a control unit 10, and supplies fuel amount to the supplied to the engine. In this way, change of air fuel ratio is restrained, and driving performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an engine control device, and more particularly to a method for providing a control device that can supply an ideal air-fuel ratio according to engine operating conditions.

[Background of the invention]

Conventionally, the air-fuel ratio for gasoline engines has been controlled by detecting the amount of air intake into the engine, which is determined by opening and closing a throttle valve mechanically connected to the accelerator, and controlling the supply of fuel accordingly. However, the speed at which air is drawn into the engine is lower than that of fuel, so the fuel cannot follow it during transient times. For example, the air-fuel ratio drops instantaneously to lean during acceleration, but becomes rich during deceleration. There were drawbacks.

[Purpose of the invention]

The purpose of the present invention is to suppress the above-mentioned drawbacks of the conventional technology, that is, to suppress fluctuations in air-fuel ratio and improve drivability, which cannot be avoided in the conventional fuel system of the intake air amount leading and fuel following type. The conventional drawbacks are improved by controlling the fuel flow rate in advance and controlling the air amount to follow this control.

[Summary of the invention]

Furthermore, although a small number of patent applications have been filed for this kind of fuel advance control, a relatively early application, JP-A-57-91343, describes a conceptual structure. However, much more improvement and ingenuity is required for practical application. It is also known that the combustion state of an engine can be detected by, for example, the cylinder pressure of the engine, and controlling the fuel using this sensor is very effective in achieving lean combustion.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to one drawing.

FIG. 1 shows a system diagram of an engine control system in which the present invention is implemented, and a throttle chamber 17 having a throttle valve 3 is attached to an intake pipe 2 of an engine 1. As shown in FIG. The amount of air taken into the engine is adjusted and controlled by opening and closing a throttle valve using a throttle actuator 4.

Also.

An electromagnetically driven injector 5, which serves as fuel supply means, is attached to the intake pipe, and fuel, which is regulated to a constant pressure by a fuel pump 14 and a pressure regulator 15, acts on this injector. . Fuel is supplied by an injector that operates in synchronization with the rotation of the engine and injects the amount of fuel determined by the valve opening time signal Ti.

The engine temperature Tw is detected by the temperature sensor 10, and the accelerator opening θ1 is detected by the sensor 9.
The rotation speed N of the engine is detected by the rotation speed sensor 7.

Further, the combustion state of the engine is detected as the combustion pressure of the engine by a pressure sensor 151 provided at the tip of the spark plug.

Next, when considering the operating condition of the engine, it is different from the conventional one. In other words, the accelerator pedal 8 operated by the driver
is mechanically separated from the throttle valve 3, and a signal indicating the opening degree of the accelerator is inputted to the control unit by the relationship sensor 9.

Various actuators can be used to open and close the throttle valve, such as steppers, motors, DC motors, negative pressure servos, and linear solenoids, but the characteristics required for actuators are good response and low resolution. In addition, the operating amount is small relative to the input, and the reference position can be clearly defined.

Next, FIG. 2 is a configuration diagram of a control system for implementing the present invention, and the control unit ECu is a ROM
, a microcontroller CPU having RAM, an I10LSi for processing input/output data signals, and input circuits INA to C9 output circuits DR including respective waveform shapes.

Further, signals indicating the operating state of the engine, input signals for accelerator opening, etc. are connected to input ports 5-61 to 6, respectively, as inputs corresponding to the shape of the signals, to the input circuit. Here, the minimum necessary input signal for the present invention is the accelerator opening degree θ.

The engine speed N, the engine temperature Tv, and, if desired, the intake air amount Q. Note that INJ connected to the output side indicates an injector which is a fuel supply means, and THAo indicates a throttle actuator.

FIG. 3 is an explanatory diagram showing an example of a throttle actuator, and shows an actuator using a DC motor. That is, the rotational motion of the DC motor 51 is decelerated by the gears 52 and 53, and converted into a linear direction by the worm 54 meshed with the gear 53, and when the lever 55 is pushed, the throttle valve 3 is rotated.
is open.

Although not explained in detail, 56 is a switch,
For example, when this switch is ON, it signals that the renovator 55 and the throttle actuator 4 are in contact.
Only in this case, measures such as operating the throttle actuator are taken.

Moreover, when closing the throttle valve, it is sufficient to apply a current in the opposite direction to the DC motor and reverse the motor.6 FIG. 4 shows the characteristics of the throttle actuator. The throttle actuator can be operated in various ways, but the example in FIG. 4 shows a case in which it acts as a pulse with a time width t to facilitate digital control. That is, as shown in FIG. 4, since the opening degree can be controlled according to the number of pulses, the throttle valve is controlled by changing the number of pulses and the time interval T at which the pulses are applied.

Figure 5 is an explanatory diagram of the structure of the injector for supplying fuel, and Figure 6 shows its performance. Spray from the nozzle at the tip.

Next, Figure 6, which describes an embodiment of control according to the present invention using the actuators and sensors described above, shows a control block diagram for implementing the present invention. The accelerator opening signal θ and the engine speed signal N are input, and in order to supply the appropriate amount of fuel, the injector valve opening signal Q is determined, and the air-fuel ratio A/F is set accordingly. In order to obtain the intake air amount of the engine, a signal θ7 is output that drives a throttle actuator THA that operates a throttle valve.

FIG. 8 is a flowchart of the control method according to the present invention, and the basic control concept will be explained using this flowchart. First, when the program is executed, it is a factor that first indicates the operating state of each engine. Sensor input θ,
, Tw, N, etc. are read. In the next step, Q according to the operating conditions and θ7 according to Q are calculated, and these values are output under steady operating conditions.

Next, to explain each part of the flowchart, first of all, at the time of starting, the relationship between Q and 07 is treated independently 6 In other words, θa is set to the opening determined by the engine temperature Tw, and Q , is appropriately set as a function of Tw and the elapsed time since starting. Furthermore, if we consider the situation during left warming up, there is a unique relationship between Q and 07 (as a line, not a surface), so 07 = 3 ・Q.

The calculation is accomplished with . Similarly, after warm-up is completed, Q t =K 4 ・θ,, θ7= 5 ・Q, and θ, Q, and θ are changed according to the respective operating conditions.
A coefficient K between 7 and 7 will be selected or adjusted.

The above control has already been patented and is a general explanation of a fuel advance control device that prioritizes fuel control over throttle opening, and is extremely effective against dilution of the air-fuel ratio in extreme situations. It is a control means. But fuel? 11
The demand for improvement of g+ is even more urgent, and it is necessary to further dilute it, including in steady state. In general, the means to implement lean burn include (1) atomization of fuel, (2) improvement of response, and (3) improvement of the engine. difference,
When considering variations in the fuel supply system, there is one obstacle to dilution and it is not possible to implement it as expected. The most effective means to solve this problem is to control the quantity and quality of the air-fuel mixture according to the combustion state of the engine.

Generally, sensor means for detecting the combustion state of an engine are as follows:
Although there are engine rotation fluctuations, torque output and fluctuations, combustion pressure, etc., the explanation here will take as an example control based on engine cylinder pressure, which most directly detects the combustion state. In the flowchart of FIG. 8, P is the engine cylinder pressure, which is attached to a representative cylinder or all cylinders in the case of a multi-cylinder engine.

With this P, the fuel amount Q is Q,' = f(P,)Q
.

It is corrected to Various methods can be considered for correcting Q, that is, f(P,), but generally speaking, the engine rotation speed N
This is done in such a way that Q is corrected according to the amount of change per time, the amount of integration per unit time or unit engine rotation angle, or the maximum value of P, which exists depending on the accelerator opening degree θ1.

That is, in the region where the engine requires output, Q is controlled by the maximum value of Pl, and in the region where the most economical efficiency is required, Q is controlled by the amount of change per hour. Specifically, as shown in FIG. 9, the combustion pressure in a given cylinder with respect to the crank angle is divided into adiabatic compression Pfo by the piston and P due to combustion, and the pressure increase due to combustion is shown by hunting.

As shown in FIG. 9, the area of the hunting is generally increased when producing output, and when economical efficiency is required, the hunting area is decreased. This area is the angle θ where the combustion pressure peak appears.
. , and Po.

Therefore, as shown in FIG. 10, for example, P3. Create a map of
Furthermore, similarly, θ. By creating a map of A, θ. and P□
It is only necessary to control Q so that Q becomes the target value.

Although not described in detail in the present invention, θo8 varies greatly depending on the ignition timing, so θ. Map 3 may be used as an ignition timing map.

Similarly, the control of Q is not limited to controlling only the quantity, but it is also considered that control of the injection timing may be introduced. Further, 5, for example, Pl, /θ as a coefficient representing an instantaneous combustion state. It is also significant to adopt Q, which allows us to control the next Q.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a system to which the present invention is applied,
3 to 6 are explanatory diagrams of the actuator used in the present invention, FIGS. 7 and 8 are detailed explanatory diagrams of the present invention, and FIG. 9 and 10 are further detailed explanatory diagrams of the invention. It is an explanatory diagram. 1... Engine, 2... Intake pipe, 3... Throttle valve,
4... Throttle actuator, 5... Injector, 9... Sensor, 10... Temperature sensor, 14...
··Fuel pump. 15...Pressure regulator, 17...Throttle cha 73 diagram υ Hal or j number - fl 50 line 6 Cause/Maruto + (paddle s2 Tomi 8 mouth ■ 9 Kasumi 10 mouth

Claims (1)

[Claims] 1. An actuator means for adjusting and controlling the fuel flow rate supplied to the engine, an actuator means for adjusting and controlling the amount of air supplied, a sensor means for detecting the operating state of the engine, and a sensor means for detecting the operating state of the engine. It has a control circuit means for actuating the actuator means in response to a driving command signal, and the fuel flow rate adjustment control means is an electromagnetically driven injection valve that determines the supply amount according to the valve opening time. The driving command signal is the accelerator opening, the fuel supply is synchronized with the engine rotation speed, and the air amount adjustment control actuator is a member that adjusts the opening of the throttle valve in relation to the accelerator opening. In a certain engine control device,
An engine control device characterized by having a sensor that detects the combustion state of the engine, and adjusting the amount of fuel supplied to the engine based on the output of the sensor. 2. An engine control device according to claim 1, comprising a sensor for detecting the combustion state of the engine, and adjusting the injection timing of fuel supplied to the engine based on the output of the sensor. . 3. An engine control device according to claim 1, comprising a sensor for detecting the combustion state of the engine, and adjusting the ignition timing of the engine based on the output of the sensor. 4. An engine control device according to claim 1, comprising a sensor that detects the combustion state of the engine, and supplies fuel asynchronously with engine rotation based on the output of this sensor.