JPS59547A - Engine control system - Google Patents

Abstract

PURPOSE:To prevent accidents due to erroneous operations of a group of sensors at the time other than idling by a method wherein an engine control system transmits no control signal to a bypass valve control section or transmits a DC signal of a predetermined level except when the engine is idling. CONSTITUTION:The control system for the engine 2 comprises the sensors 4, 6, 8, 10, 12 and 14, the engine control section 18 and the bypass control section 20 adopted to control the lifting amount of the bypass valve 30 in a pipe passage bypassing a throttle valve through the control signal 18 whose duty ratio varies depending on the operation condition of the engine 2. Except when the engine 2 is idling, the control signal including a higher harmonic component and having a variable duty ratio is not transmitted to the bypass control section 20 so that it is made possible to prevent noises from overlapping the outputs of the sensors. Further, when the engine is not idling, the bypass passage is closed and the air pressurized by a supercharger 44 prevents the lowering of the pressure of the sucked air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine control system, and more particularly to an engine control system having an idle speed control device for controlling engine speed during idling to maintain it at a target speed.

Various engine control systems have been proposed in the past as systems for constantly operating the engine of a vehicle such as an automobile in an optimal state. This type of conventional system includes, for example, a group of sensors that detect various data related to the operating state of the engine, and an engine control system that sets engine operating conditions based on the output of each sensor and outputs various control signals according to these settings. By supplying the output of the engine control section to the igniter, fuel injection valve, etc., the engine can always be operated at an appropriate amount. In addition, in this system, when performing control to maintain the engine speed at idle at the target rotation speed, this device supplies a predetermined amount of intake air to the engine even during idle, as shown in FIG. 1, for example. Its components include a bypass valve V that bypasses the throttle valve, an excitation coil L, and the like.

This excitation coil L is excited by a transistor Q as shown in FIG. 2, and can control the amount of lift of the bypass pulp (2). The base of the transistor Q is supplied with a control signal from the engine control section, the duty ratio of which changes depending on the operating conditions of the engine. Therefore, the bypass pulp V is the excitation coil L
The amount of lift is controlled according to the average value of the excitation current supplied to.

In an engine control system having such a device, intake air according to engine operating conditions can be supplied to the engine even when the engine is idling, bypassing the throttle valve, and the engine speed can be set to the target engine speed when idling. It is possible to perform control to maintain the rotational speed.

However, in the case of the above system, a signal with a varying duty ratio is supplied from the engine control section to the excitation coil L even when the engine is not idling, and control is performed to maintain the bypass pulp V at a predetermined position. Moreover, the control signal whose duty ratio changes includes harmonic components. Therefore, in this system, there is a drawback that, except when the engine is idling, harmonic components of the control signal are superimposed as noise on the sensor outputs included in the sensor group, causing the system to malfunction.

Examples of this sensor include a knock sensor that detects engine knocking, an intake air amount sensor (air flow meter) that detects the amount of intake air, and the like.

There are two types of intake air amount sensors: those whose detection output voltage decreases in proportion to the intake air amount, and those whose detection output voltage increases in proportion to the intake air amount. The latter type of engine is strongly affected by noise, especially when the amount of intake air increases and the load is high, and the latter type is strongly affected by noise when the amount of intake air is small, except when the engine is idling.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an engine control system that can prevent accidents caused by malfunctions of a group of sensors that detect various data regarding the operating state of an engine. be.

In order to achieve the above object, the present invention provides a sensor group that detects various data related to the operating state of an engine, and an engine that sets engine operating conditions based on the output of each sensor and outputs various control signals in accordance with the settings. The control unit and the valve lift amount of the bypass pulp provided in the middle of the bypass pipe that bypasses the throttle valve are controlled by the output signal of the engine control unit whose duty ratio changes depending on the engine operating conditions. an engine control system that controls to maintain the engine speed at a target speed at an idling time, the engine control system including a bypass pulp control unit that supplies side intake air to a downstream bypass of a flotz and tol pulp,
The engine control section is characterized in that it stops supplying a control signal to the bypass pulp control section or supplies a DC signal at a predetermined level to the bypass pulp control section.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows a configuration diagram of an engine control system having a supercharger, which is a preferred embodiment of the present invention.

In FIG. 3, as sensors for detecting various data related to the operating state of the engine 2, an air flow meter 4 detects the amount of intake air supplied to the intake system of the engine, a throttle sensor 6 detects the opening degree of the throttle valve, A rotation angle sensor 8 for detecting engine rotation speed, a cylinder discrimination sensor 10 for discriminating the cylinder of the engine, a knock sensor 12 for detecting knocking of the engine 2, a vehicle speed sensor 14 for detecting vehicle speed, etc. are provided. rotation angle sensor 8,
The cylinder discrimination sensor 10 is built into the distractor unit 16, and the knock sensor 12 is attached to the cylinder block of the engine 2.

The respective sensor outputs are supplied to the engine control section 18.

The engine control section 18 can set operating conditions for the engine 2 based on the outputs of the respective sensors and output various control signals according to the settings. This control signal is then supplied to the bypass valve control section 20, igniter 22, fuel injection valve 24, etc.

The bypass valve control unit 20 has a bypass valve 30 and an excitation coil 32, a bypass pipe 34 is connected to the upstream side of the throttle valve, and a bypass pipe 36 is connected to a surge tank 38 downstream of the throttle valve. Then, the excitation coil 32 is activated by a control signal from the engine control section 18.
When excited, the lift amount of the bypass pulp 30 is controlled, and the intake air upstream of the throttle valve can be bypass-supplied to the downstream side of the throttle valve in accordance with the control signal.

Further, a supercharger 44 having a compressor 40 in the intake system of the engine and a turbine 42 in the exhaust system of the engine is provided. The turbocharger 44 is powered by the exhaust gas to the turbine 4.
The engine 2 can be driven to compress the intake air of the intake system by the compressor 40, and supply the pressurized intake air to the engine 2.

FIG. 4 shows a configuration diagram in which the engine control section 18 is configured with a microcomputer.

As shown in FIG. 4, the engine control section 18 includes an MPU
50, RAM52, ROM54, human output boat 56.5
8, Output port 0.62, A/D converter 64, multiplexer 66, buffer circuit 68, 70, 72, 74
, a waveform shaping circuit 80, and drive circuits 82, 84, and 86, and an MPU 50, a ROM 54, a RAM 52, an input/output port 56.58, and an output port 0.62 are connected by a pass line 88, respectively. Then, a vehicle speed sensor 14, an air flow meter 4, a throttle sensor 6, a knock sensor 12
The detection outputs are supplied to buffer circuits 68 to 74, respectively. The detection outputs of the cylinder discrimination sensor 10 and the rotation angle sensor 8 are supplied to the input/output boat 58 via the waveform shaping circuit 80. The operations of the bypass valve control section 20, igniter 22, and fuel injection valve 24 are controlled by control signals output from drive circuits 82 to 86, respectively.

The present embodiment has the above-mentioned configuration.Next, the operation of the present invention will be explained based on the flowchart shown in FIG.

The flowchart shown in FIG. 5 is a routine for controlling the bypass valve controller. Masu, step 1
At 00, it is determined whether the engine 2 is idle based on the detection signals of the throttle sensor 6 and the vehicle speed sensor 14. That is, it is determined whether the throttle valve is fully closed and the vehicle speed is low, for example, 5 km/h or less. If the determination in this step is YES, the process moves to step 102, where control is performed to maintain the engine speed during idling at the target speed. In this case, the duty ratio of the control signal for the excitation coil 32 of the bypass valve control section 20 is determined by the engine operating conditions set based on the various sensor outputs. The time period during which the excitation of the excitation coil 32 is stopped is determined by the operating conditions of the engine.

If the determination in step 100 is No, that is, when the engine 2 is not idle, the process moves to step 104.

In step 104, the bypass valve control unit 20
A process is performed in which the supply of the control signal to the bypass valve controller 20 is stopped or a DC signal of a predetermined level is supplied to the bypass valve controller 20. That is, the bypass pulp 30 is connected to the excitation coil 32
In the case of the type in which the bypass pipe is closed by de-energization of the excitation coil 32, the supply of the control signal to the excitation coil 32 is stopped, and in the case of the type in which the bypass pulp 30 closes the bypass pipe by the excitation of the excitation coil 32, A DC signal at a predetermined level is supplied to the exciting coil 32.

As described above, in this embodiment, since no signal is supplied to the bypass valve control section 20 except when the engine 2 is idling, the knock sensor 12. It is possible to prevent noise from being superimposed on the detection output of the air flow meter 4 or the like.

Furthermore, since the bypass line is closed when the engine 2 is not idling, the intake air pressurized by the supercharger 44 is prevented from flowing backward through the bypass lines 34 and 36 and the pressure of the intake air is prevented from decreasing. be able to.

In this embodiment, an engine with a supercharger has been described, but in the case of an engine equipped with a supercharger, there is no need to perform control to close the bypass pipes 34 and 36. Even if the pulp 30 is of any of the above types, the knock sensor 12. :11
- It is possible to prevent noise from being superimposed on the aphrometer 4 and the like.

As explained above, according to the present invention, a control signal that changes the duty ratio is not supplied to the null pass valve control unit except when the engine is idling, so that malfunction of the sensor group that detects various data regarding the operating state of the engine is prevented. This has the excellent effect of preventing accidents caused by

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the structure of the pulp used in the idle speed control device, Fig. 2 is a drive circuit diagram of the excitation coil shown in Fig. 1, and Fig. 3 shows an embodiment of the present invention. FIG. 4 is a diagram for explaining the configuration of the engine control section shown in FIG. 3, and FIG. 5 is a flowchart for explaining the operation of the present invention. 2...Engine 4...Air flow meter 6°°/Throttle sensor 12...Knock sensor 14...Vehicle speed sensor 18...Engine control unit 20...Bypass pulp control 'ff1 24...Fuel Injection valve 30...Bypass pulp 32...Excitation coil 44...Supercharger Fig. 1 Fig. 4, 1ρ Fig. 5

Claims (1)

[Claims] (1) A group of sensors that detect various data related to the operating status of the engine, an engine control section that sets engine operating conditions based on the output of each sensor and outputs various control signals according to these settings, and bypasses the throttle valve. The valve lift amount of the bypass pulp provided in the middle of the bypass pipe is controlled by the engine control unit output signal whose duty ratio changes depending on the engine operating conditions, and the intake air on the upstream side of the throttle valve is bypassed to the downstream side of the throttle valve. In the engine control system, the engine control system includes a bypass pulp control unit that supplies the bypass pulp to the bypass pulp control unit, and performs control to maintain the engine rotational speed at a target rotational speed at idle, except when the engine is idle. An engine control system characterized by stopping the supply of control signals or by providing a predetermined level of control.