JPS62271002A - Electronic controller - Google Patents

Abstract

PURPOSE:To secure easy correction of the control contents even after assembly of a device to be controlled by providing a correction voltage manual control circuit at an easy-to-handle area excluding a CPU and reading the correction voltage into the CPU for correction of the arithmetic contents. CONSTITUTION:The correction voltage Vf is obtained by dividing the reference voltage VB supplied from a power supply 3 by means of resistances R1-R3. The voltage Vf is supplied to a CPU 2 via an A/D converter 5 to give change to the fuel jet value pulse calculated by the CPU 2. In this case, the resistances R2 and R3 are attached to an intake flow rate meter 6 not to the inside of a control unit 1. Here the R2 can be manually controlled. Therefore, it is possible to carry out the work for control of the variance in the mixing ratio for idle operation at the part of flow rate meter 6, not in the inside of the hard-to-reach unit 1, when a vehicle is inspected for assembly. Thus the control job is facilitated.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention The present invention relates to an electronic control device equipped with a central processing unit (CPU), for example, an electronic fuel injection device for an internal combustion engine.
In particular, the present invention relates to an electronic control device in which the calculation contents of a CPU can be corrected from the outside.

In an electronic control device equipped with a CPU that calculates and outputs a control signal for controlling a controlled device based on various input signals, it may be necessary to correct the control content after the controlled device is assembled.

For example, in electronic fuel injection systems for internal combustion engines, variations in idle mixture ratio due to product variations pose a problem. Since this variation becomes apparent only after the combination of parts is determined, it is possible to determine whether the mixture is rich or thin only by inspecting the mixture ratio during the assembly inspection of the vehicle.

Therefore, it is desirable to provide a manual idle mixture ratio tA adjustment means in a location that is easily accessible from the outside of the completed vehicle.

In an electronic fuel injection system having a conventional flap-type air flow meter, a bypass passage is provided that bypasses the main air passage having a flap. This passage forms a passage that is not measured by the flap, and adjusts the opening area of the bypass passage to adjust the idle mixture ratio to:A. The inlet opening of the bypass passage has a structure in which a large amount of air flows in when the flap is almost fully opened, and almost no air flows into the bypass passage at a position close to the fully opened flap. Although this structure is easy to prepare for yJR, the structure becomes complicated.

Furthermore, in electronic fuel injection systems that use a hot wire flow meter, the hot wire used to measure the flow rate is easily affected by the flow field, so it is not desirable to form a bypass passage in the intake pipe flow path. , therefore requiring a different means than a flap type flow meter.

As described above, in the conventional electronic control device, adjustment after assembly is performed by providing mechanical parts and the like outside the CPU, resulting in problems such as a complicated structure.

The present invention was made in order to solve the problems of the prior art as described above, and by making it possible to correct the calculation contents of the central processing unit from the outside, it is possible to eliminate the need for externally complicated mechanical parts, etc. It is an object of the present invention to provide an electronic control device that can easily correct the control contents even after the controlled device is assembled.

In order to achieve the above object, the present invention provides an electronic control device equipped with a control unit incorporating a central processing unit that calculates and outputs control signals for controlling a controlled device based on various human input signals. A correction voltage manual adjustment circuit is provided at an easily operated location outside the control unit and outputs a manually adjustable correction voltage, and the central processing unit reads the correction voltage and adjusts the calculation contents according to the correction voltage. By configuring the controller to correct the above, it is possible to correct the calculation content in the central processing unit from the outside by manually adjusting the correction voltage.

With the above configuration, in the present invention, the control contents can be easily corrected even after the controlled device is assembled, without providing any complicated external mechanical parts or the like.

Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is a diagram showing one embodiment of the present invention, and illustrates a case in which the present invention is applied to a device for manually adjusting the idle mixture ratio during an assembly inspection of a vehicle in an electronically controlled fuel injection system.

In FIG. 1, a CPU (central processing unit) 2 in a control unit 1 receives a reference voltage v8 from a power source 3 and signals from each sensor (not shown), that is, an air flow signal from a flow meter, and a crank angle sensor. Receiving various signals such as a rotational speed signal, an angle signal, and a water temperature signal from a water temperature gauge, the amount of fuel to obtain the required air-fuel ratio is calculated, and the result is sent to a pulse Ill corresponding to the time to open the fuel injection valve (not shown). The fuel is then supplied to the fuel injection device.

The above calculation is carried out by 1. For example, first, from the air flow rate signal, an initial calculated value Tp is obtained so that the ideal air-fuel ratio for the operating state at that time is obtained, and various corrections are made to this basic pulse TP.
For example, a valve opening delay correction pulse T of an injection valve, a pulse value obtained by adding correction based on water temperature, etc. is supplied to the fuel injection device.

In this embodiment, in order to adjust the variation in the idle operation mixture ratio for each vehicle during vehicle assembly operation,
A pulse correction circuit is provided for adjusting the fuel injection amount by changing the pulse value supplied by the CPU 2 when the idle switch 4 is turned on.

As shown in FIG. 1, a reference voltage Va from a power source 3 is divided by resistors R1, R2, and R1 to obtain a correction voltage vf. This correction voltage Vf is supplied to the CPU 2 via the AD converter 5, and changes the fuel injection amount pulse calculated by the CPU 2. That is, as shown in FIG. 2, the correction voltage Vf is
The correction coefficient α is determined by the arithmetic circuit in 2. The correction coefficient is 1 until the correction voltage vf reaches a certain value, and thereafter becomes a correction coefficient proportional to the voltage value. In other words, the above range of the correction coefficient 1 means that even if the correction voltage Vf changes, the correction coefficient remains 1.
This becomes a dead zone that is fixed at (correction amount O) and does not change.

In addition, in this embodiment, the resistor R of the voltage dividing circuit described above is
,,R, are attached to the flowmeter 6 instead of inside the control unit 1. The resistor R2 is a manually adjustable resistor. As a result, the work to adjust the mixture ratio variation during idling during vehicle assembly inspection is not done in the control unit 1, which is difficult to reach, but in the easily accessible part of the intake flow meter 6. can be easily carried out.

Note that the valve-opening delay correction pulse Ts of the injection valve is suitable for applying the correction coefficient α in the CPU 2.

The reason for this is that the absolute value of the pulse T is small and correction can be easily performed. However, it is also possible to correct the basic pulse Tp or the injection pulse Ti after other corrections have been completed.

As described above, in the present invention, a simple correction voltage manual adjustment circuit that outputs a correction voltage to an easily operated location outside the CPU is provided, the CPU reads the correction voltage, and the above calculation contents are corrected according to the correction voltage. By manually adjusting the correction voltage, the CP
The calculation contents in U can be easily corrected from the outside.

Therefore, an excellent effect can be obtained in that the control contents can be easily corrected even after the controlled device is assembled without providing complicated mechanical parts or the like outside the CPU.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention applied to an electronically controlled fuel injection device, and FIG. 2 is an embodiment of a graph showing the relationship between correction voltage and correction coefficient. Explanation of symbols> 1... Control unit 2... CPU 3... Power supply 4... Idle switch 5... AD converter 6... Intake flow meter

Claims (1)

[Claims] In an electronic control device equipped with a control unit with a built-in central processing unit that calculates and outputs control signals to control a controlled device based on various input signals, it is installed in an easily operated location outside the control unit, and is operated manually. A correction voltage manual adjustment circuit that outputs an adjustable correction voltage is provided, and the central processing unit is configured to read the correction voltage and correct the calculation contents according to the correction voltage, and manually adjust the correction voltage. An electronic control device characterized in that the calculation contents of the central processing unit can be corrected from the outside by adjusting the central processing unit.