JPS62131949A - Electronic engine control device - Google Patents

Abstract

PURPOSE:To make it possible to prevent erroneous operation such as inferior start or the like even if the voltage of battery is remarkably lowered, by supplying electrical source power such that a battery voltage is boosted up by a voltage booster circuit and is then lowered to a demand voltage for electronic circuit parts. CONSTITUTION:During cranking for engine start, a large capacity current for driving a starter motor runs so that the voltage of a battery 1 is remarkably lowered. In particular, during cold engine start, the battery voltage sometimes lowers down to about 6V. Thus, even if the battery voltage lowers to about 6V due to cranking, the voltage is boosted up to about 12V by a voltage booster circuit 4, and therefore, a constant voltage circuit 2 may feed a stable constant operating voltage of about 5V to a control circuit 3. Accordingly, the control circuit 3 in an electronic engine control device normally follows a predetermined control program without erroneous operation, thereby it is possible to enhance the starting ability of an automobile engine.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electronic engine control device for an automobile engine, and more particularly to a method of supplying power to a control circuit composed of a microcomputer or the like.

[Conventional technology]

FIG. 2 is a circuit diagram showing a conventional method of supplying power to an electronic engine control device. In the figure, the number 1 is usually 12
The in-vehicle battery 2 is a constant voltage circuit that generates a battery voltage of 5 V, and the voltage supplied from the battery 1 is normally
The voltage is stepped down to approximately 100 volts and maintained at a constant voltage. , 3 is a control circuit composed of a microcomputer of an electronic engine control device. In this type of electronic engine control device, the control circuit 3, which is generally composed of a microcomputer, has 5 to 8
V6! Traditionally, in order to obtain this kind of power supply voltage, a battery 1
Since the normal voltage of the battery is 12V, an operating voltage of 5 to 8V is directly generated from the 12V battery voltage through the constant voltage circuit 2 and supplied to the control circuit 3. The control circuit 3 of the electronic engine control device is supplied with a predetermined power supply voltage and enters an operating state, and the engine rotation speed sensor is activated. Inputs sensor information from the air flow meter, boost pressure sensor, engine coolant temperature sensor, etc., as well as operating status information from the idle switch, etc., and executes various control programs such as air-fuel ratio control, ignition timing control, and EQR control. Abnormality display by diagnostic function. Performs alarm and abnormality processing.

[1111 Problems to be Solved by the Invention] In the conventional electronic engine control device as described above, normally
The 4V battery voltage is stepped down to about 5 to 8V by a constant voltage circuit and supplied, but when the starter motor is cranking when starting the engine, a large amount of power from the battery is used to drive the starter motor. Because it is consumed
The battery voltage may temporarily drop significantly, especially during a cold start, and the battery voltage may drop to about 6V.As a result, the necessary operating voltage cannot be supplied to the control circuit section, which is made up of a microcomputer, and the electronic engine Control device malfunctions could occur. This malfunction causes the air-fuel ratio control system, ignition timing control system, etc. by the electronic engine control device to fail to perform optimization at the time of starting, or to perform control that deviates significantly from the optimum value, leading to poor starting. In such a state, if cranking is continued repeatedly with poor starting, the battery will eventually run out, and in the worst case scenario, the engine may become completely unable to start. This invention was made in order to solve the problems of the conventional ones as described above.Even if the battery voltage drops due to cranking when starting the engine, malfunctions of the electronic engine control device when starting the engine do not occur. It is an object of the present invention to provide an electronic engine control device that can improve the startability of an automobile engine by preventing such problems. Incidentally, as a prior art, there is Japanese Patent Application Laid-Open No. 170852/1983.

[Means to solve the problem]

An electronic engine control device according to the present invention is an electronic engine control device for an automobile engine having an electronic circuit portion.
In the I device, a booster circuit is provided between the battery and the constant voltage circuit, and after once boosting the battery voltage, the battery voltage is lowered again to a predetermined operating voltage required by the electronic circuit section of the engine control device, and the voltage is lowered to a predetermined operating voltage required by the electronic circuit portion of the engine control device. This device is characterized in that power is supplied to the control device.

[For production]

According to this invention, in the electronic engine control device, a booster circuit consisting of a DC/DC converter is interposed between the battery and a constant voltage circuit that supplies a predetermined operating voltage power to the control circuit. The voltage of the battery is increased once by a booster circuit, and then by a constant voltage circuit! −
The voltage is stepped down to the operating voltage of the control circuit and supplied as power to the control circuit. Therefore, even if the battery voltage drops significantly during cranking when starting the engine, a voltage that can secure the operating voltage of the control circuit can be supplied to the constant voltage circuit. Prevent malfunction.

【Example】

FIG. 1 is a circuit diagram of an electronic engine control 211 device showing one embodiment of the present invention. In the figure, numerals 1 to 3 are the same as the conventional ones shown in Fig. 2. 1 is a battery that normally generates a battery voltage of about 12V, and 2 is a constant voltage circuit that steps down the voltage from the battery. The voltage is maintained at a constant voltage of about 5μ and output. 3
is a control circuit composed of a microcomputer, etc., located at 9A for electronic engine control. Reference numeral 4 denotes a booster circuit according to the present invention, which is composed of a DC/DC converter and the like, and doubles the voltage supplied from the battery 1 and supplies the boosted voltage to the constant voltage circuit 2. Next, the electronic engine control system configured as described above is installed.
+Explain the operation of the device. The control circuit 3, which is made up of a microcomputer, is equipped with control programs such as air-fuel ratio control and ignition timing control. cooling water temperature, intake air temperature,
The air-fuel ratio is corrected based on information such as boost pressure, and air-fuel ratio feedback control is performed to achieve the stoichiometric air-fuel ratio based on the output signal from the oxygen intensity sensor. Also,
When starting the engine, it is not possible to stably obtain an intake air amount signal due to pulsation, so air-fuel ratio control during starting is performed by calculating the fuel injection amount based on the engine cooling water temperature and engine speed. On the other hand, in the ignition timing control program,
The ignition advance angle is determined according to engine speed, warm-up condition, and other operating conditions. The operating voltage of this control circuit 3 is
Generally, it is designed to be about 5V, and under normal conditions, the battery voltage of about 12V supplied from the battery 1 is once raised to about 24V by the promotion circuit 4 and then supplied to the constant voltage circuit 2. 2, the voltage is stepped down to a constant voltage of about 5V, and the voltage is stably supplied to the control circuit 3 while maintaining a constant operating voltage. On the other hand, during cranking to start the engine, a large current of power flows to drive the starter motor, and the voltage of the battery 1 drops significantly, and particularly during a cold start, the battery voltage may drop to about 6V. In this way, even if the battery voltage drops to about 6V due to cranking, the booster circuit 4 boosts the voltage to about 12V and supplies it to the constant voltage circuit 2. A stable and constant operating voltage can be supplied to the control circuit 3. Therefore, the control circuit 3 of the electronic engine control device operates a predetermined control program normally without malfunction, thereby improving the startability of the automobile engine.

【Effect of the invention】

As explained above, this invention is equipped with a booster circuit that boosts the battery voltage, and after boosting the battery voltage, the voltage is stepped down again to the voltage required by the electronic circuit section to supply power. Even when the battery voltage drops slowly due to engine cranking, the control circuit operates normally and does not cause malfunctions such as poor starting, improving the starting performance of automobile engines. This has the effect of being able to.

[Brief explanation of drawings]

FIG. 1 is a power supply circuit diagram of an electronic engine control device showing an embodiment of the present invention, and FIG. 2 is a conventional power supply circuit diagram. 1... Battery 2... Constant voltage circuit 3... Control circuit 4... Boost circuit.

Claims (1)

[Claims] In an electronic engine control device for an automobile engine having an electronic circuit portion, a booster circuit is provided between the battery and the constant voltage circuit, and after the battery voltage is once boosted, the demand of the electronic circuit portion of the engine control device is increased again. An electronic engine control device characterized in that the power is supplied to the engine control device by dropping the operating voltage to a predetermined operating voltage.