JPS58117351A - Fuel pump driving circuit - Google Patents

Abstract

PURPOSE:To obtain the fuel pump driving circuit which is suitable for electric power saving, by turning ON and OFF the fuel pump, and controlling the ON time in correspondence with the required amount. CONSTITUTION:A fuel injection time is computed by inputting the signal from an air quantity sensor 1, a water temperature sensor 2, and a number of rotation sensor 3. A microcomputer 4 drives an injector 12 and outputs a voltage waveform in which the ON time of a constant frequency is varied in correspondence with the fuel injection quantity. An F-V converter 5 outputs an analog voltage which is proportional to the output of the microcomputer 4. In correspondence with said voltage and the voltage of a battery 9, a pulse width converter 6 controls the ON time of a power transistor 8. A pump 7 is driven by the power transistor 8. A diode 11 flows a flywheel current during the time the transistor 8 is OFF. A smoothing circuit 10 averages the collector voltage of the power transistor 8.

Description

[Detailed Description of the Invention] The present invention relates to a fuel pump for an automobile, and is particularly suitable for power saving.
This invention relates to a fuel pump drive circuit.

In recent years, the number of electronic devices installed in automobiles has increased, and as a result, consumption power has also increased. Therefore, there is a growing demand for electronic devices to save power.

However, the fuel pump is set so that a voltage is directly applied to the fuel pump so that the maximum required amount of fuel can be supplied at all times. For example, when the engine is idling, fuel is unnecessarily supplied and most of it is returned to the fuel tank, resulting in a large energy loss.

The purpose of the present invention is to provide a drive circuit suitable for saving fuel pumps and increasing tf power.The present invention is intended to solve the conventional drawbacks by driving a fuel pump at a constant frequency (')N, OF'FL, and The 08 hours are controlled according to the amount of fuel to save power.

Embodiments of the present invention will be described using FIGS. 41 to 5. Figure 1 is a block diagram of the present invention, and its configuration is air amount sensor 1.
, water horse sensor 2, and rotation speed sensor 3 as inputs to calculate the fuel injection time and drive the injector 12. Microcombination 1-Y4R1 A voltage waveform with a constant frequency that changes according to the fuel injection amount. Output. The ON,
The 08 hour of the power transistor 8 is controlled according to the voltage of the F-V converter 5, the F'-V converter 5, and the voltage of the battery 9, which outputs an analog voltage proportional to the 08 hour of the OF'F' waveform. A pulse width converter 6, a fuel pump 7 driven by a power transistor 8, a section i where the power transistor 8 is OFF'F is a diode 11 that flows a flywheel current, and a smoothing circuit 10 that averages the collector voltage of the power transistor 8. According to the above configuration, the ON time is reduced by 08 hours depending on the required fuel 1k,
By outputting the decoute output of the OFF' pulse from the microcomputer 4, the decoute output is changed to F'.
-V converter 5 converts the annular mouth y into an analog 1d pressure proportional to 08 hours.
1=If, the power transistor is turned on according to the pressure.

By performing the OF'F control, a voltage is applied to the fuel pump 7 in accordance with the required fuel supply from the microcomputer 4. Next, the detailed circuit will be explained using FIG. 2. The ON/OFF" output of the microcomputer 4 is converted into an analog voltage by an F'-V converter 5 comprising transistors 'p, b, resistors R1, to R4, a capacitor C1, and an operational amplifier 5-a. Its input/output characteristics are shown in Fig. 3. In Fig. 3, ONN Cocoi 20V is set to approximately 1.8V and 100V is set to 3.8V.Next, the pulse width converter is set to 6 resistors R1, ~R1. , and operational amplifier 6-a, comparator 6-b1 triangular wave generator (3
-c, and its operation will be explained using FIG. A triangular wave is output from the triangular wave generator 6-c, and along with the output of the OP amplifier 5-a, -y7hv-, p6-b
As a result, the collector voltage of the transistor 8 becomes a waveform of 8-a, and direct current is applied to the fuel pump 7 only at 08 hours, and a flywheel current flows through the diode 11 at 02 hours. and collector voltage 8
-a is smoothed by Rv and Ct and added to the θ side of the operational amplifier 5-a. On the other hand, the output voltage of the F-V converter 5 is set to Vl.
, the fuel pump average pressure is vM, the battery voltage is VB, the ■ terminal voltage of the operational amplifier 6-a is αvII, the average collector voltage of the power transistor 8 is VC, then Vv:”V
It is expressed by the formula n Vc. It is performed in the ceremony ``Jintode''. This means that the fuel pump voltage vM is determined by the 08 hours of the microcomputer. FIG. 5 shows the input/output characteristics of the above configuration. The horizontal axis shows the output output from the microcomputer, and the vertical axis shows the fuel pump average voltage. From the graph, even if V at 80% output decoy varies from 13V to 18V, the average fuel pump voltage remains constant at 12V.

According to the configuration shown below, the fuel pump is turned on and off.
The voltage can be controlled, and the patch IJ also corrects the pressure, so the necessary fuel can always be supplied. Therefore, since the fuel pump can be controlled according to the operating condition of the vehicle, power consumption can be kept to the minimum necessary. In addition, the power transistor also performs a switching operation of ON and 01"[i", so power consumption can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a detailed circuit diagram, Fig. 3 is an input/output characteristic diagram of the F-V converter, Fig. 4 is a waveform diagram of the pulse width converter, and Fig. 5 is a waveform diagram of the pulse width converter. The figure shows fuel pump voltage -
It is a characteristic diagram of human decouting. 1...Air pupil sensor, 2...Water temperature sensor, 3...
Rotation speed sensor, 4... Microcomputer, 5...
・F-V converter, 6... Pulse width converter, 7... Fuel pump, 8... Power transistor, 9... (
10... Smoothing circuit, 11... Diode, 12... Injector, R1-R0... Resistor, C
7-C,... Capacitor, 5-a... Operational amplifier,
6-a...Operational amplifier, Figure 2

Claims (1)

[Claims] 1. In a fuel pump drive circuit used in an automobile equipped with a microcomputer that outputs a fuel injection signal by inputting signals from an air amount sensor, a water temperature sensor, and a rotation speed sensor, the fuel pump is driven. The electrical signal is turned on at a constant frequency of 50 Hz or higher. ('')Ti''F'l, and 08 hours during fuel pump operation, l@, characterized by being variable. 2. The fuel pump drive circuit according to claim 1, characterized in that the time period is changed according to the required fuel pulse calculated and output by a microcomputer based on the signals from each sensor. 3. In the first claim, the fuel pump drive circuit is designed to match the required fuel pulse output from the microcomputer when the battery voltage fluctuates for 08 hours.