JPH0450461A - Fuel control device - Google Patents

Abstract

PURPOSE:To supply only the necessary quantity of fuel to an engine by a simple structure by controlling output of a fuel pump so that the measured value of return flow rate of a pressure regulator becomes constant. CONSTITUTION:A pressure regulator 21 adjusts fuel pressure in a fuel passage 18 connecting a fuel pump 12 to a fuel injection device 20 to return excess fuel through a return passage 19 to a fuel tank 11. In this case, the return flow rate of the pressure regulator 21 is measured by a flowmeter 24. At this time, a control device 25 controls output of the fuel pump 12 so that the measured value of the return flow rate becomes constant. Thus, since the output of the fuel pump 12 is real-time controlled in response to the present operating condition of an engine 23, only the necessary quantity of fuel can be supplied to the engine 23 by a simple structure.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an internal combustion engine (hereinafter referred to as an engine).

), particularly regarding fuel supply devices for supplying fuel to
The present invention relates to fuel pump control technology, and relates to technology that is effective for supplying fuel to gasoline engines in automobiles, for example.

[Conventional technology]

In general, a fuel supply system for supplying fuel to an engine is configured so that the fuel pump is always operated at maximum rotational speed, and excess fuel is returned to the fuel tank via a return pipe using a pressure regulator. .

There is also a fuel supply device configured to control the discharge flow rate of the fuel pump by lowering the drive voltage of the fuel pump by two or three steps based on the drive signal of the fuel injection device.

[Problem to be solved by the invention]

However, in a fuel supply system in which the fuel pump is always operated at maximum rotation speed, there are problems in that the fuel pump makes a lot of noise and consumes a lot of energy.

In addition, in a fuel supply device that controls the discharge flow rate of the fuel pump in two or three stages, the discharge flow rate of the fuel pump is 12
0 ffi/h, fuel consumption during idling is 1 to 242/h, and when driving at low constant speed, it is 2 to 31
．． /h, 5 to 1Ofi/h when driving at high speed constant speed,!
, 50 to 1001/h during acceleration operation, and there is a large variation in fuel consumption, so there is a problem that optimal control cannot be achieved with voltage control in about two or three stages.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply device that has a simple structure and can feed only the required amount of fuel to an engine.

[Means to solve the problem]

A fuel supply device according to the present invention includes a fuel pump that sucks up and discharges fuel from a fuel tank, a fuel injection device that injects fuel from the fuel pump, and a fuel passage that connects the fuel pump and the fuel injection device. In a fuel supply device equipped with a pressure regulator that adjusts pressure and returns excess fuel to a fuel tank, the return flow rate of the pressure regulator is measured, and the output of the fuel pump is adjusted so that this measured value becomes a constant value. is characterized by being controlled.

[Effect]

According to the above-described means, the fuel pump is controlled so that its return flow rate is constant, so that, for example, when the fuel consumption increases and the return flow rate decreases during sudden acceleration, the fuel pump changes its discharge flow rate. The output will be rising in an increasing trend. As a result, the amount of fuel pumped increases, making it possible to keep up with the increase in engine consumption.
The return flow rate can be made constant.

In this way, according to the above-described means, the output of the fuel pump is controlled in real time in response to the current operating status of the engine, so it is possible to suppress the operating output status of the fuel pump to the minimum necessary level. can.

〔Example〕

FIG. 1 is a circuit diagram showing a fuel supply device according to an embodiment of the present invention, and FIGS. 2, 3, 4, and 5 are comparative diagrams for explaining the operation thereof.

In this embodiment, the fuel supply device according to the present invention includes a fuel pump 12 (not shown) installed in a fuel tank 11, and a pump section 13, which is integrally connected to the pump section 13, It includes a motor section 14 that drives the pump section 13, a suction port 15 that sucks fuel from inside the tank 11, and a discharge port 16 that discharges and pumps the sucked fuel.

A check pulp 17 is interposed at the discharge port 16 of the fuel pump 12 so as to prevent fuel from flowing back toward the pump section 13. A fuel passage 18 connected to a fuel injection device 20 is connected to the fuel pump 12 on the downstream side of the check pulp 17 at the discharge port 16, and a filter 22 is interposed in the fuel passage 18. A return passage 19 is connected to the fuel injection device 20 so as to return fuel from the fuel injection device 20 to the fuel tank 11, and a pressure regulator 21 is interposed in this return passage 19. The pressure regulator 21 adjusts the fuel pressure in the fuel passage 18 connecting the fuel pump 12 and the fuel injection device 20 to a constant pressure in response to changes in pressure in the intake manifold (not shown) of the engine 23. It is configured.

In this embodiment, a flow meter 24 is interposed in the middle of the return passage 19, and this flow meter 24 measures the return flow rate from the pressure regulator 21, and transmits the measurement result to the control device 25 as an electric signal. configured to send. The control device 25 is connected to the motor section 14 in the fuel pump 12 so as to control its output, and in response to the measurement result from the flow meter 24, controls the measured value of the flow meter 24 to a preset setting value. so that the motor part 14
The rotation speed is controlled by controlling the voltage applied to the motor.

Next, the effect will be explained.

When the fuel pump 12 is operated by the drive of the motor section 14, the fuel in the fuel tank 11 is pumped up by the pump section 13 and discharged from the discharge port 16, and the fuel is injected through the fuel passage connected thereto. It is pumped to the device 20. As a result, a predetermined amount of fuel is injected into the engine 23 from the fuel injection valve (not shown) of the fuel injection device 20 in accordance with the operating state.

Then, when the pressure inside the fuel passage 18 exceeds the set pressure,
Control port of bream regulator 21 (not shown)
is opened, and a portion of the fuel in the fuel passage 18 is returned to the fuel tank 11 via the return passage 19.

In this embodiment, the return flow rate of the return passage 19 is measured in real time by a flow meter 24. and,
The measurement results of the flowmeter 24 are sent to the control device 25 at any time. The control device 25 controls the rotation speed of the motor section 14 in the fuel pump 12 so that the measurement result of the flow meter 24 becomes a predetermined value set in advance.

Here, the return passage 1 is set in advance in the control device 25.
The predetermined value in 9 is a flow rate set with a margin necessary to reliably maintain the operation of the engine 23. and,
Keeping this flow rate constant in the return passage 19 means that the operation of the engine 23 is reliably maintained from the standpoint of fuel supply.

FIG. 2 is a diagram showing the relationship between the amount of fuel discharged and consumed and the operating state of the engine in this embodiment, where the solid line curve represents the change in the amount of fuel discharged from the fuel pump 12, and the broken line curve represents the change in the amount of fuel discharged from the fuel pump 12. 23 shows the trends in fuel consumption. The difference between the amount of fuel discharged and the amount of fuel consumed corresponds to the amount of fuel returned from the return passage 19, and in this embodiment, the amount of returned fuel is controlled to be constant.

For example, if you are suddenly accelerated from a low constant speed driving state,
Since the amount of fuel injected from the fuel injection valve in the fuel injection device 20 is increased by a command from a control device (not shown) in the fuel injection device 20, the amount of fuel consumed increases rapidly.

Fuel consumption is 2. If it increases, the amount of fuel returned from the pressure regulator 21 to the return passage 19 will decrease. This reduction in the amount of return is shown in return passage 1.
The flow rate is measured in real time by a flow meter 24 installed at 9 and immediately transmitted to the control device 25.

In order to maintain a preset return amount constant, the control device 25 increases the voltage applied to the motor section 14 to increase the rotation speed in order to discharge the flow rate necessary to make up for the decreased amount.

As the rotational speed of the motor unit 14 increases, the discharge amount from the fuel pump 12 increases, so even if the consumption amount in the fuel injection device 20 increases, the fuel pump 12 will not be able to deliver sufficient fuel to accommodate this increase. can be provided.

In this way, the flow meter 24 is configured so that the difference between the discharge amount from the fuel pump 12 and the fuel consumption amount in the fuel injection device 20, that is, the return flow rate of fuel from the pressure regulator 21 is constant at the set value. and control device 25
control is executed.

In addition, Fig. 3 shows a conventional example in which the fuel pump is operated at maximum rotation speed, Fig. 4 shows a conventional example in which the output of the fuel pump is reduced only during idling, and Fig. 5 shows the conventional example in which the fuel pump is operated at the maximum rotation speed. In the case of a conventional example in which the output of the fuel pump is reduced in stages during low-speed constant-speed operation, FIG.

By comparing FIG. 2 with each figure, it can be seen that the return amount in this example is more modestly reduced than in each of the conventional examples. As a result, the load on the fuel pump is significantly reduced compared to the conventional example, and the noise and energy consumption of the fuel pump are reduced.

〔Effect of the invention〕

As explained above, according to the present invention, by maintaining a constant return flow rate of fuel, the output of the fuel pump can be reduced, thereby dramatically extending the life of the fuel pump. At the same time, the noise and energy consumption of the fuel pump can be suppressed.

[Brief explanation of the drawing]

[Example] Fig. 1 is a circuit diagram showing a fuel supply device which is an embodiment of the present invention, and Figs. 2, 3, 4 and 5 are comparison lines for explaining the operation thereof. It is a diagram. 11...Fuel tank, 12...Fuel pump, 13.
...Pump part, 14...Motor part, 15...Suction port, 16...Discharge port, 17...Check valve, 18
...salt 11i! Road, 19... Return passage, 2o.
...Fuel injection device, 21...Pressure regulator, 22...Filter, 23...Engine, 24...
・Flowmeter, 25...Control system agent Patent attorney Kaji
Hara Tatsuyaken-- Kiri--

Claims (1)

[Claims] 1. The system adjusts the fuel pressure in the fuel pump that sucks up and discharges fuel from the fuel tank, the fuel injection device that injects the fuel from the fuel pump, and the fuel passage that connects the fuel pump and the fuel injection device to eliminate excess fuel. A fuel supply device comprising a pressure regulator for returning fuel to a fuel tank, characterized in that a return flow rate of the pressure regulator is measured, and the output of the fuel pump is controlled so that the measured value becomes a constant value. Fuel supply device.