JPS63266163A - Fuel feed device - Google Patents

Abstract

PURPOSE:To enable the feed of fuel only in a necessary amount to an engine, by a method wherein a pressure regulating valve to control so that a differential pressure between the feed pressure of a fuel feed pump and the intake air pressure of an internal combustion engine is normally kept at a specified value is provided, and a fuel delivery amount of the pump is controllable in response to the feed pressure of the pump. CONSTITUTION:A fuel feed device S of an internal combustion engine feeds fuel in a fuel tank 2, pumped up through the working of a fuel feed pump 1, to an injector 11 through a filter 5 and a pressure regulating valve 6. The pressure regulating valve 6 regulates a fuel feed pressure so that the fuel feed pressure is increased by a specified value from an intake air pressure according to a pressure in a suction manifold 8. In this case, the fuel feed pump 1 is so formed that an amount of delivered fuel is variable through control of the number of revolutions of an electric motor, contained in a pump case, through a control unit. The control unit is so formed that the electric motor is controlled according to an output from a sensor disposed in a pump and detecting the delivery fuel pressure of a pump.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply device comprising a fuel supply pump for supplying fuel to an internal combustion engine.

(Prior Art) A fuel supply device that has been conventionally used to inject and supply fuel in a fuel tank to an internal combustion engine has a fuel supply pump driven by an electric motor, and the fuel supply pump pressurizes the fuel. The pressure of the fuel in the fuel tank is adjusted by the pressure control valve, and then injected into the cylinder of the internal combustion engine by the fuel injector, and the excess fuel generated by the adjustment of the pressure control valve is returned to the fuel tank through the return oil path. returned inside. Conventional fuel supply pumps used for this purpose are always operated at maximum rotation speed,
Therefore, when the engine load is small, the amount of fuel returned to the fuel tank is large, and as the engine load increases, the amount of fuel returned to the fuel tank is reduced.

(Problems to be Solved by the Invention) As mentioned above, the conventional fuel supply pump always operates at the maximum rotation speed, so it has the problems of making a lot of noise and wasting a considerable amount of energy. have. Furthermore, since the fuel tank and the internal combustion engine are usually relatively far apart, surplus fuel must pass through a long return oil passage between them and return to the fuel tank, during which time the fuel temperature increases. increases considerably. - Under the condition that the fuel supply pump is always used at its maximum capacity as described above, there is no choice but to have a large amount of surplus fuel, and therefore the rise in fuel temperature in the fuel tank is considerably accelerated. When such high-temperature fuel is supplied, a vapor lock phenomenon occurs within the fuel supply pump or injector, and there is a possibility that fuel cannot be supplied.

The object of the invention was therefore to make it possible to send fuel to the internal combustion engine in the required amount, thereby overcoming the above-mentioned disadvantages. An object of the present invention is to provide a fuel supply device for an internal combustion engine.

(Means for Solving the Problems) A feature of the present invention for solving the above-mentioned problems in the prior art is that the pressure of the supplied fuel is always higher by a constant value than the intake pressure of the internal combustion engine to which the fuel is to be supplied. A fuel supply device for supplying fuel to an internal combustion engine device by regulating the fuel supply pump, which pressurizes fuel in a fuel tank and pressure-feeds the fuel to the internal combustion engine device; It has a sensor that detects the pressure of the fuel pumped from the pump, and a control means that responds at least to the output of the sensor and controls the fuel discharge rate of the fuel supply pump L, the sensor and the control means M1 is included in the fuel supply pump.

(Function) In an internal combustion engine device, the supply pressure of the fuel supply pump is
For example, the pressure control valve is used to adjust the internal combustion engine's intake pressure so that it is always a fixed value higher than the internal combustion engine's intake pressure, so if the internal combustion engine's load changes and the internal pressure of the intake pressure manifold increases, the pump The fuel supply pressure will also increase. That is, the supply pressure of the fuel supply pump has a value that corresponds to the load of the engine. This supply pressure is detected by a sensor, and the discharge amount of the fuel supply pump is adjusted at least in response to the output of the sensor, so that an appropriate amount of fuel is supplied that matches the load condition of the internal combustion engine, so the amount of fuel returned is always maintained. It can be a small amount that is approximately constant.

(Example) Hereinafter, the present invention will be explained in detail with reference to an illustrated embodiment.

FIG. 1 shows a schematic diagram of an embodiment of a fuel supply system for an internal combustion engine equipped with a fuel supply device according to the present invention. The fuel supply device S includes a fuel supply pump 1 connected to a fuel tank 2 by an oil passage 3, and the fuel in the fuel tank 2 is pressurized by the fuel supply pump 1 and discharged to the oil supply passage 4. Ru. A filter 5 is sunk in the middle of the oil feed path 4, and after removing dust mixed in the fuel, the fuel is inputted to the pressure regulating valve 6.

The pressure regulating valve 6 controls the pressure of the supplied fuel input through the filter 5 to a pressure Pi that is always higher than the pressure Pm in the intake manifold 8 of the gasoline engine 7 by a constant value ΔP. It is a control valve. Pressure control valve 6
The interior of the tire is divided into two chambers A and H by a diaphragm 61, and a movable plate 63 attached to the tire flamm 61 by a spring 62 provided in chamber A is divided into two chambers A and H by a diaphragm 61.
It is biased by a spring so as to be pressed against the open end of the vibro 4 provided in the. The chamber A communicates with the intake manifold 8 through a pipe 9, and fuel flows into the chamber B from the filter 5. A part of the inflow fuel is supplied to the fuel injector 11 via the oil passage 10,
The remaining fuel is taken out to the outside via the vibro 4 and returned into the fuel tank 2 via the return oil path 12.

Since the pressure in the chamber A is equal to the pressure in the intake manifold 8, the movable plate 63 moves close to or away from the open end of the vibro 4 depending on the pressure in the intake manifold 8.
The required pressure adjustment actions are performed. In this way, the amount of fuel returned into the fuel tank z is adjusted, and as a result, the supply pressure Pi of the fuel supply pump l (+ri) is maintained at the required state. It is injected from the injector 11 into the cylinder of the gasoline engine 7.

FIG. 2 shows a sectional view of the fuel supply pump 1 shown in FIG. fjS1. The fuel supply pump 1 includes a cylindrical case 31, and a control unit 50 is housed within the cylindrical case 31.

The fuel supply pump l has a fixed shaft 35 fixedly supported by support blocks 33 and 34 fixed to both ends of a cylindrical case 31, respectively, and a turbine rotatably attached to the fixed shaft 35. 36 and an electric motor 37 for rotating the turbine 36. The electric motor 37 includes a rotor 38 rotatably attached to the fixed shaft 35 so as to rotate together with the turbine 36, a cylindrical magnet 39 provided on the inner peripheral surface of the cylindrical case 31, and the rotor 38. This is a known electric motor that includes a commutator 40 provided at one end and a brush 41 that is electrically connected to the rotor coil (not shown) that is wound around the rotor 38 via the brush 41. By supplying 'i[ to , the rotor 38 rotates in a predetermined direction. As a result, the turbine 36 is rotated, and the fuel supplied from the oil passage 3 to the input boat 42 formed in the support block 33 is pressurized.
The configuration is such that fuel is delivered to the oil feed path 4 from an outlet boat 43 formed on the other support block 34. Note that reference numeral 44 is a relief valve that opens to lower the pressure inside the cylindrical case 31 when the pressure inside the cylindrical case 31 reaches a predetermined value. The fuel is returned to the fuel tank 2.

The control unit 50 is provided to control the rotation of the electric motor 37 so that the amount of fuel delivered by the fuel supply pump l described above becomes an appropriate value. A temperature sensor 51 for detecting the temperature T of fuel passing through the case 31 and a pressure sensor 52 for detecting the pressure of the fuel pumped by the fuel supply pump 32 are fixed by appropriate means. The temperature sensor 51 outputs a fuel temperature signal Tf indicating the fuel temperature T, while the pressure sensor 52 outputs a pressure signal P indicating the fuel supply pressure Pi.・It is entered in . DC power is supplied to the control unit 50 from an external battery 60, and a voltage signal E indicating the actual terminal voltage value Uo of the battery 60 is input to the control unit 50 as a control parameter.

The control unit 50 responds to the voltage signal E, the pressure signal P, and the fuel temperature signal Tf, and adjusts the discharge amount according to the value of the fuel supply pressure pt while considering the value of the terminal voltage of the battery 60 and the temperature of the fuel. A drive pulse signal DP for driving the fuel supply pump l is outputted from the control unit 50 and applied to the drive motor 37 of the fuel supply pump l so that the fuel supply pump l obtains the same amount of fuel from the fuel supply pump l. (see figure)
.

FIG. 3 shows a circuit diagram of the rrJ control unit 50 for controlling the drive of the fuel supply pump 1. As shown in FIG. Here, Ra to Rj are resistors, Da to Dc are diodes, and Ca and Cb are capacitors.

CMa and CMb are operational amplifiers.

The voltage signal E is applied to the inverting input terminal of the operational amplifier CMa, which has a reference voltage Vr of a predetermined constant level applied to the non-inverting input terminal, and the actual terminal voltage of the battery 23 is detected from the output of the operational amplifier CMa. A first output voltage signal v4 whose level changes depending on the value is output, and is applied to the inverting input terminal of the operational amplifier CMb via the diode Da and resistor Ra. FIG. 4 shows the relationship between the first output voltage signal vi and the terminal voltage Uo of the battery 60. As shown in FIG. 5, the fuel temperature signal Tf is a signal whose level increases as the fuel temperature T rises, and is applied to the inverting input terminal of the operational amplifier CMb via the resistor Rh. As shown in FIG. 6, the pressure signal P is a 4M signal whose level increases as the supply pressure Pi increases, and is applied to an operational amplifier C via a resistor Rc.
It is applied to the inverting input terminal of Mb. Note that a series circuit 21 including a diode Db, a capacitor Ca, and a resistor Rd connected in series as shown in the figure is connected in parallel to the resistor Re. Therefore, when the supply pressure Pi suddenly increases and the level of the pressure signal P changes suddenly, this change is transferred to the operational amplifier CMb via the differentiating circuit formed by the capacitor Ca and the resistor Ra. Applied to the inverting input terminal. Note that here, the resistor Ri forms a discharge circuit for the capacitor Ca.

The non-inverting input terminal of the operational amplifier CMb is connected via a resistor Rf to a resistive voltage divider circuit 22 consisting of resistors Rg and Rh, and the divided output voltage Va generated at the connection point X is connected to the resistor Rf. to its non-inverting input terminal. The connection point It has become. Note that here, resistor Rj forms a discharge circuit for capacitor cb.

The output terminal of the operational amplifier CMb is connected to its inverting input terminal via the feedback resistor Re, and the second output voltage signal vz from the operational amplifier CMb is input to the drive pulse generator 23. The drive pulse generator 23 generates a drive pulse signal DP for driving the motor 37 of the fuel supply pump 1.
In the illustrated embodiment, the duty ratio of the driving pulse signal DP is controlled according to the level of the second output voltage signal vL. As the level of the signal (2) decreases, it increases, thereby increasing the rotational speed of the motor 37.

Next, the operation of the circuit shown in FIG. 3 will be explained.

As can be seen from the characteristic diagrams in Figures 4 to 6, the fuel temperature T
and as the supply pressure Pi increases, the operational amplifier CMb
Since the potential at the inverting input terminal of VL increases by -F, the level of the second output voltage signal VL decreases and the rotational speed of the motor 37 increases. That is, when the load on the gasoline engine 7 increases, the supply pressure Pi increases, and the rotational speed of the motor 37 increases to obtain a flow rate commensurate with this increase, and the discharge acid of the fuel supply pump 1 increases in proportion to the load at that time. It is made to increase to a certain amount. Moreover, when the fuel temperature T increases,
Since the volume of fuel increases and the amount of fuel supplied substantially decreases, in order to compensate for this, the rotational speed of the motor 37 increases to make up for the shortage. As a result, fuel supply pump 1
Since the amount of fuel discharged from the fuel tank increases, it is possible to simultaneously prevent the fuel temperature from rising, thereby effectively suppressing the occurrence of the vapor lock phenomenon. Further, when the terminal voltage Uo of the battery 60 increases or decreases, the second output voltage signal v2. The level of Uo decreases and increases, thereby canceling out changes in the rotational speed of the motor 37 due to changes in the terminal voltage Uo.

In this way, the amount of fuel discharged from the fuel supply pump 1 does not change due to a change in the terminal voltage Uo of the battery 60, and the amount of fuel discharged is adjusted to match the engine's current operating state according to the engine load and fuel temperature. It is controlled to the optimum value.

Furthermore, in this embodiment, when the supply pressure Pi suddenly increases due to a sudden increase in engine load, a signal corresponding to this change is applied to the inverting input terminal of the operational amplifier CMb via the series circuit 21, thereby improving the response. It is possible to increase the fuel discharge φ. On the other hand, when the engine load suddenly decreases and the supply pressure Pi suddenly decreases, the potential at the connection point This prevents the level of the signal v2 from suddenly increasing and the value of the supply pressure Pi from further decreasing. As a result, even if the supply pressure Pi suddenly decreases, actions that would further aggravate the decrease are prevented from being performed. 1) 7. L, the motor 37, that is, the fuel supply pump 1 can be controlled stably.

(Effects of the Invention) According to the present invention, as described above, the fuel discharge amount of the fuel supply pump is controlled in accordance with at least the load condition of the internal combustion engine. Compared to other devices, the noise level of the pump can be kept low, and the energy consumption for its operation is also saved.

In addition, as a result of always supplying an appropriate amount of fuel to the internal combustion engine, only a small amount of fuel is returned to the fuel tank via the return oil path, and the temperature rise of the fuel in the fuel tank is extremely effectively suppressed. This eliminates concerns about the vapor lock phenomenon, allowing safe and reliable fuel supply. Furthermore, since the control section and necessary sensors for controlling the fuel supply pump as described above are integrated, handling is convenient.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a fuel supply system for an internal combustion engine equipped with a fuel supply device according to the present invention, FIG. 2 is a sectional view of the fuel supply pump shown in FIG. 1, and FIG. FIG. 2 is a circuit diagram of the control unit, and FIGS. 4 to 6 are characteristic diagrams of each signal shown in FIG. 3. S...Fuel supply device, l...φ fuel supply pump, 2.
...Fuel tank, 6..Pressure control valve, 7..Gasoline engine, 8.φ.Intake manifold, 50..Control unit, 52..Pressure sensor, P.Fist.Pressure signal.

Claims (1)

[Claims] 1. In a fuel supply device that supplies fuel to an internal combustion engine device by adjusting the pressure of the supplied fuel so that it is always higher than the intake pressure of the internal combustion engine to which the fuel is supplied by a certain value, the fuel in the fuel tank is pressurized. a fuel supply pump that pumps fuel to the internal combustion engine device; a sensor that detects the pressure of the fuel pumped from the fuel supply pump; and a fuel discharge amount of the fuel supply pump that is controlled in response to at least the output of the sensor. A fuel supply device comprising a control means, wherein the sensor and the control means are provided within the fuel supply pump.