CN213039381U

CN213039381U - Electronic control fuel injection system of engine

Info

Publication number: CN213039381U
Application number: CN202020060617.3U
Authority: CN
Inventors: 杨延相; 徐露明; 乐起奖; 张平
Original assignee: Zhejiang Fai Electronics Co Ltd
Current assignee: Zhejiang Fai Electronics Co Ltd
Priority date: 2019-12-31
Filing date: 2020-01-13
Publication date: 2021-04-23
Anticipated expiration: 2030-01-13
Also published as: CN113123910A

Abstract

An electronically controlled fuel injection system for an engine, comprising: the fuel injection device comprises an electromagnetic pulse fuel supply pump, a pressure fuel pipe, at least one fuel injection nozzle and an Electronic Control Unit (ECU) of the engine, and is characterized in that the fuel injection nozzle is an on-off injection valve and is controlled by the ECU to be opened and closed, fuel is injected according to the fuel injection quantity demand and stroke synchronous pulse of the engine, the fuel supply pump is also controlled by the ECU to provide the fuel which is equal to or approximately equal to the fuel injection flow of a nozzle to the pressure fuel pipe according to the metering mode of the ECU, and the fuel quantity and the pressure in the pressure fuel pipe are basically kept unchanged through the balance of the average fuel flow metered by the ECU and the nozzle.

Description

Electronic control fuel injection system of engine

Technical Field

The invention belongs to the field of engines, and particularly relates to an electronic fuel injection gasoline engine, in particular to an electronic fuel injection gasoline engine in the fields of motorcycles and general use.

Background

Electronically controlled fuel injection systems are widely used to improve fuel economy of engines, reduce exhaust gas pollutants, and improve power performance. In an electronic fuel injection system of a conventional gasoline engine, metering of fuel injection quantity by a nozzle is generally realized by using an isobaric valve timing mode, isobaric fuel is realized by a fuel supply pump and a pressure regulating valve or a pressure feedback control system, and the fuel supply pump is generally a rotary fuel delivery pump.

However, such a fuel system has many components and high cost, and particularly when such a fuel injection system is applied to a motorcycle or a general gasoline engine, there are problems that the components are difficult to mount and arrange, and the system reliability is lowered.

In addition, such a fuel system often needs to be provided with an oil return device, and a large oil return flow rate not only causes the fuel temperature to rise, but also consumes excessive driving power of the fuel supply pump, thereby bringing pressure to the electrical balance of the system.

In addition, the rotary fuel supply pump has difficulty in quickly adjusting the amount of fuel supplied due to rotational inertia, and even if the fuel is supplied on demand by feedback adjustment using a pressure sensor and a control system, which are expensive to use, accurate control of the common rail fuel pressure is still difficult.

Therefore, the fuel oil electric spraying system of the gasoline engine which seeks for simplification and miniaturization not only can improve the overall applicability of the electric spraying system, but also can increase the reliability and the safety of the whole engine to a certain extent, and can reduce the system cost.

Disclosure of Invention

The invention aims to solve the problems and aims to provide an engine electronic control fuel injection system which is simple in structure, convenient to arrange, low in cost and high in reliability.

In order to achieve the purpose, the invention adopts the following technical scheme that the engine electronic control fuel injection system comprises an electromagnetic pulse fuel supply pump, a pressure fuel pipe, at least one fuel injection nozzle and an engine Electronic Control Unit (ECU), wherein the electromagnetic pulse fuel supply pump is connected with the fuel injection nozzle through the pressure fuel pipe. The fuel injection nozzle is a switch type injection valve, the ECU controls the opening and closing of the fuel injection nozzle, fuel is injected according to the fuel injection quantity demand and stroke synchronous pulse of the engine, the fuel supply pump is also controlled by the ECU to supply fuel equal to or approximately equal to the flow of the fuel injected by the nozzle to the pressure fuel pipe according to the pulse metering mode of the ECU, and the fuel quantity and the pressure in the pressure fuel pipe are basically kept unchanged through the balance of the average flow of the fuel metered by the ECU and the pressure in the pressure fuel pipe.

The electromagnetic pulse oil supply pump comprises an electromagnetic power device and a plunger assembly, and can work in a single pulse quick response mode and accurately control the oil supply amount of each pulse. The plunger assembly includes a sleeve, a plunger, an input valve and an output valve. The sleeve, plunger, input valve and output valve form a pumping volume, and the input valve and output valve can be ball valves or flat valves or slide valves.

The electromagnetic power device comprises an energy storage device, a moving part and a static part, the electromagnetic power device is controlled by a driving current and an energy storage spring together to drive the moving part to reciprocate, the energy storage device absorbs energy from the moving part in a first reciprocating direction, and the plunger sleeve assembly pumps and conveys fuel oil under the combined action of the moving part and the energy storage device in a second reciprocating direction.

The clearance volume between the electromagnetic power device and the plunger assembly forms a low-pressure oil chamber, and fuel enters the pressure-feeding volume from the low-pressure oil chamber through the input valve and forms high-pressure fuel output under the action of the electromagnetic force driving device.

The maximum oil supply amount of the single pulse designed by the oil supply pump is 1 to 1.5 times of the maximum fuel oil amount required by each cycle when the engine is in steady-state operation, and the oil supply flow quantity is determined by the oil supply amount of the single pulse and the working pulse frequency of the pump.

For the regulation of the amount of pressurized fuel, one of the alternatives is: the method is realized by detecting the feedback parameter value of the oil supply pump through the ECU. The feedback parameter of the oil supply pump is a T3 parameter when each oil supply pulse is finished, and the T3 critical value is the minimum T3 capable of achieving the calibrated single oil supply quantity. The concrete mode comprises:

A) in an initial state, the ECU control unit is powered on, the ECU control unit drives the oil supply pump to firstly fill fuel oil into the pressure oil pipe until the internal pressure of the pressure oil pipe is increased to enable the oil quantity of the single pulse pump of the oil supply pump to be obviously reduced, and the ECU detects the reduction trend through the feedback parameter T3 of the oil supply pump, so that the fuel oil filling state is confirmed.

B) After the engine is started, the basic oil supply flow of the oil supply pump supplies oil to the pressure oil pipe according to the principle that the basic oil supply flow of the oil supply pump is equal to the flow of the fuel injected by the nozzle, and the small feedback adjustment of the oil supply flow is carried out according to the control targets that the T3 parameter is not continuously smaller than the critical value but cannot be continuously more (4 or more) larger than the critical value. That is, the ECU detects that T3 is less than the threshold T3, immediately reduces the fueling flow (e.g., by at least 5% less than the nozzle injection flow) until nozzle injection flow is restored when T3 is greater than or equal to the threshold. And immediately increasing the oil supply flow (for example, increasing the injection flow by at least 5 percent compared with the nozzle injection flow) once the ECU detects that the T3 is greater than or equal to the T3 critical value for more than 4 continuous times.

For the regulation of the pressure fuel quantity, another alternative method is as follows: the pressure relief valve is used for regulating. And a pressure relief valve opened at constant pressure is arranged on an oil path between the nozzle and the oil supply pump, and the pressure relief valve is opened when the oil supply quantity of the oil supply pump is greater than the fuel quantity sprayed by the nozzle and the pressure of the pressure oil pipe is too high. The concrete mode comprises:

A) in an initial state, the ECU is powered on, and fuel oil is filled into the pressure oil pipe according to the calibrated oil supply flow and time.

B) After the engine is started, the oil supply flow of the oil supply pump is supplied according to the flow slightly larger than the flow of the fuel oil sprayed by the nozzle, but not more than 1.1 times of the flow of the fuel oil sprayed by the nozzle. And redundant pressure fuel oil in the pressure oil pipe is discharged through the pressure release valve so as to ensure the stability of oil supply.

Above-mentioned automatically controlled fuel injection system of engine, when being applied to single cylinder engine, pressure fuel pipe is a tubule, and the internal diameter is less than 3mm, connects the delivery end of fuel feeding pump with the nozzle, and the fuel feeding pump is installed inside the fuel tank, does not have oil return system outside the fuel tank.

The engine electronic control fuel injection system is applied to a multi-cylinder engine and further comprises an oil rail arranged between the pressure oil pipe and the nozzle, the inner diameter of the oil rail is larger than that of the pressure oil pipe, the pressure oil pipe is one and connected with the oil outlet end of the oil supply pump and the oil rail, and the oil supply pump is installed inside the fuel tank.

The pressure relief valve may optionally be arranged above the oil rail. At the moment, the multi-cylinder engine system comprises an oil return pipe, the oil return pipe is connected with the oil tank and the pressure release valve, and redundant fuel oil flows back to the oil tank through the oil return pipe. The pressure release valve can also be arranged at the outlet end of the oil supply pump optionally, and the pressure release valve does not need to be externally connected with an oil return pipe.

The invention is described in further detail below with reference to the figures and specific embodiments.

Drawings

FIG. 1 is a schematic diagram of a fuel supply pump of an electronically controlled fuel injection system of an engine according to the present invention.

FIG. 2 is a schematic structural diagram of an electronically controlled fuel injection system for an engine according to the present invention.

Fig. 3 is a second schematic structural diagram of an electronically controlled fuel injection system of an engine according to the present invention.

FIG. 4 is a logic diagram of an electronically controlled fuel injection system for an engine according to one embodiment of the present invention.

FIG. 5 is a second logic diagram of an electronically controlled fuel injection system for an engine according to the present invention.

Detailed Description

The fuel feed pump 10 of the present invention is shown in fig. 1, and includes an electromagnetic force driving unit 11 and a plunger assembly 12. The plunger assembly 12 includes a sleeve 110, a plunger 109, an input valve 13 and an output valve 14. The sleeve 110, plunger 109, inlet valve 13 and outlet valve 14 define a pumping volume 118, and the plunger 109 is in sliding engagement with the sleeve 110, the relative movement of which causes the pumping volume 118 to alternate in size, thereby producing a high pressure solution. The input valve 13 is a one-way ball valve, which is initially in an open state, and the input valve 13 is disposed at one end of the sleeve 110, and includes an input valve member 113, an input valve spring 112, and an input valve seat 114, and the input valve seat 114 is a spherical surface or a conical surface that is engaged with a spherical surface of the input valve member 113. The input valve 13 includes a valve element retainer 115, and the valve element retainer 115 acts on the surface of the input valve element 113, so that the input valve element 113 cannot be seated, and the input valve 13 is always kept in an open state in a return state. The outlet valve 14 is a one-way ball valve, initially closed, and the outlet valve 14 is disposed at one end of a plunger 109 and includes an outlet valve member 107, an outlet valve spring 106 and an outlet valve seat 108.

The electromagnetic force driving device 11 includes an energy storage device 17, a moving part 15, and a stationary part 16. The energy storage device 17 includes an energy storage spring 116, a return spring 111 and a solenoid device 119. The moving part 15 includes a bobbin 102, and the bobbin 102 connects with a sleeve 110 of the plunger assembly 12 and performs a synchronous movement with the sleeve 110. The stationary portion 16 includes an upper housing 100, a lower housing 101, a yoke 103 and a magnetic resistance 120. The upper shell 100 and the lower shell 101 are connected by welding and the like, and meanwhile, the electromagnetic force driving device 11 and the plunger assembly 12 are encapsulated, a clearance volume between the electromagnetic force driving device 11 and the plunger assembly 12 forms a low-pressure oil chamber 121, the shells (100, 101) are provided with an oil inlet 104 and an oil return port 117, fuel oil in the fuel tank enters from the oil inlet 104, enters a pressure-feeding volume 118 from the low-pressure oil chamber 121 through an input valve 13, and forms high-pressure fuel oil output under the action of the electromagnetic force driving device 11. The electromagnetic force driving device 11 is controlled by a driving current and an energy storage spring 116, converts electric energy and spring force into a bidirectional driving force which is changed alternately to drive the moving part 15 to reciprocate and drive the sleeve 110 to realize cavity change of the pressure feeding volume 118, the energy storage device 17 absorbs energy from the moving part 15 in a first reciprocating direction, and the plunger assembly 12 pumps fuel under the combined action of the moving part 15 and the energy storage device 17 in a second reciprocating direction.

The operation of the fuel feed pump 10 is as follows.

In the initial state, the moving portion 15 is located at the end of the stroke in the first direction by the spring force of the return spring 111, and the fuel enters from the oil inlet 104, fills the low-pressure oil chamber 121, and enters the pumping volume 118 through the input valve 13. In the pressure-feeding stroke, the electromagnetic force driving device 11 drives the moving part 15 to move in the second direction under the action of the driving current and the spring force of the energy storage spring 116, the moving part 15 drives the sleeve 110 to compress the volume cavity of the pressure-feeding volume 118, and the input valve 13 is closed, so that the pressure in the pressure-feeding volume 118 is increased, the output valve 14 is opened, and the high-pressure fuel is output. During the return stroke, the moving part 15 moves in the first direction under the action of the reverse electromagnetic force and the return spring 111, and at the same time, the sleeve 110 starts to return to cause the cavity of the pumping volume 118 to become larger, the pressure decreases, the output valve 14 closes, the sleeve 110 continues to move, the input valve 13 opens, the liquid rapidly fills the pumping volume 118 due to the negative pressure in the pumping volume 118, and when the moving part 15 returns to the initial position, the stroke ends, and waits for the next injection cycle.

In the above process, the backflow liquid generated by the reciprocating motion of the moving part 15 is output through the oil return port 117, so as to ensure the pressure balance of the internal cavity of the fuel feed pump 10.

As shown in fig. 2, a schematic structural diagram of an electronic control fuel injection system of an engine according to the present invention includes a fuel tank 24, an electromagnetic pulse fuel supply pump 10, a pressure fuel pipe 20, a fuel rail 21, at least one fuel injector 22, and an Electronic Control Unit (ECU)23 of the engine. The electromagnetic pulse oil supply pump 10 is arranged in the oil storage tank 24, the oil supply pump 10 is connected with the oil nozzle 22 through the pressure oil pipe 20, the oil rail 21 is arranged between the pressure oil pipe 20 and the nozzle, and the inner diameter of the oil rail 21 is larger than that of the pressure oil pipe 20. The fuel injection nozzle 22 is an on-off injection valve and is controlled to open and close by the ECU 23, fuel is injected according to the fuel injection quantity demand and stroke synchronous pulse of the engine, the fuel supply pump 10 is also controlled by the ECU 23 to supply fuel equal to or approximately equal to the fuel injection flow quantity of the fuel injection nozzle 22 to the pressure fuel pipe 20 according to the self-metering mode, and the fuel quantity and the pressure in the pressure fuel pipe 20 are basically kept unchanged through the balance of the average fuel flow quantities metered by the two.

The logic diagram of the system is shown in fig. 4, and the flow rate is regulated and controlled by detecting the feedback parameter value of the fuel supply pump 10 through the ECU. The feedback parameter of the fuel feed pump 10 is a T3 parameter when each fuel feed pulse is completed, and the T3 critical value is a minimum T3 capable of achieving the calibrated single fuel supply. The concrete mode comprises:

in the initial state, the ECU control unit 23 is powered on (step 40), the ECU control unit 23 drives the supply pump 10 to first fill the pressure oil pipe 20 with fuel (step 41) until the internal pressure of the pressure oil pipe 20 rises to cause the oil amount of the single-pulse pump of the supply pump 10 to be significantly reduced, and the ECU 23 detects the reduction trend through the feedback parameter T3 of the supply pump 10 to confirm the fuel filling state (step 42).

After the engine is started, the fuel supply pump 10 supplies the pressure fuel pipe 20 with a basic fuel supply flow rate equal to the fuel flow rate injected from the fuel injection nozzle 22 (step 44), and performs a small feedback adjustment of the fuel supply flow rate according to a control target that the T3 parameter is not continuously smaller than a critical value but is not continuously larger than a plurality of (4 or more) critical values (step 45). That is, when the ECU detects that T3 is less than the threshold T3 (step 46), the fuel flow is immediately reduced (e.g., by at least 5% less than the nozzle injection flow) until nozzle injection flow is restored when T3 is greater than or equal to the threshold (step 47). And once the ECU detects that T3 is greater than or equal to the threshold T3 for more than 4 consecutive times (step 48), the fuel supply flow is increased immediately (e.g., at least 5% greater than the nozzle injection flow) (step 49).

Referring to fig. 3, a second schematic structural diagram of an engine electronic control fuel injection system according to the present invention is shown, and the difference between this embodiment and the first schematic structural diagram of the system according to the present invention is that a pressure relief valve 30 is included. The pressure release valve 30 is arranged at the outlet end of the oil supply pump 10 and is arranged in the oil storage tank 24, the pressure release valve 30 does not need to be connected with an external oil return pipe, and redundant fuel oil in the pressure oil pipe 20 returns to the oil storage tank 24 through the pressure release valve 30.

The logic diagram of the system is shown in fig. 5, and the flow regulation is realized by the regulation of the pressure relief valve 30. A pressure release valve 30 which is opened at a constant pressure is arranged on an oil path between the oil nozzle 22 and the oil supply pump 10, and the pressure release valve is opened when the oil supply quantity of the oil supply pump 10 is larger than the fuel quantity sprayed by the oil nozzle 22 and the pressure of the pressure oil pipe 20 is too high. The concrete mode comprises:

initially, the ECU control unit is powered (step 50), and the pressure line 20 is first filled with fuel at a calibrated fuel supply flow rate and time (step 51), and injection is stopped when the fuel injection amount reaches a given value (step 52).

After the engine is started (step 53), the supply pump 10 supplies fuel at a flow slightly greater than the flow of fuel injected by the fuel injector 22 (step 55), but not more than 1.1 times the flow of fuel injected by the fuel injector (step 54). Excess pressure fuel in the pressure line 20 is vented through the relief valve 30 to ensure fuel stability (step 56).

As shown in fig. 2 and fig. 3, when the electronic control fuel injection system of the engine is applied to a single-cylinder engine, the pressure fuel pipe 20 is a thin pipe, the inner diameter of the thin pipe is smaller than 3mm, the oil outlet end of the fuel feed pump 10 is connected with the nozzle, the fuel feed pump 10 is installed inside a fuel tank, and no oil return system exists outside the fuel tank.

The above examples are only for illustrating the essence of the present invention, but not for limiting the present invention. Any modifications, simplifications, or other alternatives made without departing from the principles of the invention are intended to be included within the scope of the invention.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.

Claims

1. An electronically controlled fuel injection system for an engine, comprising: the fuel injection device comprises an electromagnetic pulse fuel supply pump, a pressure fuel pipe, at least one fuel injection nozzle and an Electronic Control Unit (ECU) of the engine, and is characterized in that the fuel injection nozzle is an on-off injection valve and is controlled by the ECU to be opened and closed, fuel is injected according to the fuel injection quantity demand and stroke synchronous pulse of the engine, the fuel supply pump is also controlled by the ECU to provide the fuel which is equal to or approximately equal to the fuel injection flow of a nozzle to the pressure fuel pipe according to the pulse metering mode of the ECU, and the fuel quantity and the pressure in the pressure fuel pipe are basically kept unchanged through the balance of the average flow of the fuel metered by the ECU.

2. An electronically controlled fuel injection system for an engine according to claim 1, wherein both the single pulse supply rate and the pump operating pulse frequency of said supply pump are controllably adjusted in real time, and the supply flow rate is determined by the single pulse supply rate and the pump operating pulse frequency thereof.

3. An electronically controlled fuel injection system for an engine as set forth in claim 2 wherein the maximum single pulse fuel supply for said supply pump is set at 1 to 1.5 times the maximum fuel required per cycle at steady state engine operation.

4. An electronically controlled fuel injection system according to claim 3, wherein after said ECU is powered up, said supply pump first fills said pressure line with fuel until the pressure within said pressure line rises to cause a substantial reduction in the volume of said fuel pump, said ECU detecting said reduction via feedback from said supply pump.

5. An electronically controlled fuel injection system according to claim 4, wherein said ECU detects said feed pump feedback parameter as a parameter T3 relating to the amount of fuel delivered at the completion of each fuel pulse, and wherein the threshold T3 is the minimum T3 at which a calibrated single fuel delivery is achieved.

6. An electronically controlled fuel injection system for an engine according to claim 5, wherein said supply pump supplies said pressure line with a base supply flow rate equal to the flow rate of fuel injected from said nozzle after engine start-up operation.

7. An electronic control fuel injection system of an engine according to claim 3, characterized in that a pressure relief valve which is opened at a constant pressure is arranged on a fuel line between the nozzle and the fuel supply pump, and the pressure relief valve is opened when the pressure of the pressure fuel pipe is too high due to the fact that the fuel supply quantity of the fuel supply pump is larger than the fuel quantity sprayed by the nozzle, and the pressure relieved fuel directly flows into the fuel tank or returns to the fuel tank through an oil return device.

8. An engine electronically controlled fuel injection system according to claim 7, wherein said ECU is powered up to first fill the pressure line with fuel at a calibrated fueling flow rate and time.

9. An electronically controlled fuel injection system according to claim 8, wherein said supply pump supplies fuel at a flow rate slightly greater than the flow rate of fuel injected by said nozzle but no more than 1.1 times the flow rate of fuel injected by said nozzle after engine start-up operation.

10. An electronic control fuel injection system for an engine according to any one of claims 1 to 9, wherein when applied to a single cylinder engine, the pressure fuel pipe is a thin pipe with an inner diameter smaller than 3mm, and connects the oil outlet end of the fuel feed pump with the nozzle, and the fuel feed pump is installed inside a fuel tank without an oil return system outside the fuel tank.

11. An electronic control fuel injection system for an engine according to any one of claims 1 to 9, further comprising a fuel rail disposed between the pressure fuel line and the nozzle, the fuel rail having an inner diameter larger than that of the pressure fuel line, the pressure fuel line being one connecting the outlet end of the fuel supply pump and the fuel rail, and the fuel supply pump being installed inside the fuel tank, when used in a multi-cylinder engine.

12. An electronic control fuel injection system for an engine according to claim 9, further comprising an oil rail disposed between the pressure line and the nozzle when used in a multi-cylinder engine, wherein the pressure line is a pipe connecting the oil outlet of the fuel feed pump and the oil rail, the fuel feed pump is installed inside the fuel tank, the pressure relief valve is installed at the outlet end of the fuel feed pump, the return oil directly flows into the fuel tank, and there is no oil return system outside the fuel tank.

13. An electronic control fuel injection system for an engine according to claim 9, further comprising an oil return pipe and an oil rail disposed between the pressure oil pipe and the nozzle when used in a multi-cylinder engine, wherein the pressure oil pipe is a single pipe and connects the oil outlet end of the oil supply pump with the oil rail, the oil supply pump is installed inside the fuel tank, the pressure relief valve is installed on the oil rail, and the return oil flows back to the fuel tank through the oil return pipe.