An engine electronically controlled fuel injection system

Abstract

An engine electronically controlled fuel injection system comprises: an electromagnetic pulse fuel supply pump, a pressure oil pipe, at least one fuel injector, and an engine electronic control unit (ECU). The fuel injector is a switch-type injection valve whose opening and closing are controlled by the ECU, and fuel is pulse-injected in accordance with the engine's injection quantity requirements and in sync with the stroke. The fuel supply pump is also controlled by the ECU to supply fuel to the pressure oil pipe in a metering manner equal to or approximately equal to the fuel flow rate injected by the nozzle. The fuel quantity and pressure in the pressure oil pipe are maintained substantially constant by balancing the average fuel flow rates measured by the two pumps.

Description

Technical Field

[0001] The present invention belongs to the field of engines, and in particular relates to electronic fuel injection gasoline engines, in particular electronic fuel injection gasoline engines for motorcycles and general fields. Background Art

[0002] Electronic fuel injection systems are widely used for their advantages, including improving engine fuel economy, reducing harmful exhaust emissions, and enhancing power performance. In existing gasoline engine electronic fuel injection systems, injector metering of fuel injection is typically achieved using an isobaric valve opening timing method. This is achieved through a fuel supply pump, typically a rotary pump, and a pressure regulating valve or pressure feedback control system.

[0003] However, such a fuel system has many components and is relatively expensive. In particular, when such a fuel injection system is used on motorcycles and general-purpose gasoline engines, there are also problems such as difficulty in component installation and arrangement and reduced system reliability.

[0004] In addition, such fuel systems often require an oil return device. A large oil return flow rate not only causes the fuel temperature to rise, but also consumes too much power to drive the fuel pump, putting pressure on the system's electrical balance.

[0005] In addition, the rotary fuel supply pump is difficult to quickly adjust the fuel supply due to rotational inertia. Even if a very expensive pressure sensor and control system are used to feedback and adjust the fuel supply on demand, it is still very difficult to accurately control the common rail fuel pressure.

[0006] Therefore, seeking a simplified and miniaturized gasoline engine fuel electronic injection system can not only improve the overall applicability of the electronic injection system, but also increase the reliability and safety of the entire machine to a certain extent, and reduce the system cost. Summary of the Invention

[0007] The present invention aims to solve the above problems and to provide an electronically controlled fuel injection system for an engine with a simple structure, convenient arrangement, low cost and high reliability.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an electronically controlled engine fuel injection system comprising an electromagnetic pulse fuel pump, a pressure fuel line, at least one fuel injector, and an engine electronic control unit (ECU). The electromagnetic pulse fuel pump and the fuel injector are connected via the pressure fuel line. The fuel injector is an on / off injection valve whose opening and closing are controlled by the ECU. It pulse-injects fuel in accordance with the engine's injection quantity requirements and in sync with the engine's stroke. The fuel pump, also controlled by the ECU, provides fuel to the pressure fuel line in a pulse metering manner at a rate equal to or approximately equal to the fuel flow rate injected by the nozzle. The average fuel flow rates measured by the two pumps are balanced to maintain a substantially constant fuel volume and pressure in the pressure fuel line.

[0009] The electromagnetic pulse oil pump comprises an electromagnetic power unit and a plunger assembly, enabling rapid response to a single pulse and precise control of the oil supply volume for each pulse. The plunger assembly comprises a sleeve, a plunger, an input valve, and an output valve. These sleeve, plunger, input valve, and output valve form a pressure-delivery volume. The input and output valves can be ball valves, flat valves, or slide valves.

[0010] The electromagnetic power device includes an energy storage device, a moving part and a stationary part. The electromagnetic power device is controlled by a driving current and an energy storage spring to drive the moving part to reciprocate. In a first direction of the reciprocating motion, the energy storage device absorbs energy from the moving part. In a second direction of the reciprocating motion, the plunger-sleeve assembly pressurizes the fuel under the joint action of the moving part and the energy storage device.

[0011] The clearance volume between the electromagnetic power device and the plunger assembly forms a low-pressure oil chamber, and the fuel enters the pressure delivery 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.

[0012] The maximum fuel supply per pulse of the fuel supply pump is designed to be 1 to 1.5 times the maximum fuel required per cycle when the engine is running steadily. The fuel flow measurement is determined by its single pulse fuel supply and the pump working pulse frequency.

[0013] One method for regulating the amount of pressurized fuel is to have the ECU monitor the fuel pump's feedback parameter. The fuel pump's feedback parameter is the T3 parameter at the completion of each fueling pulse, with the critical T3 value being the minimum T3 required to calibrate the single fueling amount. Specific methods include:

[0014] A) In the initial state, when the ECU is powered on, it drives the fuel pump to first fill the pressure oil pipe with fuel until the pressure inside the pressure oil pipe increases to a level that causes the fuel pump's single-pulse oil volume to significantly decrease. The ECU detects this decreasing trend through the fuel pump's feedback parameter T3, thereby confirming the fuel filling status.

[0015] B) After the engine is started, the fuel pump supplies fuel to the pressure oil line at a base flow rate equal to the fuel flow rate ejected from the nozzle. Simultaneously, the fuel flow rate is adjusted via small feedback loops, based on the control target that the T3 parameter should be discontinuously below a critical value but not continuously above the critical value for four or more consecutive times. Specifically, if the ECU detects that T3 is less than the critical value, the fuel flow rate is immediately reduced (e.g., by at least 5% compared to the nozzle injection flow rate) until T3 is restored to the nozzle injection flow rate when it is greater than or equal to the critical value. If the ECU detects that T3 is greater than or equal to the critical value for four or more consecutive times, the fuel flow rate is immediately increased (e.g., by at least 5% compared to the nozzle injection flow rate).

[0016] Another option for regulating the amount of pressurized fuel is to use a pressure relief valve. A pressure relief valve is installed in the oil line between the nozzle and the fuel pump. This valve opens to relieve pressure when the fuel supply from the fuel pump exceeds the amount of fuel sprayed from the nozzle, causing the pressure in the pressure oil line to become too high. Specific methods include:

[0017] A) In the initial state, the ECU control unit is powered on and first fills the pressure oil pipe with fuel according to the calibrated fuel supply flow rate and time.

[0018] B) After the engine is started, the fuel pump supplies fuel at a rate slightly greater than the fuel flow rate ejected from the nozzle, but not exceeding 1.1 times the fuel flow rate ejected from the nozzle. Excess pressure fuel in the pressure oil line is discharged through the pressure relief valve to ensure stable fuel supply.

[0019] When the above-mentioned engine electronic fuel injection system is applied to a single-cylinder engine, the pressure oil pipe is a thin tube with an inner diameter of less than 3mm, connecting the oil outlet end of the fuel supply pump and the nozzle, and the fuel supply pump is installed inside the fuel tank, and there is no oil return system outside the fuel tank.

[0020] The above-mentioned engine electronic fuel injection system, when applied to a multi-cylinder engine, further includes an oil rail arranged between the pressure oil pipe and the nozzle, the inner diameter of the oil rail is larger than the inner diameter of the pressure oil pipe, and the pressure oil pipe is a single pipe connecting the oil outlet end of the oil supply pump and the oil rail, and the oil supply pump is installed inside the fuel tank.

[0021] The pressure relief valve can be located at the outlet of the fuel pump, eliminating the need for an external oil return pipe. Alternatively, it can be located on the fuel rail and include an oil return device, which is a return pipe connecting the fuel tank and the pressure relief valve. Excess fuel flows back to the fuel tank through the return pipe.

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the fuel supply pump structure of the engine electronically controlled fuel injection system provided by the present invention.

[0024] Figure 2 This is one of the structural schematic diagrams of the engine electronically controlled fuel injection system provided by the present invention.

[0025] Figure 3 This is the second structural diagram of the engine electronically controlled fuel injection system provided by the present invention.

[0026] Figure 4This is one of the logic diagrams of the engine electronic fuel injection system provided by the present invention.

[0027] Figure 5 This is the second logical diagram of the engine electronic fuel injection system provided by the present invention. DETAILED DESCRIPTION

[0028] The structural diagram of the oil supply pump 10 provided by the present invention is as follows Figure 1 As shown, it includes an electromagnetic force drive device 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, the plunger 109, the input valve 13 and the output valve 14 form a pressure-delivery volume 118. The plunger 109 and the sleeve 110 slide relative to each other, and their relative movement causes the pressure-delivery volume 118 to alternate in size, thereby generating a high-pressure solution. The input valve 13 is a one-way ball valve, which is initially in an open state. The input valve 13 is arranged 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. The input valve seat 114 is a spherical surface or a conical surface that cooperates with the spherical surface of the input valve member 113. The input valve 13 includes a valve stopper 115, which acts on the surface of the input valve 113 to prevent the input valve 113 from seating, thereby ensuring that the input valve 13 remains open when in the return position. The output valve 14 is a one-way ball valve, initially closed. The output valve 14 is arranged at one end of the plunger 109 and includes an output valve 107, an output valve spring 106, and an output valve seat 108.

[0029] The electromagnetic force drive device 11 includes an energy storage device 17, a moving portion 15, and a stationary portion 16. The energy storage device 17 includes an energy storage spring 116, a return spring 111, and a solenoid device 119. The moving portion 15 includes a coil bobbin 102, which is connected to the sleeve 110 of the plunger assembly 12 and moves synchronously with the sleeve 110. The stationary portion 16 includes an upper housing 100, a lower housing 101, a magnetic yoke 103, and a magnetic resistor 120. The upper shell 100 and the lower shell 101 are connected by welding or other means, and the electromagnetic force driving device 11 and the plunger assembly 12 are encapsulated at the same time. The 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. The fuel in the fuel tank enters from the oil inlet 104, enters the pressure delivery volume 118 from the low-pressure oil chamber 121 through the input valve 13, and forms a high-pressure fuel output under the action of the electromagnetic force driving device 11. The electromagnetic force drive device 11 is controlled by the driving current and the energy storage spring 116, converting the electrical energy and spring force into an alternating bidirectional driving force to drive the moving part 15 to reciprocate and drive the sleeve 110 to achieve cavity changes in the pressurized volume 118. In the first direction of reciprocating motion, the energy storage device 17 absorbs energy from the moving part 15. In the second direction of reciprocating motion, the plunger assembly 12 pressurizes the fuel under the combined action of the moving part 15 and the energy storage device 17.

[0030] The working process of the above-mentioned oil supply pump 10 is as follows.

[0031] In the initial state, under the action of the spring force of the return spring 111, the moving portion 15 is at the end of its travel in the first direction. Fuel enters from the fuel inlet 104, fills the low-pressure oil chamber 121, and enters the delivery volume 118 through the input valve 13. During the delivery stroke, the electromagnetic drive device 11, under the action of the driving current and the spring force of the energy storage spring 116, drives the moving portion 15 in the second direction. The moving portion 15 drives the sleeve 110 to compress the volume chamber of the delivery volume 118. At the same time, the input valve 13 closes, increasing the pressure in the delivery volume 118. The output valve 14 opens, and the fuel is delivered at high pressure. 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. At the same time, the sleeve 110 begins to return, causing the cavity of the pressure-delivering volume 118 to become larger, the pressure to decrease, and the output valve 14 to close. The sleeve 110 continues to move, causing the input valve 13 to open. Due to the negative pressure in the pressure-delivering volume 118, the liquid quickly fills the pressure-delivering volume 118. When the moving part 15 returns to its initial position, the stroke ends and waits for the next injection cycle.

[0032] During the above process, the reflux liquid generated by the reciprocating motion of the moving part 15 is output through the oil return port 117 to ensure the pressure balance of the internal cavity of the oil supply pump 10.

[0033] like Figure 2 FIG2 shows one schematic diagram of the structure of an electronically controlled fuel injection system for an engine according to the present invention. The system comprises a fuel tank 24, an electromagnetic pulse fuel pump 10, a pressure fuel line 20, a fuel rail 21, at least one fuel injector 22, and an engine electronic control unit (ECU) 23. The electromagnetic pulse fuel pump 10 is located within the fuel tank 24 and is connected to the fuel injector 22 via the pressure fuel line 20. The fuel rail 21 is positioned between the pressure fuel line 20 and the fuel injector, and its inner diameter is larger than that of the pressure fuel line 20. The fuel injector 22 is an on / off injection valve controlled by the ECU 23 to open and close. It pulses fuel in accordance with the engine's injection quantity requirements and in sync with the stroke. The fuel pump 10 is also controlled by the ECU 23 to meter fuel to the pressure fuel line 20 at a rate equal to or approximately equal to the fuel flow rate injected by the fuel injector 22. The balance of the average fuel flow rates measured by the two pumps maintains a substantially constant fuel volume and pressure in the pressure fuel line 20.

[0034] The logic diagram of the above system is as follows Figure 4 As shown, flow control is achieved by detecting the feedback parameter value of the fuel pump 10 by the ECU. The feedback parameter of the fuel pump 10 is the T3 parameter when each fuel supply pulse is completed. The T3 critical value is the minimum T3 that can achieve the calibration of the single fuel supply amount. The specific method includes:

[0035] In the initial state, the ECU control unit 23 is powered on (step 40). The ECU control unit 23 drives the fuel 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 increases to a level that causes the single-pulse pumping amount of the fuel supply pump 10 to significantly decrease. The ECU 23 detects this decreasing trend through the feedback parameter T3 of the fuel supply pump 10, thereby confirming the fuel filling status (step 42).

[0036] After the engine is started, the fuel pump 10 supplies fuel to the pressure oil pipe 20 at a basic flow rate equal to the fuel flow rate ejected from the fuel injector 22 (step 44). Simultaneously, the fuel flow rate is adjusted by small feedback adjustments based on the control target of ensuring that the T3 parameter is discontinuously below a critical value but also not continuously above the critical value for four or more consecutive times (step 45). Specifically, when the ECU detects that T3 is less than the critical value (step 46), the fuel flow rate is immediately reduced (e.g., by at least 5% compared to the nozzle injection flow rate) until T3 is restored to the nozzle injection flow rate when it is greater than or equal to the critical value (step 47). If the ECU detects that T3 is greater than or equal to the critical value for four or more consecutive times (step 48), the fuel flow rate is immediately increased (e.g., by at least 5% compared to the nozzle injection flow rate) (step 49).

[0037] like Figure 3FIG2 is a second schematic diagram of the structure of the electronically controlled fuel injection system for an engine according to the present invention. This embodiment differs from the first schematic diagram of the system structure according to the present invention in that it includes a pressure relief valve 30. The pressure relief valve 30 is located at the outlet of the fuel pump 10 and within the fuel tank 24. The pressure relief valve 30 does not require an external return line. Excess fuel in the pressure fuel line 20 is returned to the fuel tank 24 through the pressure relief valve 30.

[0038] The logic diagram of the above system is as follows Figure 5 As shown, flow control is achieved by adjusting the pressure relief valve 30. A pressure relief valve 30 that opens at a constant pressure is provided in the oil line between the fuel injector 22 and the fuel pump 10. It opens to relieve pressure when the fuel supply from the fuel pump 10 exceeds the fuel sprayed from the fuel injector 22, causing the pressure in the pressure oil pipe 20 to be too high. Specific methods include:

[0039] In the initial state, the ECU control unit is powered on (step 50 ), and firstly fills the pressure oil pipe 20 with fuel according to the calibrated fuel supply flow rate and time (step 51 ), and stops the injection when the fuel injection amount reaches a given value (step 52 ).

[0040] After the engine starts (step 53), the fuel pump 10 supplies fuel at a rate slightly greater than the fuel flow rate injected by the fuel injector 22 (step 55), but not exceeding 1.1 times the fuel flow rate injected by the injector (step 54). Excess pressure fuel in the pressure fuel pipe 20 is discharged through the pressure relief valve 30 to ensure stable fuel supply (step 56).

[0041] like Figure 2 、 Figure 3 When the engine electronic fuel injection system is applied to a single-cylinder engine, the pressure oil pipe 20 is a thin tube with an inner diameter of less than 3 mm, connecting the oil outlet end of the oil supply pump 10 and the nozzle, and the oil supply pump 10 is installed inside the fuel tank, and there is no oil return system outside the fuel tank.

[0042] The above embodiments are only used to illustrate the essence of the present invention, but do not limit the present invention. Without departing from the principle of the present invention, any modification, simplification or other replacement methods are included in the protection scope of the present invention.

[0043] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

Claims

1. A method for controlling an electronically controlled fuel injection system of an engine, the injection system comprising: An electromagnetic pulse fuel supply pump, a pressure oil pipe, at least one nozzle, and an engine electronic control unit (ECU), wherein the nozzle is an on / off injection valve and is controlled by the ECU to open and close, injecting fuel in pulses synchronized with the engine's injection quantity requirements and strokes. The fuel supply pump is also controlled by the ECU to supply fuel to the pressure oil pipe in a pulse metering manner equal to the fuel flow rate injected by the nozzle, and the fuel volume and pressure in the pressure oil pipe are maintained substantially constant by balancing the average fuel flow rates measured by the two pumps. The single pulse oil supply volume and pump working pulse frequency of the oil supply pump can be controlled and adjusted in real time, and the oil supply flow measurement is determined by the single pulse oil supply volume and the pump working pulse frequency; After the ECU is powered on, the fuel supply pump first fills the pressure oil pipe with fuel until the internal pressure of the pressure oil pipe increases to a level that causes a significant reduction in the amount of fuel pumped by the fuel supply pump in a single pulse, and the ECU detects this reduction through feedback parameters of the fuel supply pump; The ECU detects the feedback parameter of the fuel supply pump as a parameter T3 related to the fuel supply amount of each fuel supply pulse when the fuel supply pulse is completed, and the critical value of T3 is the minimum T3 that can achieve the calibration of the single fuel supply amount; After the engine is started, the basic fuel supply flow of the fuel supply pump is supplied to the pressure oil pipe in accordance with the principle of being equal to the fuel flow rate ejected from the nozzle, and the fuel supply amount is adjusted in real time according to the following method: with the T3 parameter being discontinuously less than the critical value but not being greater than the critical value for four or more consecutive times as the control target, the fuel supply flow is adjusted by small feedback, that is, when the ECU detects that T3 is less than the T3 critical value, the fuel supply flow is immediately reduced until T3 is greater than or equal to the critical value and restored to the nozzle injection flow rate. Once the ECU detects that T3 is greater than or equal to the T3 critical value for more than four consecutive times, the fuel supply flow is immediately increased.

2. The control method of the engine electronic fuel injection system according to claim 1, characterized in that: The maximum fuel supply amount per single pulse of the fuel supply pump is 1 to 1.5 times the maximum fuel amount required per cycle when the engine is running in a steady state.

3. The control method of the engine electronic fuel injection system according to claim 2, characterized in that: A pressure relief valve that opens at a constant pressure is provided in the oil circuit between the nozzle and the fuel supply pump. When the fuel supply of the fuel supply pump is greater than the fuel amount sprayed from the nozzle, causing the pressure in the pressure oil pipe to be too high, it opens to relieve pressure. The relieved fuel flows directly into the fuel tank or returns to the fuel tank through an oil return device.

4. The control method of the engine electronic fuel injection system as claimed in claim 3, characterized in that: After the ECU is powered on, the pressure oil pipe is first filled with fuel according to the calibrated fuel supply flow rate and time.

5. The control method of the engine electronic fuel injection system as claimed in claim 4, characterized in that: After the engine is started, the fuel supply pump supplies fuel at a flow rate slightly greater than the fuel flow rate sprayed out of the nozzle, but not exceeding 1.1 times the fuel flow rate sprayed out of the nozzle.

6. The control method of the engine electronic fuel injection system according to any one of claims 1 to 5, characterized in that: When used on a single-cylinder engine, the pressure oil pipe is a thin tube with an inner diameter of less than 3mm, connecting the oil outlet end of the oil supply pump and the nozzle. The oil supply pump is installed inside the fuel tank, and there is no oil return system outside the fuel tank.

7. The control method of the engine electronic fuel injection system according to any one of claims 1 to 5, characterized in that: When used on a multi-cylinder engine, it also includes an oil rail arranged between the pressure oil pipe and the nozzle. The inner diameter of the oil rail is larger than the inner diameter of the pressure oil pipe. There is one pressure oil pipe connecting the oil outlet end of the oil supply pump and the oil rail, and the oil supply pump is installed inside the fuel tank.

8. The control method of the engine electronic fuel injection system as claimed in claim 3, characterized in that: When used on a multi-cylinder engine, it also includes an oil rail arranged between the pressure oil pipe and the nozzle. The pressure oil pipe is one and connects the oil outlet end of the oil supply pump and the oil rail. The oil supply pump is installed inside the fuel tank, and the pressure relief valve is installed at the outlet end of the oil supply pump. The return oil flows directly into the fuel tank, and there is no oil return system outside the fuel tank.

9. The control method of the engine electronic fuel injection system as claimed in claim 3, characterized in that: When used on a multi-cylinder engine, it also includes a return oil pipe and an oil rail arranged between the pressure oil pipe and the nozzle. The pressure oil pipe is one and connects the oil outlet end of the oil supply pump and the oil rail. The oil supply pump is installed inside the fuel tank. The pressure relief valve is installed on the oil rail. The return oil flows back to the fuel tank through the return oil pipe.

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