A method for bleeding fuel system

Abstract

The present invention relates to the technical field of engine performance testing, and specifically discloses a method for venting a fuel system, wherein the method adjusts the travel of a metering valve in a fuel regulator and simultaneously adjusts the opening of a vent valve in the fuel system, thereby adjusting the fuel flow rate of the vent port of the fuel regulator, so that the fuel in the fuel system is fully circulated and filled, thereby achieving a fully unsealed effect. The method for venting a fuel system provided by the present invention can reduce the engine failure rate and the cost of repeated engine testing.

Description

Technical Field

[0001] The invention relates to the technical field of engine performance testing, in particular to a technology for deflation and filling of an engine fuel system after long-term storage. Background Art

[0002] The engine fuel system is mainly composed of fuel filter, fuel gear pump, fuel regulator and other structures. The main function of the fuel system is to provide metered fuel to the combustion chamber according to the control law to ensure the reliable operation of the engine. If the fuel in the fuel system is not filled sufficiently and there is a lot of air, especially for engines that have been stored for a long time, as the sealing performance of the seals decreases, the amount of fuel missing from the oil seals in the fuel system increases, and a large amount of fuel is lost from the oil seals. During the engine start-up process, due to the large amount of fuel missing in the fuel system, the fuel pressure supplied to the fuel nozzle may be insufficient, resulting in ignition delay, and in severe cases, the engine may fail to start. At the same time, when there is a lot of air in the fuel system, it will also affect the normal operation of the fuel gear pump and fuel regulator, mainly affecting the accuracy of the movement of precision valves such as the metering valve, equal pressure differential valve, and duty cycle valve in the fuel system, reducing the adjustment accuracy in the fuel system, and the actual fuel flow rate deviates from the fuel flow rate calculated according to the control law. The resulting fuel flow rate deviation further causes fluctuations in parameters such as the engine speed and exhaust temperature. In severe cases, the engine will report a fault and stop.

[0003] At present, the traditional methods of bleeding fuel systems generally include static pressurization bleeding of the fuel system and false engine start bleeding. The main problems with these two bleeding methods are that the bleeding effect of the engine fuel system is not ideal, and the fuel system is not fully filled with fuel, mainly because the control chamber in the fuel regulator is not fully filled with fuel. The main reason is static pressurization bleeding of the fuel system or false engine start bleeding. The moving stroke of the metering needle in the fuel regulator is limited, the fuel flow in the control chamber is insufficient, and the internal air cannot be fully removed. During the engine starting process, the air in the control chamber is not fully discharged, the fuel pressure in the control chamber fluctuates, and the actual position of the metering needle deviates from the target position, which further causes fluctuations in parameters such as engine fuel flow, speed and exhaust temperature.

[0004] Therefore, it is necessary to design an efficient and effective engine fuel system bleeding test procedure to ensure that the fuel system is fully bled and improve the reliability of engine operation. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to fully deflate the engine fuel system, improve the unsealing effect of the engine fuel system, and improve the working reliability of the engine.

[0006] Technical solution: To achieve the above purpose, the present invention adopts the following technical solution:

[0007] A method for venting a fuel system, the method adjusts the travel of a metering valve in a fuel regulator and simultaneously adjusts the opening of a vent valve in the fuel system, thereby adjusting the fuel flow rate of the vent port of the fuel regulator, so that the fuel in the fuel system is fully circulated and filled, thereby achieving a fully unsealed effect.

[0008] Furthermore, according to the structure and principle of the engine fuel system, the method for adjusting the movement stroke of the metering valve in the fuel regulator is: the operating console sends a control command to the engine controller, and when the engine controller receives the start preparation command for a period of time, when it receives the fuel unsealing / oil sealing command, it connects the parking solenoid valve and disconnects the starting solenoid valve; after receiving the fuel unsealing / oil sealing command for a period of time, the parking solenoid valve is disconnected and the starting solenoid valve is connected at the same time; after an interval of time, the engine controller gives the fuel regulator metering oil needle a step to the maximum command, and after maintaining for a period of time, the engine controller gives the metering oil needle to step to the minimum command, and then automatically stops after an interval of time.

[0009] Furthermore, during the adjustment of the movement stroke of the metering valve in the fuel regulator, the length of the instruction interval is determined according to the engine start control law.

[0010] Furthermore, according to the adjustment method of the movement stroke of the metering valve in the fuel regulator, the corresponding control software is designed, and the adjustment method is implemented in code. When the engine fuel system is unsealed, the engine controller runs the control software, which reduces the workload of repeatedly downloading software and improves efficiency.

[0011] Furthermore, the bleed port of the fuel regulator is connected to a bleed tool, and an adjusting pin is designed inside the bleed tool. By adjusting the stroke of the adjusting pin, the opening of the fuel system bleed valve can be changed.

[0012] Furthermore, during the execution of the deflation control software, the priority is lower than the parking instruction, and when the parking instruction is received, the parking is executed immediately.

[0013] Furthermore, during the operation of the control software, it does not respond to the start-up instructions and status control instructions sent by the console.

[0014] Beneficial technical effects:

[0015] The new fuel system bleed method provided by the present invention, under the control of the corresponding engine controller, the metering needle in the fuel system moves fully according to the control requirements, so that the air in the fuel system can be fully discharged, avoiding the pressure, speed, exhaust temperature and other parameter fluctuations caused by insufficient bleed during the operation of the engine, and improving the working reliability of the engine. The fuel system bleed method provided by the present invention can reduce the engine failure rate and reduce the cost of repeated engine testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of the present invention,

[0017] Figure 2 This is a schematic diagram of the deflation tool;

[0018] Among them, 1-drain oil pipeline, 2-adjusting nail, 3-take-over nozzle, 4-housing, 5-jacket nut. DETAILED DESCRIPTION

[0019] In order to ensure that the engine fuel system is fully vented, improve the unsealing effect of the engine fuel system, and improve the working reliability of the engine, the present invention specifically designs a new method for venting the fuel system, by adjusting the movement stroke of the metering valve in the fuel regulator, increasing the fuel flow rate of the venting port of the fuel regulator, so that the fuel in the fuel system is fully circulated and filled, thereby achieving the effect of full unsealing.

[0020] The venting method is based on the structure and principle of the engine fuel system, and the corresponding controller software is specifically designed. The control software is used to adjust the stroke of the metering oil needle in the fuel regulator according to a certain control law to achieve the effect of fully unsealing and venting the engine fuel system.

[0021] According to the adjustment method of the movement stroke of the metering valve in the fuel regulator, the corresponding control software is designed, and the adjustment method is implemented in code. When the engine fuel system is unsealed, the engine controller runs the control software to reduce the workload of repeatedly downloading software and improve efficiency.

[0022] See attached Figure 2 In order to better cooperate with the fuel deflation method proposed in the present invention, an adapted fuel deflation tool is designed, which includes a pipeline 1, an adjustment pin 2, a pipe nozzle 3, a shell 4, and a sleeve nut 5. The two ends of the shell 4 are respectively provided with a pipe nozzle 3 and an adjustment pin 2, and the front end of the adjustment pin 2 passes through the pipe nozzle 3; the pipe nozzle 3 is connected to the pipeline 1, and the pipeline 1 is arranged in the middle section of the shell 4; when in use, the sleeve nut 5 is connected to the deflation port of the deflation valve, and the adjustment pin 2 is rotated, and the front end of the adjustment pin 2 presses down the deflation valve, and the fuel flows out from the pipeline 1. The fuel system deflation tool is designed with an adjustment pin inside, and the opening of the fuel system deflation valve can be changed by adjusting the stroke of the adjustment pin.

[0023] The fuel system bleed tool adds a rubber ring sealing structure, which can ensure that its own fuel flow loss is small and will not have a throttling effect. At the same time, it can ensure that external air cannot enter the fuel system.

[0024] A transparent hose structure is designed inside the fuel system bleed tool, which can observe the fuel flow at the outlet of the fuel system bleed valve and whether there are bubbles in the fuel, to assist in judging the unsealing effect of the fuel system.

[0025] Implementation Cases

[0026] Taking a certain type of engine as an example, a flow chart of a method for fully bleeding fuel system provided by the present invention is provided. The method for fully bleeding fuel system provided by the present invention comprises:

[0027] Step 1: Design the corresponding fuel system bleed control software and download the software to the corresponding engine controller. The specific corresponding control software requirements are as follows;

[0028] a) In the engine control command, D6 is the fuel unsealing / oil sealing command. D6=1 means the fuel unsealing / oil sealing command has been issued, and D6=0 means the fuel unsealing / oil sealing command has not been issued. The control console sends the fuel unsealing / oil sealing command 10 times in succession, and the engine controller receives it twice in succession. The command is sent from the control console to the controller.

[0029] b) After the engine controller receives the start preparation instruction 4.5s (time adjustable), when receiving the fuel unsealing / oil sealing instruction, it connects the parking electromagnetic valve and disconnects the starting electromagnetic valve; 0.8 seconds after receiving the fuel unsealing / oil sealing instruction, it disconnects the parking electromagnetic valve and connects the starting electromagnetic valve at the same time; after an interval of 2 seconds (time adjustable), it gives a metering oil needle step to the maximum instruction, and after maintaining for 10s (time adjustable), it gives a metering oil needle step to the minimum instruction, and then automatically stops after an interval of 2 seconds (time adjustable); in the specific implementation process, the above time intervals are determined according to the engine start control law;

[0030] c) It is required that during the operation of the control software, the start command and status control command Ncor sent by the console shall not be responded;

[0031] d) In the original state or after receiving the stop command or 27VDC stop command, it does not respond to the fuel unseal / oil seal command sent by the control console; the control software will not run after the control software is executed;

[0032] e) After receiving the start preparation or fuel unsealing / oil sealing instructions, when receiving the stop instruction or "27VDC stop instruction", the stop control function is executed; the stop instruction has a higher priority than the control software. During the execution of the bleed control software, if a stop instruction is received at any stage, the vehicle can be stopped immediately; during the test, if an accident occurs, the vehicle can be stopped immediately;

[0033] f) In the self-test results and feedback instructions (**MOR3), D6=1 means the fuel unseal / oil seal instruction is received, and D6=0 means the fuel unseal / oil seal instruction is not received; after the console sends the instruction to the controller, the controller gives the console corresponding feedback to ensure the instantaneous interaction;

[0034] g) In the state word (**state), D12=1 indicates the fuel unsealing / oil sealing state, and D12=0 indicates the non-fuel unsealing / oil sealing state; the controller can read the definition of the execution state of the engine state and judge the engine execution state through the engine test parameters;

[0035] h) After receiving the fuel unseal / oil seal command, perform fault diagnosis and send out an alarm signal. During the test, the fault code in the engine test parameters is used to issue a fault alarm;

[0036] Step 2: Adaptively add the fuel bleed command of the console according to the fuel system bleed control software to activate the fuel bleed control software and enter the running state;

[0037] Step 3: Connect the engine fuel system to the bleed tool;

[0038] Step 4: The engine is tested according to the control software, and the air in the fuel system is released by the air bleed tool; the opening of the fuel system air bleed valve is determined by the movement stroke of the metering valve in the fuel regulator, and is adjusted synchronously;

[0039] Step 5: Stop the engine, remove the bleed tool, and seal the fuel system as required;

[0040] Step 6: Completely bleed the engine fuel system.

[0041] The above specific implementation methods or cases are only used to explain the technical solutions of the present invention, and are not intended to limit the present application. Any parts not described in detail are deemed to be conventional technical means or common knowledge in the field. A person of ordinary skill in the art should understand that based on the design concept of the present application, the technical solutions described in the aforementioned implementation methods should be adaptively modified, or some or all of the technical features therein should be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for bleeding a fuel system, characterized in that: The method adjusts the travel of the metering valve in the fuel regulator and the opening of the vent valve of the fuel system synchronously, thereby adjusting the fuel flow of the vent port of the fuel regulator, so that the fuel in the fuel system is fully circulated and filled, and the effect of fully unsealing is achieved; the method for adjusting the travel of the metering valve in the fuel regulator is as follows: the operating console sends a control instruction to the engine controller, and when the engine controller receives the start preparation instruction for a period of time, when it receives the fuel unsealing / oil sealing instruction, the parking electromagnetic valve is connected and the starting electromagnetic valve is disconnected; after receiving the fuel unsealing / oil sealing instruction for a period of time, the parking electromagnetic valve is disconnected and the starting electromagnetic valve is connected; after an interval of a period of time, the engine controller gives a fuel regulator metering oil needle step to the maximum instruction, and after a period of time, the engine controller gives a metering oil needle step to the minimum instruction, and then automatically stops after an interval of a period of time.

2. The method for bleeding fuel system according to claim 1, characterized in that: During the adjustment of the travel of the metering valve in the fuel regulator, the length of the command interval is determined according to the engine start control law.

3. The method for bleeding fuel system according to claim 1, characterized in that: According to the adjustment method of the moving stroke of the metering valve in the fuel regulator, the corresponding deflation control software is designed, and when the engine fuel system is unsealed, the engine controller runs the control software.

4. The method for bleeding fuel system as claimed in claim 3, characterized in that: During the execution of the deflation control software, the priority is lower than the parking instruction. When the parking instruction is received, the parking is executed immediately.

5. The method for bleeding fuel system as claimed in claim 3, characterized in that: During the operation of the control software, it does not respond to the start-up instructions and status control instructions sent by the console.

6. The method for bleeding fuel system according to claim 1, characterized in that: During the adjustment process of the metering valve movement stroke in the fuel regulator, the definition of the execution state of the engine state can be read by the controller, and the engine execution state can be judged through the engine test parameters.

7. The method for bleeding fuel system according to claim 1, characterized in that: After receiving the fuel unseal / oil seal command, the system performs fault diagnosis and sends out an alarm signal.

8. The method for bleeding fuel system according to claim 1, characterized in that: The bleed port of the fuel regulator is connected to the bleed tool, which includes a pipeline, an adjusting pin, a pipe nozzle, a shell, and a sleeve nut. A pipe nozzle and an adjusting pin are respectively provided at both ends of the shell, and the front end of the adjusting pin passes through the pipe nozzle; the pipe nozzle is connected to the pipeline, and the pipeline is provided in the middle section of the shell. By adjusting the stroke of the adjusting pin, the opening of the fuel system bleed valve is changed.

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