High-pressure fuel cooperative control system based on multi-gear rail pressure sensing

Abstract

The invention provides a high-pressure fuel cooperative control system based on multi-gear rail pressure sensing, which is characterized in that a variable frequency motor is in transmission connection with a rotor type high-pressure oil pump through a coupler, an oil outlet of the rotor type high-pressure oil pump is communicated with a pressure-stabilizing common-rail pipe through a common-rail oil inlet pipe, and the rotor type high-pressure oil pump is further communicated with a fuel tank through a first oil return pipe; the pressure-stabilizing common-rail pipe is connected with the oil sprayer through a high-pressure oil pipe A mechanical control valve is arranged at one end of the pressure stabilizing common rail pipe and communicated with the fuel tank through a second oil return pipe. An electromagnetic valve is arranged at the other end of the pressure stabilizing common rail pipe and is communicated with the fuel tank through a third oil return pipe; a pressure storage cavity is formed in the pressure stabilizing common rail pipe, a plurality of independent channels are formed in the pressure storage cavity, each channel is correspondingly provided with a rail pressure sensor, a circulation valve is arranged at an input port of each channel, and the circulation valves and the rail pressure sensors are electrically connected with a controller. Accurate measurement within a large pressure range can be achieved, and the stability of the fuel flow of the fuel injector is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engine fuel injection test, and particularly relates to a high-pressure fuel collaborative control system based on multi-grade rail pressure sensing. BACKGROUND

[0002] The high-pressure fuel injection system is the core of the engine, and the rail pressure control precision and measurement range directly affect the power, economy and emission performance of the engine. In the prior art, the rail pressure measurement of the high-pressure fuel system mostly uses a single rail pressure sensor. In order to cover a wide pressure range, a large-range sensor needs to be selected, but such a sensor has low measurement precision in the low pressure range and cannot meet the precise control requirements of the engine under low load conditions. If a small-range high-precision sensor is selected, the high pressure demand of the engine under high load cannot be covered, resulting in a mutual restriction between the measurement range and the precision.

[0003] In terms of pressure control, the traditional system mostly uses a single control element. The mechanical pressure relief valve can achieve large flow relief, but has poor control precision and cannot meet the small regulation requirements of the rail pressure of the modern engine. When only an electromagnetic valve is used for control, although precise regulation can be achieved, under large pressure fluctuation or overpressure conditions, problems such as breakdown and component damage are prone to occur, causing unstable fuel injection.

[0004] In addition, in the current multi-grade measurement system, the installation channels of different grade sensors are prone to mutual interference, and pressure fluctuation is prone to occur during switching, further affecting the measurement precision. At the same time, the measurement and control links are disconnected, and the precise measurement data cannot be effectively converted into precise control instructions, resulting in poor collaboration of the overall system. SUMMARY

[0005] Therefore, the application aims to provide a high-pressure fuel collaborative control system based on multi-grade rail pressure sensing to solve at least one of the above problems.

[0006] To achieve the above-mentioned purpose, the technical scheme of the application is as follows: The application provides a high-pressure fuel collaborative control system based on multi-grade rail pressure sensing, comprising a variable frequency motor, a rotor type high-pressure oil pump, a pressure stabilizing common rail pipe, an oil injector and a fuel tank. The variable frequency motor is drivingly connected to the rotor type high-pressure oil pump through a shaft coupling, the oil outlet of the rotor type high-pressure oil pump is communicated with the pressure stabilizing common rail pipe through a common rail oil inlet pipe, the rotor type high-pressure oil pump is further communicated with the fuel tank through a first oil return pipe, and the pressure stabilizing common rail pipe is connected to the oil injector through a high-pressure oil pipe to form a fuel supply channel. One end of the stable pressure common rail pipe is provided with a mechanical control valve, the mechanical control valve is communicated with the fuel tank through a second oil return pipe to form an oil return circuit; the other end of the stable pressure common rail pipe is provided with a solenoid valve, the solenoid valve is communicated with the fuel tank through a third oil return pipe to form a pressure regulating circuit; The stable pressure common rail pipe is provided with a pressure accumulation cavity, a plurality of independent channels are formed in the pressure accumulation cavity, a rail pressure sensor is correspondingly arranged on each channel, and a flow-through valve is arranged at the input port of each channel, and the flow-through valve and the rail pressure sensor are electrically connected with the controller.

[0007] Further, three independent channels are formed in the pressure accumulation cavity, and a first gear rail pressure sensor, a second gear rail pressure sensor and a third gear rail pressure sensor are correspondingly arranged on the three channels to collect fuel pressure signals of different gears. The first gear rail pressure sensor, the second gear rail pressure sensor and the third gear rail pressure sensor are electrically connected with the controller through a solenoid valve control line.

[0008] Further, the first gear rail pressure sensor is a low-pressure gear rail pressure sensor, and the range of the low-pressure gear rail pressure sensor is 5bar~50bar. The second gear rail pressure sensor is a medium-pressure gear rail pressure sensor, and the range of the low-pressure gear rail pressure sensor is 30bar~150bar. The third gear rail pressure sensor is a high-pressure gear rail pressure sensor, and the range of the low-pressure gear rail pressure sensor is 100bar~1000bar.

[0009] Further, the electronic control unit receives signals of each gear rail pressure sensor, and according to the pressure value in the stable pressure common rail pipe at present, the opening and closing of the channel flow-through valve of the corresponding range sensor is controlled, wherein in the overlapping range area, the controller adopts a low gear priority principle, including: In response to the pressure value being 5bar~40bar, only the first gear rail pressure sensor is opened; In response to the pressure value being 40bar~100bar, the second gear rail pressure sensor is switched on; In response to the pressure value being 100bar~1000bar, the third gear rail pressure sensor is switched on.

[0010] Further, the maximum oil discharge flow of the mechanical control valve is not less than 50L / min.

[0011] Further, the flow regulation accuracy of the solenoid valve is not less than 0.01L / min, and the response time is not more than 10ms.

[0012] Further, the variable frequency motor adjusts the rotating speed according to the control signal output by the controller, so as to drive the rotor type high-pressure oil pump to extract fuel from the fuel tank and input the pressurized fuel into the stable pressure common rail pipe, and the stable pressure common rail pipe offsets the pressure fluctuation in the fuel delivery process through its volume to perform preliminary pressure stabilization.

[0013] Compared with the prior art, the high-pressure fuel collaborative control system based on multi-grade rail pressure sensing has the following beneficial effects: (1) The rail pressure sensor with three overlapping ranges and the multi-channel independent pressure accumulation cavity are matched, so that full coverage of 5bar-1000bar is realized, and each pressure interval is within the effective measurement range of the corresponding sensor, so that the measurement error is small, and the problem of "incompatible range and precision" of the traditional single sensor is solved.

[0014] (2) The mechanical pressure relief valve is used to realize the rapid return of overpressure (greatly reducing the response time of coarse adjustment), and the precise flow regulation of the battery valve is used to realize the 0.1 bar level correction of the rail pressure, and the two are cooperated, so that the control stability under large pressure fluctuation is ensured, and the high-precision control requirement is met, and the rail pressure control precision and range are improved synchronously.

[0015] (3) The multi-channel independent pressure accumulation cavity used in the application is isolated from each other, so that the pressure interference during sensor switching is avoided; the low-pressure grade is given priority in the overlapping range area, so that the high-precision measurement area of the pressure sensor is effectively utilized, the reliability of the measurement data is improved, and the measurement error is reduced.

[0016] (4) The system described in the application can be widely applied to various high-pressure fuel injection scenes, and by calibrating different pressure relief thresholds and sensor switching logic, it can adapt to the fuel supply requirements of different pressure requirements, and has strong universality. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve to explain the present application. The accompanying drawings do not constitute an inappropriate limitation on the present application. In the drawings: Figure 1 A structure schematic diagram of a high-pressure fuel collaborative control system based on multi-grade rail pressure sensing according to an embodiment of the present application; Figure 2 A structure schematic diagram of a multi-channel independent pressure accumulation cavity according to an embodiment of the present application.

[0018] Explanation of reference signs: 1, variable frequency motor; 2, shaft coupling; 3, rotor type high pressure oil pump; 4, common rail oil inlet pipe; 5, stable pressure common rail pipe; 5-1, mechanical control valve; 5-2, electromagnetic valve; 6, pressure accumulation cavity; 6-1, first flow valve; 6-2, second flow valve; 6-3, third flow valve; 6-4, first gear rail pressure sensor; 6-5, second gear rail pressure sensor; 6-6, third rail pressure sensor; 7, high pressure oil pipe; 8, fuel injector; 9, second return oil pipe; 10, third return oil pipe; 11, first return oil pipe; 12, fuel tank; 13, controller; 14, electromagnetic valve control line; 15, sensor signal line. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and drawings.

[0020] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the general meaning understood by those skilled in the art to which the present application belongs. The terms "first", "second" and the like used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. The terms "include" or "contain" and the like mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and the like are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. The terms "up", "down", "left", "right" and the like are only used to represent relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] Referring to Figure 1 As shown in the drawings, the embodiment provides a high pressure fuel cooperative control system based on multi-gear rail pressure sensing, which comprises a variable frequency motor 1, a rotor type high pressure oil pump 3, a stable pressure common rail pipe 5, a fuel injector 8 and a fuel tank 12. The variable frequency motor 1 is drivingly connected with the rotor type high pressure oil pump 3 through the shaft coupling 2, the oil outlet of the rotor type high pressure oil pump 3 is communicated with the stable pressure common rail pipe 5 through the common rail oil inlet pipe 4, the rotor type high pressure oil pump 3 is also communicated with the fuel tank 12 through the first return oil pipe 11, and the stable pressure common rail pipe 5 is connected with the fuel injector 8 through the high pressure oil pipe 7 to form a fuel supply channel. One end of the stable pressure common rail pipe 5 is provided with a mechanical control valve 5-1, the mechanical control valve 5-1 is communicated with the fuel tank 12 through the second return oil pipe 9 to form a drain circuit, and the other end of the stable pressure common rail pipe 5 is provided with an electromagnetic valve 5-2, the electromagnetic valve 5-2 is communicated with the fuel tank 12 through the third return oil pipe 10 to form a pressure regulating circuit. The steady pressure common rail pipe 5 is provided with an accumulator chamber 6, a plurality of independent channels are formed in the accumulator chamber 6, a rail pressure sensor is correspondingly arranged on each channel, and a flow valve is arranged at the input port of each channel, and the flow valve and the rail pressure sensor are electrically connected with the controller 13.

[0022] Specifically, in the embodiment, the variable frequency motor 1 and the rotor type high pressure oil pump 3 provide fuel pressure input according to the flow demand, the steady pressure common rail pipe 5 isolates pressure fluctuation, the multi-channel independent accumulator chamber 6 is arranged on the steady pressure common rail pipe 5, is used for installing a plurality of gear rail pressure sensors, electronic channel flow valves are arranged on different channels, and are used for connecting or closing the passage between the rail pressure sensor and the steady pressure common rail pipe 5; the high pressure oil pipe 7 is used for connecting the steady pressure common rail pipe 5 and the fuel injector 8, and realizes the fuel supply of the fuel injector 8.

[0023] When the system works, the variable frequency motor 1 drives the rotor type high pressure oil pump 3 to supply oil to the steady pressure common rail pipe 5, the steady pressure common rail pipe 5 has a large enough volume to eliminate pressure fluctuation, the rail pressure sensor is used for measuring the pressure in the independent accumulator chamber 6 of the steady pressure common rail pipe 5, to determine the fuel injection pressure and feed back to the controller 13, the controller 13 controls the opening and closing of the electronic flow valve on the multi-channel independent accumulator chamber 6 according to the measured value of the rail pressure sensor, realizes the pressure measurement of different range, and adjusts the pressure by the mechanical control valve 5-1 to a large extent, and the electromagnetic valve 5-2 is used for precise control of the pressure, to realize the precise control of the actual fuel pressure in the different steady pressure common rail pipes 5, meet the high precision control of the fuel pressure of the fuel injector 8, and ensure the precise measurement of the nozzle flow.

[0024] In some embodiments, as shown in Figure 2 the inside of the accumulator chamber 6 is provided with three independent channels, the three channels are correspondingly provided with a first gear rail pressure sensor 6-4, a second gear rail pressure sensor 6-5 and a third gear rail pressure sensor, and the first gear rail pressure sensor 6-4, the second gear rail pressure sensor 6-5 and the third gear rail pressure sensor are electrically connected with the controller 13 through the electromagnetic valve 5-2 control line; Among them, the first gear rail pressure sensor 6-4 is a low pressure gear rail pressure sensor, the range of the low pressure gear rail pressure sensor is 5bar~50bar; the second gear rail pressure sensor 6-5 is a medium pressure gear rail pressure sensor, the range of the low pressure gear rail pressure sensor is 30bar~150bar; the third gear rail pressure sensor is a high pressure gear rail pressure sensor, the range of the low pressure gear rail pressure sensor is 100bar~1000bar.

[0025] Specifically, in the embodiment, the controller 13 is connected with the low pressure gear rail pressure sensor, the medium pressure gear rail pressure sensor and the high pressure gear rail pressure sensor through the electromagnetic valve 5-2 control line, realizes the signal acquisition of different gear fuel pressures, and the ranges of the three gears are partially overlapped, to ensure the seamless connection of pressure measurement.

[0026] The controller 13 receives the signals of each range rail pressure sensor in real time, and controls the opening and closing of the electronic passage flow valve corresponding to the range sensor according to the pressure value in the current stable pressure common rail 5, which specifically includes: When the pressure is 5bar~50bar, only the low-pressure range electronic passage flow valve is opened, at which time the low-pressure range rail pressure sensor can accurately and effectively measure the pressure in the stable pressure common rail 5; When the pressure is 30bar~150bar, the medium-pressure range electronic passage flow valve is switched on, at which time the medium-pressure range rail pressure sensor measures the pressure; When the pressure is 100bar~1000bar, the high-pressure range electronic passage flow valve is switched on, at which time the high-pressure range rail pressure sensor measures the pressure; in the overlapping range, the controller 13 adopts the low-range priority principle to improve the measurement accuracy.

[0027] At the same time, the controller 13 controls the communication of the solenoid valve 5-2 with the first flow valve 6-1 (i.e. the low-pressure range electronic passage flow valve), the second flow valve 6-2 (i.e. the medium-pressure range electronic passage flow valve), and the third flow valve 6-3 (i.e. the high-pressure range electronic passage flow valve) to realize the on-off control of the oil passage of different ranges.

[0028] In this embodiment, the channels of the multi-channel independent pressure accumulation chamber 6 are isolated from each other, avoiding pressure interference when the sensor switches; in the overlapping range, the low-pressure range priority principle is adopted to effectively utilize the high-precision measurement range of the pressure sensor, improve the reliability of the measurement data, and reduce the measurement error. At the same time, through the cooperation of the three-range overlapping rail pressure sensor and the multi-channel independent pressure accumulation chamber 6, full coverage of 5bar-1000bar can be realized, and each pressure interval is within the effective measurement range of the corresponding sensor, with small measurement error, solving the problem of "incompatible range and precision" of traditional single sensor.

[0029] In some embodiments, the mechanical control valve 5-1 is installed on one side of the stable pressure common rail 5, the inlet thereof is communicated with the stable pressure common rail 5, and the outlet thereof is connected to the first oil return pipe 11 and finally communicated with the fuel tank 12, forming an effective oil discharge circuit; The solenoid valve 5-2 is installed on the other side of the stable pressure common rail 5, the inlet thereof is communicated with the stable pressure common rail 5, and the outlet thereof is connected to the second oil return pipe 9 and finally communicated with the fuel tank 12, forming an effective pressure regulating circuit.

[0030] Specifically, in this embodiment, the predicted pressure relief threshold of the mechanical control valve 5-1 can be calibrated according to system requirements, such as 50bar, 100bar, 1000bar, and the maximum oil discharge flow rate is not less than 50L / min to meet the rapid oil discharge demand in emergency situations.

[0031] The flow regulation accuracy of the electromagnetic valve 5-2 is not weaker than 0.01 L / min, and the response time is not more than 10 ms, so as to meet the purpose of quickly stabilizing the oil pressure.

[0032] When the pressure in the pressure stabilizing common rail pipe 5 exceeds the target rail pressure setting value, the mechanical control valve 5-1 is automatically opened due to the hydraulic force, large flow pressure relief is performed, the rail pressure is quickly reduced to the target range interval, and then the mechanical control valve 5-1 is automatically closed under the action of the spring force.

[0033] The electronic control unit adjusts the oil discharge flow of the electromagnetic valve 5-2 according to the real-time accurate measurement data of the rail pressure sensor, and performs millibar-level accurate correction (fine adjustment) on the rail pressure; at the same time, the electronic control unit cooperatively adjusts the rotating speed of the variable frequency motor 1, changes the oil delivery pressure and flow of the rotor type high-pressure oil pump 3, forms the triple cooperative control of "supply pressure regulation + pressure relief coarse adjustment + rail pressure fine adjustment", and realizes stepless accurate control of the rail pressure in the range of 5 bar to 1000 bar.

[0034] The large flow pressure relief of the mechanical pressure relief valve in the embodiment realizes the rapid return of overpressure (greatly reduces the response time of coarse adjustment), and the accurate flow regulation of the battery valve realizes the 0.1 bar level correction of the rail pressure. The two cooperate with each other, which not only guarantees the control stability in the case of large pressure fluctuation, but also meets the high-precision control requirement, and the rail pressure control precision and range are simultaneously improved.

[0035] In some embodiments, the variable frequency motor 1 adjusts the rotating speed according to the control signal of the controller 13, drives the rotor type high-pressure oil pump 3 to extract fuel from the fuel tank 12, pressurizes the fuel and inputs the fuel into the pressure stabilizing common rail pipe 5, and the pressure stabilizing common rail pipe 5 offsets the pressure fluctuation in the fuel delivery process through its volume, so as to realize preliminary pressure stabilization.

[0036] The high-pressure fuel in the pressure stabilizing common rail pipe 5 is delivered to the fuel injector 8 through the high-pressure oil pipe 7, the fuel injector 8 is opened according to the instruction of the controller 13, the fuel is atomized and sprayed into the engine combustion chamber or the measuring unit, and the accurate rail pressure control can ensure the stability of the fuel supply of the fuel injector 8.

[0037] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

[0038] Embodiments of the present application are intended to embrace all such alterations, modifications, and variations that fall within the broad scope of the appended claims. Accordingly, any one or more features of a given embodiment are intended to be illustrative only and not limiting of the scope of the application.

Claims

1. A high-pressure fuel cooperative control system based on multi-level rail pressure sensing, characterized in that: Includes variable frequency motor, rotor-type high-pressure oil pump, pressure-stabilizing common rail, injector and fuel tank; The variable frequency motor is connected to the rotor-type high-pressure oil pump via a coupling. The oil outlet of the rotor-type high-pressure oil pump is connected to the pressure-stabilizing common rail via a common rail inlet pipe. The rotor-type high-pressure oil pump is also connected to the fuel tank via a first return oil pipe. The pressure-stabilizing common rail is connected to the injector via a high-pressure oil pipe to form a fuel supply channel. One end of the pressure-stabilizing common rail is equipped with a mechanical control valve, which is connected to the fuel tank through a second return oil pipe to form a drain circuit; the other end of the pressure-stabilizing common rail is equipped with a solenoid valve, which is connected to the fuel tank through a third return oil pipe to form a pressure regulating circuit. The pressure-stabilizing common rail pipe is provided with a pressure storage chamber. The pressure storage chamber has multiple independent channels inside. Each channel is equipped with a rail pressure sensor. Each channel has a flow valve at its input port. The flow valve and the rail pressure sensor are electrically connected to the controller.

2. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 1, characterized in that: The accumulator chamber has three independent channels inside, and the three channels are equipped with a first gear rail pressure sensor, a second gear rail pressure sensor and a third gear rail pressure sensor to collect fuel pressure signals at different gears. The first gear rail pressure sensor, the second gear rail pressure sensor, and the third gear rail pressure sensor are electrically connected to the controller via a solenoid valve control line.

3. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 2, characterized in that: The first gear rail pressure sensor is a low-pressure gear rail pressure sensor, and the range of the low-pressure gear rail pressure sensor is 5 bar to 50 bar. The second gear rail pressure sensor is a medium-pressure gear rail pressure sensor, and the low-pressure gear rail pressure sensor has a range of 30 bar to 150 bar. The third-position rail pressure sensor is a high-pressure rail pressure sensor, and the low-pressure rail pressure sensor has a range of 100 bar to 1000 bar.

4. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 3, characterized in that: The electronic control unit receives signals from the rail pressure sensors at each range and controls the opening and closing of the flow valve of the corresponding range sensor based on the current pressure value in the regulated common rail. In the overlapping range region, the controller adopts a low-range priority principle, including: When the pressure value is 5 bar to 40 bar, only the first gear rail pressure sensor is activated; In response to a pressure value of 40 bar to 100 bar, switch to open the second gear rail pressure sensor; In response to a pressure value of 100 bar to 1000 bar, the third gear rail pressure sensor is switched on.

5. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 1, characterized in that: The maximum oil discharge flow rate of the mechanical control valve is not less than 50 L / min.

6. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 1, characterized in that: The flow regulation accuracy of the solenoid valve is not less than 0.01 L / min, and the response time is not more than 10 ms.

7. The high-pressure fuel cooperative control system based on multi-level rail pressure sensing according to claim 1, characterized in that: The variable frequency motor adjusts its speed according to the control signal output by the controller to drive the rotor-type high-pressure oil pump to draw fuel from the fuel tank, pressurize it, and input it into the pressure-stabilizing common rail. The pressure-stabilizing common rail uses its own volume to offset the pressure fluctuations during the fuel delivery process to perform initial pressure stabilization.

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