A common rail pressure control valve reliability test system

Abstract

The application discloses a common rail pressure control valve reliability test system, which is characterized by comprising an oil tank, a common rail pump, a common rail pipe, a test tool, a low-pressure oil return passage and a control unit; the common rail pipe is provided with a plurality of high-pressure interfaces; the test tool is connected to the high-pressure interfaces of the common rail pipe through high-pressure oil pipes; a test common rail pressure control valve can be installed on the test tool; a low-pressure oil return interface of the test common rail pressure control valve returns oil to the oil tank through the low-pressure oil return passage; and the control unit tests the reliability of the test common rail pressure control valve by controlling the current of the test common rail pressure control valve and monitoring the change of the oil return flow of the low-pressure oil return passage. The test system of the application creatively adopts the common rail pump and the common rail pipe to realize the reliability test of one or more common rail pressure control valves. By applying a current signal with a duty ratio sinusoidal change to the test common rail pressure control valve, the sinusoidal change of the pressure in the common rail pipe is realized under the condition that the oil return of the common rail pressure control valve is stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pressure control valve testing, and particularly relates to a common rail pressure control valve reliability testing system. BACKGROUND

[0002] The common rail pressure control valve is used in the common rail fuel system in cooperation with the oil inlet metering valve to control the oil inlet amount and the rail pressure, so as to realize more accurate rail pressure control, lower system leakage and lower thermal load.

[0003] There is no public technology that can test the reliability of the common rail pressure control valve. Chinese patent CN2021108968218 discloses a performance testing method of the common rail pressure control valve, and only one common rail pressure control valve can be tested at the same time. Chinese patent CN201220498714 discloses a high-pressure common rail pressure regulating valve characteristic testing device, but does not provide a reliability testing method of the common rail pressure control valve. Therefore, there is an urgent need for a device that can test the reliability of the common rail pressure control valve. SUMMARY

[0004] The purpose of the present application is to provide a common rail pressure control valve reliability testing system to overcome the defects of the prior art.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme: a common rail pressure control valve reliability testing system, characterized in that it comprises an oil tank, a common rail pump, a common rail pipe, a test tool, a low-pressure oil return passage and a control unit.

[0006] The oil tank is filled with test oil, which is delivered to the common rail pipe by the common rail pump; the common rail pipe is provided with a plurality of high-pressure interfaces, the test tool is connected to the high-pressure interface of the common rail pipe through a high-pressure oil pipe, the test common rail pressure control valve can be installed on the test tool, and the low-pressure oil return interface of the test common rail pressure control valve returns oil to the oil tank through the low-pressure oil return passage.

[0007] The control unit tests the reliability of the test common rail pressure control valve by controlling the current of the test common rail pressure control valve and monitoring the change of the low-pressure oil return passage oil return flow; the number of test common rail pressure control valves tested at the same time is 1-3.

[0008] Further, the common rail pump comprises a low-pressure oil delivery pump, an oil inlet metering valve and a high-pressure plunger pump, which are connected to the high-pressure interface of the common rail pipe through a pipeline; the inlet of the low-pressure oil delivery pump is provided with a first coarse filter, a second coarse filter, a first pressure sensor and a first temperature sensor, the first pressure sensor is used to detect the oil suction negative pressure, and the first temperature sensor is used to detect the oil inlet temperature.

[0009] Further, a fine filter is arranged between the outlet of the low-pressure oil delivery pump and the inlet of the oil inlet metering valve.

[0010] Furthermore, the common rail is equipped with a first rail pressure sensor and a first common rail pressure control valve, and a pressure reducing valve and a level switch are connected to the high-pressure interface. The pressure reducing valve opens when the first common rail pressure control valve detects that the rail pressure is higher than 3000 bar, and the level switch is used to detect whether the pressure reducing valve is open. High-pressure plugs are installed on other high-pressure interfaces of the common rail to achieve high-pressure sealing. The low-pressure return oil interface of the first common rail pressure control valve is connected to the first plate heat exchanger and the second temperature sensor is connected to the return oil tank.

[0011] Furthermore, the first common rail pressure control valve or the common rail pressure control valve under test is used in conjunction with the connecting fixture. The lower part of the connecting fixture is a high-pressure sealing cone surface, and the side of the connecting fixture is the low-pressure return oil interface of the common rail pressure control valve.

[0012] Furthermore, the low-pressure return oil passage of the common rail pressure control valve under test is equipped with a plate heat exchanger for the test circuit, a fine filter for the test circuit, a temperature sensor for the test circuit, and a flow meter for the test circuit.

[0013] Furthermore, the testing fixture is equipped with a second rail pressure sensor and a third temperature sensor.

[0014] Furthermore, the control unit includes control circuitry and a testing module;

[0015] The control circuit includes NI boards PCIe-6323 and PCIe-6361, a drive circuit, a current sensor, and a DC power supply. The analog voltage output channels of the NI boards PCIe-6323 and PCIe-6361 generate PWM voltage signals to control the on / off state of the MOSFETs in the drive circuit. The current sensor is used to detect the current of the tested common rail pressure control valve, the inlet metering valve, and the first common rail pressure control valve. The analog voltage input channel of the NI board PCIe-6361 acquires the output signals of the current sensor at a rate of 200k / s to obtain the current waveforms of each valve, and acquires the output signals of the second rail pressure sensor to obtain the rail pressure waveform.

[0016] The test module is used to perform reliability tests on the common rail pressure control valve under test through the control circuit.

[0017] Furthermore, the reliability testing of the test module adopts the following steps:

[0018] (1) Set the current of the test common rail pressure control valve, the oil inlet metering valve and the first common rail pressure control valve to 0, and set the speed of the common rail pump to 3200 r / min;

[0019] (2) After the speed of the common rail pump stabilizes, set the duty cycle of the PWM voltage signal of the first common rail pressure control valve to 40% and close the valve; after the values ​​of the tested common rail pressure control valve and the tested circuit flow meter stabilize, increase the duty cycle of the PWM voltage signal of the inlet metering valve so that the flow meters of each tested circuit stabilize at 40±10L / h.

[0020] (3) The duty cycle of the PWM signal of the common rail pressure control valve under test is controlled to change in a sinusoidal manner. By adjusting the frequency and amplitude of the duty cycle change, the maximum rail pressure of the common rail is 2200±100 bar and the minimum rail pressure is 700±100 bar. The duty cycle change frequency obtained in the test is 5 Hz and the amplitude is 12%. The pressure change of the common rail lags behind the change of the current of the common rail pressure control valve under test, which meets the reliability test requirements of the common rail pressure control valve.

[0021] (4) Reliability testing can be achieved by continuously running the common rail pressure control valve under test according to different specifications.

[0022] Furthermore, during the test in step (4), if the common rail pressure control valve under test exhibits one of the following two phenomena, it indicates that the common rail pressure control valve under test has malfunctioned:

[0023] (1) The return oil flow rate of the tested common rail pressure control valve showed a significant change;

[0024] (2) The maximum or minimum value of the rail pressure changes significantly;

[0025] When testing multiple common rail pressure control valves, it is necessary to retest the performance of the common rail pressure control valves to identify any failures.

[0026] The testing system of this invention creatively employs a common rail pump and common rail pipe to achieve reliability testing of one or more common rail pressure control valves. By applying a current signal with a sinusoidal duty cycle variation to the tested common rail pressure control valve, a sinusoidal change in pressure within the common rail pipe is achieved while ensuring stable oil return from the common rail pressure control valve. The testing system of this invention provides a testing method for reliability assessment of common rail pressure control valves. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the common rail pressure control valve reliability testing system in an embodiment.

[0028] Figure 2 This is an example of a common rail pressure control valve and connecting fixtures.

[0029] Figure 3 This is a cross-sectional view of the reliability testing fixture for the common rail pressure control valve in the embodiment.

[0030] Figure 4This is a schematic diagram of the control circuit of the common rail pressure control valve reliability test system in an embodiment.

[0031] Figure 5 This is a sinusoidal waveform showing the duty cycle of the PWM voltage signal of the common rail pressure control valve in the embodiment.

[0032] Figure 6 This is the actual waveform from the reliability test of the common rail pressure control valve in the embodiment. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0034] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0035] As attached Figure 1 As shown, tank 1 contains test oil conforming to ISO 4113 standard. A common rail pump, consisting of a low-pressure oil transfer pump 6, an inlet metering valve 8, and a high-pressure plunger pump 9, pumps the test oil from tank 1 to the common rail 11. The inlet of the low-pressure oil transfer pump 6 is equipped with a first coarse filter 2, a second coarse filter 3, a first pressure sensor 4, and a first temperature sensor 5. The first pressure sensor 4 detects the suction negative pressure, and the first temperature sensor 5 detects the inlet oil temperature. A first fine filter 7 is installed between the outlet of the low-pressure oil transfer pump 6 and the inlet of the inlet metering valve 8. The outlet of the high-pressure plunger pump 9 is connected to the first high-pressure port of the common rail 11, and the return oil goes directly back to the tank. The common rail pump is driven by a variable frequency motor.

[0036] The common rail pipe 11, model 0 445 226 136, is manufactured by BOSCH, Germany, and comes with a first rail pressure sensor 10 and a first common rail pressure control valve 14. The fourth high-pressure port of the common rail pipe 11 is connected to the test fixture 17 via a high-pressure oil pipe. The seventh high-pressure port of the common rail pipe 11 is connected to a pressure reducing valve 12 (model 402633-45, manufactured by HIP, USA) and a level switch 13. The pressure reducing valve 12 functions as a safety valve, opening when the rail pressure exceeds 3000 bar, and the level switch 13 detects its opening. Other high-pressure ports of the common rail pipe 11 are fitted with high-pressure plugs to achieve high-pressure sealing. The low-pressure return port of the common rail pipe 11 (including the first common rail pressure control valve 14) is connected to a first plate heat exchanger 15 and a second temperature sensor 16.

[0037] As attached Figure 2 As shown, the common rail pressure control valve is used in conjunction with the connecting fixture. The lower part of the connecting fixture is a high-pressure sealing cone surface, and the side of the connecting fixture is the low-pressure return oil interface of the common rail pressure control valve.

[0038] The test fixture 17 is equipped with a second common rail pressure control valve 20 (first test piece), a third common rail pressure control valve 21 (second test piece), a fourth common rail pressure control valve 22 (third test piece), a second rail pressure sensor 19 (model 4067E3600DS1, Kistler, Switzerland), and a third temperature sensor 18. (See attached...) Figure 3 As shown, the high-pressure oil passages of the second common rail pressure control valve 20, the third common rail pressure control valve 21, the fourth common rail pressure control valve 22, and the second rail pressure sensor 19 are connected. The third temperature sensor 18 is only used to detect the temperature of the test fixture 17.

[0039] As attached Figure 1 As shown, the low-pressure return oil from the second common rail pressure control valve 20 returns to the oil tank 1 after passing through the second plate heat exchanger 23, the second fine filter 24, the fourth temperature sensor 25, and the first flow meter 26.

[0040] As attached Figure 1 As shown, the low-pressure return oil from the third common rail pressure control valve 21 returns to the oil tank 1 after passing through the third plate heat exchanger 27, the third fine filter 28, the fifth temperature sensor 29, and the second flow meter 30.

[0041] As attached Figure 1 As shown, the low-pressure return oil from the fourth common rail pressure control valve 22 returns to the oil tank 1 after passing through the fourth plate heat exchanger 31, the fourth fine filter 33, the sixth temperature sensor 32, and the third flow meter 34.

[0042] Cooling water is introduced into the inlets of the first plate heat exchanger 15, the second plate heat exchanger 23, the third plate heat exchanger 27, and the fourth plate heat exchanger 31, and is always flowing, to cool the low-pressure return oil of the first common rail pressure control valve 14, the second common rail pressure control valve 20, the third common rail pressure control valve 21, and the fourth common rail pressure control valve 22, respectively.

[0043] As attached Figure 4 As shown, the control circuit for the common rail pressure control valve and the inlet metering valve consists of NI boards PCIe-6323 and PCIe-6361, a drive circuit, current sensors, and a DC power supply 40. The analog voltage output channels of the NI boards PCIe-6323 and PCIe-6361 generate PWM voltage signals to control the on / off state of the MOSFETs in the drive circuit. Current sensors 35-39 detect the currents of the second common rail pressure control valve 20, the third common rail pressure control valve 21, the fourth common rail pressure control valve 22, the inlet metering valve 8, and the first common rail pressure control valve 14, respectively. The analog voltage input channels AI0-AI4 of the NI board PCIe-6361 acquire the output signals of the current sensors 35-39 at a rate of 200kbps to obtain the current waveforms of each valve.

[0044] The analog voltage input channel AI5 of the NI board PCIe-6361 acquires the output signal of the second rail pressure sensor 19 at a rate of 200k / s to obtain the rail pressure waveform.

[0045] Adopting attachment Figure 1 The steps for testing the common rail pressure control valve reliability testing system shown are as follows:

[0046] The current of the second common rail pressure control valve 20, the third common rail pressure control valve 21, the fourth common rail pressure control valve 22, the inlet metering valve 8, and the first common rail pressure control valve 14 are all set to 0, and the speed of the common rail pump is set to 3200 r / min. After the speed of the common rail pump stabilizes, the duty cycle of the PWM voltage signal of the first common rail pressure control valve 14 is set to 40%, thus closing the valve. After the values ​​of the second rail pressure sensor 19, the first flow meter 26, the second flow meter 30, and the third flow meter 34 stabilize, the duty cycle of the PWM voltage signal of the inlet metering valve 8 is increased so that the values ​​of the first flow meter 26, the second flow meter 30, and the third flow meter 34 stabilize at 40±10 L / h.

[0047] As attached Figure 5 As shown, the PWM signal duty cycles of the second common rail pressure control valve 20, the third common rail pressure control valve 21, and the fourth common rail pressure control valve 22 are programmed to change in a sinusoidal manner. By adjusting the frequency and amplitude of the duty cycle change, the maximum rail pressure is set to 2200±100 bar, and the minimum rail pressure to 700±100 bar. The experimentally obtained duty cycle change frequency is 5 Hz and the amplitude is 12%. (See attached diagram)Figure 6 As shown, the pressure change in the common rail 11 lags behind the change in the current of the common rail pressure control valve under test, which is consistent with the actual situation and meets the reliability test requirements of the common rail pressure control valve. Therefore, 600 hours of continuous operation is sufficient to achieve 10.8 million reliability tests for each of the second common rail pressure control valve 20, the third common rail pressure control valve 21, and the fourth common rail pressure control valve 22.

[0048] During the test, if the values ​​of the first flow meter 26, the second flow meter 30, and the third flow meter 34 change significantly, or if the maximum or minimum value of the rail pressure changes significantly, it indicates that one or more of the second common rail pressure control valve 20, the third common rail pressure control valve 21, and the fourth common rail pressure control valve 22 are malfunctioning. In this case, it is necessary to retest the performance of each valve to identify the faulty component.

[0049] If the value of the first pressure sensor 4 shows obvious abnormality during the test, it indicates that the common rail pump has failed and needs to be replaced before the test can continue.

[0050] During the test, if the value of the second temperature sensor 16 rises significantly but does not exceed 70°C, it indicates that the first common rail pressure control valve 14 has failed and needs to be replaced before the test can continue.

[0051] If any of the values ​​of the second temperature sensor 16, the fourth temperature sensor 25, the fifth temperature sensor 29, and the sixth temperature sensor 32 exceed 70°C during the test, it indicates an abnormality in the cooling water and the test can only continue after the problem is investigated.

[0052] During the test, the third temperature sensor 18 must not exceed 120°C. Otherwise, it indicates that one or more of the second common rail pressure control valve 20, the third common rail pressure control valve 21, and the fourth common rail pressure control valve 22 are overheating. The test can only continue after the maximum rail pressure is reduced or the flow rate is decreased.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A common rail pressure control valve reliability test system, characterized by The test device comprises an oil tank, a common rail pump, a common rail pipe, a test tool, a low-pressure return oil passage and a control unit. The oil tank is filled with test oil, and the test oil is delivered to the common rail pipe by the common rail pump. The common rail pipe is provided with a plurality of high-pressure interfaces, and the test tool is connected to the high-pressure interfaces of the common rail pipe through high-pressure oil pipes. The test common rail pressure control valve can be installed on the test tool, and the low-pressure return oil interface of the test common rail pressure control valve returns oil to the oil tank through the low-pressure return oil passage.

2. The common rail pressure control valve reliability test system of claim 1, wherein: The control unit controls the current of the test common rail pressure control valve and monitors the change of the return oil flow of the low-pressure return oil passage to test the reliability of the test common rail pressure control valve.

3. The common rail pressure control valve reliability test system of claim 2, wherein: The number of test common rail pressure control valves tested at the same time is 1-3.

4. The common rail pressure control valve reliability test system of claim 1, wherein: The common rail pump comprises a low-pressure oil delivery pump, an oil inlet metering valve and a high-pressure plunger pump, which are connected to the high-pressure interfaces of the common rail pipe through pipelines.

5. The common rail pressure control valve reliability test system of claim 4, wherein: The inlet of the low-pressure oil delivery pump is provided with a first coarse filter, a second coarse filter, a first pressure sensor and a first temperature sensor.

6. The common rail pressure control valve reliability test system of claim 1, wherein: The first pressure sensor is used to detect the suction negative pressure, and the first temperature sensor is used to detect the oil inlet temperature.

7. The common rail pressure control valve reliability test system of claim 1, wherein: The outlet of the low-pressure oil delivery pump and the inlet of the oil inlet metering valve are provided with a fine filter.

8. The common rail pressure control valve reliability test system of claim 1, wherein: The common rail pipe is provided with a first rail pressure sensor and a first common rail pressure control valve, and a pressure reducing valve and a liquid level switch are connected to the high-pressure interfaces. The pressure reducing valve is opened when the first common rail pressure control valve detects that the rail pressure is higher than 3000bar, and the liquid level switch is used to detect whether the pressure reducing valve is opened. The other high-pressure interfaces of the common rail pipe are provided with high-pressure plugs to realize high-pressure sealing.

9. The common rail pressure control valve reliability test system of claim 8, wherein: The low-pressure return oil interface of the first common rail pressure control valve is connected to a first plate heat exchanger and a second temperature sensor to return to the oil tank. The first common rail pressure control valve or the test common rail pressure control valve is used with a connecting tool. The lower part of the connecting tool is a high-pressure sealing cone surface, and the side surface of the connecting tool is a low-pressure return oil interface of the common rail pressure control valve. The low-pressure return oil passage of the test common rail pressure control valve is provided with a test return plate heat exchanger, a test return fine filter, a test return temperature sensor and a test return flowmeter. The test tool is provided with a second rail pressure sensor and a third temperature sensor. The control unit comprises a control circuit and a test module. The control circuit comprises NI board cards PCIe-6323 and PCIe-6361, a driving circuit, a current sensor and a direct current power supply. The analog voltage output channel of the NI board cards PCIe-6323 and PCIe-6361 generates a PWM voltage signal to control the on-off of the MOS tube of the driving circuit. The current sensor is used to detect the current of the test common rail pressure control valve, the oil inlet metering valve and the first common rail pressure control valve. The analog voltage input channel of the NI board card PCIe-6361 respectively collects the output signals of the current sensor at a rate of 200k / s to obtain the current waveforms of the valves and the rail pressure waveform of the second rail pressure sensor. The test module is used to test the reliability of the test common rail pressure control valve through the control circuit. The test module tests the reliability by the following steps: (1) Set the current of the test common rail pressure control valve, the oil inlet metering valve and the first common rail pressure control valve to 0, and set the rotation speed of the common rail pump to 3200 r / min; (2) After the rotation speed of the common rail pump is stabilized, set the PWM voltage signal duty cycle of the first common rail pressure control valve to 40%, i.e. close the valve; after the values of the test common rail pressure control valve and the test circuit flow meter are stabilized, increase the PWM voltage signal duty cycle of the oil inlet metering valve so that each test circuit flow meter is stabilized at 40±10 L / h; (3) Control the PWM signal duty cycle of the test common rail pressure control valve to change in a sinusoidal manner, and adjust the change frequency and amplitude of the duty cycle so that the maximum rail pressure of the common rail pipe is 2200±100 bar and the minimum rail pressure is 700±100 bar. The test obtains a change frequency of 5 Hz and an amplitude of 12% for the duty cycle. The pressure change of the common rail pipe lags behind the change of the measured common rail pressure control valve current, i.e. meets the reliability test requirements of the common rail pressure control valve; (4) According to different specification requirements, the test common rail pressure control valve is continuously operated, i.e. the reliability test is realized.

10. The common rail pressure control valve reliability test system of claim 9, wherein: During the test process of step (4), if the test common rail pressure control valve appears one of the following two phenomena, it means that the test common rail pressure control valve has an abnormality: (1) The oil return flow of the test common rail pressure control valve changes obviously; (2) The maximum or minimum value of the rail pressure changes obviously; When multiple test common rail pressure control valves are used, the performance of the test common rail pressure control valve needs to be retested to troubleshoot failed parts.

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