TECHNICAL FIELD
The present subject matter relates to high-pressure common rail fuel injectors, especially to a test bench for endurance test of fuel injector.
BACKGROUND
High-pressure common rail fuel injection technology is widely used in 5 diesel engines and fuel injectors are important parts of diesel engines which employ high-pressure common rail fuel injection technology. It is usually necessary to develop fuel injectors with various performances in order to meet the demands of various diesel engines and to enhance the performances of diesel engines. Before finalizing a design of a newly-developed fuel injector, it is 10 necessary to carry out an endurance test on a test bench for endurance test of fuel injector. The test bench for endurance test of fuel injector simulates behavior of the fuel injector in engines and tests the backflow quantity of the fuel injector in a given period of time. During operation, if any fuel injector fails, its backflow quantity will change significantly. Therefore, by measuring, recording and 15 analyzing the backflow quantity of the fuel injector in a period of time, it can be determined whether the fuel injector fails.
A test bench for endurance test of fuel injector typically comprises an electric motor, a high-pressure pump driven by the electric motor, a common rail for receiving fuel from the high-pressure pump, a device adapted for mounting fuel 20 injectors to be tested, flow meters connected with the backflow lines of the fuel injectors to measure the backflow quantity of the fuel injectors to be tested, and a control module electrically connected with the flow meters to receive an electrical signal from the flow meters so as to determine whether the fuel injector fails. The mounted-in-position fuel injectors to be tested receive high-pressure fuel from the 25 common rail, a part of the fuel flows back to the fuel tank after being injected by the injector, and a pan of the fuel flows through a backflow line and flows back to the fuel tank via the flow meter. Normally, a plurality of fuel injectors to be tested is mounted in position simultaneously for testing in order to simulate a real situation. For example, if the injectors are developed for a six-cylinder engine, then 30
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six identical injectors are mounted in position simultaneously for testing. In a conventional test bench for endurance test of fuel injector, there normally is only one flow meter to test the overall backflow quantity of a plurality of fuel injectors to be tested. In such a case, when the overall backflow quantity of the plurality of fuel injectors to be tested appears abnormal, it can not be determined which 5 specific injector fails. So all of the plurality of fuel injectors to be tested have to be returned to the design department for structural analysis. This will cause a huge amount of workload and thus decrease the general testing efficiency.
Therefore, it is necessary to make improvements on the conventional test bench for endurance test of fuel injector. 10
SUMMARY
An object of the present subject matter is to provide an improved test bench for endurance test of fuel injector, which can determine which one of a plurality of fuel injectors to be tested fails so as to enhance considerably the testing efficiency.
To this end, according to one aspect of the present subject matter, a test 15 bench for endurance test of fuel injector is provided, characterized in that, the test bench for endurance test of fuel injector comprises a plurality of flow meters, each one of the plurality of flow meters communicates with a backflow line of a respective one of a plurality of fuel injectors to be tested to measure a backflow quantity of each one of the plurality of fuel injectors to be tested respectively. 20
Preferably, the test bench for endurance test of fuel injector further comprises an electric motor, a high-pressure pump driven by the electric motor, a common rail for receiving fuel from the high-pressure pump, a device adapted for mounting the plurality of fuel injectors to be test, and a control module electrically connected with the plurality of flow meters to receive an electrical signal from the 25 plurality of flow meters.
Preferably, the control module records and analyzes the electrical signal from each flow meter so as to determine whether a fuel injector fails on basis of whether the backflow quantity of each fuel injector appears abnormal.
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Preferably, the control module is further designed to output an alarm signal indicating failure of a certain fuel injector when the backflow quantity of this fuel injector appears abnormal.
Preferably, the test bench for endurance test of fuel injector further comprises a flow meter supporting plate for supporting the plurality of flow meters. 5 Preferably, the flow meter supporting plate comprises a baseplate made of heat conduction material, and a first channel and/or a second channel corresponding to each flow meter are formed in the baseplate.
Preferably, the first channel and/or the second channel are straight.
Preferably, the first channel and/or the second channel are bent. 10
Preferably, a plurality of first holes is fanned in the base plate through which fixtures pass to fix the flow meters onto the baseplate. Preferably, a plurality of second holes is fanned in the baseplate through which fixtures pass to fix the baseplate onto a bracket.
According to the present subject matter, individual flow meter is provided 15 for each one of the plurality of fuel injectors to be tested to measure the back flow of the respective fuel injector, whereby it is easy to determine whether each fuel injector fails on basis of backflow of each fuel injector. Therefore the testing efficiency can be enhanced considerably.
BRIEF DESCRIPTION OF THE DRAWINGS 20
FIG. 1 is an illustration of the main parts of a test bench for endurance test of fuel injector according to the present subject matter;
FIG. 2 is a perspective illustration of the flow meter supporting plate of the test bench for endurance test of fuel injector according to the present subject matter; 25
FIG. 3 is a front view of the flow meter supporting plate as illustrated in FIG. 2, wherein the flow meter supporting plate is partially cut out;
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FIG. 4 is a top view of the flow meter supporting plate as illustrated in FIG. 2; and
FIG. 5 is a sectional view taken along a line 5-5 of FIG. 4.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Various preferred embodiments of the present subject matter will be 5 described in detail hereafter in combination with examples. A person skilled in the art should understand that the embodiments herein are exemplary, and it does not mean to impose any limitation on the present subject matter.
Like a conventional test bench for endurance test of fuel injector, the test bench for endurance test of fuel injector according to the present subject matter 10 also comprises an electric motor, a high-pressure pump driven by the electric motor, a common rail for receiving fuel from the high-pressure pump, a device adapted for mounting a plurality of fuel injectors to be tested, and a control module electrically connected with a flow meter to receive an electrical signal from the flow meter so as to determine whether the fuel injector fails. However, different 15 from the conventional test bench for endurance test of fuel injector, the test bench for endurance test of fuel injector according to the present subject matter comprises a plurality of flow meters. Each one of the plurality of flow meters communicates with a backflow line of a respective one of the plurality of fuel injectors to be tested to measure a backflow quantity of each one of the plurality of fuel injectors 20 to be tested respectively.
FIG. 1 is an illustration of the main parts of the test bench for endurance test of fuel injector according to the present subject matter. The parts of the test bench for endurance test of fuel injector according to the present subject matter identical with the conventional test bench for endurance test of fuel injector are 25 omitted in FIG. 1, and thus the explanations for these identical parts are omitted as well. As illustrated in FIG. 1, six fuel injectors are mounted simultaneously on the device adapted for mounting a plurality of fuel injectors to be tested. However, it should be understood that, according to design condition, the number of the fuel
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injectors to be tested may be more than six, e.g., eight, or less than six, e.g., three or four.
As illustrated in FIG. 1, in a case that six fuel injectors 1 are tested simultaneously, the test bench for endurance test of fuel injector according to the present subject matter comprises six flow meters 3 and each of the flow meters 3 5 corresponds to a respective fuel injector 1. After the high-pressure fuel from the common rail (not shown) is transmitted to each fuel injector 1, a part Fl of the fuel flows directly back to the fuel tank 5 after being injected by the fuel injector, another part F2 of the fuel flows through the respective flow meter 3 and then back to the fuel tank 5. Each flow meter 3 measures the backflow quantity of the 10 respective fuel injector 1 and transmits the electrical signal representative of the backflow quantity of each fuel injector 1 to the control module 7. The control module 7 records and analyzes the electrical signal from each flow meter 3. On basis of whether the backflow quantity of a certain fuel injector appears abnormal during a period of time, the control module 7 can determine whether this fuel 15 injector fails. Preferably, the control module 7 can also be designed to output an alarm signal indicating failure of a certain fuel injector when the backflow quantity of this fuel injector appears abnormal. The alarm signal can be acoustical signal and/or visual signal.
In a case that the test bench for endurance test of fuel injector comprises a 20 plurality of the flow meters 3, a flow meter supporting plate 9 for supporting the plurality of flow meters 3 is provided to ensure the reliable communication between the plurality of the flow meters 3 and the fuel injectors 1 and to save mounting space. As is well known, the temperature of the backflow of the fuel injector can be more than one hundred degree, which may accelerate the aging of 25 the fuel. In order to delay the aging of the fuel, it can be envisaged to allow the backflow to flow through the flow meter supporting plate 9 made of heat conduction material before and/or after it flows through the flow meters 3.
FIGs. 2-5 illustrate a preferred embodiment of the flow meter supporting plate of the test bench for endurance test of fuel injector according to the present 30
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subject matter. FIG. 2 is a perspective illustration of the flow meter supporting plate of the test bench for endurance test of fuel injector according to the present subject matter. FIG. 3 is a front view of the flow meter supporting plate as illustrated in FIG. 2. FIG. 4 is a top view of the flow meter supporting plate as illustrated in FIG. 2. And FIG. 5 is a sectional view taken along a line 5-5 of FIG. 5 4. As illustrated in FIGs. 2-5, the flow meter supporting plate 9 of the test bench for endurance test of fuel injector according to the present subject matter comprises a baseplate 11 made of such heat conduction materials as aluminum, copper or stainless steel. First channels 13 and second channels 15 in pairs corresponding to each flow meter 3 are formed in the baseplate. An inlet 13a of the first channel 13 10 is adapted to communicate with the backflow line of the respective fuel injector 1. An outlet 13b of the first channel 13 is adapted to communicate with an inlet line of the respective flow meter 3. An inlet 15a of the second channel 15 is adapted to communicate with an outlet line of the respective flow meter 3. An outlet 15b of the second channel 15 is adapted to communicate with the fuel tank 5 through a 15 line. Because the baseplate 11 of the flow meter supporting plate 9 has a relatively large surface area, the flow meter supporting plate 9 acts as a heat sink when the backflow at high temperature flows through the flow meter supporting plate 9. The temperature of the backflow can be rapidly decreased, thereby delaying or preventing the aging of the backflow. 20
A plurality of first holes 17 can be formed in the baseplate 11. Such fixtures as bolts pass through the first holes so as to fix the flow meters 3 onto the baseplate 11. In a case that the flow meters 3 are fixed upon the baseplate11, mounting space for flow meters can be saved considerably, thereby reducing the overall size of the test bench for endurance test of fuel injector. In order to make the air around the 25 baseplate 11 to flow so as to enhance the cooling effect, the flow meter supporting plate 9 may be supported in the air. For this purpose, a plurality of second holes 19 may also be formed in the baseplate 11. Such fixtures as bolts pass through the second holes so as to fix the baseplate 11 onto a bracket (not shown).
It should be understood that, with respect to each flow meter 3, it is possible 30 to form only one of the first channel 13 and the second channel 14 in the baseplate
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11. Although in FIGs. 2-5 both the first channel 13 and the second channel 15 are shown to be straight, it should also be understood that the first channel 13 and the second channel 15 may be bent. In this case, the effective length of the first 13 and the second channel 15 may be prolonged without changing the size of the baseplate 11, thereby further enhancing the cooling effect. 5
The present subject matter has been described in detail above in combination with specific embodiments. It is obvious that the embodiments described above and illustrated in the appended drawings shall be understood to be exemplary, and impose no limitation on the present subject matter. For a person skilled in the art, various variation or modification can be made without deviating 10 from the spirits of the present subject matter, all these variation or modification do not deviate from the scope of the present subject matter.

I/We Claim:
1. A test bench for endurance test of fuel injector, characterized in that, the test bench for endurance test of fuel injector comprises a plurality of flow meters (3), each one of the plurality of flow meters (3) communicates with a backflow line of a 5 respective one of a plurality of fuel injectors (1) to be tested to measure a backflow quantity of each one of the plurality of fuel injectors to be tested respectively.
2. The test bench for endurance test of fuel injector as claimed in claim l, characterized in that, the test bench for endurance test of fuel injector further 10 comprises an electric motor, a high-pressure pump driven by the electric motor, a common rail for receiving fuel from the high-pressure pump, a device adapted for mounting the plurality of fuel injectors to be test, and a control module (7) electrically connected with the plurality of flow meters to receive an electrical signal from the plurality of flow meters. 15
3. The test bench for endurance test of fuel injector as claimed in claim 2, characterized in that, the control module (7) records and analyzes the electrical signal from each flow meter (3) so as to determine whether a fuel injector fails on basis of whether the backflow quantity of each fuel injector appears abnormal. 20
4. The test bench for endurance test of fuel injector as claimed in claim 3, characterized in that, the control module (7) is further designed to output an alarm signal indicating failure of a certain fuel injector when the backflow quantity of this fuel injector appears abnormal. 25
5. The test bench for endurance test of fuel injector as claimed in claim 1, characterized in that, the test bench for endurance test of fuel injector further
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comprises a flow meter supporting plate (9) for supporting the plurality of flow meters (3).
6. The test bench for endurance test of fuel injector as claimed in claim 5, characterized in that, the flow meter supporting plate (9) comprises a baseplate (11) 5 made of heat conduction material, and a first channel (13) and/or a second channel (15) corresponding to each flow meter (3) are formed in the baseplate (11).
7. The test bench for endurance test of fuel injector as claimed in claim 6, characterized in that, the first channel (13) and/or the second channel (15) are 10 straight.
8. The test bench for endurance test of fuel injector as claimed in claim 6, characterized in that, the first channel (13) and/or the second channel (15) are bent.
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9. The test bench for endurance test of fuel injector as claimed in claim 6, characterized in that, a plurality of first holes (17) is formed in the baseplate (11) through which fixtures pass to fix the flow meters (3) onto the baseplate(11).
10. The test bench for endurance test of fuel injector as claimed in claim 6, 20 characterized in that, a plurality of second holes (19) is formed in the baseplate (11) through which fixtures pass to fix the baseplate (11) onto a bracket.