Micro leakage device and common rail pipe

Abstract

The present invention discloses a micro-leakage device and a common rail pipe, wherein the micro-leakage device comprises a valve seat, a valve seat oil passage is arranged in the valve seat, an oil inlet and an oil return port connected to the valve seat oil passage are arranged in the valve seat, a valve core and a first limiting structure are arranged in the valve seat, the valve core and the valve seat clearance are matched, the clearance between the valve core and the valve seat are respectively connected to the oil inlet and the oil return port, the two ends of the valve core are respectively the first end of the valve core and the second end of the valve core, along the fuel flow direction, the first end of the valve core is located upstream of the second end of the valve core, and the second end of the valve core abuts against the first limiting structure. The present invention adds a micro-leakage device to the common rail pipe, when the rail pressure is too high, it leaks out through the micro-leakage device, and the excessive rail pressure is unloaded, so that the actual rail pressure of the engine has good followability with the set rail pressure, and solves the problem of poor followability of rail pressure of micro-leakage injectors.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a micro-leakage device and a common rail pipe. Background Art

[0002] In actual application of high-pressure common rail engines, there is a problem of poor followability between the actual rail pressure of the common rail pipe and the set rail pressure, that is, the actual rail pressure lags behind the set rail pressure. To solve the above problem, the following three solutions are generally used in the prior art:

[0003] (1) The common rail fuel system remains unchanged, the injector is replaced from a static leakage injector to a non-static leakage injector, and the empty injection strategy is used;

[0004] (2) The common rail system uses a fuel injector without static leakage, and an electronically controlled pressure relief valve is added to the common rail pipe. The rail pressure is controlled by the ECU;

[0005] (3) A pressure relief unit is added to the common rail pipe. The pressure relief unit includes a plunger and a spring. The rail pressure overcomes the spring preload to open the plunger and allow the high-pressure fuel to leak.

[0006] However, the above three technical solutions have the following problems:

[0007] Disadvantages of solution (1): The empty injection strategy causes the ball valve of the injector to open and close at a high frequency, which can easily cause serious wear of the valve seat and shorten the life of the injector. In addition, after the injector ages, the nozzle will not close tightly, causing fuel to be sprayed into the combustion chamber, causing emissions to deteriorate.

[0008] Disadvantages of solution (2): adding an electronically controlled pressure relief valve to the common rail pipe is expensive, complicated to calibrate, and prolongs the development cycle.

[0009] Disadvantages of solution (3): The existing processing technology for the pressure relief hole on the common rail pipe has a diameter of more than 0.1 mm, which is similar to the diameter of the nozzle nozzle. The hole diameter is too large, causing excessive leakage of high-pressure fuel, resulting in the common rail system oil balance not meeting the requirements and the rail pressure failing to reach the set value. Summary of the invention

[0010] In view of the above problems, the first technical problem to be solved by the present invention is to provide a micro-leakage device, which can relieve part of the rail pressure.

[0011] Based on the same inventive concept, the second technical problem to be solved by the present invention is to provide a common rail pipe using the above-mentioned micro-leakage device to solve the problem of poor rail pressure followability of the non-static leakage injector.

[0012] To solve the above-mentioned first technical problem, the first technical solution of the present invention is:

[0013] A micro-leakage device comprises: a valve seat, a valve seat oil passage is arranged in the valve seat, an oil inlet and an oil return port connected to the valve seat oil passage are arranged in the valve seat, a valve core and a first limiting structure are arranged in the valve seat, the valve core and the valve seat are clearance-matched, the two ends of the valve core are respectively a first end of the valve core and a second end of the valve core, along the fuel flow direction, the first end of the valve core is located upstream of the second end of the valve core, and the second end of the valve core abuts against the first limiting structure.

[0014] Preferably, the gap between the valve core and the valve seat is in micrometer order.

[0015] Preferably, the valve core and the valve seat are not interchangeable.

[0016] Preferably, an oil drain groove is provided on the end surface of the second end of the valve core.

[0017] Preferably, an annular oil groove is provided on the inner surface of the valve seat, and the annular oil groove covers the outside of the second end of the valve core. One end of the annular oil groove is connected to the gap between the valve seat and the valve core, and the other end of the annular oil groove is connected to the oil drain groove.

[0018] Preferably, the first limiting structure is a limiting ring fixed to the inner surface of the valve seat, the second end of the valve core abuts against the limiting ring, the inner cavity surrounded by the limiting ring is a limiting ring oil channel, one end of the limiting ring oil channel is connected to the oil drain groove, and the other end of the limiting ring oil channel is connected to the oil return port.

[0019] Preferably, a limiting groove is provided on the inner surface of the valve seat, an annular retaining ring is provided in the limiting groove, and the first end of the valve core abuts against the retaining ring.

[0020] To solve the above second technical problem, the second technical solution of the present invention is:

[0021] A common rail pipe, wherein a common rail oil passage is arranged inside the common rail pipe, the above-mentioned micro-leakage device is fixedly arranged at one end of the common rail pipe, and the oil inlet is communicated with the common rail oil passage.

[0022] Preferably, the valve seat is threadedly connected to the common rail pipe.

[0023] After adopting the above technical solution, the beneficial effects of the present invention are:

[0024] The present invention adds a micro-leakage device to the common rail pipe. When the rail pressure is too high, it leaks out through the micro-leakage device to reduce the excessive rail pressure, so that the actual rail pressure of the engine has good followability with the set rail pressure, thus solving the problem of poor rail pressure followability of the micro-leakage injector.

[0025] Since the gap between the valve seat and the valve core is in the micron level, the smaller the gap, the smaller the fuel leakage, thus achieving a trace leakage of fuel, which not only ensures the follow-up of the actual rail pressure and the set rail pressure, but also does not affect the oil balance of the engine.

[0026] Since the valve seat and the valve core are matched with each other, that is, the valve seat and the valve core are not interchangeable, there will be no jamming between the valve core and the valve seat, and the structure is reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the cross-sectional structure of the assembly of the micro-leakage device and the common rail pipe of the present invention;

[0028] Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure of the second end of the middle valve core;

[0029] Figure 3 This is the oil circuit diagram of the engine micro-leak fuel system;

[0030] Figure 4 It is the time-pressure diagram of the engine rail pressure followability test when the rail pressure drops;

[0031] In the figure: 1-common rail pipe; 11-common rail pipe oil channel; 2-valve core; 21-oil drain groove; 3-retaining ring; 4-valve seat; 41-limiting groove; 42-annular oil groove; 43-limiting ring oil channel; 44-limiting ring; 45-oil inlet; 46-oil return port; 5-injector; 6-injection pump; 7-oil tank. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Figure 3 The arrows shown in the figure indicate the direction of fuel flow.

[0034] like Figure 1 and Figure 2As shown together, a micro-leakage device includes a valve seat 4, a valve seat oil passage is provided in the valve seat 4, an oil inlet 45 and an oil return port 46 connected to the valve seat oil passage are provided in the valve seat 4, an external thread is provided on the oil inlet end surface of the valve seat 4, a valve core 2 is provided in the valve seat 4, the valve seat 4 and the valve core 2 are clearance-matched, the clearance is at the micron level, the valve seat 4 and the valve core 2 are matched in pairs, and are not interchangeable, the two ends of the valve core 2 are respectively a first end of the valve core and a second end of the valve core, along the fuel flow direction, the first end of the valve core is located upstream of the second end of the valve core, the first end of the valve core abuts against the annular retaining ring 3, the second end of the valve core abuts against the limiting ring 44, the second end face of the valve core is provided with a straight-line oil leakage groove 21, which can also be a cross shape or a M-shape, etc., an annular oil groove 42 is also provided on the inner surface of the valve seat 4, the annular oil groove 42 covers the outside of the second end of the valve core, and the oil leakage groove 21 is communicated with the annular oil groove 42.

[0035] like Figure 1 As shown, the inner surface of the valve seat 4 is provided with an annular limiting groove 41, and the retaining ring 3 is arranged in the limiting groove 41. The limiting ring 44 is fixed to the inner surface of the valve seat 4, and the cavity surrounded by the limiting ring 44 is a limiting ring oil passage 43, one end of the limiting ring oil passage 43 is connected to the oil drain groove 21, and the other end is connected to the oil return port 46.

[0036] like Figure 1 As shown, when the micro-leakage device is assembled with the common rail pipe 1, the valve seat 4 is threadedly connected to the common rail pipe 1, the common rail pipe oil passage 11 in the common rail pipe 1 is connected with the oil inlet 45, and the oil return port 46 is connected with the oil return pipe.

[0037] like Figure 3 As shown, when the engine is working, the fuel injection pump 6 pressurizes the fuel in the fuel tank 7 and supplies it to the common rail pipe 1, and the common rail pipe 1 distributes the fuel to each injector 5. The return oil generated by the common rail pipe 1 and the injector 5 flows back to the fuel tank 7 through the return oil pipe. When the fuel pressure in the common rail pipe 1 is too high, a small amount of fuel flows out of the common rail pipe 1 through the oil inlet 45, the retaining ring 3, the gap between the valve seat 4 and the valve core 2, the annular oil groove 42, the oil drain groove 21, the limit ring oil channel 43 and the return oil port 46 in sequence, and then flows back to the fuel tank 7 through the return oil pipe.

[0038] The present invention adds a micro-leakage device to the common rail pipe 1. When the rail pressure is too high, it leaks out through the micro-leakage device to relieve the excessive rail pressure, thereby solving the problem of poor rail pressure following performance of the micro-leakage injector. Figure 4 As shown, the engine rail pressure with the micro-leakage device has good tracking performance with the set rail pressure of the engine. At the same time, the gap between the valve seat 4 and the valve core 2 is micron-level. The smaller the gap, the smaller the fuel leakage, thus achieving a micro-leakage of the fuel, which not only ensures the tracking performance of the actual rail pressure with the set rail pressure, but also does not affect the oil balance of the engine; in addition, since the valve seat 4 and the valve core 2 are paired and do not have interchangeability, the valve core 2 and the valve seat 4 will not get stuck, and the structure is reliable.

[0039] The above is an example of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. A micro-leakage device, characterized in that: The invention comprises: a valve seat, a valve seat oil passage is arranged in the valve seat, an oil inlet and an oil return port connected with the valve seat oil passage are arranged in the valve seat, a valve core and a first limiting structure are arranged in the valve seat, the valve core and the valve seat are matched with each other in clearance, the clearance between the valve core and the valve seat is at the micron level, the valve core and the valve seat are not interchangeable, the clearance between the valve core and the valve seat are respectively connected with the oil inlet and the oil return port, the two ends of the valve core are respectively a first end of the valve core and a second end of the valve core, along the fuel flow direction, the first end of the valve core is located upstream of the second end of the valve core, a limiting groove is arranged on the inner surface of the valve seat, an annular retaining ring is arranged in the limiting groove, the first end of the valve core abuts against the retaining ring, and the second end of the valve core abuts against the first limiting structure.

2. The micro-leakage device according to claim 1, characterized in that: An oil drain groove is provided on the end surface of the second end of the valve core.

3. The micro-leakage device according to claim 2, characterized in that: An annular oil groove is provided on the inner surface of the valve seat, and the annular oil groove covers the outside of the second end of the valve core. One end of the annular oil groove is connected to the gap between the valve seat and the valve core, and the other end of the annular oil groove is connected to the oil drain groove.

4. The micro-leakage device according to claim 2, characterized in that: The first limiting structure is a limiting ring fixed to the inner surface of the valve seat, the second end of the valve core abuts against the limiting ring, the inner cavity surrounded by the limiting ring is a limiting ring oil channel, one end of the limiting ring oil channel is connected to the oil drain groove, and the other end of the limiting ring oil channel is connected to the oil return port.

5. A common rail pipe, wherein a common rail oil passage is provided in the common rail pipe, characterized in that: One end of the common rail pipe is fixedly provided with a micro-leakage device as described in any one of claims 1 to 4, and the oil inlet is connected to the oil channel of the common rail pipe.

6. The common rail pipe according to claim 5, characterized in that: The valve seat is threadedly connected to the common rail pipe.

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