Oil pumping system for high-pressure oil pump of common rail system

Abstract

The utility model discloses an oil pumping system for a high-pressure oil pump of a common rail system, which belongs to the technical field of fuel injection systems of diesel engines and comprises a plunger sleeve, a plunger, an oil inlet valve, a nut and an oil seal, an oil inlet channel and an oil return channel corresponding to the oil inlet valve are arranged on the plunger sleeve; the plunger pump is characterized in that a stepped hole with the inner diameter larger than that of the oil return channel is formed in the oil inlet valve installation cavity of the plunger sleeve, the circular center of the stepped hole and the oil return channel are concentrically arranged, and a wave absorbing component is installed in the stepped hole. According to the oil pumping system, the wave absorbing structure is arranged in the oil inlet valve mounting cavity of the plunger sleeve, so that the pressure fluctuation in the oil return channel is effectively reduced, the impact force on the oil seal is reduced, and the service life of the oil seal is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of diesel engine fuel injection systems, in particular to an oil pump system for a high-pressure oil pump of a common rail system. Background Art

[0002] In diesel engine fuel injection systems, the common rail system's high-pressure fuel pump plays a crucial role, with its performance directly impacting the engine's fuel injection, combustion efficiency, and emissions. The traditional common rail system's high-pressure fuel pump system primarily consists of a plunger and sleeve assembly, an inlet valve, a nut, a sealing ring, and an oil seal. However, as engines increasingly demand higher fuel delivery efficiency from high-pressure fuel pumps, pressure fluctuations within the oil return channel increase, posing significant challenges to key components like the oil seal.

[0003] Specifically, in traditional oil pump systems, fuel flowing through the oil inlet directly impacts the upper end face of the oil seal. As pressure fluctuations within the oil return channel increase, the impact forces on the oil seal also increase. This prolonged high impact force can gradually weaken the oil seal's sealing function, leading to failure, which can cause fuel leakage and other problems, seriously impacting engine performance and stability. Utility Model Content

[0004] To address the problems of the prior art, the present invention provides an improved oil pump system for a common rail system high-pressure oil pump. By installing a wave-absorbing structure within the inlet valve mounting cavity of the plunger sleeve, the oil pump system effectively reduces pressure fluctuations within the oil return channel, thereby reducing the impact force on the oil seal and extending the service life of the oil seal.

[0005] The utility model is achieved in this way. It is an oil pump system for a high-pressure oil pump of a common rail system, including a plunger sleeve and a plunger, an oil inlet valve and a nut installed on the upper part of the plunger sleeve, an oil seal installed in the lower part of the plunger sleeve and sleeved on the plunger, and an oil inlet channel and an oil return channel are provided on the plunger sleeve corresponding to the oil inlet valve; the utility model is characterized in that a stepped hole with an inner diameter larger than that of the oil return channel is provided in the installation cavity of the oil inlet valve of the plunger sleeve, the circular center of the stepped hole is connected to the oil return channel, and a wave absorbing component is installed in the stepped hole.

[0006] Further preferably, the wave-breaking component includes a cylindrical body having the same shape as the stepped hole, and a through-going variable-diameter channel is provided inside the cylindrical body, including a large-diameter channel adjacent to the oil inlet valve mounting cavity and a small-diameter throttling channel adjacent to the oil return channel.

[0007] Further preferably, the inner diameter of the small-diameter throttling channel is 0.05-0.1 mm.

[0008] Further preferably, the lower end portion of the wave-breaking component is provided with a conical guiding surface.

[0009] Further preferably, the stepped hole is a two-level stepped hole, wherein the first-level stepped hole is used to reserve space for assembly tooling; and the wave-breaking component is installed in the second-level stepped hole.

[0010] The technical effects and advantages of the present invention: The present invention significantly solves the problem of oil seal failure caused by large pressure fluctuations in the oil return channel by adding a wave-breaking valve to the oil system of the high-pressure oil pump. When the engine requires the high-pressure oil pump to provide more oil, the high-pressure oil pump improves the oil supply efficiency, and the pressure fluctuations in the oil return channel will increase, causing a greater impact on the oil seal. However, the wave-breaking valve in the present invention utilizes the principle of small-hole throttling, and effectively eliminates the pressure fluctuations in the oil return channel through the throttling holes thereon, so that the pressure acting on the oil seal remains stable, thereby extending the service life of the oil seal and reducing the risk of oil seal failure. This design not only improves the reliability of the fuel system, but also enhances the performance and stability of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the utility model;

[0012] Figure 2 It is a schematic diagram of the wave-breaking component structure.

[0013] In the figure, 1, plunger sleeve; 1-1, stepped hole; 2, plunger; 3, oil inlet valve; 4, nut; 5, oil seal; 6, oil inlet channel; 7, oil return channel; 8, wave-breaking component; 8-1, large-diameter channel; 8-2, small-diameter throttling channel; 8-3, tapered guide hole; 8-4, tapered assembly guide surface. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0015] See also Figure 1 and Figure 2A pump system for a high-pressure oil pump in a common rail system includes a plunger sleeve 1 and a plunger 2, an oil inlet valve 3 and a nut 4 mounted on the upper portion of the plunger sleeve, and an oil seal 5 mounted within the lower portion of the plunger sleeve and sleeved on the plunger. The plunger sleeve is provided with an oil inlet passage 6 and an oil return passage 7 corresponding to the oil inlet valve. A stepped hole 1-1 having an inner diameter larger than the oil return passage is provided within the inlet valve mounting cavity of the plunger sleeve. The stepped hole having an inner diameter larger than the oil return passage within the inlet valve mounting cavity of the plunger sleeve provides space for the subsequent installation of a wave-breaking component. This design not only ensures a compact structure but also enables a smooth transition of fuel pressure. The circular center of the stepped hole is connected to the oil return passage and can be arranged either concentrically or eccentrically. A wave-breaking component 8 is installed within the stepped hole. The concentric arrangement of the stepped hole and the oil return passage ensures smooth and stable fuel flow. The wave-breaking component installed within the stepped hole effectively reduces pressure fluctuations generated during fuel flow, thereby protecting key components such as the oil seal from impact and increasing their service life.

[0016] Further preferably, the wave-breaking member 8 comprises a cylindrical body shaped like the stepped hole. Within this cylindrical body are interpenetrating variable-diameter passages, including a large-diameter passage 8-1 adjacent to the fuel inlet valve mounting cavity and a small-diameter throttling passage 8-2 adjacent to the fuel return passage. The cylindrical body design ensures a tight fit between the wave-breaking member and the stepped hole. The variable-diameter passages ensure that fuel flows through the large-diameter passage first, then the small-diameter throttling passage, effectively controlling fuel flow rate and pressure and further reducing fuel pressure fluctuations.

[0017] Furthermore, the inner diameter of the small-diameter throttling channel is preferably 0.05-0.1 mm. This precise design ensures that while maintaining smooth fuel flow, it minimizes fuel flow velocity and pressure fluctuations. This design not only meets the engine's fuel supply needs but also protects components such as the oil seal from impact.

[0018] Furthermore, a tapered guide hole 8-3 is preferably provided at the junction of the large-diameter channel and the small-diameter throttling channel within the wave-breaking component, with the large diameter of the tapered guide hole adjacent to the large-diameter channel. This tapered guide surface allows fuel to flow more smoothly into the small-diameter throttling channel, avoiding pressure fluctuations caused by sudden changes in flow velocity. Furthermore, the tapered guide surface effectively prevents the accumulation of impurities in the fuel within the wave-breaking component, ensuring its long-term stable performance. 设计 The purpose of the tapered guide hole is to reduce the difficulty of processing the small hole that is too long. It is actually a process requirement. The small hole is at the bottom to avoid deformation caused by direct contact between the tooling and the small hole surface during the press-fitting process.

[0019] The outer circumference of the lower end of the wave-breaking component is provided with a tapered assembly guide surface 8-4. Its function is to guide assembly: the tapered assembly guide surface can provide a clear guide when installing the wave-breaking component, allowing the wave-breaking component to be accurately and smoothly installed in the stepped hole, thereby ensuring the accuracy and reliability of installation.

[0020] Function 2: Damage Prevention: Without a tapered guide surface, minor deviations or misalignments during installation can cause friction or collision between the wave-breaking component and the stepped hole, resulting in damage to both. The tapered guide surface effectively reduces this friction and collision, protecting the wave-breaking component and the stepped hole from damage.

[0021] Further preferably, the stepped hole is a two-stage stepped hole, wherein: the first-stage stepped hole reserves space for the assembly tool; the wave-breaking component is installed in the second-stage stepped hole adjacent to the oil return channel. The design of the two-stage stepped hole makes the installation of the wave-breaking component more stable and reliable. At the same time, installing the wave-breaking component in the second-stage stepped hole adjacent to the oil return channel can more effectively reduce the pressure fluctuations generated by the fuel during the oil return process, further improving the stability and reliability of the system.

[0022] Working process of this utility model:

[0023] During engine operation, fuel, pressurized by the fuel transfer pump, flows through the oil inlet hole into the oil return channel. As the plunger descends to absorb fuel, the oil pressure causes the suction valve core to move downward, allowing fuel to enter the plunger sleeve. As the plunger ascends to pump fuel, the fuel is compressed to a high pressure, pushing the suction valve core upward, creating tight contact with the mating components to maintain a seal. The high-pressure oil is then sprayed into the common rail pressure accumulator chamber through the oil pipe connected to the high-pressure oil pump.

[0024] During the reciprocating oil suction and oil compression process of the plunger, the fuel in the oil return channel is constantly consumed and replenished, causing the pressure in the oil return channel to fluctuate. However, in the present utility model, due to the presence of the small-diameter throttling channel of the wave-breaking component, these pressure fluctuations acting on the oil seal are effectively suppressed and eliminated. When the fuel flows through the small-diameter throttling channel, the flow rate and pressure are stably controlled due to the throttling effect of the small-diameter throttling channel, thereby avoiding sudden changes in the pressure in the oil return channel. This design keeps the pressure acting on the oil seal stable, avoiding the problem of oil seal failure caused by excessive pressure fluctuations. At the same time, stable pressure also helps to improve the operating efficiency of the fuel system and the performance of the engine.

[0025] In summary, the utility model provides a common rail system high-pressure oil pump oil system with a unique design and structure, which brings significant advantages such as reducing fuel pressure fluctuations, optimizing fuel flow, enhancing assembly accuracy, improving sealing performance and improving system reliability, providing a strong guarantee for the efficient and stable operation of the diesel engine.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An oil pump system for a high-pressure oil pump of a common rail system, comprising a plunger sleeve and a plunger, an oil inlet valve and a nut mounted on the upper portion of the plunger sleeve, an oil seal mounted in the lower portion of the plunger sleeve and sleeved on the plunger, an oil inlet channel and an oil return channel being provided on the plunger sleeve corresponding to the oil inlet valve; characterized in that: A step hole with an inner diameter larger than that of the oil return channel is provided in the oil inlet valve installation cavity of the plunger sleeve. The circular center of the step hole is connected to the oil return channel. A wave absorbing component is installed in the step hole.

2. The high-pressure oil pump system for the common rail system according to claim 1, characterized in that: The wave-breaking component includes a cylindrical body with the same shape as the stepped hole. A through-going variable-diameter channel is provided inside the cylindrical body, including a large-diameter channel adjacent to the oil inlet valve installation cavity and a small-diameter throttling channel adjacent to the oil return channel.

3. The high-pressure oil pump system for the common rail system according to claim 2, characterized in that: The inner diameter of the small-diameter throttling channel is 0.05-0.1 mm.

4. The high-pressure oil pump system for the common rail system according to claim 2, characterized in that: A tapered guide hole is provided at the junction of the large-diameter channel and the small-diameter throttling channel in the wave-breaking component, wherein the large diameter of the tapered guide hole is adjacent to the large-diameter channel.

5. The high-pressure oil pump system for the common rail system according to claim 2, characterized in that: The outer circumference of the lower end portion of the wave-absorbing component is provided with a tapered assembly guide surface.

6. The high-pressure oil pump system for the common rail system according to claim 1, characterized in that: The step hole is a two-level step hole, wherein the first-level step hole is used to reserve space for assembly tooling; and the wave-breaking component is installed in the second-level step hole.

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