An engine oil pressure control system and an engine

Abstract

The present invention discloses an oil pressure control system and an engine. The oil pump body, the stator and the rotor cooperate to pressurize the oil. The pressure port of the pressure limiting valve is communicated with the main oil passage of the engine lubrication system, and the pressure limiting state of the pressure limiting valve is adjusted according to the pressure of the main oil passage. The oil inlet of the pressure limiting valve is communicated with the oil chamber behind the pump of the oil pump body, and the oil outlet of the pressure limiting valve is communicated with the oil sump of the engine. As the engine speed increases, the pressure of the main oil passage rises. When the engine speed is in the first speed range, the first-stage control chamber of the pressure limiting valve connects the oil inlet and the oil outlet of the pressure limiting valve, and discharges the high-pressure oil in the oil chamber behind the pump to the oil sump through the first-stage control chamber and the oil outlet of the pressure limiting valve. When the engine speed continues to rise to the second speed range, the pressure limiting valve switches to the second-stage pressure limiting state under the action of the main oil passage pressure, and the second-stage control chamber of the pressure limiting valve connects the oil inlet and the oil outlet of the pressure limiting valve, controlling the main oil passage pressure at a relatively stable level.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly to an oil pressure control system and an engine. Background Art

[0002] With the progress of technology, the thermal efficiency of engines is continuously improving, and higher requirements are also put forward for the engine lubrication system. The oil pressure of the system should be as consistent as possible with the required oil pressure. On the one hand, this can meet the reliability requirements of the engine, and on the other hand, it avoids power loss caused by excessive oil pressure. In the current oil pump scheme with a pressure limiting valve, usually when the engine starts the pressure limiting valve at a higher speed, part of the oil is discharged to maintain the oil pressure at a relatively stable value. However, the actual pressure curve of the engine lubrication system is higher than the system pressure demand curve, so there is an area with excessive pressure, resulting in additional power loss. Summary of the Invention

[0003] The present invention discloses an oil pressure control system and an engine, which can reduce the lubrication system pressure on the premise of meeting the pressure requirements of the engine lubrication system, thereby reducing the shaft power of the oil pump.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides an oil pressure control system, including: an oil pump body, a stator, a rotor, and a pressure limiting valve;

[0006] An oil inlet chamber and a post-pump oil chamber are provided inside the oil pump body;

[0007] The pressure limiting valve has a pressure port, a pressure limiting valve inlet, and a pressure limiting valve outlet. A pressure chamber, a first-stage control chamber, and a second-stage control chamber are provided inside the pressure limiting valve. The pressure chamber is communicated with the main oil passage of the engine lubrication system through the pressure port; the pressure limiting valve inlet is communicated with the post-pump oil chamber of the oil pump body, and the pressure limiting valve outlet is communicated with the engine oil sump;

[0008] The pressure limiting valve has a first-stage pressure limiting state and a second-stage pressure limiting state;

[0009] When the pressure limiting valve is in the first-stage pressure limiting state, the first-stage control chamber communicates the pressure limiting valve inlet and the pressure limiting valve outlet, and the engine speed is in a first speed range;

[0010] When the pressure limiting valve is in the second-stage pressure limiting state, the second-stage control chamber communicates the pressure limiting valve inlet and the pressure limiting valve outlet, and the engine speed is in a second speed range, and the minimum value in the second speed range is greater than the maximum value in the first speed range.

[0011] In the above oil pressure control system, the oil pump body, stator, and rotor cooperate to pressurize the oil. The pressure port of the pressure limiting valve is connected to the main oil passage of the engine lubrication system, and the pressure limiting state of the pressure limiting valve is adjusted according to the pressure of the main oil passage. The oil inlet of the pressure limiting valve is connected to the oil chamber behind the pump of the oil pump body, and the oil outlet of the pressure limiting valve is connected to the oil sump of the engine. As the engine speed increases, the pressure of the main oil passage rises. When the engine speed is in the first speed range, the first-stage control chamber of the pressure limiting valve connects the oil inlet and the oil outlet of the pressure limiting valve, and discharges the high-pressure oil in the oil chamber behind the pump to the oil sump through the first-stage control chamber and the oil outlet of the pressure limiting valve. However, the pressure of the main oil passage still rises to a certain extent. When the engine speed continues to increase to the second speed range, along with the slow increase of the main oil passage pressure, the pressure limiting valve switches to the second-stage pressure limiting state under the action of the main oil passage pressure. The second-stage control chamber of the pressure limiting valve connects the oil inlet and the oil outlet of the pressure limiting valve, and can control the main oil passage pressure at a relatively stable level. The first speed range can be relatively defined as the intermediate speed, and the second speed range can be relatively defined as the high speed. Therefore, the two-stage control chambers of the pressure limiting valve can reduce the oil pressure of the engine lubrication system at medium and high engine speeds respectively, thereby reducing the shaft power of the oil pump and improving the output power and thermal efficiency of the engine.

[0012] In some embodiments, when the pressure limiting valve is in the first-stage pressure limiting state, when the opening degree of the oil inlet of the pressure limiting valve is 100%, the opening degree of the oil outlet of the pressure limiting valve is less than 100%; when the opening degree of the oil outlet of the pressure limiting valve is 100%, the opening degree of the oil inlet of the pressure limiting valve is less than 100%.

[0013] In some embodiments, when the pressure limiting valve is in the second-stage pressure limiting state, when the opening degree of the oil inlet of the pressure limiting valve is 100%, the maximum opening degree of the oil outlet of the pressure limiting valve is 100%; when the opening degree of the oil outlet of the pressure limiting valve is 100%, the maximum opening degree of the oil inlet of the pressure limiting valve is 100%.

[0014] In some embodiments, the side of the oil outlet of the pressure limiting valve away from the pressure port is the lower boundary Y1 of the outlet of the pressure limiting valve, and the side of the oil outlet of the pressure limiting valve close to the pressure port is the upper boundary Y2 of the outlet of the pressure limiting valve; the side of the oil inlet of the pressure limiting valve away from the pressure port is the lower boundary Y3 of the inlet of the pressure limiting valve, and the side of the oil inlet of the pressure limiting valve close to the pressure port is the upper boundary Y4 of the inlet of the pressure limiting valve; the lower boundary Y3 of the inlet of the pressure limiting valve is located on the side close to the pressure port of the upper boundary Y2 of the outlet of the pressure limiting valve.

[0015] In some embodiments, the side of the first-stage control chamber away from the pressure port is the lower boundary X1 of the first-stage control chamber, and the side of the first-stage control chamber close to the pressure port is the upper boundary X2 of the first-stage control chamber;

[0016] The height L of the first - stage control cavity X1X2 Satisfies:

[0017] L X1X2 <L Y1Y4

[0018] Wherein, L Y1Y4 Is the height between the lower boundary Y1 of the pressure - limiting valve outlet and the upper boundary Y4 of the pressure - limiting valve inlet.

[0019] In some embodiments, the side of the second - stage control cavity away from the pressure port is the lower boundary X3 of the second - stage control cavity, and the side of the second - stage control cavity close to the pressure port is the upper boundary X4 of the second - stage control cavity;

[0020] The height L of the second - stage control cavity X3X4 Satisfies:

[0021] L X3X4 >L Y1Y4

[0022] Wherein, L Y1Y4 Is the height between the lower boundary Y1 of the pressure - limiting valve outlet and the upper boundary Y4 of the pressure - limiting valve inlet.

[0023] In some embodiments, the pressure - limiting valve includes a valve body, a valve core and an elastic reset member located inside the valve body;

[0024] The pressure port, the oil inlet of the pressure - limiting valve and the oil outlet of the pressure - limiting valve are all arranged on the valve body;

[0025] One end of the elastic reset member is connected to the valve core, and the other end is connected to the valve body, and is used to always provide a force for the valve core to act towards the pressure port;

[0026] The valve core and the valve body cooperate to form the pressure cavity, the first - stage control cavity and the second - stage control cavity, and the pressure cavity, the second - stage control cavity and the first - stage control cavity are arranged in sequence along the movement direction of the valve core away from the pressure port.

[0027] In some embodiments, the displacement Z1 of the valve core when the pressure - limiting valve is switched from the fully - closed state to the initial opening of the first - stage control cavity satisfies:

[0028] Z1 = P1×A / K - Z0

[0029] Wherein, P1 is the pressure value of the main oil passage when the first - stage control cavity of the pressure - limiting valve starts to open, A is the internal cross - sectional area of the pressure - limiting valve body, K is the stiffness of the elastic reset member, and Z0 is the pre - compression amount of the elastic reset member when the pressure - limiting valve is in the fully - closed state; or,

[0030] The height L of the first - stage control cavity X1X2 Satisfies:

[0031] L X1X2 = P2 × A / K + L Y2Y3

[0032] Wherein, P2 is the increase value of the main oil passage pressure between the initial opening and the closing of the first - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, K is the stiffness of the elastic reset member, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet; or,

[0033] The height L between the upper boundary X2 of the first - stage control chamber and the lower boundary X3 of the second - stage control chamber X2X3 satisfies:

[0034] L X2X3 = P3 × A / K - L Y2Y3

[0035] Wherein, P3 is the increase value of the main oil passage pressure between the closing of the first - stage control chamber and the initial opening of the second - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, K is the stiffness of the elastic reset member, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet; or,

[0036] The height L between the lower boundary Y1 of the pressure - limiting valve outlet and the upper boundary Y2 of the pressure - limiting valve outlet Y1Y2 satisfies:

[0037] L Y1Y2 = P4 × A / K

[0038] Wherein, P4 is the increase value of the main oil passage pressure between the initial opening and the full opening of the second - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, and K is the stiffness of the elastic reset member.

[0039] In some embodiments, the height value L between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet Y2Y3 satisfies:

[0040] L Y2Y3 < P3 × A / K

[0041] Wherein, P3 is the increase value of the main oil passage pressure between the closing of the first - stage control chamber and the initial opening of the second - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, and K is the stiffness of the elastic reset member; or,

[0042] The height L of the second - stage control chamber X3X4 satisfies:

[0043] L X3X4 ≥ L Y1Y4

[0044] LY1Y4 It is the height value between the lower boundary Y1 of the outlet of the pressure limiting valve and the upper boundary Y4 of the inlet of the pressure limiting valve.

[0045] In a second aspect, the present invention further provides an engine, including an engine lubrication system and an oil pressure control system as described in any one of the first aspects; the engine lubrication system includes an oil pan and a main oil passage; the oil pan is communicated with the outlet of the pressure limiting valve in the oil pressure control system, and the main oil passage is communicated with the pressure port in the oil pressure control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a graph of the main oil passage pressure increasing with the engine speed in Related Art 1;

[0047] Figure 2 It is a graph of the main oil passage pressure increasing with the engine speed in Related Art 2;

[0048] Figure 3 It is a schematic structural diagram of an oil pressure control system provided by an embodiment of the present invention;

[0049] Figure 4 It is a schematic structural diagram of the valve core;

[0050] Figure 5 It is a schematic structural diagram when the pressure limiting valve is in a fully closed state;

[0051] Figure 6 It is a schematic structural diagram when the primary control chamber is in an initial opening state;

[0052] Figure 7 It is a schematic structural diagram when the flow area of the primary control chamber is the largest;

[0053] Figure 8 It is a schematic structural diagram when the primary control chamber is closed;

[0054] Figure 9 It is a schematic structural diagram when the secondary control chamber is in an initial opening state;

[0055] Figure 10 It is a schematic structural diagram when the secondary control chamber is fully opened;

[0056] Figure 11 It is a graph of the main oil passage oil pressure increasing with the engine speed.

[0057] Icons: 100 - oil pump body; 200 - stator; 300 - rotor; 400 - pressure limiting valve; 410 - valve body; 420 - valve core; 430 - elastic reset member; 401 - pressure port; 402 - pressure limiting valve inlet; 403 - pressure limiting valve outlet; 404 - pressure chamber; 405 - primary control chamber; 406 - secondary control chamber; 421 - core shaft; 422 - first core segment; 423 - second core segment; 424 - third core segment. Detailed implementation manners

[0058] First, introduce the application scenario of this application: Since the shaft power of the oil pump satisfies: the shaft power of the oil pump = the output pressure of the oil pump × the output flow rate of the oil pump ÷ the efficiency of the oil pump, reducing the output pressure or flow rate of the oil pump can reduce the shaft power of the oil pump. However, in the existing fixed-displacement oil pump with a pressure limiting valve, the pressure limiting valve only opens at high speeds, discharging part of the oil to maintain the oil pressure at a relatively stable value. As Figure 1 shown, the actual pressure curve of the engine lubrication system is higher than the system pressure demand curve, so there is an area with excessive pressure, resulting in additional power loss. For the existing variable-displacement oil pump, as Figure 2 shown, by adjusting the eccentricity of the rotor, the displacement of the oil pump is changed, thereby reducing both the oil flow rate and the system pressure at some speeds, thus reducing the power loss. However, in order to achieve variable displacement, the structure of the oil pump becomes complex, which on the one hand reduces the overall reliability, and on the other hand increases the cost.

[0059] Based on the above application scenario, the embodiments of this application provide an oil pressure control system, which has a simple structure and can reduce the oil pressure of the lubrication system at medium and high engine speeds respectively, thereby reducing the shaft power of the oil pump and improving the output power and thermal efficiency of the engine.

[0060] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] In the first aspect, as Figure 3As shown in the figure, an embodiment of the present invention provides an oil pressure control system, including: an oil pump body 100, a stator 200, a rotor 300, and a pressure limiting valve 400; an oil inlet cavity and a post-pump oil cavity are provided inside the oil pump body 100; the pressure limiting valve 400 has a pressure port 401, a pressure limiting valve oil inlet 402, and a pressure limiting valve oil outlet 403. A pressure cavity 404, a primary control cavity 405, and a secondary control cavity 406 are provided inside the pressure limiting valve 400. The pressure cavity 404 is communicated with the main oil passage of the engine lubrication system through the pressure port 401; the pressure limiting valve oil inlet 402 is communicated with the post-pump oil cavity of the oil pump body 100, and the pressure limiting valve oil outlet 403 is communicated with the oil pan of the engine; the pressure limiting valve 400 has a primary pressure limiting state and a secondary pressure limiting state; when the pressure limiting valve 400 is in the primary pressure limiting state, the primary control cavity 405 communicates the pressure limiting valve oil inlet 402 and the pressure limiting valve oil outlet 403, and the engine speed is in a first speed range; when the pressure limiting valve 400 is in the secondary pressure limiting state, the secondary control cavity 406 communicates the pressure limiting valve oil inlet 402 and the pressure limiting valve oil outlet 403, and the engine speed is in a second speed range, and the minimum value in the second speed range is greater than the maximum value in the first speed range.

[0062] In the above oil pressure control system, the oil pump body 100, the stator 200, and the rotor 300 cooperate to pressurize the oil. The pressure port 401 of the pressure limiting valve 400 is communicated with the main oil passage of the engine lubrication system, and the pressure limiting state of the pressure limiting valve 400 is adjusted according to the pressure of the main oil passage. The pressure limiting valve oil inlet 402 is communicated with the post-pump oil cavity of the oil pump body 100, and the pressure limiting valve oil outlet 403 is communicated with the oil pan of the engine. As the engine speed increases, the pressure of the main oil passage rises. When the engine speed is in the first speed range, the primary control cavity 405 of the pressure limiting valve 400 connects the pressure limiting valve oil inlet 402 and the pressure limiting valve oil outlet 403, and discharges the high-pressure oil in the post-pump oil cavity to the oil pan through the primary control cavity 405 and the pressure limiting valve oil outlet 403. However, the pressure of the main oil passage still rises to a certain extent. When the engine speed continues to increase to the second speed range, along with the slow increase of the main oil passage pressure, the pressure limiting valve 400 switches to the secondary pressure limiting state under the action of the main oil passage pressure. The secondary control cavity 406 of the pressure limiting valve 400 connects the pressure limiting valve oil inlet 402 and the pressure limiting valve oil outlet 403, and can control the main oil passage pressure at a relatively stable level. The first speed range can be relatively defined as the intermediate speed, and the second speed range can be relatively defined as the high speed. Therefore, the two-stage control cavities of the pressure limiting valve 400 can reduce the oil pressure of the engine lubrication system at medium and high engine speeds respectively, thereby reducing the shaft power of the oil pump and improving the output power and thermal efficiency of the engine.

[0063] In some embodiments, the pressure limiting valve 400 is in the first-stage pressure limiting state. When the opening degree of the oil inlet 402 of the pressure limiting valve is 100%, the opening degree of the oil outlet 403 of the pressure limiting valve is less than 100%; when the opening degree of the oil outlet 403 of the pressure limiting valve is 100%, the opening degree of the oil inlet 402 of the pressure limiting valve is less than 100%.

[0064] It should be noted that when the engine is in the first speed range, i.e., the intermediate speed, the first-stage control chamber 405 connects the oil inlet 402 and the oil outlet 403 of the pressure limiting valve to drain the high-pressure oil in the post-pump oil chamber to the oil pan, realizing the first-stage pressure limiting. Since the engine speed is not high at this time and large-flow oil drainage is not required, the oil inlet 402 and the oil outlet 403 of the pressure limiting valve can only be opened partially, that is, the opening degrees cannot reach 100% simultaneously. Therefore, although oil is drained, the main oil passage pressure still rises to a certain extent, which further prompts the pressure limiting valve 400 to switch to the second-stage pressure limiting state.

[0065] In some embodiments, the pressure limiting valve 400 is in the second-stage pressure limiting state. When the opening degree of the oil inlet 402 of the pressure limiting valve is 100%, the maximum opening degree of the oil outlet 403 of the pressure limiting valve is 100%; when the opening degree of the oil outlet 403 of the pressure limiting valve is 100%, the maximum opening degree of the oil inlet 402 of the pressure limiting valve is 100%.

[0066] It should be noted that when the engine reaches a higher speed and the engine speed is in the second speed range, as the main oil passage pressure continues to rise, the second-stage control chamber 406 connects the oil inlet 402 and the oil outlet 403 of the pressure limiting valve to drain the high-pressure oil in the post-pump oil chamber to the oil pan, realizing the second-stage pressure limiting. Since the opening degrees of the oil inlet 402 and the oil outlet 403 of the pressure limiting valve can both reach the maximum, that is, the opening degrees can reach 100% simultaneously, the oil drainage flow area is large, and the main oil passage pressure can be controlled at a relatively stable level.

[0067] In some embodiments, the pressure limiting valve 400 includes a valve body 410, a valve core 420 and an elastic reset member 430 located inside the valve body 410; the pressure port 401, the oil inlet 402 and the oil outlet 403 of the pressure limiting valve are all arranged on the valve body 410; one end of the elastic reset member 430 is connected to the valve core 420, and the other end is connected to the valve body 410, and is used to always provide a force for the valve core 420 to act towards the pressure port 401; the valve core 420 and the valve body 410 cooperate to form a pressure chamber 404, a first-stage control chamber 405 and a second-stage control chamber 406, and the pressure chamber 404, the second-stage control chamber 406 and the first-stage control chamber 405 are arranged in sequence along the movement direction of the valve core 420 away from the pressure port 401.

[0068] In a possible implementation manner, such as Figure 3 and Figure 4As shown, the pressure limiting valve 400 includes a valve body 410, a valve core 420 and an elastic reset member 430 located inside the valve body 410; the valve core 420 has a three-section structure. Referring to Figure 4 , the valve core 420 includes a core shaft 421, and a first core section 422, a second core section 423 and a third core section 424 connected by the core shaft 421. There is a first-stage control cavity 405 between the first core section 422 and the second core section 423; there is a second-stage control cavity 406 between the second core section 423 and the third core section 424. An installation groove is provided at one end of the first core section 422 away from the second core section 423, and part of the elastic reset member 430 is installed in the installation groove, which can play a guiding and positioning role for the elastic reset member 430. As Figure 4 shown, the height of the first core section 422 is greater than the height of the second core section 423, and the height of the second core section 423 is greater than the height of the third core section 424. The elastic reset member 430 can be but is not limited to a spring.

[0069] In some embodiments, the side of the pressure limiting valve oil outlet 403 away from the pressure port 401 is the lower boundary Y1 of the pressure limiting valve outlet, and the side of the pressure limiting valve oil outlet 403 close to the pressure port 401 is the upper boundary Y2 of the pressure limiting valve outlet; the side of the pressure limiting valve oil inlet 402 away from the pressure port 401 is the lower boundary Y3 of the pressure limiting valve inlet, and the side of the pressure limiting valve oil inlet 402 close to the pressure port 401 is the upper boundary Y4 of the pressure limiting valve inlet; the lower boundary Y3 of the pressure limiting valve inlet is located on the side of the upper boundary Y2 of the pressure limiting valve outlet close to the pressure port 401.

[0070] In a possible implementation manner, as Figure 3 and Figure 5 shown, the pressure limiting valve oil outlet 403 is located on the side of the pressure limiting valve oil inlet 402 away from the pressure port 401, that is, the pressure limiting valve oil outlet 403 and the pressure limiting valve oil inlet 402 are at different heights. During the first-stage pressure limiting state process of the pressure limiting valve 400, the first-stage control cavity 405 can make the pressure limiting valve oil inlet 402 and the pressure limiting valve oil outlet 403 only open partially, realizing the first-stage pressure limiting.

[0071] It should be noted that the pressure limiting valve oil outlet 403 can also be located between the pressure limiting valve oil inlet 402 and the pressure port 401, as long as it is ensured that the first-stage control cavity 405 makes the pressure limiting valve oil inlet 402 and / or the pressure limiting valve oil outlet 403 open partially.

[0072] In a possible implementation manner, the pressure limiting valve oil inlet 402 is connected to the oil cavity behind the pump, the pressure limiting valve oil outlet 403 is connected to the oil pan, and the pressure cavity 404 of the pressure limiting valve 400 is connected to the main oil passage of the engine lubrication system. As the engine speed increases, the pressure in the main oil passage rises, and the engine oil in the main oil passage enters the pressure cavity 404 of the pressure limiting valve 400 and pushes the valve core 420 of the pressure limiting valve 400 to move. In a possible implementation manner, as Figure 5 and Figure 6As shown Figure 5 is a schematic structural diagram when the pressure limiting valve is in a fully closed state Figure 5 In it, the lower boundary X1 of the first-stage control chamber 405 is lower than the upper boundary Y4 of the pressure limiting valve inlet and higher than the lower boundary Y3 of the pressure limiting valve inlet, that is, the oil inlet 402 of the pressure limiting valve is communicated with the first-stage control chamber 405; the lower boundary X1 of the first-stage control chamber 405 is higher than the upper boundary Y2 of the pressure limiting valve outlet, that is, the oil outlet 403 of the pressure limiting valve is not communicated with the first-stage control chamber 405. At this time, the pressure limiting valve 400 is in a fully closed state Figure 6 is a schematic structural diagram when the first-stage control chamber 405 is in an initial opening state. Here, the initial opening of the first-stage control chamber 405 can be understood as the initial moment when the first-stage control chamber 405 communicates the oil inlet 402 of the pressure limiting valve and the oil outlet 403 of the pressure limiting valve Figure 6 In it, the upper boundary X2 of the first-stage control chamber 405 is slightly lower than the upper boundary Y4 of the pressure limiting valve inlet or at the same height as the upper boundary Y4 of the pressure limiting valve inlet, and the upper boundary X2 of the first-stage control chamber 405 is higher than the lower boundary Y3 of the pressure limiting valve inlet. The lower boundary X1 of the first-stage control chamber 405 is lower than the lower boundary Y3 of the pressure limiting valve inlet, that is, the oil inlet 402 of the pressure limiting valve is communicated with the first-stage control chamber 405; the lower boundary X1 of the first-stage control chamber 405 is slightly lower than the upper boundary Y2 of the pressure limiting valve outlet, so that the high-pressure oil in the oil chamber after the pump can flow out of the oil outlet 403 of the pressure limiting valve from the first-stage control chamber 405. When the engine is at an intermediate speed, the valve core 420 of the pressure limiting valve 400 makes the first-stage control chamber 405 communicate the oil inlet 402 of the pressure limiting valve and the oil outlet 403 of the pressure limiting valve to achieve first-stage pressure limiting

[0073] In some embodiments, the side of the first-stage control chamber 405 away from the pressure port 401 is the lower boundary X1 of the first-stage control chamber 405, and the side of the first-stage control chamber 405 close to the pressure port 401 is the upper boundary X2 of the first-stage control chamber 405

[0074] The height L of the first-stage control chamber 405 X1X2 satisfies

[0075] L X1X2 <L Y1Y4

[0076] wherein, L Y1Y4 is the height between the lower boundary Y1 of the pressure limiting valve outlet and the upper boundary Y4 of the pressure limiting valve inlet

[0077] Due to the height L of the valve core 420 of the first-stage control chamber 405 X1X2 <L Y1Y4 , the oil inlet 402 and the oil outlet 403 of the pressure limiting valve can only be opened partially Figure 7 is a schematic structural diagram when the flow area of the first-stage control chamber 405 is the largest Figure 7The upper boundary X2 of the first-stage control chamber 405 is lower than the upper boundary Y4 of the inlet of the pressure-limiting valve and higher than the lower boundary Y3 of the inlet of the pressure-limiting valve. The lower boundary X1 of the first-stage control chamber 405 is lower than the upper boundary Y2 of the outlet of the pressure-limiting valve and higher than the lower boundary Y1 of the outlet of the pressure-limiting valve. At this time, the opening degree of the oil inlet 402 of the pressure-limiting valve is the same as that of the oil outlet 403 of the pressure-limiting valve, and the flow area of the first-stage control chamber 405 of the pressure-limiting valve 400 is the largest. However, since the opening degrees of both the oil inlet 402 and the oil outlet 403 of the pressure-limiting valve do not reach 100%, although the pressure-limiting valve 400 drains oil in the first-stage pressure-limiting state, the pressure in the main oil passage still rises to a certain extent.

[0078] When the engine reaches a relatively high speed, along with the slow increase in the pressure of the main oil passage, the spool 420 gradually moves until the first-stage control chamber 405 of the spool 420 is closed. Here, the closing of the first-stage control chamber 405 can be understood as the first-stage control chamber 405 no longer communicating with the oil inlet 402 and the oil outlet 403 of the pressure-limiting valve. Figure 8 It is a schematic structural diagram when the first-stage control chamber 405 is closed, that is, the initial moment when the first-stage control chamber 405 no longer communicates with the oil inlet 402 and the oil outlet 403 of the pressure-limiting valve. Figure 8 In the upper boundary X2 of the first-stage control chamber 405 is at the same height as the lower boundary Y3 of the inlet of the pressure-limiting valve, that is, the oil inlet 402 of the pressure-limiting valve and the first-stage control chamber 405 just cannot communicate. After the pressure-limiting valve 400 stops draining oil, the pressure in the main oil passage will rise rapidly. A small increase in the engine speed causes a large movement of the spool 420 until the second-stage control chamber 406 of the spool 420 makes the oil inlet 402 and the oil outlet 403 of the pressure-limiting valve communicate again, realizing second-stage pressure limitation. As Figure 9 shown, Figure 9 It is a schematic structural diagram when the second-stage control chamber 406 is initially opened. Here, the initial opening of the second-stage control chamber 406 can be understood as the initial moment when the second-stage control chamber 406 communicates with the oil inlet 402 and the oil outlet 403 of the pressure-limiting valve. Figure 9 In the lower boundary X3 of the second-stage control chamber 406 is lower than the lower boundary Y3 of the inlet of the pressure-limiting valve, and the upper boundary X4 of the second-stage control chamber 406 is higher than the upper boundary Y4 of the inlet of the pressure-limiting valve, that is, the oil inlet 402 of the pressure-limiting valve communicates with the second-stage control chamber 406; the lower boundary X3 of the second-stage control chamber 406 is slightly lower than the upper boundary Y2 of the outlet of the pressure-limiting valve, so that the high-pressure oil in the oil chamber after the pump can flow out of the oil outlet 403 of the pressure-limiting valve from the second-stage control chamber 406.

[0079] In some embodiments, the side of the second-stage control chamber 406 away from the pressure port 401 is the lower boundary X3 of the second-stage control chamber, and the side of the second-stage control chamber 406 close to the pressure port 401 is the upper boundary X4 of the second-stage control chamber;

[0080] The height L of the second-stage control chamber 406 X3X4 satisfies:

[0081] LX3X4 > L Y1Y4

[0082] wherein, L Y1Y4 is the height between the lower boundary Y1 of the pressure limiting valve outlet and the upper boundary Y4 of the pressure limiting valve inlet.

[0083] As Figure 10 shown, Figure 10 it is a schematic structural diagram when the secondary control chamber 406 is fully opened. Figure 10 In it, the lower boundary X3 of the secondary control chamber is lower than the lower boundary Y3 of the pressure limiting valve inlet, and the upper boundary X4 of the secondary control chamber is higher than the upper boundary Y4 of the pressure limiting valve inlet, that is, the oil inlet 402 of the pressure limiting valve is communicated with the secondary control chamber 406; the lower boundary X3 of the secondary control chamber is lower than the lower boundary Y1 of the pressure limiting valve outlet. At this time, the opening degrees of both the oil inlet 402 and the oil outlet 403 of the pressure limiting valve are 100%. Due to the height L of the secondary control chamber 406 of the valve core 420 X1X2 > L Y1Y4 , the opening degrees of the oil inlet 402 and the oil outlet 403 of the pressure limiting valve can reach the maximum, and the oil discharge flow area is large, which can control the main oil passage pressure at a relatively stable level.

[0084] The curve of the engine oil pressure in the main oil passage increasing with the engine speed is as Figure 11 shown. In the existing scheme, the engine oil pressure in the main oil passage increases according to the o-e-d-c curve as the engine speed increases. While adopting the engine oil pressure control system provided by the embodiment of the present invention, the engine oil pressure in the main oil passage increases according to the o-e-f-a-d-c curve as the engine speed increases. At the same speed, the curve o-e-f-a-d-c is between the system pressure demand curve o-a-b-c and the curve o-e-d-c. Therefore, under the premise of meeting the system pressure demand, the embodiment of the present invention reduces the lubrication system pressure, thereby reducing the shaft power of the oil pump and improving the engine output power and thermal efficiency. At the same time, the structure of the present invention is simple, highly reliable, and has a low cost.

[0085] In some embodiments, the displacement Z1 of the valve core 420 when the pressure limiting valve 400 is switched from the fully closed state to the initial opening of the primary control chamber 405 satisfies:

[0086] Z1 = P1 × A / K - Z0

[0087] wherein, P1 is the pressure value of the main oil passage when the primary control chamber 405 of the pressure limiting valve 400 is initially opened, A is the internal cross-sectional area of the valve body 410 of the pressure limiting valve 400, K is the stiffness of the elastic resetting member 430, and Z0 is the pre-compression amount of the elastic resetting member 430 when the pressure limiting valve 400 is in the fully closed state; or,

[0088] the height L of the primary control chamber 405 X1X2 satisfies:

[0089] L X1X2 = P2 × A / K + L Y2Y3

[0090] Wherein, P2 is the increase value of the main oil passage pressure between the initial opening and the closing of the first - stage control chamber 405 of the pressure - limiting valve 400, A is the internal cross - sectional area of the valve body 410 of the pressure - limiting valve 400, K is the stiffness of the elastic reset member 430, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet; or,

[0091] The height L between the upper boundary X2 of the first - stage control chamber and the lower boundary X3 of the second - stage control chamber X2X3 Satisfies:

[0092] L X2X3 = P3 × A / K - L Y2Y3

[0093] Wherein, P3 is the increase value of the main oil passage pressure between the closing of the first - stage control chamber 405 and the initial opening of the second - stage control chamber 406 of the pressure - limiting valve 400, A is the internal cross - sectional area of the valve body 410 of the pressure - limiting valve 400, K is the stiffness of the elastic reset member 430, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet; or,

[0094] The height L between the lower boundary Y1 of the pressure - limiting valve outlet and the upper boundary Y2 of the pressure - limiting valve outlet Y1Y2 Satisfies:

[0095] L Y1Y2 = P4 × A / K

[0096] Wherein, P4 is the increase value of the main oil passage pressure between the initial opening and the full opening of the second - stage control chamber 406 of the pressure - limiting valve 400, A is the internal cross - sectional area of the valve body 410 of the pressure - limiting valve 400, and K is the stiffness of the elastic reset member 430.

[0097] In some embodiments, the height value L between the upper boundary Y2 of the pressure - limiting valve outlet and the lower boundary Y3 of the pressure - limiting valve inlet Y2Y3 Satisfies:

[0098] L Y2Y3 < P3 × A / K

[0099] Wherein, P3 is the increase value of the main oil passage pressure between the closing of the first - stage control chamber 405 and the initial opening of the second - stage control chamber 406 of the pressure - limiting valve 400, A is the internal cross - sectional area of the valve body 410 of the pressure - limiting valve 400, K is the stiffness of the elastic reset member 430; or,

[0100] The height L of the second - stage control chamber 406 X3X4Satisfy:

[0101] L X3X4 ≥L Y1Y4

[0102] L Y1Y4 is the height value between the lower boundary Y1 of the outlet of the pressure-limiting valve and the upper boundary Y4 of the inlet of the pressure-limiting valve.

[0103] To make the solution provided by the embodiments of the present invention easier to understand, the determination of key structural parameters will be described in detail below.

[0104] Referring to Figures 5 - 11 , taking the spring as an example for the elastic reset member 430, the spring compression amount or the displacement amount of the valve core 420 of the pressure-limiting valve 400 is as follows:

[0105] Z0 is the pre-compression amount of the spring when the valve core 420 is in the fully closed state; Z1 is the displacement amount of the valve core 420 when the primary control chamber 405 of the valve core 420 starts to open; Z2 is the displacement amount of the valve core 420 between the start and the close of the primary control chamber 405 of the valve core 420; Z3 is the displacement amount of the valve core 420 between the close of the primary control chamber 405 of the valve core 420 and the start of the secondary control chamber 406 of the valve core 420; Z4 is the displacement amount of the valve core 420 between the start and the full open of the secondary control chamber 406 of the valve core 420.

[0106] The change value of the main oil passage pressure is as follows:

[0107] P1 is the main oil passage pressure when the primary control chamber 405 of the valve core 420 starts to open; P2 is the increase amount of the main oil passage pressure between the start and the close of the primary control chamber 405 of the valve core 420; P3 is the increase amount of the main oil passage pressure between the close of the primary control chamber 405 of the valve core 420 and the start of the secondary control chamber 406 of the valve core 420; P4 is the increase amount of the main oil passage pressure between the start and the full open of the secondary control chamber 406 of the valve core 420.

[0108] Define the inner diameter of the valve body 410 in the pressure-limiting valve 400 as D, then the cross-sectional area

[0109] Define the stiffness of the spring as K

[0110] From the state diagram of the pressure-limiting valve 400 "fully closed" ( Figure 5 ) and "the primary control chamber 405 starts to open" ( Figure 6 ), it can be known that:

[0111] P1×A = K×(Z0 + Z1)

[0112] where Z1 = L X1Y2

[0113] From the state diagram of the pressure-limiting valve 400 "the primary control chamber 405 starts to open" (Figure 6 ) and "the flow area of the primary control chamber 405 is the largest" Figure 7 ) and "the primary control chamber 405 is closed" Figure 8 ) It can be known that:

[0114] P2 × A = K × Z2

[0115] where Z2 = L X1X2 -L Y2Y3 , and the prerequisite is that L X1X2 -L Y2Y3 ≤ L Y1Y2 .

[0116] From the state diagram of the pressure limiting valve 400, "the primary control chamber 405 is closed" Figure 8 ) and "the secondary control chamber 406 is initially opened" Figure 9 ) It can be known that:

[0117] P3 × A = K × Z3

[0118] where Z3 = L X2X3 +L Y2Y3 , so L Y2Y3 < P3 × A / K

[0119] From the state diagram of the pressure limiting valve 400, "the secondary control chamber 406 is initially opened" Figure 9 ) and "the secondary control chamber 406 is fully opened" Figure 10 ) It can be known that:

[0120] P4 × A = K × Z4

[0121] where Z4 = L Y1Y2 , and the prerequisite is that L X3X4 ≥ L Y1Y4

[0122] In summary, given P1, P2, P3, P4, K, A, Z0, it can be obtained that:

[0123] L X1Y2 = P1 × A / K - Z0

[0124] L X1X2 = P2 × A / K + L Y2Y3

[0125] L X2X3 = P3 × A / K - L Y2Y3

[0126] L Y1Y2 = P4 × A / K

[0127] And it satisfies:

[0128] L Y2Y3 < P3 × A / K

[0129] L X3X4 ≥ L Y1Y4

[0130] In addition, L Y2Y3 ≥ L X1X2 -L Y1Y2 = P2 × A / K + L Y2Y3 -P4 × A / K, that is, P4 ≥ P2

[0131] In the oil pressure control system provided by the embodiment of the present invention, there are two-stage control cavities on the valve core 420 of the pressure limiting valve 400, thereby reducing the oil pressure of the lubrication system at medium and high engine speeds, reducing the shaft power of the oil pump, and improving the output power and thermal efficiency of the engine. And through the control targets P1, P2, P3, P4 of the engine main oil passage pressure and the structural parameters K, A, Z0 of the pressure limiting valve 400, the key design parameters of the oil pressure control system can be deduced.

[0132] In a second aspect, the present invention further provides an engine, including an engine lubrication system and an oil pressure control system according to any one of the first aspect; the engine lubrication system includes an oil pan and a main oil passage; the oil pan is communicated with the oil outlet 403 of the pressure limiting valve in the oil pressure control system, and the main oil passage is communicated with the pressure port 401 in the oil pressure control system.

[0133] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. An engine oil pressure control system, characterized in that, Comprising: An oil pump body, a stator, a rotor and a pressure limiting valve; An oil inlet chamber and a post-pump oil chamber are provided inside the oil pump body; The pressure limiting valve has a pressure port, a pressure limiting valve oil inlet and a pressure limiting valve oil outlet. Inside the pressure limiting valve, there are a pressure chamber, a primary control chamber and a secondary control chamber. The pressure chamber is communicated with the main oil passage of the engine lubrication system through the pressure port; the pressure limiting valve oil inlet is communicated with the post-pump oil chamber of the oil pump body, and the pressure limiting valve oil outlet is communicated with the engine oil sump; The pressure limiting valve has a primary pressure limiting state and a secondary pressure limiting state; When the pressure limiting valve is in the primary pressure limiting state, the primary control chamber communicates the pressure limiting valve oil inlet and the pressure limiting valve oil outlet, and the engine speed is in the first speed range; When the pressure limiting valve is in the secondary pressure limiting state, the secondary control chamber communicates the pressure limiting valve oil inlet and the pressure limiting valve oil outlet, and the engine speed is in the second speed range, and the minimum value in the second speed range is greater than the maximum value in the first speed range; On the side of the pressure limiting valve oil outlet away from the pressure port is the lower boundary Y1 of the pressure limiting valve outlet, and on the side of the pressure limiting valve oil inlet close to the pressure port is the upper boundary Y4 of the pressure limiting valve inlet; On the side of the primary control chamber away from the pressure port is the lower boundary X1 of the primary control chamber, and on the side of the primary control chamber close to the pressure port is the upper boundary X2 of the primary control chamber; The height L of the primary control chamber X1X2 satisfies: L X1X2 <L Y1Y4 Among them, L Y1Y4 is the height between the lower boundary Y1 of the pressure-limiting valve outlet and the upper boundary Y4 of the pressure-limiting valve inlet.

2. The engine oil pressure control system according to claim 1, wherein When the pressure limiting valve is in the primary pressure limiting state, when the opening of the pressure limiting valve oil inlet is 100%, the opening of the pressure limiting valve oil outlet is less than 100%; when the opening of the pressure limiting valve oil outlet is 100%, the opening of the pressure limiting valve oil inlet is less than 100%.

3. The engine oil pressure control system according to claim 2, characterized in that When the pressure limiting valve is in the secondary pressure limiting state, when the opening of the pressure limiting valve oil inlet is 100%, the maximum opening of the pressure limiting valve oil outlet is 100%; when the opening of the pressure limiting valve oil outlet is 100%, the maximum opening of the pressure limiting valve oil inlet is 100%.

4. The engine oil pressure control system according to claim 3, characterized in that On the side of the pressure limiting valve oil outlet close to the pressure port is the upper boundary Y2 of the pressure limiting valve outlet; on the side of the pressure limiting valve oil inlet away from the pressure port is the lower boundary Y3 of the pressure limiting valve inlet; the lower boundary Y3 of the pressure limiting valve inlet is located on the side of the upper boundary Y2 of the pressure limiting valve outlet close to the pressure port.

5. The engine oil pressure control system according to claim 4, wherein, On the side of the secondary control chamber away from the pressure port is the lower boundary X3 of the secondary control chamber, and on the side of the secondary control chamber close to the pressure port is the upper boundary X4 of the secondary control chamber; The height L of the secondary control cavity X3X4 satisfies: L X3X4 > L Y1Y4 .

6. The engine oil pressure control system according to claim 5, wherein The pressure limiting valve includes a valve body and a valve core and an elastic reset member located inside the valve body; The pressure port, the pressure limiting valve oil inlet and the pressure limiting valve oil outlet are all arranged on the valve body; One end of the elastic reset member is connected to the valve core, and the other end is connected to the valve body, and is used to always provide a force for the valve core to act towards the pressure port; The valve core and the valve body cooperate to form the pressure chamber, the primary control chamber and the secondary control chamber, and the pressure chamber, the secondary control chamber and the primary control chamber are arranged in sequence along the action direction of the valve core away from the pressure port.

7. The oil pressure control system according to claim 6, wherein The displacement Z1 of the valve core during the process of the pressure limiting valve switching from the fully closed state to the initial opening of the primary control chamber satisfies: Z1 = P1 × A / K - Z0 where P1 is the pressure value of the main oil passage when the first - stage control chamber of the pressure - limiting valve starts to open, A is the internal cross - sectional area of the pressure - limiting valve body, K is the stiffness of the elastic resetting member, and Z0 is the pre - compression amount of the elastic resetting member when the pressure - limiting valve is in a fully - closed state; or, The height L of the primary control chamber X1X2 Satisfies: L X1X2 = P2 × A / K + L Y2Y3 Wherein, P2 is the increase value of the main oil passage pressure between the initial opening and the closing of the first-stage control chamber of the pressure-limiting valve, A is the internal cross-sectional area of the pressure-limiting valve body, K is the stiffness of the elastic reset member, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure-limiting valve outlet and the lower boundary Y3 of the pressure-limiting valve inlet; or, The height L between the upper boundary X2 of the first - stage control cavity and the lower boundary X3 of the second - stage control cavity X2X3 Satisfies: L X2X3 = P3 × A / K - L Y2Y3 Among them, P3 is the increase value of the main oil passage pressure between the closing of the first-stage control chamber and the initial opening of the second-stage control chamber of the pressure-limiting valve, A is the internal cross-sectional area of the pressure-limiting valve body, K is the stiffness of the elastic reset component, and L Y2Y3 is the height value between the upper boundary Y2 of the pressure-limiting valve outlet and the lower boundary Y3 of the pressure-limiting valve inlet; or The height L between the lower boundary Y1 and the upper boundary Y2 of the pressure limiting valve outlet Y1Y2 Satisfies: L Y1Y2 = P4 × A / K where P4 is the increase value of the main oil passage pressure between the initial opening and the full opening of the second - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, and K is the stiffness of the elastic resetting member.

8. The engine oil pressure control system according to claim 6, wherein The height value L between the upper boundary Y2 of the pressure-limiting valve outlet and the lower boundary Y3 of the pressure-limiting valve inlet Y2Y3 Satisfies: L Y2Y3 <P3×A / K where P3 is the increase value of the main oil passage pressure between the closing of the first - stage control chamber and the initial opening of the second - stage control chamber of the pressure - limiting valve, A is the internal cross - sectional area of the pressure - limiting valve body, and K is the stiffness of the elastic resetting member.

9. An engine, characterized in that, It includes an engine lubrication system and an oil - pressure control system as described in any one of claims 1 - 8; the engine lubrication system includes an oil pan and a main oil passage; the oil pan is communicated with the oil outlet of the pressure - limiting valve in the oil - pressure control system, and the main oil passage is communicated with the pressure port in the oil - pressure control system.

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