Automotive Variable Lubricant Pump Asymmetric Control Ring
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Solution Overview
Problem
Existing automotive variable mechanical lubricant pumps face issues with hydraulic overpressure during engine startup, which can damage rotor vanes and engine components due to low initial gallery pressure and high rotational speeds.
Innovation Solution
The lubricant pump incorporates a dissymmetric hydraulic outlet chamber with an effective anti-spring surface larger than the counter-acting pro-spring surface, allowing the control ring to shift into a low eccentricity position to mitigate overpressure, and a hydraulic control valve regulated by remote gallery pressure to manage pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mechanical lubricant pump runs with maximum eccentricity during engine startup, then the pump can quickly fill the hydraulic system with pressurized lubricant, but hydraulic overpressure occurs which can damage rotor vanes and engine components
Solution Approach 1:
The outlet chamber is designed with a dissymmetric structure where the anti-spring surface area is larger than the pro-spring surface area. This asymmetry creates a pressure-dependent force imbalance that automatically limits the control ring's movement to a safe range, preventing overpressure damage while allowing sufficient lubricant delivery during startup.
Solution Approach 2:
The patent converts the potentially harmful outlet pressure into a beneficial control mechanism. The outlet pressure acts on the dissymmetric surfaces to generate a limiting force that prevents overpressure, transforming the harmful pressure into a self-regulating safety feature that protects the rotor vanes and engine components.
2Reliability
If a separate hydraulic control valve is used to regulate gallery pressure, then precise pressure control is achieved, but the system complexity increases and response time during startup is delayed
Solution Approach 1:
The system uses the outlet pressure itself to control the control ring position through the dissymmetric surface mechanism. The outlet pressure automatically regulates the eccentricity by creating a balancing force against the preload spring, eliminating the need for external sensors, controllers, or complex feedback circuits while maintaining reliable pressure control.
Solution Approach 2:
The control function is merged into the outlet chamber structure itself. The dissymmetric surfaces are integrated directly into the control ring assembly, combining the pressure regulation function with the existing mechanical structure rather than adding separate control components, thereby reducing system complexity while maintaining control precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design prevents damage from hydraulic overpressure by ensuring the control ring moves into a low eccentricity position upon engine startup, maintaining component safety and proper lubrication, without the need for additional overpressure valves.
Implementation Method 1
one control ring preload spring for pushing the control ring into the maximum eccentricity position
Implementation Method 2
one single counter-acting hydraulic pilot chamber for pushing the control ring into the minimum eccentricity position. The pilot control chamber is directly charged with the pump outlet pressure or with the gallery pressure
Implementation Method 3
the effective anti-spring hydraulic surface of the control ring circumference in the hydraulic outlet chamber is larger than the counter-acting pro-spring hydraulic surface... a resulting anti-spring force pushes the control ring into the low eccentricity direction
Implementation Method 4
The mechanical lubricant pump is designed as a positive displacement pump
Data Source
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AI summary
The invention is directed to an automotive variable mechanical lubricant pump (20) for providing pressurized lubricant for an internal combustion engine (12), comprising a pump rotor (26) with numerous slidable vanes (28) rotating in a shiftable control ring (27) which is shiftable between a maximum eccentricity position and a minimum eccentricity position, a control ring preload spring (34) for pushing the control ring (27) into the maximum eccentricity position, a hydraulic pilot chamber (31) for pushing the control ring (27) into the minimum eccentricity position, the hydraulic pilot chamber (31) being charged with the pump outlet-pressure (PO), the pump outlet-pressure (PO) or a gallery pressure (PG) of the engine (12), and a dissymmetric hydraulic outlet chamber (36) surrounding a part of the outer circumference (29) of the control ring (27), being directly charged with the pump outlet pressure (PO) and being directly connected to a pump outlet (90) for the pressurized lubricant, wherein the effective anti-spring hydraulic surface (291) of the control ring circumference (29) in the hydraulic outlet chamber (36) is larger than the counter-acting pro-spring hydraulic surface (292). The invention avoids right after starting the engine a too high overpressure in the pumping chamber which could damage the rotor vanes and the engine components like filter or cooler.