Automotive Oil Pump Relief Valve for Parasitic Load Reduction
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Solution Overview
Problem
Existing lubrication systems for automotive engines with fixed displacement oil pumps struggle to manage oil flow efficiently across varying engine speeds, leading to increased parasitic loads and reduced fuel economy, as they lack the adaptive control capabilities of variable displacement pumps, which are costly and complex.
Innovation Solution
A lubrication pumping system with a two-piece relief valve featuring a multidimensional bore and spring-biased pistons, where pilot pressure is selectively connected to manage oil pressure versus engine speed, allowing multiple operational modes to minimize parasitic loads by controlling flow between the pump outlet and inlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed displacement oil pump is used, then the pump structure is simple and cost-effective, but the parasitic load increases at high engine speeds due to excessive oil flow
Solution Approach 1:
The relief valve is divided into two separate functional sections: a primary piston handling main relief flow and a secondary piston handling pilot pressure control. This segmentation allows independent optimization of each function, enabling precise flow control at high speeds while maintaining simple fixed pump structure.
Solution Approach 2:
A pilot pressure system is introduced as an intermediary control mechanism. The secondary piston responds to pilot pressure changes to modulate the primary piston position, indirectly controlling main oil flow. This intermediary approach enables adaptive flow control without modifying the fixed displacement pump itself.
2Loss of energy
If a variable displacement pump is used, then the parasitic load is reduced through adaptive flow control, but the system complexity and cost increase
Solution Approach 1:
The relief valve system is designed to automatically respond to engine operating conditions through spring-biased pistons and pressure-responsive control. The secondary piston self-adjusts based on pilot pressure variations, which reflect engine speed and load conditions, eliminating the need for external sensors, actuators, or electronic control systems.
Solution Approach 2:
The invention uses purely hydraulic mechanisms with spring-biased pistons and pressure-responsive control. The secondary piston responds to pilot pressure changes to modulate the primary piston position, enabling adaptive flow control through fluid pressure alone, without mechanical linkages to the pump or electronic intervention.
3Adaptability or versatility
If pilot pressure control is implemented, then multiple operational modes are achieved for optimizing fuel economy, but the valve structure becomes more complex
Solution Approach 1:
The pilot pressure control system and main relief valve are merged into a single integrated assembly. The secondary piston and primary piston operate within the same valve body, sharing common hydraulic passages and spring mechanisms. This merging achieves multiple operational modes while minimizing structural complexity through unified design.
Solution Approach 2:
The secondary piston assembly is nested within the primary piston assembly, with the secondary piston operating in an inner chamber while the primary piston handles outer flow control. This nested configuration allows compact integration of multiple control functions within a single valve structure, achieving adaptability without proportional increase in complexity.
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
The system effectively reduces parasitic loads and maintains a constant flow rate and pressure differential across varying engine speeds, enhancing fuel economy without the complexity and cost of variable displacement pumps.
Implementation Method 1
a spring biased primary piston have a first landing for metering flow between a pump discharge connection and a pump inlet connection
Implementation Method 2
Adjacent the intersection of the first and second sections of the valve housing bore is a pilot pressure connection that is selectively connected with a pilot pressure
Implementation Method 3
The second diameter section is connected with the main oil gallery pressure to allow engine at pressure to act upon the secondary piston
Data Source
AI summary
A lubrication pumping system for an oil lubricated engine is provided that includes a pump with an outlet and inlet. A relief valve is included having a housing with a multidimensional bore having a first diameter section axially intersecting with a second different diameter section. Slidably mounted in the first section is a spring biased primary piston have a first landing for metering flow between a pump discharge connection and a pump inlet connection. A secondary piston is provided in a second different diameter section of the valve housing bore. The inventive system allows for multiple modes of operation of oil pressure versus engine speed relationships by control of the pilot pressure to minimize parasitic loads exerted by the oil pump on the vehicle engine.