Two-Stage Gear Reduction Oil Pump for High-RPM Engines
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Solution Overview
Problem
High-rpm race engines using OEM wet sump oil pumps experience excessive oil pressures, cavitation, foaming, and oil starvation due to high acceleration forces, leading to bearing failures and power loss, which existing solutions attempt to address with bypass valves but are inadequate.
Innovation Solution
A 2-stage gear reduction wet sump oil pump system incorporating a scavenge pump and pressure pump with a gear set transmission that reduces the pressure pump's speed to ¼ of the engine speed, allowing for controlled oil return and collection from the oil pan, and an externally accessible bypass valve for pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If OEM wet sump oil pumps are used in high-rpm race engines, then the pump structure is simple and easy to manufacture, but the pump produces excessive oil pressure causing cavitation, foaming and power pumping loss
Solution Approach 1:
The oil pump system is divided into two separate pumps: a scavenge pump and a pressure pump. Each pump is optimized for its specific function, allowing the pressure pump to operate at reduced speed (1/4 engine speed) while the scavenge pump handles oil collection. This segmentation resolves the contradiction by enabling reliable oil pressure control without requiring complete redesign of the entire pump system.
Solution Approach 2:
The transmission gear set serves dual functions: it acts as the drive mechanism for the pressure pump while simultaneously functioning as the scavenge pump. This multi-functionality reduces the number of separate components needed, maintaining ease of manufacture while achieving reliable oil pressure control through the dual-pump architecture.
2Reliability
If bypass valves are used to regulate pump output, then oil pressure is controlled, but the bypass valve engages at 2000-3000 engine rpms which is insufficient for high-rpm race engines
Solution Approach 1:
The pressure pump's speed is dynamically controlled through the transmission gear reduction system, maintaining a constant 1/4 engine speed ratio. This dynamic speed control allows the pump to adapt to high-rpm race engine conditions throughout the entire RPM range, unlike fixed engagement bypass valves that only activate at 2000-3000 RPM.
3Device complexity
If the pressure pump runs at normal speed, then the pump structure is simple, but the pump causes oil starvation during high G acceleration and deceleration
Solution Approach 1:
The oil pump function is segmented into two independent systems: the scavenge pump collects oil from the pan bottom during high-G conditions, while the pressure pump delivers pressurized oil to the engine. This segmentation ensures reliable oil supply consistency by separating the oil collection function (which must operate during high-G events) from the pressure delivery function.
Solution Approach 2:
The transmission gear set acts as an intermediary between the engine's camshaft drive and the pressure pump. By providing gear reduction, it mediates the speed difference between the high-speed engine and the slower-operating pressure pump, enabling the pressure pump to run at 1/4 engine speed while still being driven by the engine's rotation.
4Reliability
If the pressure pump speed is reduced to 1/4 engine speed, then oil pressure issues are reduced, but the pump requires a transmission gear reduction system
Solution Approach 1:
The transmission gear set is designed to serve multiple functions simultaneously: it provides the gear reduction needed to drive the pressure pump at 1/4 engine speed, and it also functions as the scavenge pump that collects oil from the pan. This multi-functionality resolves the contradiction by incorporating the transmission as an integral part of the pump system rather than adding it as a separate component.
Solution Approach 2:
The scavenge pump function and the pressure pump drive mechanism are merged into a single integrated system. The transmission gear set that reduces speed for the pressure pump also serves as the scavenge pump, combining two previously separate functions into one unified component that reduces overall system 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 reduces oil pressure issues, improves oil quality and collection efficiency, and allows for compact integration into standard oil pans with external bypass adjustment, enhancing engine performance and reliability.
Implementation Method 1
a gear set (transmission) that reduces the pressure pump's speed to 1/4 of the engine speed
Implementation Method 2
high 'G' acceleration and deceleration forces that move the oil in the pan so violently
Data Source
AI summary
A fluid pump system for an engine includes a transmission acting as a first pump and a second pump. In one embodiment, the first pump is a scavenge pump and the second pump is a pressure pump with the transmission being a gear set for altering a drive ratio between a transmission input drive and an input drive of the second pump, thereby allowing additional control of a speed of the second pump in comparison to the engine. The transmission, acting as a scavenge pump, can provide a scavenge pump function to an oil pan of the engine, returning engine oil that is present there from both normal drain back and acceleration/deceleration forces.