Opposed-Piston Undercrown Cooling via Bearing Oil Reservoir
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Solution Overview
Problem
Current piston thermal management systems for opposed-piston engines face challenges in maintaining consistent undercrown cooling throughout the piston's operational cycle without increasing system complexity and cost, as existing methods either rely on inertial pumping that only cools during half the cycle or require separate channels for cooling and lubrication.
Innovation Solution
Pressurized lubricating oil is accumulated in the piston's bearing reservoir and used to deliver continuous cooling jets to the undercrown through stationary or oscillating nozzles, ensuring consistent cooling throughout the cycle without adding complexity or cost to the lubrication system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If inertial pumping is used to cool the undercrown, then cooling is achieved during upward piston movement, but cooling is interrupted during downward movement (half-cycle cooling)
Solution Approach 1:
The bearing reservoir stores pressurized lubricating oil in advance, preparing the cooling medium before it is needed. This preliminary accumulation of pressurized oil enables continuous cooling jet delivery throughout the entire piston cycle, eliminating the half-cycle limitation of inertial pumping.
Solution Approach 2:
The bearing reservoir acts as an intermediary component between the lubrication system and the cooling function. It decouples the continuous pressurized oil supply from the intermittent inertial pumping mechanism, enabling independent control of cooling duration and intensity through the stored pressurized oil.
2Temperature
If separate channels are used for cooling and lubrication, then dedicated cooling function is achieved, but system complexity and cost increase
Solution Approach 1:
The patent merges the cooling function with the existing lubrication system by using the bearing reservoir and pressurized lubricating oil for both lubrication and cooling purposes. This integration eliminates the need for separate cooling channels and components, reducing system complexity and cost while maintaining effective undercrown cooling.
Solution Approach 2:
The bearing reservoir and pressurized lubricating oil system are designed to serve multiple functions: both lubrication of the bearing and cooling of the undercrown. This multi-functionality approach allows a single system to accomplish what would traditionally require separate dedicated systems, thereby reducing overall 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
This approach provides continuous undercrown cooling, reducing thermal stress and wear, and maintaining piston integrity by utilizing existing lubrication infrastructure, thus enhancing thermal management and operational efficiency.
Implementation Method 1
at least one jet of pressurized lubricating oil from the bearing is delivered to cool the undercrown by liquid impingement
Implementation Method 2
The piston bearing includes a reservoir that accumulates pressurized lubricating oil
Data Source
AI summary
Pressurized lubricating oil is accumulated in the bearings of opposed pistons and accumulated oil is dispensed therefrom for bearing lubrication and also for cooling the undercrowns of the pistons by jets of oil emitted from the bearings.