Piston Cooling Jet Single Spring Valve Design
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Solution Overview
Problem
Existing piston cooling jets are complex and costly due to the use of multiple coil springs, including a shape memory alloy, and struggle to maintain the valve open state when foreign matter clogs the oil path, which can hinder effective cooling.
Innovation Solution
A piston cooling jet design featuring a housing, a valve, a leak gap, and a single coil spring, with a filter integrated in the valve to remove foreign matter and adjust internal pressure based on temperature and hydraulic pressure, ensuring the valve remains open even when the oil path is clogged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple coil springs including shape memory alloy are used in the piston cooling jet, then the valve can be controlled to switch between open and closed states based on temperature and pressure, but the structure becomes complex and manufacturing cost increases
Solution Approach 1:
The patent combines the functions of multiple coil springs (bias spring and shape memory spring) into a single coil spring that performs both biasing and temperature-responsive actuation. This merging of components simplifies the overall structure while maintaining the dual functionality of pressure-based closing and temperature-based opening control.
Solution Approach 2:
The single coil spring is designed to serve multiple functions: it provides the bias force to keep the valve closed during normal operation and simultaneously acts as a shape memory alloy element that opens the valve when exposed to high temperatures. This multi-functionality eliminates the need for separate springs and reduces component count.
2Reliability
If multiple coil springs including shape memory alloy are used in the piston cooling jet, then the valve can be controlled to switch between open and closed states based on temperature and pressure, but manufacturing cost increases
Solution Approach 1:
The patent combines the functions of multiple coil springs (bias spring and shape memory spring) into a single coil spring that performs both biasing and temperature-responsive actuation. This merging of components simplifies the overall structure while maintaining the dual functionality of pressure-based closing and temperature-based opening control.
Solution Approach 2:
The single coil spring is designed to serve multiple functions: it provides the bias force to keep the valve closed during normal operation and simultaneously acts as a shape memory alloy element that opens the valve when exposed to high temperatures. This multi-functionality eliminates the need for separate springs and reduces component count.
3Device complexity
If the hydraulic valve mechanism opens based on hydraulic pressure alone without temperature sensing, then the structure is simple, but the piston cooling jet may be actuated during cold times when cooling is not needed
Solution Approach 1:
The coil spring itself serves as the temperature sensing element through its shape memory alloy properties. When the piston and surrounding environment are hot, the coil spring automatically changes shape to open the valve. This self-service approach eliminates the need for separate temperature sensors while ensuring cooling is activated only when thermally necessary.
Solution Approach 2:
The patent utilizes the temperature-dependent physical properties of the shape memory alloy in the coil spring to detect and respond to thermal conditions. The coil spring's shape and elastic properties change with temperature, automatically controlling valve operation based on the actual thermal state of the piston without requiring external temperature sensing mechanisms.
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 simplifies the structure, reduces manufacturing costs, and ensures continuous oil spraying to the piston by automatically switching to the valve open state when foreign matter clogs the filter, maintaining effective cooling.
Implementation Method 1
the coil spring on the upper side (upstream side) is a shape memory spring made of a shape memory alloy. The urging force of the coil spring is varied in accordance with the temperature.
Implementation Method 2
This causes oil in the main oil gallery to be sprayed toward the back surface of the piston by the piston cooling jet. The spray of oil cools the piston.
Data Source
AI summary
A piston cooling jet includes a housing, a nozzle, a valve, a pressure chamber, a pressure adjusting passage, and a filter. The nozzle is provided to project outward from the housing, and capable of spraying oil toward a piston. The valve is capable of moving reciprocally inside the housing, and configured to receive a load due to a hydraulic pressure in an engine-side oil passage applied from a front side of the valve. The valve includes a valve-side oil passage that communicates with the engine-side oil passage. The pressure chamber communicates with the valve-side oil passage. The pressure adjusting passage is disposed between the pressure chamber and a space outside the housing. The filter is disposed in the valve, and configured to remove foreign matter that cannot pass through the pressure adjusting passage from oil passing through the valve-side oil passage.