Bimetallic-Actuated Oil Valve for Combustion Engine
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Solution Overview
Problem
Existing valves in internal combustion engine oil circulation systems have long switching times due to the use of expansion elements, making them unsuitable for rapid switching, and shape memory alloys, while fast, are expensive and large due to low actuating forces.
Innovation Solution
A pressure- and temperature-controlled valve using a bimetallic element or shape memory alloy to control a pressure-controlled piston, where the bimetallic element only opens or closes the inlet opening to the pressure chamber, allowing the piston to be adjusted by oil pressure, enabling fast and cost-effective switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If expansion elements are used to control the valve, then the structure is simple, but the switching time is long
Solution Approach 1:
The patent introduces a pressure chamber as an intermediary between the bimetallic element and the valve element. The bimetallic element only needs to open or close the inlet opening to the pressure chamber, and the pressure differential then drives the piston to move the valve element, achieving fast switching without requiring the temperature-controlled element to directly actuate the valve
Solution Approach 2:
The patent uses hydraulic pressure from the oil circuit itself to actuate the valve. The pressure chamber receives pressurized oil when the inlet opening is opened by the bimetallic element, and this hydraulic pressure moves the piston rapidly to close the valve, converting thermal control into hydraulic actuation for fast response
2Loss of time
If shape memory alloys are used for fast switching, then the switching time is short, but the cost and size increase
Solution Approach 1:
The pressure chamber acts as a force amplifier and mediator. The bimetallic element only needs to perform a simple opening/closing action at the inlet opening, while the accumulated hydraulic pressure in the pressure chamber provides the substantial force needed to move the valve element, allowing the use of a simple and inexpensive bimetallic element instead of expensive shape memory alloys
Solution Approach 2:
The patent replaces the direct mechanical action of a large, expensive shape memory alloy with a thermal-mechanical-hydraulic system. The bimetallic element provides thermal sensing and initial actuation, while the hydraulic system provides the force multiplication needed for valve actuation, achieving fast switching with a much smaller and cheaper temperature-controlled element
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 valve achieves almost instantaneous switching while being inexpensive due to the small size and low actuating forces required for the bimetallic element, effectively managing oil flow by routing it through a filter or cooler based on temperature.
Implementation Method 1
the inlet opening (11) to the pressure chamber (8) can be closed and opened as a function of temperature by a bimetallic element (12)
Implementation Method 2
a switching element (13) having a shape memory alloy
Implementation Method 3
with a restoring spring (10) being arranged in the counter-pressure chamber (9)
Implementation Method 4
the pressure chamber (8) is charged with oil delivered by an oil pump, which leads to an adjustment of the piston to its second position and thus to a closing of the valve
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a pressure- and temperature-controlled valve (1) in an oil circuit (2) of a combustion engine (3), comprising a pressure-controlled piston (4) which is mounted in a cylinder (5) such that it can be translationally adjusted, and which is raised from a valve seat (7) in a first position, thereby permitting a through-flow through the valve (1), while the piston (4) is pressed on the valve seat (7) by a valve head (6) in a second position, closing the valve (1), wherein the piston (4) divides the cylinder (5) into a pressure chamber (8) and a counter pressure chamber (9), wherein a return spring (10) is arranged in the counter pressure chamber (9), wherein the pressure chamber (8) has a supply opening (11) which can be opened and closed depending on the temperature by a bimetallic element (12) or a switch element (13) having a shape-memory alloy.