Dual-Element Thermostat Valve for Fast Coolant Feedback
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Solution Overview
Problem
Conventional cooling systems in heavy vehicles with hydraulic retarders suffer from slow reaction times to temperature changes, leading to 'temperature cycling' and reduced radiator lifespan due to inadequate feedback mechanisms.
Innovation Solution
A compact thermostat device with two thermal expansion elements and a common valve body, which directs coolant flow to a radiator or bypass line based on temperatures at two positions in the cooling system, providing rapid regulation and reducing component count through a pilot chamber outlet passage that eliminates the need for a separate return line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional thermostat with single-position temperature sensing is used, then the device complexity is low, but the reaction time to temperature changes is slow and temperature cycling occurs
Solution Approach 1:
The thermostat device is segmented into two independent temperature sensing circuits: a pilot circuit that senses temperature at the radiator outlet and a main circuit that senses temperature at the thermostat inlet. Each circuit has its own thermal expansion element, allowing independent temperature monitoring at different locations without requiring a single complex sensing mechanism.
Solution Approach 2:
The pilot circuit acts as an intermediary system that provides early temperature feedback from the radiator outlet. This intermediary sensing mechanism detects temperature changes before they reach the main thermostat, enabling proactive control adjustments and preventing temperature cycling.
2Speed
If a pilot circuit with separate return line is added to enable rapid temperature feedback, then the reaction time to temperature changes is improved, but the device complexity and number of components increase
Solution Approach 1:
The return line of the pilot circuit is merged with the main coolant flow path. The pilot circuit draws a portion of the coolant flow and returns it to join the main flow at the thermostat inlet, eliminating the need for a separate return line. This integration reduces component count while maintaining rapid feedback capability.
Solution Approach 2:
The main coolant flow path serves dual functions: it provides the primary coolant circulation and simultaneously serves as the return path for the pilot circuit. This multi-functionality eliminates redundant components and simplifies the overall system architecture.
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 solution enables rapid temperature feedback and regulation, reducing temperature cycling and extending radiator lifespan by efficiently distributing coolant flow based on temperature changes at multiple points in the cooling system.
Implementation Method 1
A first thermal expansion element which is arranged in the pilot chamber. The first thermal expansion element provides a first stroke of the valve body in response to the coolant temperature in the pilot chamber.
Implementation Method 2
A second thermal expansion element which is arranged in the thermostat chamber. The second thermal expansion element provides a second stroke of the valve body in response to the coolant temperature in the thermostat chamber.
Data Source
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AI summary
The present invention relates to a thermostat device (8) for a cooling system in a vehicle. The thermostat device (8) comprises a thermostat housing (15) enclosing a movably arranged valve body (16, 20, 34, 44) which is configured to distribute coolant from a thermostat chamber (15a) to a radiator bypass line (9) and a radiator (11) in dependence on its position. The thermostat device (8) comprises a first thermal expansion element (31) providing a first stroke of a valve body (16, 20, 34, 44) in response to the temperature of the coolant in a the pilot chamber (14a), and a second thermal expansion element (32) providing a second stroke of the valve body (16, 20, 34, 44) in response to the temperature of the coolant in an thermostat chamber (15a) such that the valve body (16, 20, 34, 44) is moved to a position defined by the strokes from the thermal expansion elements (31, 32). The pilot chamber (14a) comprises an outlet passage (14b) direct coolant from the pilot chamber (14a) to the thermostat chamber (15a).