Magnetorheological Clutch for Variable Engine Coolant Pump Speed
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Solution Overview
Problem
Existing engine coolant pump systems face inefficiencies due to constant operation and high parasitic losses, as they are designed to operate at worst-case engine speeds, leading to increased fuel consumption and energy wastage, and existing solutions like electric motor-driven pumps incur significant power losses and shock loads.
Innovation Solution
A magnetorheological fluid (MRF) clutch is integrated between the engine and coolant pump, allowing for continuously variable torque transfer and pump speed control through sensor feedback and electronic control, enabling efficient and adaptive coolant flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an engine belt-driven coolant pump is used, then the pump operates continuously with the engine, but this results in constant parasitic power losses and increased fuel consumption
Solution Approach 1:
The patent applies a magnetorheological fluid (MRF) clutch that enables dynamic, continuously variable torque transfer between the engine and coolant pump. The MRF clutch allows the pump speed to be adjusted continuously from zero to maximum based on actual cooling demand, replacing the traditional belt-driven constant speed connection. This dynamic control resolves the contradiction by maintaining reliable cooling operation while eliminating constant parasitic power losses through adaptive speed modulation.
Solution Approach 2:
The patent changes the operational parameters of the coolant pump from fixed engine-speed coupling to variable speed control via MRF clutch. By altering the torque transfer parameter continuously through magnetic field control of the MRF, the system can adjust pump speed to match actual cooling requirements, thereby reducing energy losses while maintaining adequate cooling performance.
2Adaptability or versatility
If an electric motor-driven coolant pump is used, then on-demand coolant flow is provided, but significant power losses occur through the alternator, power electronics, and motor
Solution Approach 1:
The patent replaces the electric motor-driven system with a direct engine-driven MRF clutch system. Instead of converting mechanical energy to electrical energy and back to mechanical energy (which causes losses in alternator and power electronics), the MRF clutch directly modulates the mechanical torque transfer from the engine to the pump. This mechanical substitution eliminates the intermediate energy conversion steps and their associated losses while maintaining on-demand coolant flow capability.
3Adaptability or versatility
If an electrically operated clutch driven coolant pump is used, then the pump can be switched on or off, but this causes shock loads on the engine due to abrupt engagement
Solution Approach 1:
The MRF clutch provides dynamic, smooth torque transfer characteristics that eliminate shock loads during engagement. Unlike electrically operated clutches that abruptly engage or disengage, the MRF clutch can gradually modulate torque transfer by controlling the magnetic field strength, allowing smooth transitions between different operating states. This dynamic control resolves the contradiction by enabling on-demand operation without causing harmful shock loads to the engine.
4Reliability
If the coolant pump is designed for worst-case engine speed, then adequate cooling is provided at all speeds, but this results in much higher pump flow at higher engine speeds than necessary
Solution Approach 1:
The MRF clutch enables dynamic adjustment of pump speed to match actual cooling demands at different engine operating conditions. Instead of running the pump at maximum capacity designed for worst-case scenarios, the system continuously adapts pump speed to the actual thermal load, thereby maintaining adequate cooling reliability while eliminating excessive coolant circulation and associated energy losses during normal operating conditions.
Solution Approach 2:
The patent applies partial action by providing only the necessary cooling capacity required at each operating condition rather than continuously providing maximum cooling capacity. The MRF clutch allows the pump to operate at reduced speed when full cooling capacity is not needed, thereby avoiding the excessive action of circulating more coolant than necessary and the associated energy losses.
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 minimizes parasitic power losses, improves fuel economy, reduces packaging and costs, and enhances reliability by providing variable coolant flow and speed control, optimizing engine cooling and reducing emissions.
Implementation Method 1
The MRF clutch includes a torque input section coupled to a torque output section via a MRF, the torque input section being configured to receive a torque input from the engine
Implementation Method 2
the magnetic field generator is capable of generating a variable strength magnetic field that is in field communication with the first portion, the second portion, the rotor, and the MRF
Data Source
AI summary
An engine coolant pump drive system for a vehicle having an engine, an engine coolant system, and at least one sensor for sensing at least one operational condition of the vehicle is disclosed. The pump drive system includes a magnetorheological fluid (MRF) clutch, and a coolant pump. The MRF clutch includes a torque input section coupled to a torque output section via a MRF, the torque input section being configured to receive a torque input from the engine. The coolant pump is configured for operable communication with the torque output section of the MRF clutch. In response to a signal from the at least one sensor, the MRF clutch is configured to provide a continuously variable torque transfer from the torque input section to the torque output section, thereby providing for variable coolant flow in the engine coolant system via the coolant pump capable of a continuously variable speed.