Vehicle Auxiliary Heater Control for Cold Coolant Flow Limits
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Solution Overview
Problem
In extreme cold conditions, the increased viscosity of engine coolant reduces the flow rate when pumped by an auxiliary coolant pump, leading to potential overheating and system failure in fuel-operated heaters used in vehicles and other applications.
Innovation Solution
A method and system that adjust the heating profile of a fuel-operated heater based on the flow capability of the coolant, using sensors to determine the viscosity and current drawn by the pump, allowing for a lower initial heat transfer rate to prevent overheating, and switching to a higher rate once the coolant flow improves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heater operates at high heat transfer rate in extreme cold conditions, then preheating efficiency is improved, but coolant overheating occurs due to reduced flow capability
Solution Approach 1:
The heater operates in different operational modes (first mode and second mode) that dynamically adjust the heat transfer rate based on coolant flow capability. The control system switches between modes to optimize preheating efficiency while preventing overheating, making the system adaptive rather than static.
Solution Approach 2:
The system changes the operational parameters of the heater by switching between different operational modes. In the first mode, a higher heat transfer rate is used when flow capability is sufficient, while in the second mode, a lower heat transfer rate is applied when flow capability is reduced, thus adapting to changing conditions.
2Object-affected harmful factors
If the coolant flow rate is increased to prevent overheating, then heat dissipation is improved, but pump power requirements increase beyond available reserves
Solution Approach 1:
The control system takes preliminary action by detecting reduced flow capability (through temperature sensors, viscosity sensors, or current sensors) before overheating occurs. It proactively switches to the second operational mode with lower heat transfer rate, preventing the harmful condition rather than reacting to it.
Solution Approach 2:
The system uses feedback from temperature sensors, viscosity sensors, or current sensors to continuously monitor coolant flow capability. This feedback informs the control system to adjust the heater's operational mode, creating a closed-loop control that prevents overheating without requiring excessive pump power.
3Loss of time
If the heater operates continuously at maximum capacity, then preheating speed is improved, but system reliability decreases due to overheating risks
Solution Approach 1:
The heater dynamically adjusts its operation between two modes based on real-time flow capability assessment. This dynamic operation allows the system to maintain high preheating speed when conditions permit while ensuring reliability when flow capability is compromised by extreme cold.
Solution Approach 2:
The control system prepares for potential overheating by having a pre-defined second operational mode ready. When flow capability is assessed as reduced, the system cushioningly transitions to the lower-power mode before overheating can occur, preventing system failure and maintaining reliability.
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
Prevents overheating of the coolant in the heat exchanger, ensuring efficient preheating of vehicle components and reducing the risk of system failure, even at low temperatures.
Implementation Method 1
determining, prior to commencing heating of the fluid, a parameter value indicative of a flow capability of the fluid in dependence on data received from a temperature sensor and/or a fluid viscosity sensor
Implementation Method 2
A fuel operated heater may be provided to heat the coolant; fuel normally used to power the combustion engine of the vehicle is ignited to produce heat which is transferred to the coolant
Implementation Method 3
an auxiliary coolant pump is used to pump the coolant about the fluidic circuit of the engine and the HEVAC when the vehicle's engine is not running
Implementation Method 4
fuel normally used to power the combustion engine of the vehicle is ignited to produce heat which is transferred to the coolant
Data Source
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AI summary
A heater system for preheating a vehicle and method of operating the same, wherein the method of operation is dependent upon the temperature of the coolant fluid in the vehicle coolant system.