Hybrid Engine Control Device for Coolant Temperature Uniformity
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Solution Overview
Problem
In hybrid vehicles, non-uniform coolant temperatures can lead to deteriorated engine start-up performance when the engine is stopped with partially low temperatures, as the existing technologies do not adequately address the temperature disparities detected by coolant sensors.
Innovation Solution
A control device and method that restricts coolant flow rate when the temperature is lower than a threshold, using a coolant temperature sensor to detect and increase the flow rate with the electric water pump before determining whether to stop the engine, ensuring overall coolant temperature is sufficiently high before engine shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric water pump is stopped to facilitate engine warm-up when coolant temperature is low, then energy consumption is reduced and warm-up is facilitated, but temperature uniformity of coolant deteriorates and engine start-up performance may be compromised
Solution Approach 1:
The control unit drives the water pump at a first duty ratio before determining whether to stop the engine, even when coolant temperature exceeds the stopping threshold. This preliminary action ensures temperature uniformity is established before engine shutdown, preventing localized cold spots that would deteriorate start-up performance.
Solution Approach 2:
The system dynamically adjusts the water pump duty ratio based on operating conditions. The pump operates at a first duty ratio during engine operation and switches to a second duty ratio (higher than the first) when the engine is stopped, optimizing both energy consumption and temperature uniformity across different operational states.
2Loss of energy
If the engine is stopped when coolant temperature exceeds the permission temperature, then fuel economy is improved, but engine start-up performance deteriorates due to non-uniform temperature distribution
Solution Approach 1:
Before allowing engine shutdown based on coolant temperature threshold, the control unit first drives the water pump at a first duty ratio to ensure uniform temperature distribution throughout the coolant system. This preliminary temperature equalization prevents localized cold spots that would otherwise deteriorate engine start-up performance.
Solution Approach 2:
The control unit continuously monitors coolant temperature and uses this feedback to determine both when to allow engine shutdown and when to reactivate the water pump. The system only permits engine stopping when temperature uniformity is confirmed, and can reactivate the pump if temperature differences develop during idle periods.
3Stability of the object's composition
If the water pump operates at high duty ratio continuously, then coolant temperature uniformity is maintained, but energy consumption increases
Solution Approach 1:
The water pump duty ratio is dynamically adjusted based on engine operational state and temperature conditions. During engine operation, the pump operates at a first duty ratio. When the engine is stopped and coolant temperature is sufficient, the pump operates at a second duty ratio (higher than the first) temporarily to equalize temperature, then can be reduced or stopped to conserve energy.
Solution Approach 2:
Instead of continuous high-duty-ratio operation, the water pump operates periodically based on temperature monitoring. The pump is activated at specific intervals or conditions to maintain temperature uniformity, rather than running continuously, thereby reducing overall energy consumption while still achieving temperature equalization when needed.
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 approach minimizes temperature differences and prevents engine start-up performance deterioration by ensuring the coolant is adequately warmed before engine shutdown, enhancing restart performance.
Implementation Method 1
Coolant is circulated by a water pump... coolant is circulated by an electric water pump to cool an engine
Implementation Method 2
a coolant temperature sensor that detects a temperature of the coolant
Data Source
AI summary
A control device is provided for an engine equipped with an electric oil pump for circulating coolant, and having a flow rate of the coolant restricted, when a temperature of the coolant is lower than a threshold value, as compared to a case where the temperature of the coolant is equal to or higher than the threshold value, and the engine control device includes a coolant temperature sensor detecting a temperature of the coolant, and a control unit stopping the engine in accordance with the temperature to be detected by the coolant temperature sensor after the pump is driven so as to increase the flow rate of the coolant, in a case where the flow rate of the coolant is restricted.