Hybrid Vehicle Air Conditioning Control for Engine Re-Operation
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Solution Overview
Problem
In hybrid vehicles, the air conditioning system's inability to accurately control the temperature door opening angle in motor drive mode leads to reduced vehicle room heating efficiency and frequent engine re-operation, resulting in compromised fuel efficiency.
Innovation Solution
An air conditioning system with a control unit that adjusts the engine re-operation based on target air injection temperature and engine cooling water temperature, optimizing the temperature door opening angle to match actual vehicle room air temperature changes, and controlling engine re-operation to prevent unnecessary engine restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped during motor drive mode to reduce fuel consumption, then fuel efficiency is improved, but the heater core temperature decreases and vehicle room heating efficiency is reduced
Solution Approach 1:
The control unit predicts future engine stop events during motor drive mode and proactively adjusts the temperature door opening angle before the engine actually stops. This preliminary adjustment ensures that when the engine stops and cooling water temperature drops, the temperature door is already positioned to maximize hot air flow compensation, maintaining heater core temperature and vehicle room heating efficiency throughout the engine stop period
2Temperature
If the temperature door opening angle is adjusted to compensate for cooling water temperature drop, then vehicle room temperature is maintained, but the control accuracy is insufficient leading to suboptimal heating efficiency
Solution Approach 1:
The control unit continuously monitors actual vehicle room temperature and compares it with the target temperature. Based on this feedback, the control unit dynamically adjusts the temperature door opening angle in real-time during motor drive mode, not just using predetermined positions. This closed-loop control ensures accurate temperature maintenance while optimizing heating efficiency by precisely positioning the temperature door according to actual temperature deviations
3Temperature
If the engine is frequently re-operated to maintain cooling water temperature, then heater core temperature is maintained, but fuel efficiency is reduced due to unnecessary engine restarts
Solution Approach 1:
The control unit predicts when engine stop events will occur during motor drive mode and proactively adjusts the temperature door opening angle before the engine stops. This prevents the need for frequent engine re-operations to maintain heating capability, as the temperature door is already optimally positioned to compensate for the expected cooling water temperature drop, thereby maintaining fuel efficiency
Solution Approach 2:
The system uses the temperature door adjustment mechanism to self-compensate for heating temperature drops during engine stop periods, eliminating the need to re-start the engine for heating purposes. The temperature door acts as a self-regulating component that automatically adjusts hot air flow based on predicted engine operation states, preventing unnecessary engine re-operations
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 ensures accurate temperature control in motor drive mode, reduces engine re-operation, and enhances fuel efficiency by optimizing engine re-start points based on target temperatures and door positions.
Implementation Method 1
The evaporator 5 and a heater core 7 are installed in the air conditioner case 1... The heater core 7 is configured to receive high-temperature cooling water from an engine 8
Data Source
AI summary
An air conditioning system for hybrid vehicles includes a control unit configured to re-operate an engine if an engine cooling water temperature is reduced to a lower limit value or less after entry into a motor drive mode, and configured to stop the engine if the engine cooling water temperature is increased to an upper limit value or more. The control unit is configured to change the upper limit value and the lower limit value depending on a target air injection temperature calculated according to an internal/external temperature condition and a user-set temperature so that, in the motor drive mode, a re-operation time point of the engine is actively changed according to the target air injection temperature.