Vehicle Air Conditioning Compressor Control During Fuel Cut Deceleration
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Solution Overview
Problem
Existing air conditioning systems for vehicles face issues with insufficient or excessive evaporator cooling power during deceleration and fuel cut recovery, due to the reliance on predetermined time settings, which can lead to suboptimal cooling performance and compromised fuel economy.
Innovation Solution
The system increases the compressor operation rate when the vehicle speed drops below a first permitted speed during deceleration, ensuring sufficient cooling power by maintaining the compressor on for a predetermined period before fuel cut recovery, and adjusts compressor operation based on refrigerant pressure and deceleration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a predetermined time Tup is set to control compressor operation after deceleration lock-up, then fuel economy is improved, but evaporator cooling power becomes insufficient or excessive
Solution Approach 1:
The control device increases the compressor operation rate before the fuel cut recovery timing is reached. By anticipating the timing when fuel cut will end and the air conditioner will resume operation, the system proactively adjusts compressor performance to ensure continuous cooling capability, preventing evaporator temperature fluctuations while maintaining fuel efficiency during deceleration.
2Reliability
If the compressor operation rate is increased before fuel cut recovery, then evaporator cooling power is maintained, but energy consumption increases
Solution Approach 1:
The control device dynamically adjusts the compressor operation rate based on real-time vehicle deceleration state and predicted fuel cut recovery timing. The system increases compressor operation rate only during the specific period before fuel cut recovery, and reduces it afterward, creating a time-varying control strategy that balances cooling requirements with energy consumption optimization.
3Reliability
If the predetermined time Tup is extended to maintain cooling, then evaporator cooling power is sufficient, but fuel economy deteriorates
Solution Approach 1:
The control device changes the compressor operation rate parameter dynamically based on the vehicle's deceleration state and predicted fuel cut recovery timing. Instead of using a fixed predetermined time Tup, the system adjusts the compressor operation rate to increase before fuel cut recovery and reduce after, optimizing both cooling performance and fuel economy through adaptive parameter control.
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 maintains consistent evaporator cooling power, enhances air conditioning effectiveness, and improves fuel economy by optimizing compressor operation in response to varying vehicle deceleration conditions.
Implementation Method 1
a compressor for sucking, compressing and discharging a refrigerant
Implementation Method 2
a condenser for condensing the high-temperature and high-pressure refrigerant discharged from the compressor
Implementation Method 3
an expansion valve for decompressing the refrigerant condensed in the condenser
Implementation Method 4
an evaporator for evaporating the refrigerant through heat exchange between the refrigerant reduced in pressure by the expansion valve and surrounding air
Implementation Method 5
heat exchange between the refrigerant reduced in pressure by the expansion valve and surrounding air
Data Source
AI summary
An air conditioning device for vehicle includes a refrigeration cycle including a compressor for sucking, compressing and discharging a refrigerant, a condenser for condensing the high-temperature and high-pressure refrigerant discharged from the compressor, an expansion valve for decompressing the refrigerant condensed in the condenser and an evaporator for evaporating the refrigerant through heat exchange between the refrigerant reduced in pressure by the expansion valve and surrounding air. This air conditioning device for vehicle increases an operation rate of the compressor more than that before a vehicle speed drops below a first permitted vehicle speed higher than a fuel cut recovery vehicle speed when an air conditioner is on, at which the compressor is actuated, when the vehicle speed drops below the first permitted vehicle speed during the deceleration of a vehicle associated with a fuel cut.