AC Cut Cycles for Vehicle HVAC Compressor Load Reduction
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Solution Overview
Problem
Vehicle air conditioning systems increase the load on the engine due to continuous operation of the compressor, which can lead to increased engine torque, water temperature, and fuel consumption, especially in high ambient temperature conditions.
Innovation Solution
Implementing a compressor cut cycle operation based on engine water temperature and ambient temperature thresholds, where the compressor is switched to an OFF state for predetermined periods, reducing the load on the vehicle powertrain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor operates continuously to cool the passenger compartment, then the cooling effect is maintained, but the engine load and fuel consumption increase
Solution Approach 1:
The patent applies periodic action by implementing AC cut cycles where the compressor is turned off during predetermined time periods when ambient temperature exceeds a threshold. This periodic on-off operation reduces the overall runtime of the compressor, thereby decreasing fuel consumption while still providing cooling during lower temperature periods when the system is active.
2Temperature
If the compressor operates continuously, then the cooling performance is maintained, but the engine torque increases
Solution Approach 1:
The patent implements periodic action through AC cut cycles that periodically shut down the compressor during high ambient temperature conditions. This reduces the continuous torque demand on the engine, improving overall vehicle performance and reducing the burden on the powertrain during hot weather operation.
3Temperature
If additional cooling heat exchangers are installed to reduce engine temperature, then the cooling capacity increases, but the device complexity and packaging space increase
Solution Approach 1:
The patent applies the extraction principle by removing the need for additional cooling heat exchangers. Instead of adding hardware to cool the engine, the system extracts or eliminates the requirement for extra cooling components by using intelligent control of the AC compressor through AC cut cycles, thereby reducing device complexity and packaging requirements.
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 reduces engine torque, water temperature, and fuel consumption, minimizing heat damage and enhancing vehicle performance, particularly in high load conditions, and eliminates the need for additional cooling heat exchangers, improving packaging and safety.
Implementation Method 1
a water temperature sensor operable to measure an engine water temperature
Implementation Method 2
an ambient temperature sensor operable to measure an ambient temperature
Implementation Method 3
a compressor can be powered by a vehicle powertrain and used to compress refrigerant vapor to a higher pressure
Implementation Method 4
The compressed refrigerant can be routed through a condenser, where the refrigerant can be cooled
Implementation Method 5
The cooled refrigerant can be routed to an evaporator where the liquid refrigerant evaporates back to a vapor state as the refrigerant receives heat from air blown by a blower
Data Source
AI summary
A vehicle heating, ventilating, and air conditioning (HVAC) system can reduce a load applied to a vehicle powertrain during certain conditions. The system can include a fixed compressor operable between an ON state and in an OFF state. Systems and methods can determine whether an engine water temperature meets a forced HVAC recirculation intake threshold. Responsive to determining that the engine water temperature meets the forced HVAC recirculation intake threshold, it can be determined if the engine water temperature meets a high water temperature threshold. Responsive to determining that the engine water temperature meets the high water temperature threshold, it can be determined if an ambient temperature meets an ambient temperature threshold. Responsive to determining that the ambient temperature does not meet the ambient temperature threshold, the compressor can be operated according to an AC cut cycle.