Hybrid Vehicle Silent Start Climate Control via Electric AC
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Solution Overview
Problem
Hybrid electric vehicles face challenges in meeting climate control demands during silent key start, especially when the internal combustion engine is off, and remote start systems are used for climate control purposes.
Innovation Solution
A method for controlling hybrid electric vehicles that involves starting the engine if climate control demands require cooling or heating, either by remote or local start requests, while ensuring silent starts when not needed, and cycling the engine as necessary to maintain battery state of charge and meet climate control requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine is started to meet climate control demands during silent key start, then climate control functionality is improved, but the silent start feature deteriorates
Solution Approach 1:
The system changes the operational parameters of the air conditioning system by switching from a mechanical AC compressor (engine-dependent) to an electric AC compressor (battery-powered). This parameter change allows the climate control system to operate without engine running, maintaining silent start while providing climate control functionality through the electric motor-powered compressor.
2Loss of energy
If the engine is kept off during silent key start, then fuel economy is improved, but climate control capability deteriorates
Solution Approach 1:
The patent replaces the mechanical air conditioning system (which requires engine operation to drive the compressor) with an electric air conditioning system powered by the high voltage traction battery. This substitution eliminates the need for engine operation during silent key start while maintaining climate control capability, thus reducing fuel consumption without sacrificing comfort.
3Ease of operation
If remote start is used for climate control, then user comfort is improved, but engine wear increases
Solution Approach 1:
By replacing the mechanical AC system with an electric AC system powered by the traction battery, the patent enables remote start functionality to operate the climate control system without starting the internal combustion engine. The electric motor-driven compressor can be activated remotely through the battery, providing user comfort while avoiding engine wear and associated reliability concerns.
Data Source
AI summary
A hybrid electric vehicle includes an internal combustion engine, a high voltage traction battery, an electric motor powered by the traction battery, an electric air conditioning (AC) system, and a controller. The controller is programmed to start the vehicle. The vehicle is started by, if a climate control demand requires cooling: (a) if a vehicle start request is a remote start request, starting the engine; (b) if the vehicle start request is a local start request, avoiding starting the engine to provide a silent start.