Vehicle HVAC Dual-Loop Operation for Engine-Off Cabin Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current over-the-road vehicle HVAC systems cannot operate when the engine is turned off, forcing drivers to choose between continuous engine idling for comfort or resting in extreme temperatures, which affects safety and fuel efficiency.
Innovation Solution
A vehicle HVAC system that includes a primary air conditioning loop operable with the engine on and a secondary loop operable with the engine off, using an electrically-driven compressor and shared components to maintain interior temperature control during engine-off conditions, managed by an intelligent power generation management controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine is continuously run to provide heating or air conditioning during rest periods, then the driver has a comfortable temperature-controlled environment, but fuel consumption increases significantly
Solution Approach 1:
The air conditioning system is segmented into two independent loops: a primary loop that operates when the engine is running, and a secondary loop that operates when the engine is off. Each loop has its own compressor (belt-driven for primary, electrically-driven for secondary), allowing the system to provide temperature control without requiring continuous engine operation, thus reducing fuel consumption while maintaining comfort.
2Use of energy by moving object
If the engine is turned off during rest periods, then fuel consumption is reduced, but the HVAC system cannot operate and the driver rests in extreme temperatures
Solution Approach 1:
The system divides the HVAC functionality into two separate operational loops that can function independently. The secondary loop with the electrically-driven compressor is specifically designed to operate when the engine is off, ensuring temperature control is maintained during rest periods without requiring fuel consumption from continuous engine operation.
Solution Approach 2:
The HVAC system is designed with multi-functionality to operate in two distinct modes: engine-on mode using the primary loop with belt-driven compressor, and engine-off mode using the secondary loop with electrically-driven compressor. This universality allows the system to provide temperature control regardless of engine status, eliminating the trade-off between fuel consumption and comfort.
3Device complexity
If a belt-driven compressor is used for the air conditioning system, then the system is simple and utilizes existing engine components, but the system cannot operate when the engine is turned off
Solution Approach 1:
The compressor system is segmented into two separate compressors: a belt-driven compressor for the primary loop that operates with the engine, and an electrically-driven compressor for the secondary loop that operates independently when the engine is off. This segmentation maintains the simplicity of the belt-driven system while adding the versatility of engine-off operation through the electrically-driven component.
Solution Approach 2:
The air conditioning system achieves multi-functionality by incorporating both belt-driven and electrically-driven compressors, allowing it to adapt to different operational conditions. The system can switch between engine-on and engine-off modes, providing versatility without significantly increasing overall system complexity since both compressors share common components like the evaporator and condenser.
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
Enables continuous temperature control of vehicle compartments regardless of engine status, reducing fuel consumption and improving driver safety by allowing HVAC operation during no-idle conditions without engine idling, while conserving energy and extending system operation duration.
Implementation Method 1
an electrically-driven compressor when a belt-driven compressor is idle
Implementation Method 2
shares an evaporator
Implementation Method 3
evaporator to maintain temperature control
Implementation Method 4
primary air conditioning loop
Data Source
AI summary
A heating, ventilating and air conditioning (HVAC) system for use in an over-the-road or off road vehicle is provided. The HVAC system may be operated regardless of the operational state of the engine. That is, the HVAC system may be operated to condition the interior compartments of an over-the-road vehicle while the engine is running and while the engine is in a no-idle (off) condition. In general, the HVAC system efficiently shares one or more typical air conditionings components with those already found in the vehicle. In one instance, the HVAC system operates an electrically-driven compressor when a belt-driven compressor is idle. In another case, the HVAC system operates both an electrically-driven compressor and a no-idle condenser when a belt-driven compressor and condenser are idle. In yet another embodiment, the HVAC system shares an evaporator.