Coolant Flow Apportioning for AC and Engine Cooling
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Solution Overview
Problem
Vehicle coolant systems face issues such as fuel economy loss, pump wear, and delayed cabin cooling due to continuous operation of the coolant pump, as well as challenges in meeting simultaneous air conditioning and engine cooling demands, particularly when the AC condenser is positioned away from the front of the vehicle, leading to increased reliance on the coolant pump and potential overheating.
Innovation Solution
A method that adjusts coolant flow through the AC condenser and charge air cooler in parallel based on AC head pressure and CAC outlet temperature, using a proportioning valve and coolant pump adjustments to optimize coolant distribution, ensuring both cabin and engine cooling demands are met efficiently, while maintaining a minimum coolant flow rate to reduce delays and warranty issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the coolant pump operates continuously to provide maximum AC cooling, then cabin cooling performance is improved, but fuel economy deteriorates and pump wear increases
Solution Approach 1:
The system dynamically adjusts coolant pump operation based on real-time monitoring of AC head pressure and CAC outlet temperature. The controller modulates pump runtime and flow rate to match actual cooling demands, transitioning from continuous operation to demand-responsive operation, thereby reducing energy consumption while maintaining cooling performance.
Solution Approach 2:
The system changes operational parameters (coolant flow rate, pump runtime) based on measured conditions (AC head pressure, CAC outlet temperature). By adjusting these parameters dynamically, the system optimizes the balance between cooling performance and energy consumption, avoiding both over-cooling and under-cooling scenarios.
2Productivity
If the AC condenser is positioned at the front end of the vehicle, then cooling air intake is improved, but space for other components (radiator) is reduced
Solution Approach 1:
The system uses a shared coolant circuit that serves multiple functions: cooling the AC condenser, cooling the charge air cooler, and maintaining engine temperature. This multi-functional approach allows flexible component positioning while ensuring all cooling needs are met through coordinated control of coolant distribution.
Solution Approach 2:
The shared coolant circuit acts as an intermediary that mediates between the AC system and engine cooling requirements. By using coolant flow rate and temperature as control variables, the system coordinates heat rejection from multiple sources without requiring dedicated positioning for each component.
3Temperature
If coolant flow is increased to meet simultaneous AC and engine cooling demands, then cooling performance is improved, but pump wear and energy consumption increase
Solution Approach 1:
The system dynamically adjusts coolant flow rate based on the relative cooling demands of the AC system and engine. The controller monitors AC head pressure and CAC outlet temperature to determine when high flow is necessary and when reduced flow suffices, thereby minimizing pump operation intensity and wear while maintaining adequate cooling performance.
4Loss of energy
If the coolant pump is deactivated when there is no AC demand, then fuel economy is improved, but cabin cooling response time deteriorates
Solution Approach 1:
The system maintains a minimum coolant flow rate even when AC cooling demand is low or zero. This preliminary action ensures that the coolant system remains primed and ready, eliminating startup delays when AC cooling is subsequently demanded, while still achieving significant fuel savings compared to continuous full-flow operation.
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 enhances fuel efficiency, reduces pump wear, and allows for effective cooling demand management, enabling both cabin and engine cooling demands to be met without compromising performance, thereby reducing the need for additional cooling components and improving engine cooling performance.
Implementation Method 1
The coolant flow may absorb heat from some components (thereby expediting cooling of those components) and transfer the heat to other components (thereby expediting heating of those components)
Implementation Method 2
Heat from the heated coolant may be dissipated to the atmosphere upon passage through a radiator including a fan
Implementation Method 3
a heat exchanger enables heat exchange between a charge air cooling coolant circuit and a refrigerant circuit of the condenser
Data Source
AI summary
Methods and systems are provided for controlling coolant flow through parallel branches of a coolant circuit including an AC condenser and a charge air cooler. Flow is apportioned responsive to an AC head pressure and a CAC temperature to reduce parasitic losses and improve fuel economy. The flow is apportioned via adjustments to a coolant pump output and a proportioning valve.