Variable Coolant Flow Control for AC Condenser and Charge Air Cooler
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Solution Overview
Problem
Vehicle coolant systems face issues such as fuel economy loss and pump wear due to continuous operation, and the AC condenser's front-end location leading to refrigerant loss in collisions, which also affects warranty and cooling efficiency.
Innovation Solution
A method to adjust coolant flow through a charge air cooler and AC condenser using a pump and proportioning valve, responsive to charge air cooler temperature and AC compressor head pressure, optimizing coolant flow to meet cooling demands while reducing parasitic losses and improving AC performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the AC system is configured to provide maximum cooling at all times, then AC cooling performance is improved, but fuel economy deteriorates due to continuous pump operation
Solution Approach 1:
The patent applies dynamics by making the coolant flow rate variable rather than constant. The ECU dynamically adjusts the coolant flow rate through the condenser based on real-time AC head pressure feedback, allowing the system to provide maximum cooling when needed while reducing flow rate (and energy consumption) when cooling demand is lower, thus resolving the contradiction between AC performance and fuel economy
Solution Approach 2:
The patent implements a feedback control system where the ECU continuously monitors AC head pressure and adjusts coolant flow rate accordingly. This closed-loop feedback mechanism ensures the AC system maintains optimal performance while consuming only the necessary amount of energy, preventing both over-cooling (wasting fuel) and under-cooling (poor AC performance)
2Temperature
If the coolant pump operates continuously to provide maximum cooling, then cooling performance is improved, but pump wear increases resulting in warranty issues
Solution Approach 1:
The system dynamically adjusts coolant flow rate based on actual AC cooling demand and head pressure conditions. The pump operates at variable speeds rather than continuously at maximum capacity, reducing mechanical wear while maintaining adequate cooling performance through precise flow rate control matched to system needs
Solution Approach 2:
The patent changes the operating parameters of the coolant pump by adjusting flow rate and speed based on feedback from head pressure sensors. This parameter optimization allows the pump to operate efficiently at lower speeds during normal conditions, reducing wear and extending service life while still providing sufficient cooling when required
3Productivity
If the AC condenser is positioned at the front end of the vehicle, then cooling efficiency is improved by receiving more vehicle cooling air, but refrigerant loss increases due to collision risk
Solution Approach 1:
The patent extracts the AC condenser from its traditional front-end position and relocates it to a rearward position in the under-hood area. This spatial extraction removes the condenser from the high-risk collision zone while the system compensates for reduced airflow by optimizing coolant flow rate through the condenser, maintaining cooling efficiency without the refrigerant loss risk
Solution Approach 2:
The coolant system acts as an intermediary to transfer heat from the AC condenser to the atmosphere. By enhancing coolant flow rate control and heat transfer efficiency through the relocated condenser, the system compensates for the less optimal airflow position, allowing the condenser to be safely positioned rearward while maintaining adequate cooling performance
4Reliability
If the AC condenser is moved further away from the front end to reduce refrigerant loss, then safety is improved, but cooling efficiency deteriorates due to reduced vehicle cooling air
Solution Approach 1:
The ECU uses feedback from head pressure sensors to continuously monitor AC system performance and dynamically adjusts coolant flow rate to compensate for the relocated condenser's reduced airflow exposure. This feedback control ensures cooling efficiency is maintained despite the safer rearward position
Solution Approach 2:
The system changes the coolant flow rate parameter to optimize heat transfer at the relocated condenser position. By increasing or adjusting coolant flow rate as needed, the system compensates for the reduced ambient airflow to the condenser, maintaining cooling efficiency while allowing the safety-beneficial rearward relocation
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 improves fuel economy, reduces pump wear, and minimizes warranty issues by optimizing coolant flow, allowing for efficient cooling and reducing the need for additional radiators and fans, while also relocating the AC condenser to a rearward position for safety.
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
Implementation Method 2
Heat from the heated coolant may be transferred to a heater core (for heating a vehicle cabin), and/or dissipated to the atmosphere upon passage through a radiator including a fan
Implementation Method 3
dissipated to the atmosphere upon passage through a radiator including a fan
Implementation Method 4
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.