HVAC Recirculation Valve Control for Engine Water Injection
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Solution Overview
Problem
Existing methods for refilling water storage tanks in water injection systems of internal combustion engines are inadequate, as they rely on ambient conditions for condensate collection, which may not meet demand and can reduce fuel economy by running the AC compressor unnecessarily.
Innovation Solution
Adjusting the position of the HVAC recirculation valve to vary the ratio of fresh ambient air to recirculated cabin air through the AC evaporator based on the water level in the tank and humidity levels, allowing for increased condensate collection during AC operation, thereby automatically replenishing the water storage tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the AC compressor is run to collect condensate from the HVAC system, then water supply for the water injection system is improved, but fuel economy deteriorates due to unnecessary compressor operation
Solution Approach 1:
The system proactively collects water from the HVAC system during periods when the AC is already operating or ambient conditions are favorable, storing it in advance in the water storage tank. This preliminary action ensures water availability for future injection demands without requiring compressor operation at the moment of demand, thereby avoiding unnecessary fuel consumption.
Solution Approach 2:
The system utilizes the HVAC system's existing operation to generate condensate that automatically refills the water storage tank. By integrating the water collection function with the HVAC system's normal operation, the system serves itself by producing water during AC usage without requiring separate dedicated compressor operation solely for water collection.
2Quantity of substance
If the AC compressor is run when ambient conditions are favorable but AC has not been requested, then water collection is improved, but fuel economy deteriorates
Solution Approach 1:
The system leverages the HVAC system's own operation to produce condensate for water collection. When the AC is requested and operating, the evaporator naturally produces condensate that is directed to the water storage tank, eliminating the need for separate dedicated compressor operation solely for water collection.
Solution Approach 2:
The HVAC system serves dual purposes: providing cabin cooling when requested and simultaneously generating water for the water injection system through condensate collection. This multi-functionality allows the same system component to address both climate control and water supply needs without requiring separate dedicated systems or operations.
3Quantity of substance
If water is collected only when ambient temperature is high and water storage tank level is below demand level, then water injection demand is met, but reliability deteriorates due to insufficient water supply under varying conditions
Solution Approach 1:
The system continuously monitors water storage tank levels and proactively collects water during favorable conditions (high ambient temperature, AC operation) before water levels become critically low. This advance preparation ensures water availability is maintained across varying operating conditions and prevents injection demand from going unmet.
Solution Approach 2:
The system employs continuous monitoring of water storage tank levels and ambient conditions, using this feedback to dynamically control HVAC operation and condensate collection. When water levels drop below thresholds or favorable collection conditions arise, the system adjusts operation to replenish water, ensuring reliable water supply for injection demands under varying conditions.
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 ensures a consistent water supply for the water injection system, reduces the likelihood of running out of water, and improves fuel economy by optimizing AC compressor usage.
Implementation Method 1
collecting water (or condensate) from other vehicle systems on-board the vehicle, such as collecting water from an air conditioning (AC) of a heating, ventilation, and air conditioning (HVAC) system
Implementation Method 2
When water is injected into the engine intake air, heat is transferred from the intake air and/or engine components to the water. This heat transfer leads to evaporation, which results in cooling.
Data Source
AI summary
Methods and systems are provided for adjusting a position of an air recirculation valve of a HVAC system to adjust a ratio of ambient to recirculated air routed to an AC evaporator to collect condensed water for water injection into an engine. In one example, a method may include adjusting the position of the air recirculation valve of the HVAC system based on a water level in a water storage tank of the water injection system. Further, the method may include adjusting the position of the air recirculation valve of the HVAC system based on a determined humidity of the ambient air and a determined humidity of the recirculated air.