Adaptive Water Injection Location for Engine Charge Cooling
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Solution Overview
Problem
The effectiveness of water injection in internal combustion engines is limited by ambient humidity, as evaporative cooling is reduced in humid conditions, and the charge dilution effect is compromised by the need for warmer air, leading to suboptimal fuel efficiency and increased reliance on spark retardation for knock relief.
Innovation Solution
Adaptive water injection strategies that adjust the location and amount of water injection based on ambient temperature and humidity conditions, utilizing pre-CAC injection for charge dilution during dry and cold conditions and post-CAC injection for charge cooling during warm and humid conditions, leveraging the charge air cooler's heat flow directions to enhance water evaporation and cooling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water injection is used for charge cooling during humid conditions, then evaporative cooling effect is reduced, but charge dilution effect can still provide benefits
Solution Approach 1:
The system dynamically switches between pre-CAC and post-CAC water injection based on ambient conditions. During humid conditions, it transitions to post-CAC injection where evaporative cooling is more effective, while during dry conditions it uses pre-CAC injection for charge dilution. This dynamic adaptation resolves the contradiction by optimizing injection location according to environmental factors.
Solution Approach 2:
The invention changes the injection location parameter (pre-CAC vs post-CAC) based on ambient humidity and temperature. This parameter change allows the system to exploit different heat flow directions in the CAC to maximize water injection benefits regardless of ambient conditions, addressing the limitation of reduced evaporative cooling during humidity.
2Productivity
If water is injected upstream of CAC for charge dilution during dry and cold conditions, then fuel efficiency is improved, but charge cooling effect is reduced
Solution Approach 1:
The system dynamically selects injection location based on operating conditions. During warm and humid conditions when charge cooling is critical, it switches to post-CAC injection to maximize evaporative cooling effect. During dry and cold conditions where knock is less of an issue, it uses pre-CAC injection for charge dilution to improve fuel efficiency. This dynamic switching resolves the contradiction between cooling effectiveness and fuel efficiency.
Solution Approach 2:
The invention changes the water injection location parameter based on ambient temperature and humidity conditions. By adjusting this parameter, the system can optimize for either charge cooling (post-CAC injection during hot/humid conditions) or charge dilution (pre-CAC injection during dry/cold conditions), thereby resolving the trade-off between temperature control and fuel efficiency.
3Device complexity
If fixed water injection location is used, then system complexity is reduced, but adaptability to different ambient conditions is limited
Solution Approach 1:
The system employs dynamic control of water injection location based on sensor feedback regarding ambient temperature and humidity. This dynamic adaptation allows the system to optimize performance across varying environmental conditions without requiring multiple physical injection systems, thereby maintaining relatively simple device architecture while achieving high adaptability.
Solution Approach 2:
The invention makes a single water injection system perform multiple functions by changing injection location. The same water injection infrastructure can provide charge cooling during hot/humid conditions or charge dilution during dry/cold conditions, making the system universal and adaptable to different ambient conditions without significantly increasing device complexity.
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 extends the benefits of water injection across a wider range of engine operating conditions, improving fuel economy and reducing spark retard usage by optimizing water usage and engine performance through targeted water injection, enhancing both charge dilution and cooling effects.
Implementation Method 1
coolant flow through the charge air cooler is used to maintain the temperature of aircharge exiting the cooler. During conditions when boost is provided by the upstream compressor, aircharge entering the cooler is hot, and the coolant flow cools the aircharge before it enters the engine.
Implementation Method 2
When water is injected into the engine intake air may increase fuel economy and engine performance, as well as decrease engine emissions. When water is injected into the engine intake or cylinders, 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 selecting a location for water injection during a water injection event based on ambient temperature and humidity, as well as engine operating conditions. In one example, a method may include injecting water upstream of a charge air cooler in response to operating the cooler in heater mode and injecting water downstream of the cooler in response to operating the cooler in cooler mode. Further, the method may include operating the cooler in heater mode based on dry, cold ambient conditions and a dilution demand and operating the cooler in cooler mode based on engine boost conditions and engine knock.