Direct Fuel Injector Temperature Control in Multi-Fuel Engines
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Solution Overview
Problem
Multi-fuel system internal combustion engines face challenges in protecting direct injectors from overheating and carbon deposit formation, especially when switching between liquid and gaseous fuel modes, leading to inefficient fuel consumption and performance issues.
Innovation Solution
A method and apparatus that continuously monitor and manage the temperature of direct fuel injectors by selectively switching between direct injection and fumigation modes, adjusting fuel quantities, and modifying equivalence ratios, spark timing, and combustion phasing to maintain optimal temperatures, using engine operating parameters to determine the most effective mitigation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the engine operates in port injection natural gas fuelled mode with dormant liquid fuel in direct injectors, then natural gas can be used as an alternative fuel to reduce emissions and cost, but the direct fuel injectors may overheat and form carbon deposits that foul the injectors and impact liquid fuel injection performance
Solution Approach 1:
The system performs preliminary cooling of the direct fuel injector by flowing liquid fuel through the injector before switching to port injection natural gas mode. This preliminary action prevents the injector from overheating and forming carbon deposits during subsequent natural gas operation, thereby maintaining injector reliability while enabling multi-fuel versatility.
Solution Approach 2:
The engine control system continuously monitors injector temperature and dynamically adjusts the liquid fuel flow rate through the direct injector. When the injector temperature approaches critical levels, the system increases cooling fuel flow; when temperature is adequate, it reduces or stops cooling flow. This feedback control maintains injector temperature within safe operating ranges, preventing carbon deposit formation while enabling flexible fuel mode switching.
2Reliability
If liquid fuel is flowed through the high pressure fuel injector to cool the injector during gas operation, then the injector temperature is maintained below critical values, but carburetor fuel is consumed unnecessarily when the injector temperature is already below the critical value
Solution Approach 1:
The system uses temperature sensors to continuously monitor direct fuel injector temperature and feeds this information back to the control system. Based on the real-time temperature reading, the controller dynamically adjusts the liquid fuel flow rate through the injector, increasing flow when temperature is high and reducing or stopping flow when temperature is already below critical thresholds. This feedback control eliminates unnecessary fuel consumption while maintaining reliable temperature management.
Solution Approach 2:
Instead of continuously flowing liquid fuel through the direct injector during all natural gas operation, the system applies partial cooling only when and where needed - specifically when the injector temperature exceeds predetermined thresholds. This partial action approach maintains sufficient cooling to prevent carbon deposit formation while minimizing unnecessary liquid fuel consumption during periods when cooling is not required.
3Reliability
If a predetermined minimum volume of liquid fuel is flowed through the injector to cool it during gas operation, then the injector is cooled, but the amount of fuel used is based on empirical estimates rather than actual temperature requirements, leading to inefficient fuel consumption
Solution Approach 1:
The system replaces empirical predetermined cooling volumes with real-time temperature-based feedback control. Temperature sensors provide continuous information about actual injector temperature, and the control system adjusts liquid fuel flow rate accordingly. This feedback mechanism ensures that cooling fuel volume matches actual thermal requirements, eliminating waste and improving overall fuel efficiency while maintaining reliable injector cooling.
Solution Approach 2:
The system dynamically changes the liquid fuel flow rate parameter based on real-time injector temperature measurements rather than using a fixed predetermined volume. The control system adjusts the cooling fuel flow rate as a variable parameter that responds to temperature conditions, enabling optimal cooling efficiency and minimizing unnecessary fuel consumption while maintaining injector reliability.
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 effectively reduces the risk of injector damage, minimizes fuel consumption, and maintains engine performance across various fuel modes by precisely controlling injector temperatures and reducing the formation of carbon deposits.
Implementation Method 1
combustion of port injected fuel elevates the temperature of the liquid fuel inside the direct fuel injectors
Implementation Method 2
a natural gas port injection fuel system which introduces natural gas into the intake air upstream of intake valves
Data Source
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AI summary
A technique for fuel system protection for an internal combustion engine comprising introducing a directly injected fuel into a combustion chamber through a direct fuel injector; introducing a fumigated fuel upstream of an intake valve; selectively operating the internal combustion engine with at least one of the directly injected fuel and the fumigated fuel; determining a temperature of the direct fuel injector as a first function of engine operating parameters; and performing a temperature mitigation technique when the temperature rises above a first predetermined value such that the temperature is maintained below a second predetermined value.