Multi-Fuel Injector Protection via Partial Fuel Injection
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Solution Overview
Problem
Multi-fuel engines face challenges in protecting direct injection fuel systems, particularly when operating with natural gas, as the heat from combustion can damage injectors and lead to carbon deposits, causing fouling and performance issues, and existing methods consume unnecessary liquid fuel to cool injectors.
Innovation Solution
The method involves co-fuelling cylinders with both directly injected fuel and a secondary fuel, delaying and integrating the direct fuel injection, and adjusting the air-fuel ratio to minimize direct fuel usage and prevent injector damage, using an electronic controller to manage the fuel system operation.
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 fuel injectors, then the engine can run on natural gas, but the heat from combustion elevates the temperature of liquid fuel above threshold causing injector damage or carbon deposits
Solution Approach 1:
The system implements periodic activation of direct fuel injectors during natural gas operation, switching between dormant and active states in scheduled intervals. This periodic action prevents continuous exposure to high temperatures while maintaining multi-fuel capability, thereby protecting injectors from damage and carbon deposits.
2Reliability
If liquid fuel is continuously injected to cool direct fuel injectors during natural gas operation, then injector temperature is controlled, but unnecessary liquid fuel is consumed
Solution Approach 1:
Instead of continuous liquid fuel injection, the system applies partial action by injecting small amounts of liquid fuel only when necessary for injector cooling. This partial injection approach provides sufficient thermal protection while minimizing unnecessary fuel consumption, optimizing the balance between reliability and energy efficiency.
3Reliability
If direct fuel injectors are activated frequently to prevent fouling, then carbon deposits are reduced, but liquid fuel consumption increases
Solution Approach 1:
The system employs feedback control by monitoring injector temperature and carbon deposit levels, activating direct fuel injectors only when thresholds are exceeded. This feedback mechanism ensures injector protection is maintained while minimizing liquid fuel consumption by avoiding unnecessary activations.
4Loss of substance
If the engine operates exclusively on port injected natural gas, then liquid fuel consumption is minimized, but direct fuel injectors become fouled and performance degrades
Solution Approach 1:
The system performs preliminary protective actions by scheduling direct fuel injector activations before severe fouling occurs. This preventive maintenance approach, implemented through engine control unit scheduling, maintains injector performance and prevents degradation while minimizing overall liquid fuel consumption through optimized activation timing.
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 and fouling by maintaining optimal temperatures and reducing unnecessary fuel consumption, enhancing the longevity and performance of direct injection fuel systems in multi-fuel engines.
Implementation Method 1
the quantity of the directly injected fuel to introduce into the multi-fuel engine is determined based on the temperature of the combustion chamber and the directly injected fuel injector
Implementation Method 2
an electronic controller programmed to determine a temperature of the combustion chamber; determine a temperature of the directly injected fuel injector based on the temperature of the combustion chamber
Data Source
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AI summary
A method of protecting a direct injection fuel injector in a multi-fuel engine, the method comprising selectively operating the multi-fuel engine with at least one of a directly injected fuel introduced through the direct injection fuel injector and a second fuel; when fuelling the multi-fuel engine with the second fuel, selectively commanding a fuel system protection technique when determining that at least one of the direct injection fuel injector requires cooling, an age of directly injected fuel is above a predetermined value, transmission status has changed, an engine shutdown event has occurred and a global positioning system signal indicates an engine shutdown event will occur; wherein the fuel system protection technique comprises commanding that the directly injected fuel be a portion of total fuel consumed and reducing quantities of the second fuel that is injected so that total fuel consumed equals a desired amount of fuel measured on an energy basis.