Dual Fuel Engine Injection Control via Pressure Threshold
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Solution Overview
Problem
Dual fuel internal combustion engines face challenges in matching the performance and efficiency of conventional diesel engines due to limitations in introducing gaseous fuels, which can lead to poor combustion, higher emissions, and reduced engine power when gaseous fuel is not available at the required pressure.
Innovation Solution
An apparatus and method that utilize a pressure sensor to determine when to switch between dual fuel mode and secondary fuel mode, allowing the engine to operate with either main fuel and secondary fuel or secondary fuel alone, based on available injection pressure, ensuring efficient combustion and reduced emissions by integrating a secondary-fuel injection valve and main-fuel injection valve into a single assembly and using accumulators to manage pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gaseous fuel is introduced into the intake air manifold at relatively low pressures, then the engine can operate with gaseous fuel available, but the engine cannot match the performance and efficiency of conventional diesel engines
Solution Approach 1:
The fuel injection system is segmented into two separate injection valves: a first fuel injection valve for introducing gaseous fuel at high pressure directly into the combustion chamber, and a second fuel injection valve for introducing liquid fuel. This segmentation allows independent control of each fuel type's injection timing and pressure, enabling the engine to achieve diesel-like performance when using gaseous fuel while maintaining the ability to operate on liquid fuel alone.
2Productivity
If both main fuel and secondary fuel are injected into the combustion chamber, then combustion efficiency is improved, but the device complexity increases
Solution Approach 1:
The first fuel injection valve and second fuel injection valve are integrated into a single common rail assembly, sharing a common fuel delivery system and control electronics. This merging approach allows dual-fuel injection capability while reducing overall system complexity compared to using completely separate injection systems for each fuel type.
Solution Approach 2:
The common rail assembly serves multiple functions: it can inject gaseous fuel through the first injection valve, inject liquid fuel through the second injection valve, or operate with either fuel type independently. This multi-functionality reduces the need for separate dedicated systems for each fuel mode, simplifying the overall device architecture.
3Reliability
If gaseous fuel supply pressure is not sufficient, then the engine can continue operating, but emissions increase and combustion is poor
Solution Approach 1:
The electronic control unit continuously monitors the pressure of gaseous fuel in the common rail and automatically switches between dual-fuel mode and liquid-fuel-only mode based on whether the pressure threshold is met. This feedback mechanism ensures that poor combustion and high emissions are avoided by preventing dual-fuel operation when gaseous fuel pressure is insufficient, while maintaining continuous operation capability.
4Object-generated harmful factors
If the engine operates with only secondary fuel, then emissions are reduced, but the duration of operation is limited
Solution Approach 1:
The engine control system dynamically adjusts the fuel injection strategy based on real-time gaseous fuel pressure conditions. When pressure is sufficient, the system operates in dual-fuel mode for reduced emissions. When pressure drops below the threshold, the system automatically transitions to liquid-fuel-only mode to ensure continuous operation, and can switch back when pressure is restored. This dynamic adaptation resolves the contradiction between emission reduction and operation duration.
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 solution enables the engine to maintain performance and efficiency by ensuring the correct fuel injection pressure and timing, reducing emissions and extending operation time with secondary fuel alone, while preventing excessive oscillations between operating modes.
Implementation Method 1
a pressure sensor associated with the main-fuel supply system for determining an available injection pressure inside the main-fuel injection valve
Implementation Method 2
using accumulators to manage pressure
Implementation Method 3
internal combustion engine
Data Source
AI summary
In an internal combustion engine that can burn two fuels, the main fuel may become unavailable, either temporarily or until the main fuel is replenished. The present apparatus determines when to fuel an engine with main fuel and secondary fuel, or secondary fuel alone. The apparatus includes a main-fuel supply system comprising a main-fuel injection valve that introduces main fuel into an engine combustion chamber; a secondary-fuel injection system comprising a secondary-fuel injection valve that introduces secondary fuel directly into the combustion chamber; a pressure sensor associated with the main-fuel supply system for determining injection pressure inside the main-fuel injection valve; and an electronic controller in communication with the pressure sensor and programmable to separately command actuation of the secondary-fuel and the main-fuel injection valve when injection pressure is greater than a predetermined threshold, and to otherwise command actuation of the secondary-fuel injection valve and not the main-fuel injection valve.