Dual Fuel Engine Pressure Control Strategy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dual fuel compression ignition engines face challenges in maintaining a desired pressure differential between liquid diesel fuel and natural gas fuel, leading to potential leakage and damage, while venting natural gas is undesirable due to its greenhouse gas properties.
Innovation Solution
A pressure control strategy using an electronic controller and pressure control algorithms to manage liquid and gaseous fuel pressures, ensuring the liquid fuel pressure remains above the gaseous fuel pressure during transitions, without venting the gaseous fuel, by controlling the liquid fuel pressure through a high-pressure pump and fuel injectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure relief valves are used to vent excess natural gas fuel to maintain pressure differential, then the pressure differential between liquid fuel and gaseous fuel is maintained, but harmful greenhouse gases are released to atmosphere
Solution Approach 1:
The patent introduces an intermediary approach by using a gaseous fuel pressure control valve instead of direct venting. This valve acts as a mediator to regulate and maintain the pressure differential between gaseous and liquid fuel systems, preventing both leakage and unnecessary venting of greenhouse gases while ensuring reliable operation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the gaseous fuel pressure based on operating conditions. The control system modifies pressure setpoints and differential thresholds to maintain optimal conditions without venting, resolving the contradiction between pressure management and environmental protection.
2Productivity
If liquid fuel pressure is decreased rapidly to reduce fuel pressure, then fuel pressure is reduced, but gaseous fuel may leak into liquid fuel passages
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the gaseous fuel pressure before the liquid fuel pressure decreases to a level where leakage could occur. The control system predicts potential leakage conditions and preemptively modifies gaseous fuel pressure to maintain the safety margin, preventing leakage while allowing rapid liquid fuel pressure reduction.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the pressure differential between gaseous and liquid fuel systems. The control algorithm adjusts gaseous fuel pressure based on real-time differential measurements, ensuring that liquid fuel pressure can be reduced rapidly without causing gaseous fuel leakage into liquid fuel passages.
3Reliability
If gaseous fuel pressure is increased to maintain pressure differential, then pressure differential is maintained, but energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the gaseous fuel pressure control adaptive rather than static. The system dynamically adjusts pressure setpoints based on actual operating conditions, load requirements, and real-time differential measurements, maintaining pressure differential only when necessary and reducing energy consumption during stable conditions.
Solution Approach 2:
The patent uses parameter changes by varying the gaseous fuel pressure setpoint based on operating conditions. Instead of maintaining constant high pressure, the system optimizes pressure parameters to maintain differential only when needed, reducing overall energy consumption while ensuring reliability.
Data Source
AI summary
A method of operating a dual fuel compression ignition engine includes controlling a liquid fuel pressure within the liquid fuel common rail toward a desired liquid fuel pressure, and controlling a gaseous fuel pressure within the gaseous fuel common rail toward a desired gaseous fuel pressure that is less than the desired liquid fuel pressure. The method also includes commanding a change in the liquid fuel pressure to a decreased liquid fuel pressure that is less than both the desired liquid fuel pressure and a current gaseous fuel pressure. The liquid fuel pressure is maintained above the gaseous fuel pressure during a transition of the liquid fuel pressure toward the decreased liquid fuel pressure by executing the pressure control algorithm.