Pilot Fuel Injection Timing Control for Generator Synchronization
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Solution Overview
Problem
Gas-operated internal combustion piston engines in electric power generator sets face challenges in efficiently managing pilot fuel injection timing and quantity, leading to inefficient operation and increased emissions during grid disturbances, which can cause desynchronization and methane slip emissions.
Innovation Solution
The method involves controlling the timing of pilot fuel injection based on engine operational parameters and grid state, retarding the injection by a predetermined crank angle during grid disturbances to rapidly adjust engine load without causing over-speeding, while ensuring continued combustion of gaseous fuel to reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the timing of pilot fuel injection is not adjusted during grid disturbances, then the engine operates efficiently under normal conditions, but the generator may desynchronize from the grid due to power imbalance
Solution Approach 1:
The patent applies dynamics by making the pilot fuel injection timing adjustable and variable based on operating conditions. The injection timing is dynamically retarded during grid disturbances to rapidly reduce engine load and prevent desynchronization, while returning to optimal timing under normal conditions to maintain engine efficiency.
Solution Approach 2:
The patent changes the injection timing parameter in response to grid disturbances. By retarding the injection timing, the combustion event is delayed, which rapidly reduces the engine's mechanical power output to match the reduced electrical load demand during grid faults, preventing synchronizing torque loss.
2Reliability
If the pilot fuel injection timing is retarded to rapidly adjust engine load during grid disturbances, then synchronization is maintained, but combustion efficiency decreases
Solution Approach 1:
The patent applies periodic action by implementing temporary, fault-duration-limited timing retardation. The retarded injection timing is applied only during the period of grid disturbance and automatically restored after fault clearance, ensuring synchronization is maintained during faults while minimizing the duration of reduced combustion efficiency.
Solution Approach 2:
The system prepares for grid disturbances by having the capability to rapidly retard injection timing already in place. When a disturbance is detected, the timing is immediately retarded to cushion against the potential for desynchronization, preventing the more severe consequence of losing synchronization entirely.
3Power
If the pilot fuel quantity is increased to maintain power output during grid disturbances, then power production is maintained, but nitrogen oxide emissions increase
Solution Approach 1:
Instead of increasing pilot fuel quantity to maintain power output during grid disturbances, the patent inverts the approach by retarding the injection timing. This delays combustion and rapidly reduces engine load to match the reduced electrical demand, avoiding the need to burn more fuel and thereby preventing increased NOx emissions.
4Reliability
If the pilot fuel injection timing is delayed during grid disturbances, then engine load is rapidly reduced to maintain synchronization, but combustion completeness decreases leading to unburned hydrocarbon emissions
Solution Approach 1:
The patent maintains continuity of useful action by ensuring that even though injection timing is retarded during grid disturbances, the combustion process continues to occur within the available time. The retarded timing is calibrated to ensure combustion still completes sufficiently to minimize unburned hydrocarbons, while achieving the necessary load reduction for synchronization.
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 minimizes the discrepancy between required and produced power during grid disturbances, prevents desynchronization, and reduces methane slip emissions by ensuring efficient combustion, even at varying loads.
Implementation Method 1
gaseous fuel is fed as a main fuel into combustion chambers of the engine along with the combustion air and the mixture of the gaseous fuel and air is ignited by injecting an amount of pilot fuel
Data Source
Figure 1
AI summary
Invention relates to method of operating an electric power generator set (1) comprising a gas operated internal combustion piston engine (10) coupled with an electric generator (12) in which gaseous fuel is fed as a main fuel into combustion chambers of the engine along with the combustion air and the mixture of the gaseous fuel and air is ignited by injecting an amount of pilot fuel (28), the timing and duration of the pilot fuel injection is controlled based on engine's operational parameters and the state of the electric grid (16), to which the generator is connected, is monitored. In the method in case of a disturbance in the grid is detected, the control of the timing and/or duration of the pilot fuel injection is effected based on the grid disturbance.