Gaseous Fuel Engine Start-Up Cylinder Deactivation
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Solution Overview
Problem
Starting gaseous fuel internal combustion engines, such as Otto engines and dual fuel engines, is challenging due to the need for adaptive control algorithms and initial power requirements to overcome inertia, and existing methods do not effectively ensure proper ignition system and gas admission valve functionality before activating gaseous fuel supply.
Innovation Solution
The method involves a phased start-up process where all cylinders are initially fired to overcome inertia, followed by selective cylinder firing based on speed and load thresholds, with control of air/fuel ratio, blow-off valve, and waste gate valve to optimize engine speed and efficiency, and includes pre-checks for ignition and gas admission valve functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If all cylinders are fired initially to overcome inertia, then the engine can achieve desired speed, but power consumption is high
Solution Approach 1:
The starting process is divided into multiple phases: initial phase where all cylinders are fired to overcome inertia, and subsequent phases where cylinders are selectively deactivated based on speed thresholds. This segmentation allows the engine to use full power only when necessary for acceleration, reducing overall power consumption while ensuring adequate starting performance.
Solution Approach 2:
The system dynamically adjusts the number of active cylinders based on real-time engine speed measurements. As the engine accelerates and reaches predetermined speed thresholds, the control algorithm selectively deactivates cylinders, transitioning from a static all-cylinders-on approach to a dynamic adaptive approach that matches power output to actual demand.
2Reliability
If gaseous fuel supply is activated early, then combustion can be initiated, but ignition system and valve functionality cannot be verified
Solution Approach 1:
The control algorithm performs preliminary diagnostic actions before activating gaseous fuel supply. It monitors cylinder pressure measurements and combustion characteristics during the initial pilot fuel combustion phase to verify that ignition systems and gas admission valves are functioning properly. Only after successful verification does the system proceed to activate full gaseous fuel supply, ensuring reliability while maintaining diagnostic capability.
Solution Approach 2:
The system continuously monitors cylinder pressure measurements and combustion characteristics during the starting sequence. This feedback mechanism allows the control algorithm to detect and diagnose issues with ignition systems or gas admission valves in real-time, verifying functionality before full gaseous fuel supply is activated, thereby ensuring reliable combustion initiation.
3Productivity
If adaptive control algorithms are used, then engine operation can be optimized, but starting complexity increases
Solution Approach 1:
The adaptive control algorithm is segmented into discrete speed thresholds and corresponding cylinder deactivation strategies. Rather than implementing a complex continuous control system, the patent divides the starting process into distinct phases with predetermined threshold values, simplifying the control logic while maintaining optimization benefits.
Solution Approach 2:
The control system optimizes engine operation by changing key parameters during the starting sequence: it adjusts the number of active cylinders, modifies air/fuel ratios, and varies valve timing based on engine speed thresholds. These parameter changes enable efficient engine operation without requiring overly complex control architecture, as each parameter adjustment follows predetermined rules based on measured speed.
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 enables a smoother and more reliable engine start, efficiently achieving desired engine speed while ensuring proper system functionality, reducing power consumption after initial acceleration.
Implementation Method 1
a piston (18) configured to move within the cylinder (26)
Implementation Method 2
an ignition device (90) configured to ignite the gaseous fuel and air mixture within the combustion chamber (16)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for starting a gaseous fuel internal combustion engine (10) is disclosed. According to the disclosed method, the engine is rotated using a start device until a first speed threshold is reached. After reaching the first speed threshold, pilot fuel is supplied to a plurality of cylinders (26A-26D) of the engine to combust the same. After performing an ignition health check, gaseous fuel is supplied to a relatively large number of cylinders (26A-26D) to start accelerating the engine up to a second speed threshold. After reaching said second speed threshold, the engine is operated with a lower number of cylinders until a rated speed of the engine is reached.