Engine Shutdown Control for Cylinder Moisture Scavenging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In internal combustion engines using hydrogen gas as fuel, moisture generated by combustion can condense on cylinder walls leading to misfiring, and existing control devices do not effectively address this issue during shutdown.
Innovation Solution
A control device that calculates a higher target rotational speed based on engine coolant temperature, continues fuel injection with a fully open throttle during shutdown, and utilizes inertia to rotate the engine post-injection for scavenging to remove moisture from cylinder walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the engine is shut down immediately after combustion, then shutdown time is reduced, but moisture condenses on cylinder walls causing misfiring
Solution Approach 1:
The control device performs preliminary action by continuing fuel injection and maintaining throttle valve opening after the shutdown request is detected, before the engine is fully stopped. This creates a scavenging effect that removes moisture from cylinder walls in advance, preventing misfiring during subsequent shutdown operations.
2Reliability
If fuel injection is continued with throttle fully opened during shutdown, then moisture is removed from cylinder walls, but energy consumption increases
Solution Approach 1:
The control device applies periodic action by controlling fuel injection in a timed manner during shutdown. Fuel injection is continued only for a predetermined period or until engine speed reaches a predetermined value, then stopped. This periodic control achieves moisture removal while limiting energy consumption to necessary duration only.
3Reliability
If engine rotational speed is increased during shutdown, then scavenging effect is enhanced to remove moisture, but mechanical stress increases
Solution Approach 1:
The control device changes operational parameters by adjusting the relationship between throttle valve opening degree and engine rotational speed during shutdown. By maintaining throttle opening while controlling fuel injection quantity and duration, the system achieves effective scavenging at moderate rotational speeds, avoiding the need for high-speed operation that would increase mechanical stress.
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
Effectively suppresses misfiring by efficiently removing moisture from cylinder walls, reducing air resistance, and shortening the time required for engine shutdown.
Implementation Method 1
scavenging inside of a cylinder of the internal combustion engine, by allowing an output shaft of the internal combustion engine to rotate under inertia
Implementation Method 2
When the combusted gasses containing moisture come into contact with inner walls of cylinders, the moisture that is contained in the combusted gasses is cooled, and condensation occurs
Data Source
AI summary
The control device of the internal combustion engine calculates the target rotational speed so that the target rotational speed increases as the engine coolant temperature decreases when the shutdown request of the internal combustion engine is detected. Next, racing is executed by the fuel injection is continuously executed until the engine rotational speed reaches the target rotational speed in a state where the throttle valve is fully opened. Further, the control device stops the fuel injection in a state where the throttle valve is fully opened when the engine rotational speed reaches the target rotational speed. When the output shaft of the internal combustion engine is rotated by inertia to scavenge the inside of the cylinder of the internal combustion engine, moisture generated on the inner wall of the cylinder can be blown off, so that occurrence of misfire can be suppressed.