Hydrogen Engine Valve Timing to Suppress Backfire Losses
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Solution Overview
Problem
Hydrogen engines face issues with backfire due to its wide combustible range and fast combustion speed, leading to potential damage to intake paths and decreased engine efficiency when fuel is supplied through the intake port.
Innovation Solution
A hydrogen engine design with a separate fuel supply port and intake port, utilizing a valve train that synchronizes the opening and closing of intake and fuel supply valves, with the fuel supply valve timing retarded relative to the intake valve, and incorporating a collar or cover portion to control fuel flow, ensuring efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hydrogen fuel is injected into the intake port, then fuel supply is simplified, but backfire occurs and intake path damage risk increases
Solution Approach 1:
The patent divides the fuel supply system into two separate paths: one for hydrogen fuel (through the fuel supply valve and fuel supply port) and one for air intake (through the intake valve and intake port). This segmentation prevents hydrogen from entering the intake port, thereby eliminating backfire risk while maintaining separate control mechanisms for fuel and air supply.
2Object-affected harmful factors
If fuel gas is supplied to the combustion chamber separately from the intake port, then backfire is suppressed, but engine efficiency decreases due to fuel discharge through exhaust port
Solution Approach 1:
The patent employs dynamic valve timing control where the fuel supply valve opening timing is retarded relative to the intake valve opening timing. This dynamic adjustment ensures that fuel is supplied only when the exhaust valve is closed, preventing fuel discharge through the exhaust port while maintaining efficient combustion. The timing relationship between valves is continuously optimized based on engine operating conditions.
3Object-affected harmful factors
If a separate fuel supply port is provided, then backfire is suppressed, but device complexity increases
Solution Approach 1:
The patent designs the valve train to serve multiple functions: it controls both the intake valve for air supply and the fuel supply valve for hydrogen delivery. The camshaft and associated mechanisms are configured to actuate both valves, making the valve train a multi-functional component that reduces overall system complexity despite the addition of the fuel supply port.
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
The design effectively suppresses backfire and maintains high engine efficiency by preventing unburned fuel from being discharged through the exhaust port, enhancing the engine's operational reliability and performance.
Implementation Method 1
a valve train commonly provided for the intake valve and the fuel supply valve, and configured to open and close the intake valve and the fuel supply valve in conjunction with each other
Implementation Method 2
The hydrogen engine is configured such that a valve opening timing of the fuel supply valve is more retarded than a valve opening timing of the intake valve
Implementation Method 3
a cover portion configured to cover at least a part of an outlet portion of the fuel supply port on a side of the exhaust port in at least a part of a valve opening period of the fuel supply valve
Implementation Method 4
a cylinder; a piston movable within the cylinder; a cylinder head forming a combustion chamber with the piston
Data Source
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AI summary
A hydrogen engine using fuel gas containing hydrogen, including: a cylinder; a piston movable within the cylinder; a cylinder head forming a combustion chamber with the piston, and including an intake port connected to the combustion chamber and a fuel supply port connected to the combustion chamber; an intake valve for opening and closing the intake port; a fuel supply valve for opening and closing the fuel supply port; and a valve train commonly provided for the intake valve and the fuel supply valve, and configured to open and close the intake valve and the fuel supply valve in conjunction with each other. The hydrogen engine is configured such that a valve opening timing of the fuel supply valve is more retarded than a valve opening timing of the intake valve.