Engine Fuel Pressure Control With Synchronized Valve Overlap
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Solution Overview
Problem
Pressure fluctuations in the fuel supply to fuel injection valves of internal combustion engines, particularly when using gaseous fuels like hydrogen, lead to decreased injection accuracy.
Innovation Solution
A controller that adjusts fuel pressure downstream of an electromagnetic valve by synchronized opening and closing operations to maintain a prescribed pressure, overlapping the valve opening periods of the electromagnetic valve with the fuel injection valves to stabilize fuel pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel pressure is reduced from tank pressure to injection pressure using an electromagnetic valve, then the fuel pressure at the injection valve is controlled to a prescribed pressure, but pressure fluctuations occur in the fuel supply to the injection valve
Solution Approach 1:
The controller opens the electromagnetic valve in advance before the fuel injection valve opens, and closes it after the fuel injection valve closes. This preliminary action ensures that fuel is already available in the delivery pipe when injection occurs, and prevents pressure drops during injection by maintaining valve openness throughout the injection period.
Solution Approach 2:
The electromagnetic valve performs repeated opening and closing operations at predetermined intervals to maintain fuel pressure within a target range. This periodic control compensates for pressure fluctuations caused by fuel consumption during injection cycles, ensuring stable pressure delivery to the injection valves.
2Reliability
If the electromagnetic valve is opened and closed repeatedly to control fuel pressure, then fuel pressure is maintained at a prescribed level, but the valve opening period must be precisely coordinated with the fuel injection valve operation
Solution Approach 1:
The controller monitors fuel pressure in the delivery pipe and adjusts the electromagnetic valve operation based on pressure feedback. When pressure exceeds the upper limit, the valve is closed; when pressure drops below the lower limit, the valve is opened. This feedback mechanism automatically coordinates valve timing with injection demands without complex manual scheduling.
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
Suppresses fuel pressure fluctuations, ensuring accurate fuel injection and improved engine performance by balancing fuel outflow and inflow to maintain stable fuel pressure.
Implementation Method 1
an electromagnetic valve that is provided in the fuel passage so as to selectively open and close the fuel passage
Implementation Method 2
a fuel injection valve that supplies fuel to a cylinder
Data Source
AI summary
A controller is configured to control an internal combustion engine. The controller is configured to perform a fuel pressure control of adjusting a fuel pressure downstream of an electromagnetic valve in a flow direction of fuel in a fuel passage to a prescribed pressure lower than a fuel pressure upstream of the electromagnetic valve by repeatedly performing opening and closing operations of the electromagnetic valve. The controller includes processing circuitry. The processing circuitry is configured to execute a process of setting opening and closing time points of the electromagnetic valve such that a valve opening period of the electromagnetic valve during execution of the fuel pressure control overlaps with a valve opening period of the fuel injection valve.