Fuel Injection Device Hydrodynamic Valve Control
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Solution Overview
Problem
Existing fuel injection devices for internal combustion engines face challenges in accurately controlling the small amount of fuel injection required for low engine outputs, leading to instability in fuel flow rates and increased costs due to the need for pressure sensors, making them unsuitable for gasoline engines.
Innovation Solution
The fuel injection device uses a hydrodynamic force to control the valve closing operation at an intermediate position, allowing for precise control of the valve lift and reducing the complexity and cost by eliminating the need for pressure sensors, thereby stabilizing fuel injection and reducing individual differences in flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the valve is directly operated by electromagnetic force with pulse width control, then the amount of injection can be controlled, but the valve behavior becomes unstable at short pulse widths and intermediate positions
Solution Approach 1:
A pressure control chamber is introduced as an intermediary between the electromagnetic valve and the needle valve. The pressure control chamber receives pressure control signal from the ECU and transmits it to the needle valve, mediating the control process to achieve stable valve positioning at intermediate lift positions without direct electromagnetic operation
Solution Approach 2:
The patent uses hydraulic pressure control to manage valve lift. The pressure control chamber uses fluid pressure (from the fuel system) to control the needle valve position, replacing direct electromagnetic force control with hydraulic actuation for more stable intermediate positioning
2Measurement precision
If pressure sensors and tightly sealed pressure control chambers are used to control needle valve lift, then intermediate position control is achieved, but the device complexity and cost increase
Solution Approach 1:
The pressure control chamber uses the existing fuel pressure from the fuel injection system itself to control the needle valve, without requiring external pressure sensors or additional sealing mechanisms. The system serves itself by utilizing its own operational pressure for control purposes
Solution Approach 2:
The pressure control chamber serves multiple functions: it acts as both a pressure transmission medium and a control element. The same fuel pressure that drives injection also controls valve lift, eliminating the need for separate control systems
3Loss of energy
If the smallest amount of injection is reduced for low fuel consumption, then fuel efficiency improves, but the valve behavior at intermediate positions becomes more unstable
Solution Approach 1:
The ECU provides pressure control signals to the pressure control chamber based on engine operating conditions. This feedback mechanism allows the system to adjust the pressure control signal to maintain stable valve behavior even at very small injection amounts required for low fuel consumption operation
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 solution enables accurate control of fuel injection amounts, reduces costs, and stabilizes fuel flow rates, making it suitable for both diesel and gasoline engines by leveraging hydrodynamic forces to manage valve lift effectively.
Implementation Method 1
the amount of injection in the fuel injection device that allows a valve to be directly operated by an electromagnetic force is controlled by changing a time during which the valve is opened
Implementation Method 2
A hydrodynamic force exerted on the valve body in a direction of closing the valve increases up to a lift position where the valve closing operation starts
Data Source
AI summary
A method of controlling a fuel injection device that can control a small amount of injection is provided. A fuel injection device for use in an internal combustion engine, includes: a valve body that can open and close a fuel passage, a needle that transfers a force with the valve body, and executes valve opening/closing operation, and an electromagnet that includes a coil and a magnetic core provided as a driver for driving the needle, and a cylindrical nozzle holder disposed on an outer periphery of the magnetic core and the needle, in which a current is supplied to the coil to exert a magnetic attractive force between the magnetic core and the needle to open the valve body.