Currentless Open Electromagnetic Valve Fuel Metering Control
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Solution Overview
Problem
The use of electromagnetic valves in fuel systems of portable handheld internal combustion engines, which are manually started and lack batteries, is hindered by the need for additional energy to control fuel metering, as existing solutions require more energy than what these engines can efficiently provide.
Innovation Solution
A method that controls an electromagnetic valve in a fuel system by using a currentless open state, where the valve is open without voltage, and only applies supply voltage when underpressure is present in the intake channel, allowing the valve to block fuel flow only when necessary, thereby minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an electromagnetic valve is used to control fuel metering in a fuel system of a manually started internal combustion engine, then fuel metering control is improved, but energy consumption increases
Solution Approach 1:
The electromagnetic valve is activated only during specific periodic intervals corresponding to the engine's operating cycle when underpressure is detected in the intake channel. The control unit monitors the operating cycle and applies voltage to the electromagnetic valve only during the necessary phases, rather than continuously, thereby reducing overall energy consumption while maintaining effective fuel metering control during critical periods.
Solution Approach 2:
The system utilizes the naturally occurring underpressure in the intake channel during engine operation to trigger valve closure. The control unit detects the underpressure condition and activates the electromagnetic valve only when this natural physical condition exists, allowing the system to leverage its own operational characteristics to minimize external energy input while maintaining control functionality.
2Productivity
If the electromagnetic valve is kept closed during the entire blocking time interval, then fuel flow control is improved, but energy consumption increases
Solution Approach 1:
Instead of maintaining continuous closure, the electromagnetic valve is activated in periodic pulses only during specific phases of the blocking time interval when underpressure is present. The control unit monitors the intake channel pressure and activates the valve intermittently, achieving effective fuel flow control during critical periods while minimizing energy consumption during periods when natural pressure conditions already prevent fuel flow.
3Ease of operation
If a larger generator and energy store are designed to provide additional energy for valve control, then valve control capability is improved, but device complexity and weight increase
Solution Approach 1:
The system uses the engine's own operational characteristics - specifically the underpressure naturally generated in the intake channel during the engine cycle - to determine when valve activation is necessary. This self-regulating approach eliminates the need for separate, oversized energy storage systems or larger generators, as the valve is activated only when the engine's natural pressure conditions indicate fuel metering control is needed, thereby maintaining control capability without increasing overall device complexity.
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 allows for efficient fuel metering with minimal energy requirements, enabling the use of electromagnetic valves in engines with low power generators and those without batteries, optimizing fuel metering while meeting strict exhaust-gas values, especially in two-stroke engines.
Implementation Method 1
an electromagnetic valve (21) having an excitation coil (21c) and being mounted in the fuel line (19) and being switchable between a first position wherein the valve is deenergized and open and a second position wherein the valve is energized and closed
Implementation Method 2
The electrical energy, which is available, is generated via an ignition generator which comprises an induction coil. The induction coil coacts with a magnet which rotates with the crankshaft.
Data Source
AI summary
A method is for controlling the metering of fuel in a fuel system (30) of an internal combustion engine (1) which is to be started manually. This control is with a currentless open electromagnetic valve (21). The electromagnetic valve (21) is only switched into the closed state when a supply voltage (Uv) is applied and current flows. Within a blocking time (47), which is pregiven by an engine control (13), a supply voltage (Uv) is switched onto the excitation coil of the electromagnetic valve (21) only and the valve (21) is supplied with current only when an underpressure is present in the intake channel (11) of the fuel system (30); whereas, in the remaining time span (50) of the blocking time (47), wherein no underpressure is present, the control unit (20) switches off the supply voltage (Uv) and the valve (21) is in the currentless open state.