Handheld Work Apparatus Electronic Ignition Control
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Solution Overview
Problem
Handheld work apparatuses with combustion engines face challenges in simplifying the starting process to avoid operating errors and eliminate the need for manual actuation of mechanical starting devices.
Innovation Solution
A handheld work apparatus with a control device that automatically switches between starting and operating modes, controlling ignition time and fuel quantity electronically, eliminating the need for mechanical starting devices and allowing the combustion engine to start directly from a switched-off state without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical starting device with manual actuation is used, then the combustion engine can be started, but the construction becomes more complex and operating errors may occur
Solution Approach 1:
The patent replaces the mechanical starting device with an electronic control system. The control device electronically actuates the fuel valve and spark plug based on detection of cranking motion, eliminating the need for mechanical choke elements, starting devices, and associated linkages. This substitution reduces mechanical complexity while improving reliability through electronic control.
Solution Approach 2:
The control device automatically detects when the combustion engine is being cranked and autonomously actuates the fuel valve and spark plug without requiring manual intervention. The system serves itself by monitoring its own state and making the necessary control decisions, eliminating the need for operator interaction with mechanical starting components.
2Ease of operation
If a choke element is provided for starting position, then the starting process can be controlled, but the construction becomes more complex
Solution Approach 1:
The patent extracts and removes the choke element from the system entirely. Instead of using a separate choke mechanism to control air-fuel mixture during starting, the invention relies on electronic control of the fuel valve and spark plug timing to achieve reliable starting with the existing throttle element, which the operator uses for normal operation.
Solution Approach 2:
The existing throttle element is made to serve dual purposes: it controls the air-fuel mixture during both starting and normal operation. By coordinating the electronic control of fuel injection and ignition timing with the throttle position, the single throttle element performs the function previously requiring separate choke and throttle mechanisms.
3Extent of automation
If manual actuation of starting device is required, then the starting position can be set, but operating errors may occur
Solution Approach 1:
The control device incorporates feedback by detecting the cranking motion of the combustion engine and using this information to automatically actuate the fuel valve and spark plug. This closed-loop approach ensures the engine receives the correct fuel and ignition timing precisely when needed, eliminating operating errors associated with manual starting device actuation.
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 simplifies the construction and operation of handheld work apparatuses by eliminating the need for mechanical starting devices, reducing the risk of operating errors and allowing for seamless engine starting without manual actuation, while maintaining control over ignition and fuel supply for efficient engine operation.
Implementation Method 1
a centrifugal clutch; the combustion engine having a crankcase and a crankshaft mounted in the crankcase; the crankshaft being operatively connected to the tool via the centrifugal clutch
Data Source
AI summary
A handheld work apparatus has a combustion engine, a pull-rope starter, and a stop button for switching off the combustion engine. A throttle element is arranged in an intake channel of the combustion engine. The work apparatus has a control device for activating a spark plug and a fuel valve. The control device has a starting mode wherein the combustion engine can be started via the pull-rope starter, and an operating mode wherein the operator can adjust the throttle to vary the rotational speed (n) of the combustion engine. The operating and starting mode differ in terms of the control of ignition time and fuel quantity to be supplied. When the combustion engine is started from the switched-off state, the control device is automatically in starting mode, such that after the combustion engine is switched off, the work apparatus is immediately ready for restarting via the pull-rope starter.