Switch Position Detection via Inductive Load Voltage Amplitude
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The complexity of electrical wiring in handheld work apparatuses for internal combustion engines, such as chainsaws, is high due to the need to connect sensors like microswitches to control units, which complicates the identification of switch positions and operation states.
Innovation Solution
An arrangement using inductive loads and zener diodes in parallel voltage branches allows for the identification of switch positions by evaluating the amplitude of induced switch-off voltages, eliminating the need for direct wiring between sensors and control units, and enabling simple bus system connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are directly wired to the control unit, then reliable sensor signal transmission is achieved, but electrical wiring complexity increases
Solution Approach 1:
The patent merges the sensor signal transmission path with the existing inductive load control path by connecting sensors in parallel to the control unit. This allows both functions (sensor signal acquisition and inductive load control) to share the same wiring infrastructure, eliminating the need for separate sensor wiring and reducing overall electrical wiring complexity while maintaining reliable signal transmission.
Solution Approach 2:
The control unit is designed to perform multiple functions: it controls inductive loads (fuel valve, ignition coil) and simultaneously reads sensor signals (choke position, throttle position, safety brake status). This multi-functionality allows a single wiring system to serve multiple purposes, reducing the need for dedicated sensor wiring and simplifying the overall electrical architecture.
2Reliability
If multiple sensors are added to monitor engine operating states, then operational reliability is improved, but wiring complexity increases
Solution Approach 1:
Multiple sensors (choke position sensor, throttle position sensor, safety brake sensor) are merged into the same parallel wiring structure that controls inductive loads. All sensors share common connection lines with the control unit, eliminating the need for separate wiring harnesses for each sensor and reducing overall wiring complexity while enabling comprehensive monitoring of engine operating states.
3Measurement precision
If sensors are arranged close to the engine components they monitor, then measurement accuracy is improved, but wiring length and complexity increase
Solution Approach 1:
The control unit serves as a multi-functional hub that both controls inductive loads and reads sensor signals. By utilizing the existing control wiring infrastructure for dual purposes, the patent eliminates the need for long dedicated sensor wiring runs, reducing wiring length and complexity while maintaining accurate switch position detection through the use of simple switch contacts positioned near engine components.
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 reduces wiring complexity, allows for reliable identification of switch positions, and enables efficient control of internal combustion engine operations by evaluating the amplitude of switch-off voltages, thereby simplifying the integration of sensors and control units.
Implementation Method 1
an inductive load being configured to cause an induced switch-off voltage having an amplitude when the inductive load is switched off
Implementation Method 2
the first zener diode being configured to limit the amplitude of the induced switch-off voltage
Data Source
AI summary
The invention relates to an arrangement for identifying a switching position of a switch (on an internal combustion engine in a handheld work apparatus. An energy source for supplying power to an inductive electrical load is provided, it being possible to connect the load to the energy source in order to be switched on and off via a controller. The switch is arranged in a voltage branch which is connected in parallel with the inductive load and in which a zener diode is also connected. The zener diode is activated or inactivated via the switch as a function of the switching position of the switch. The amplitude of the switch-off voltage, which is induced when the inductive load is disconnected, is limited by the zener diode, so that it is possible to read from the magnitude of the amplitude whether the switch is closed or open.