Ignition Unit for Internal Combustion Engine with Electronic Timing
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Solution Overview
Problem
Modern internal combustion engines in portable power tools face challenges with precise ignition timing due to mechanical fluctuations in the arrangement of ignition components, leading to cooling issues and thermal stress, as well as the need for angle-of-rotation sensors that complicate the mechanical configuration and precision of the ignition system.
Innovation Solution
A separate ignition unit that processes alternating voltage signals from a signal generator to determine the crankshaft angle position electronically, eliminating the need for angle-of-rotation sensors and allowing the ignition unit to be positioned flexibly, with the high-voltage unit near the spark plug and the processor unit at a thermally advantageous location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ignition trigger is mechanically arranged on the crankcase with fixed components, then the ignition device structure is simple, but the ignition timing precision deteriorates due to mechanical fluctuations and tolerance errors
Solution Approach 1:
The patent replaces the mechanical arrangement system for determining ignition timing with an electronic system. The signal generator produces electrical signals that are processed by a control unit to determine the precise crankshaft angle position, eliminating the need for mechanically arranged ignition triggers and their associated tolerance errors. This substitution of mechanical positioning with electronic angle determination resolves the contradiction by achieving high precision without mechanical complexity.
2Temperature
If the ignition generator, ignition module, and engine speed sensor are arranged within the cooling air passage, then the mechanical configuration is compact, but the cooling performance deteriorates causing thermal stress on the cylinder
Solution Approach 1:
The patent extracts the ignition generator and ignition module from the cooling air passage and positions them in separate locations. The signal generator is mounted on the outer periphery of the crankcase, and the ignition module is positioned separately from the cooling path. This extraction eliminates the obstruction of cooling airflow while maintaining functional integration through electrical connections, thereby resolving the contradiction between compact arrangement and cooling performance.
3Measurement precision
If angle-of-rotation sensors are used to determine crankshaft position, then the ignition timing can be precisely controlled, but the device complexity and mechanical tolerance requirements increase
Solution Approach 1:
The patent replaces mechanical angle-of-rotation sensors with an electronic signal generation system. The signal generator produces electrical signals whose characteristics (frequency, phase) directly indicate the crankshaft angle position. This electronic approach eliminates mechanical sensors and their associated mechanical tolerances, achieving high measurement precision through electrical signal processing rather than mechanical measurement.
4Temperature
If the ignition unit is integrated with the motor unit, then the overall structure is compact, but the cooling air passage is obstructed and thermal management becomes difficult
Solution Approach 1:
The patent segments the ignition system into separate functional modules: the signal generator is mounted on the crankcase outer periphery, the ignition module is positioned separately from the cooling path, and the high-voltage unit is integrated with the spark plug. This segmentation allows each component to be optimally positioned for its function while maintaining overall system compactness through modular design, resolving the contradiction between integration and thermal management.
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 configuration simplifies the ignition system, reduces mechanical tolerance errors, and enables precise ignition timing, allowing each device to self-calibrate during operation, improving performance and reducing thermal stress on the engine cylinder.
Implementation Method 1
the signal generator, advantageously embodied as an alternating current generator (alternator), is connected by only one electric line to the ignition unit
Data Source
AI summary
An ignition device for a motor unit with an internal combustion engine provided with a piston, a combustion chamber with a spark plug, a crankshaft driven by the piston, an intake port supplying combustion air to the combustion chamber, an exhaust for removing combustion gases from the combustion chamber, a signal generator driven by the crankshaft and emitting for one crankshaft revolution an alternating voltage signal, has an ignition unit that triggers a spark at the spark plug at a preselectable timing. The ignition unit is a module separate from the motor unit. An alternating voltage signal generated by the signal generator is supplied to the ignition unit as an information signal sufficient for operating the internal combustion engine. The alternating voltage signal is supplied to a first unit for energy processing and to a second unit for processing information for control of the internal combustion engine.