Engine-Generator Starting Apparatus Compression Stroke Control
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Solution Overview
Problem
Existing engine-generator starting apparatuses face issues with losing motor rotation control capability and producing device-damaging current spikes when increasing current values to move the piston beyond the compression stroke, especially without a crankshaft position sensor.
Innovation Solution
An engine-generator starting apparatus with a three-phase winding, an inverter unit, and an electronic control unit that supplies first current to reverse-rotate the crankshaft to stop the piston at a compression stroke position, then second current to forward-rotate it after a predetermined time, ensuring reliable movement beyond the compression stroke without increasing current values, and ignites fuel after the second current is supplied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current value is increased to move past compression stroke, then engine starting reliability is improved, but motor rotation control capability is lost causing step-out
Solution Approach 1:
The system performs preliminary action by reverse-rotating the crankshaft to position the piston at a specific location in the compression stroke before supplying high current. This preliminary positioning ensures that when high current is subsequently applied, the piston is already optimally positioned, allowing reliable starting without prolonged high current that would cause step-out.
Solution Approach 2:
The system uses periodic action by alternating between reverse rotation mode and forward rotation mode. First, reverse current is supplied to rotate the crankshaft backward and position the piston, then forward current is supplied to rotate the crankshaft forward and move past compression stroke. This periodic switching of current direction enables reliable starting while maintaining control capability.
2Reliability
If current value is increased to move past compression stroke, then engine starting reliability is improved, but device damaging current spikes occur
Solution Approach 1:
The system performs preliminary positioning of the piston through reverse rotation before applying high current. This ensures the piston is at the optimal position when high current is applied, reducing the duration and magnitude of current spikes needed to achieve starting, thereby preventing device damage.
Solution Approach 2:
The system dynamically adjusts current direction and magnitude based on crankshaft position. By switching from reverse rotation to forward rotation at the appropriate moment, the system optimizes current application timing, reducing unnecessary high current exposure and associated damaging spikes while maintaining starting reliability.
3Reliability
If current value is increased to move past compression stroke, then piston movement beyond compression stroke is ensured, but motor rotation control capability is lost
Solution Approach 1:
The system performs preliminary action by reverse-rotating the crankshaft to precisely position the piston in the compression stroke before supplying high current. This preliminary positioning ensures reliable piston movement beyond compression stroke when high current is applied, while the controlled timing prevents loss of rotation control capability.
Solution Approach 2:
The system uses feedback by monitoring crankshaft rotation and detecting the appropriate moment to switch from reverse to forward current. This feedback mechanism ensures the piston is properly positioned before high current application, guaranteeing reliable movement while maintaining control through precise timing based on actual rotation state.
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
Prevents step-out and ensures stable engine starting by lengthening the run-up period to compression top dead center, gathering momentum for reliable movement beyond the compression stroke without increasing current values, thus preventing device damage.
Implementation Method 1
a three-phase winding (24) equipped with a generating unit (2) that rotates relative to rotation of a crankshaft of an engine
Implementation Method 2
an inverter unit that converts alternating current outputted from the generating unit to alternating current in predetermined frequency
Implementation Method 3
an ignition control unit that ignites fuel supplied to the engine after the second current control unit supplies the second current to the three-phase winding
Data Source
AI summary
An engine-generator starting apparatus a three-phase winding equipped with a generating unit that rotates relative to rotation of a crankshaft of an engine, and an electronic control unit that controls supply of electric current the three-phase winding to rotate the crankshaft and start the engine. In the apparatus, the electronic control unit controls to supply first current to the three-phase winding to make the engine crankshaft of rotate reverse, the first current is of a level for stopping the piston connected to the crankshaft at a position in a compression stroke. Then it controls to supply second current (that is greater than the first current) to the three-phase winding to make the crankshaft of the engine rotate forward when a predetermined time period has elapsed, and control to ignite fuel supplied to the engine after the second current is supplied to the three-phase winding.