Generator Torque Control for Crank Stop Position Holding
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Solution Overview
Problem
The crank position deviates from the target stop position due to a reaction force caused by cylinder internal pressure remaining in the cylinder after the engine stops, leading to decreased settling accuracy of the crankshaft.
Innovation Solution
A generator control method that determines when the engine stops and adjusts the crank position to a target stop position, continuing operation if the cylinder internal pressure exceeds a threshold to maintain the crank position, using a generator torque to counteract the residual pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the generator is operated to adjust the crank position to the target stop position when the engine stops, then the crank position control is achieved, but the crank position deviates from the target stop position due to reaction force from remaining cylinder internal pressure
Solution Approach 1:
The control device continuously monitors cylinder internal pressure and uses this feedback to determine when to continue generator operation. When pressure exceeds the threshold, the system feedbacks to maintain generator operation, thereby compensating for the reaction force and preventing crank position deviation.
Solution Approach 2:
The system determines a threshold value for cylinder internal pressure in advance. By comparing real-time pressure against this pre-established threshold, the control device can proactively continue generator operation before significant crank position deviation occurs, rather than reacting after the problem manifests.
2Measurement precision
If the generator operation is continued to maintain crank position when cylinder internal pressure is high, then the crank position is maintained accurately, but the operation time of the generator is extended
Solution Approach 1:
The generator operation duration is made dynamic rather than fixed. The control device continuously monitors cylinder internal pressure and adjusts the operation duration accordingly - continuing operation only as long as the pressure exceeds the threshold. This dynamic adjustment ensures accurate crank position maintenance while minimizing unnecessary extended operation time.
Solution Approach 2:
The system uses real-time feedback from cylinder internal pressure monitoring to determine when to stop generator operation. Once the pressure drops below the threshold, the feedback signal triggers termination of generator operation, thereby optimizing the operation time to match the actual need for crank position maintenance.
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
The crank position is reliably maintained at the target stop position, preventing deviation caused by residual cylinder pressure after engine stop.
Implementation Method 1
a vehicle that executes crank position control for stopping a crankshaft of an engine at a desired target stop position by braking the crankshaft by an alternator (generator)
Implementation Method 2
the crank position deviates from the target stop position due to a reaction force caused by a cylinder internal pressure remaining in a cylinder after the stop of the engine
Data Source
AI summary
Provided is a generator control method for controlling a generator driven by an engine via a crankshaft of the engine. In this generator control method, it is determined whether the engine stops, and when it is determined that the engine stops, the generator is operated to adjust a crank position of the crankshaft to a prescribed target stop position. It is also determined whether a cylinder internal pressure of the engine is equal to or greater than a prescribed threshold, and when the cylinder internal pressure is equal to or greater than the threshold, the operation on the generator is continued to maintain the crank position at the target stop position.