Engine Start Control Crankshaft Windback Speed
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Solution Overview
Problem
Existing engine start control devices take too long to complete the windback control process during idling stop, as the duty ratio of the ACG starter motor before applying the motor brake force is not high enough, leaving room for further time reduction.
Innovation Solution
An engine start control device with a swingback controller, windback reverse controller, and motor brake controller, where the motor current for windback is set equal to or higher than that for swingback, and a motor brake control process is performed by rotating the crankshaft in the normal direction or through short-circuit braking, using batteries with different voltages and an overcurrent protection circuit to manage current levels, and a motor brake execution determining table to monitor position and speed for timely braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the duty ratio of the ACG starter motor is increased to shorten windback control time, then the time to complete windback control is reduced, but the risk of excessive motor current and potential damage increases
Solution Approach 1:
The overcurrent protection circuit is activated before high-current windback control is executed to detect potential current excessive conditions in advance, allowing preventive action to be taken before damage occurs
Solution Approach 2:
The overcurrent protection circuit acts as an intermediary between the power supply and the ACG starter motor, monitoring and controlling the current flow to prevent excessive current from reaching the motor during high-duty-ratio windback operation
2Manufacturing precision
If the motor brake force is applied more aggressively to prevent rollback, then the crankshaft position control precision is improved, but the complexity of the control system increases
Solution Approach 1:
The controller continuously monitors the crankshaft position and motor current, using this feedback to dynamically adjust the motor brake force application, enabling precise control without requiring complex mechanical brake systems
Solution Approach 2:
The mechanical motor brake means is replaced with an electronically controlled braking mechanism that uses electrical current control to achieve the same rollback prevention function, reducing mechanical complexity while maintaining control precision
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 approach allows for quicker crankshaft windback during idling stop, preventing the crank position from exceeding the compression-stroke top dead center and reducing rollback, thereby enhancing the efficiency of the engine start process.
Implementation Method 1
a motor brake controller (102) for performing a motor brake control process for braking the crankshaft (51) reversed by the windback control process
Implementation Method 2
reversing a crankshaft (51) after the engine (E) is stopped with a motor (70) that rotates the crankshaft (51) in a normal direction or reverses the crankshaft (51)
Data Source
AI summary
An engine start control device that is capable of winding back a crankshaft more quickly at the time of an idling stop includes a swingback controller for performing a swingback control process for reversing a crankshaft when an engine is started by operating a starter switch, a windback reverse controller for performing a windback control process for reversing the crankshaft immediately after the engine is stopped by the idling stop control process, and a motor brake controller for performing a motor brake control process for braking the crankshaft reversed by the windback control process by rotating the crankshaft in the normal direction after the windback control process performed by the windback reverse controller. The value of a motor current supplied at the time the crankshaft is reversed by the windback reverse controller is set as a value equal to or larger than the value of a motor current supplied at the time the crankshaft is reversed by the swingback controller.