Engine Start Determination via Crank Angular Acceleration Increments
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Solution Overview
Problem
Conventional techniques for determining engine start-up in hybrid vehicles with dynamo-electric machines are inefficient, requiring excessive time and often resulting in inaccurate assessments, as they struggle to differentiate between engine self-sustaining rotation and rotation dependent on motor generator output.
Innovation Solution
An engine start determining apparatus that calculates the increment in crank angular acceleration every piston stroke and determines engine start-up based on whether these increments exceed a standard value, set according to intake air and crankshaft angular velocity, allowing for rapid and accurate assessment of engine momentum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional techniques measure elapsed time since motor generator output falls below reference value or temporarily cancel torque assist to determine engine start-up, then the determination accuracy is improved, but the determination time becomes excessively long
Solution Approach 1:
The invention changes the parameter used for determination from time-based (elapsed time, torque assist setting time) to acceleration-based (crank angular acceleration increment). By monitoring whether the crank angular acceleration increment exceeds a standard value, the system can determine engine start-up rapidly without waiting for predetermined time periods to elapse, thus resolving the contradiction between determination accuracy and determination time.
2Speed
If the motor generator cranks the engine with high rotational speed, then the cranking performance is improved, but the discrimination between self-sustaining revolution and motor generator-dependent revolution becomes more difficult
Solution Approach 1:
The invention applies dynamics by monitoring the temporal change (increment) of crank angular acceleration rather than static speed values. By detecting whether the acceleration increment exceeds a standard value, the system can identify the transition point where the engine achieves self-sustaining revolution even during high-speed cranking, thus maintaining accurate discrimination capability despite high cranking speeds.
Data Source
AI summary
An apparatus includes a dynamo-electric machine driving an engine, and a calculator calculating an increment in a crank angular acceleration of the engine every certain period from a base time after the driving of the engine by the dynamo-electric machine. The apparatus further includes a determiner determining that the engine has started by the dynamo-electric machine on a condition that the increment calculated by the calculator exceeds a standard value.