Belt-Driven Starter Generator Pre-Powering for Low-Tension Restart Control
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Solution Overview
Problem
Conventional restart standby control methods for internal-combustion engines, which apply preliminary powering torque to the engine via a motor generator connected via a belt transmission mechanism, lead to increased engine revolution speed resonance time, prolonged engine shutdown time, and energy wastage, while also deteriorating noise and vibration characteristics.
Innovation Solution
The method involves controlling preliminary powering torque to be higher in the low-tension period and zero in the high-tension period of the belt's periodic tension variation, ensuring that preliminary powering is only applied when the belt tension is low, thereby avoiding unnecessary torque application during high-tension periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If preliminary powering torque is applied continuously to remove belt slack, then start responsiveness is improved, but engine revolution speed resonance time increases and noise/vibration characteristics deteriorate
Solution Approach 1:
The patent applies preliminary powering torque periodically rather than continuously. The controller determines timing based on crankshaft rotation angle to apply torque only during low-tension periods of the belt, creating a periodic action pattern that removes slack while minimizing resonance and noise.
Solution Approach 2:
The patent dynamically adjusts the application of preliminary powering torque based on real-time conditions. The controller monitors crankshaft rotation angle and belt tension conditions, applying torque only when conditions are favorable (low-tension periods), making the system adaptive rather than static.
2Reliability
If preliminary powering torque is applied continuously, then belt slack is removed, but energy consumption increases
Solution Approach 1:
The patent uses periodic action by applying preliminary powering torque only during low-tension periods determined by crankshaft rotation angle. This intermittent application removes belt slack effectively while minimizing energy consumption compared to continuous torque application.
Solution Approach 2:
The patent applies partial action by providing preliminary powering torque only during specific portions of the crankshaft rotation cycle (low-tension periods) rather than throughout the entire cycle. This partial application is sufficient to remove belt slack while reducing overall energy consumption.
3Reliability
If preliminary powering torque is applied continuously, then belt slack is removed, but belt tension becomes excessively high
Solution Approach 1:
The patent applies preliminary powering torque periodically during low-tension periods rather than continuously. This timing strategy removes belt slack while avoiding excessive belt tension that would occur with continuous torque application during high-tension periods.
Solution Approach 2:
The patent uses beforehand cushioning by applying preliminary powering torque in advance during low-tension periods to gradually remove belt slack. This prevents sudden tension spikes that would occur if torque were applied when the belt is already under high tension.
Data Source
AI summary
An internal-combustion engine includes a belt-driven starter generator and makes an idling stop while a vehicle is at a stop. In the process of the engine revolution speed decreasing with cutting of fuel to stop the vehicle, to suppress the reduction in restart responsiveness caused by slack in a belt, preliminary powering of the starter generator is performed. The belt tension during deceleration microscopically changes periodically between a relatively high-tension period and a relatively low-tension period due to pulsation of the engine revolution speed. Slack in the belt does not occur in the high tension period, and thus preliminary powering torque is applied only in the low-tension period.