Pinion Rotation Timing Adjustment for Smooth Engine Restart
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Solution Overview
Problem
Existing engine stop-and-start systems experience noise and non-smooth engagement issues due to the pinion's premature rotation with the ring gear during engine restart, leading to increased friction and noise during the engagement process.
Innovation Solution
A system that includes a pinion shift unit, an engagement determining unit, and a rotation adjusting unit to delay the start timing of the pinion's rotation until it is fully or partially engaged with the ring gear, ensuring proper cranking of the internal combustion engine while reducing noise and improving engagement smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pinion is pre-engaged with the ring gear during engine coasting before restart, then the engine can restart immediately and noise during engagement is reduced, but the pinion may be engaged with the ring gear just before it stops rotating causing increased noise and non-smooth engagement
Solution Approach 1:
The system performs preliminary engagement of the pinion with the ring gear during engine coasting before restart is requested. The pinion shift unit starts shifting the pinion to engage with the ring gear during coasting, so that when restart is requested, the engagement is already complete or nearly complete, enabling immediate engine restart without waiting for engagement to occur.
Solution Approach 2:
The system dynamically adjusts the pinion rotation timing based on the engagement state. The rotation adjusting unit delays the start timing of pinion rotation until the engagement determining unit confirms that the pinion and ring gear have achieved the first positional relationship (pinion at least partly engaged with ring gear) or second positional relationship (pinion in abutment with ring gear), ensuring smooth engagement while maintaining restart reliability.
2Object-generated harmful factors
If the pinion rotation is delayed until engagement is confirmed, then engagement smoothness is improved and noise is reduced, but the engine restart response time may be increased
Solution Approach 1:
The pinion shift unit initiates the engagement process during engine coasting before restart is requested. This preliminary engagement action ensures that when restart is requested, the pinion is already in or near its engaged position, minimizing the time delay while still allowing the rotation to be delayed until engagement is confirmed to reduce noise.
Solution Approach 2:
The engagement determining unit continuously monitors the positional relationship between the pinion and ring gear, providing feedback to the rotation adjusting unit. When the first or second positional relationship is detected, the feedback signal triggers the pinion rotation to start, optimizing the balance between restart response time and engagement smoothness.
Data Source
AI summary
In a system, a pinion shift unit starts shift of a pinion to a ring gear for engagement therebetween during an internal combustion engine coasting in a forward direction after an automatic stop of the internal combustion engine. An engagement determining unit determines whether the pinion and the ring gear have any one of first and second positional relationships therebetween. The first positional relationship represents that the pinion is at least partly engaged with the ring gear. The second positional relationship represents that the pinion is in abutment with the ring gear. When an engine restart condition is met before it is determined that the pinion and the ring gear have any one of first and second positional relationships therebetween after the start of the shift of the pinion to the ring gear, a rotation adjusting unit adjusts a start timing of rotation of the pinion.