Engine Restart Control Device Speed-Adaptive Gear Meshing
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Solution Overview
Problem
Conventional engine restart techniques for automatic engine stop and start systems in vehicles face challenges such as delayed engine restart due to large differences in rotation speed between the pinion gear and ring gear, leading to discomfort and increased power consumption, and lack a method to detect the optimal time for smooth meshing.
Innovation Solution
A control device with multiple engine restart control means that adjusts the restart process based on the current rotation speed range of the internal combustion engine, including restarting fuel injection without cranking, synchronizing rotation speeds, and meshing the pinion gear with the ring gear at optimal times to minimize power consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the pinion gear is meshed with the ring gear when the rotation speed of the internal combustion engine is almost zero, then the gear meshing noise is reduced, but the engine restart delay increases
Solution Approach 1:
The patent applies dynamics by making the gear meshing timing adaptable rather than fixed. The control device dynamically adjusts the meshing timing based on real-time rotation speed detection. When the engine rotation speed is high (above threshold), the pinion gear meshes with the ring gear immediately without waiting for speed synchronization, reducing restart delay. When the rotation speed is low (below threshold), the system waits for speed synchronization before meshing, reducing gear meshing noise. This dynamic adaptation resolves the contradiction between noise reduction and restart speed.
2Object-generated harmful factors
If the pinion gear rotation speed is synchronized with the ring gear rotation speed before meshing, then the gear meshing noise is reduced, but the engine restart delay increases
Solution Approach 1:
The patent applies parameter changes by using a rotation speed threshold parameter to determine meshing strategy. The control device compares the detected engine rotation speed against this threshold parameter. When the rotation speed exceeds the threshold, the system changes its behavior to immediate meshing without synchronization, reducing restart delay. When the rotation speed is below the threshold, the system performs speed synchronization before meshing, reducing gear meshing noise. This parameter-based decision-making resolves the contradiction between noise reduction and restart speed.
3Productivity
If the starter motor rotates the pinion gear to crank the engine immediately after restart request, then the engine restart speed increases, but the power consumption increases
Solution Approach 1:
The patent applies parameter changes by using the engine rotation speed threshold to control starter motor operation timing. When the engine rotation speed is high (above threshold), the system skips the speed synchronization phase and proceeds directly to immediate meshing and cranking, reducing restart delay and maintaining high restart speed. When the rotation speed is low (below threshold), the system performs speed synchronization first, then meshes and cranks. This parameter-based control optimizes the balance between restart speed and power consumption by avoiding unnecessary synchronization operations when the engine is already rotating at sufficient speed.
Data Source
AI summary
A control device performs fuel injection without cranking when engine-speed Ne is within a first-range (Ne>N1) and an engine-restart request occurs. The device performs the cranking after the synchronization in rotation-speed between pinion and ring gears, and the gear meshing operation between them when the engine-speed Ne is within a second range (N1≧Ne>N2) and the engine-restart request occurs. The device performs the cranking after the gear meshing operation and drives a starter to rotate the pinion gear when the engine-speed Ne is within a third-range (N3≧Ne) and the above request occurs. When the above request occurs in an engine restart ready-range (N2≧Ne>N3), the control device performs the cranking after the engine-speed Ne is decreased to a value within the third-range (N3≧Ne) and after the completion of the gear meshing operation.