Vehicle Drive Control Device for Upshift Torque Management
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Solution Overview
Problem
Existing control devices for vehicle drive systems with superchargers and automatic transmissions often delay shift operations, leading to unsatisfied driver torque requests and increased shift shock, which deteriorates drivability due to inconsistent engine rotation speeds during upshifts.
Innovation Solution
A control device that increases supercharging pressure before the completion of an upshift, setting a target pressure based on the predicted engine operation state to ensure a smoother torque transition, while maintaining a predefined engine torque after the upshift to prevent delayed drive force increases, thus improving drivability by starting the supercharging pressure increase early and ensuring a sufficient grace period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upshift of the automatic transmission is delayed until the supercharging pressure increases, then the engine torque can be maintained, but the drive force request from the driver cannot be satisfied timely and shift shock increases
Solution Approach 1:
The control device starts increasing the supercharging pressure before the upshift is completed, rather than waiting for the upshift to finish. This preliminary action ensures that the supercharging pressure reaches the target value during the upshift process, allowing the engine torque to be maintained without delaying the shift operation, thereby resolving the contradiction between torque maintenance and shift response speed.
2Reliability
If the upshift is delayed to allow supercharging pressure to increase, then engine torque can be maintained, but drivability deteriorates due to inconsistent engine rotation speeds
Solution Approach 1:
By initiating the supercharging pressure increase before the upshift completion, the system ensures that the pressure reaches the target value in time, maintaining engine torque stability without causing inconsistent engine rotation speeds that would harm drivability.
Solution Approach 2:
The control device monitors the supercharging pressure and adjusts the increase rate based on the actual pressure level and the predicted engine operation state after upshift. This feedback mechanism ensures that the supercharging pressure reaches the target value at the appropriate time, maintaining both torque stability and smooth drivability during the transition.
3Speed
If the supercharging pressure increases quickly to satisfy drive force requests, then acceleration performance improves, but shift shock expands
Solution Approach 1:
The control device dynamically adjusts the supercharging pressure increase rate based on the actual engine operation state and the predicted state after upshift. By optimizing the increase rate in real-time, the system achieves quick acceleration performance while preventing excessive shift shock through controlled pressure adjustment.
Solution Approach 2:
The control device changes the supercharging pressure parameter dynamically during the upshift process, adjusting the increase rate based on the actual pressure level and predicted engine operation state. This parameter optimization allows the system to achieve both quick acceleration and minimal shift shock by finding the optimal pressure increase trajectory.
Data Source
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AI summary
Provided is a control device for a vehicle drive device, capable of improving the drivability of a drive device for a vehicle comprising an engine with a supercharger and an automatic transmission. When increasing the supercharging pressure (Pcmout) at the end of upshifting of the automatic transmission (12) to higher than at the start of upshifting, in order to increase the engine torque (Te) at end of upshifting to greater than at the start of upshifting, the control device starts to increase the supercharging pressure (Pcmout) before completion of upshifting and progresses the gear shift operation of the automatic transmission (12), such that the supercharging pressure (Pcmout) changes to a target supercharging pressure determined by a predicted engine operation state at the end of upshifting. Accordingly, when a time delay in the increase in supercharging pressure (Pcmout) occurs, that time delay is compensated for, and the drive force request by the driver is more readily fulfilled at end of upshifting. As a result, the drivability during said upshifting is improved.