Hybrid Vehicle Clutch Control Gradient Strategy
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Solution Overview
Problem
The existing control methods for hybrid vehicles cause a trade-off between acceleration performance and engagement shock when shifting the second clutch from a slip state to a full engagement state, as a steep increase gradient improves acceleration but worsens shock, while a gentle gradient suppresses shock but compromises acceleration.
Innovation Solution
A control device with a second clutch slip amount controlling section that increases the transmission torque capacity at a first gradient and then transitions to a gentler second gradient, optimizing acceleration performance while minimizing engagement shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the increase gradient of transmission torque capacity is set to be steep to improve acceleration performance, then acceleration performance is improved, but engagement shock occurs at the time of full engagement
Solution Approach 1:
The increase gradient of transmission torque capacity is segmented into two distinct phases: a first increase gradient (steeper) applied when the second clutch is in the slip state, and a second increase gradient (gentler) applied when transitioning to the full engagement state. This segmentation allows the system to prioritize acceleration performance during the slip phase while preventing engagement shock during the transition phase, thereby resolving the technical contradiction between acceleration performance and engagement shock suppression.
2Object-generated harmful factors
If the increase gradient is set to be gentle to suppress engagement shock, then engagement shock is suppressed, but acceleration performance deteriorates
Solution Approach 1:
The control system dynamically adjusts the increase gradient of transmission torque capacity based on the operational state of the second clutch. When the clutch is in the slip state, a steeper first increase gradient is applied to maximize acceleration performance. When transitioning to the full engagement state, the system dynamically switches to a gentler second increase gradient to suppress engagement shock. This dynamic adjustment strategy resolves the contradiction by adapting the gradient selection to the specific operational phase.
Data Source
AI summary
Present invention provides a control device for hybrid vehicle which can ensure acceleration performance while suppressing second clutch engagement shock at engine start. The control device has second clutch (CL2) which is interposed between motor/generator (MG) and driving wheels (rear-left and right wheels RL, RR) and whose transmission torque capacity is variable, a second clutch slip amount controlling section (400b) performing full engagement operation that shifts second clutch (CL2) from slip state to full engagement state at a time when lock-up condition of the second clutch (CL2) is satisfied (S107) in the slip state of the second clutch (CL2). The second clutch slip amount controlling section (400b) first increases transmission torque capacity of second clutch (CL2) at first increase gradient (R1) (S109) and subsequently increases the transmission torque capacity of the second clutch (CL2) at second increase gradient (R2) that is gentler than the first increase gradient (R1) (S111).