Braking Force Control for Shift Shock Reduction
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Solution Overview
Problem
During vehicle coasting, the independent control of gear shift and regenerative power generation leads to shift shocks due to temporary instability in gear ratio and output torque, deteriorating riding comfort.
Innovation Solution
A braking force control apparatus that predicts the timing of gear shifts in a stepped automatic transmission and stops regenerative power generation before the shift occurs, based on vehicle speed and battery state, to prevent regenerative power generation from stopping during gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If regenerative power generation and gear shift control are executed independently, then control simplicity is improved, but shift shock occurs due to torque instability during gear shift transition
Solution Approach 1:
The control apparatus predicts the timing of gear shift operations in advance and stops regenerative power generation before the gear shift occurs. This preliminary action prevents torque instability during the gear shift transition period, eliminating shift shock while maintaining independent control of the two systems.
Solution Approach 2:
The control apparatus uses vehicle speed information to predict future gear shift timing and adjusts regenerative power generation accordingly. This feedback mechanism allows the system to anticipate and prevent shift shock before it occurs, while keeping the control systems independently structured.
2Object-affected harmful factors
If regenerative power generation is stopped during gear shift, then shift shock is reduced, but energy recovery efficiency decreases
Solution Approach 1:
Regenerative power generation is stopped in advance before gear shift occurs, rather than during the shift itself. This timing optimization minimizes energy loss while preventing shift shock, as the generator resumes power generation immediately after the gear shift completes.
Solution Approach 2:
The control apparatus changes the operational state of the generator based on predicted gear shift timing. By dynamically adjusting the generator's operating parameters (on/off state) according to the predicted gear shift event, the system optimizes both comfort and energy recovery efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces shift shocks and enhances riding comfort by ensuring a smooth transition during gear shifts in the coasting state.
Implementation Method 1
a regenerative generator (300) capable of performing regenerative power generation
Data Source
AI summary
A braking force control apparatus includes: a prediction unit that predicts a time from a present time until a next start of the gear shift operation in the stepped automatic transmission based on a speed of the vehicle; an acquisition unit that acquires a state of a battery charged by a regenerative power generation of the regenerative generator; and a control unit that stops the regenerative power generation by the regenerative generator before the gear shift of the stepped automatic transmission is started, when it is determined, during the regenerative power generation by the regenerative generator, that the regenerative power generation by the regenerative power generator may be stopped due to the state of the battery during the gear shift operation of the stepped automatic transmission, based on a prediction result by the prediction unit and the state of the battery acquired by the acquisition unit.