Vehicle Driving Force Ramp Control After Range Switching
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Solution Overview
Problem
Vehicles equipped with mechanisms to hold braking force before starting may fail to start smoothly when the order of range switching and accelerator pedal operation is reversed, leading to sudden starting or inability to move on uphill roads.
Innovation Solution
A driving force control method that limits the upper limit of the driving force to a value larger than the holding threshold but smaller than the required force, and adjusts the increase gradient to prevent sudden starting, using a control unit to calculate the driver's required driving force based on the accelerator pedal operation and employing a holding device to release the braking force when the driving force exceeds the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the driving force is limited to prevent sudden starting, then sudden starting is suppressed, but the vehicle cannot move forward on uphill roads
Solution Approach 1:
The patent applies dynamics by making the driving force limitation adjustable rather than fixed. The control unit dynamically changes the upper limit value based on detected vehicle state (horizontal vs. uphill). When uphill is detected, the limitation is relaxed or canceled, allowing sufficient driving force to overcome gravity and prevent rollback while still providing protection against sudden starting on level ground.
Solution Approach 2:
The patent changes the parameter of driving force upper limit based on operating conditions. The control unit modifies the limitation parameter according to the vehicle's inclination state, using sensors to detect whether the vehicle is on an uphill slope. This parameter adaptation allows the system to optimize between preventing sudden starting and ensuring adequate starting capability on inclines.
2Ease of operation
If the holding threshold value is decreased to allow vehicle starting, then the vehicle can start, but the vehicle may rollback on uphill roads
Solution Approach 1:
The patent makes the holding threshold dynamically adjustable based on vehicle state. When the control unit detects that the vehicle is on an uphill slope, it adjusts the holding threshold to prevent rollback. This dynamic adjustment ensures that the holding mechanism provides sufficient force to counteract gravity on inclines while allowing normal operation on level ground.
Solution Approach 2:
The patent changes the holding threshold parameter according to the detected uphill condition. The control unit modifies this critical parameter based on sensor input regarding vehicle inclination, enabling the system to adapt the holding force to match the gravitational component acting on the vehicle during startup on slopes.
3Speed
If the driving force increases rapidly to overcome holding force, then the vehicle can start, but sudden starting occurs
Solution Approach 1:
The patent applies preliminary action by having the control unit detect the driver's intent to start (accelerator pedal operation) before the vehicle actually moves. Upon detecting this preliminary action, the control unit proactively adjusts the driving force upper limit to an appropriate value that prevents sudden starting while still enabling smooth acceleration. This advance preparation ensures controlled vehicle response from the moment the driver intends to move.
Solution Approach 2:
The patent implements feedback by continuously monitoring the accelerator pedal operation amount and using this information to adjust the driving force limitation. The control unit receives feedback from the pedal sensor and dynamically modifies the upper limit of driving force accordingly, creating a closed-loop control system that prevents sudden starting while responding to driver intent.
Data Source
AI summary
When an accelerator pedal operation amount is large enough to generate a driving force after switching from a stopping range to a starting range is performed, in order to prevent a sudden starting immediately after the range switching, an upper limit of the driving force of a driving source is limited to a driving force larger than a holding threshold value for releasing holding of a stopping state of a vehicle and smaller than a required driving force based on the accelerator pedal operation amount.