Vehicle Drive Unit Reactivation Control During Coasting
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Solution Overview
Problem
When a vehicle is coasting due to a mistakenly deactivated power supply, sudden reactivation of the drive unit can lead to abrupt changes in driving force, making it difficult to control and potentially unsafe.
Innovation Solution
A controller is implemented to limit the driving force transmitted to the wheels based on the accelerator pedal operation, ensuring that the driving force does not suddenly increase when the drive unit is reactivated during coasting, by setting the accelerator opening degree to zero until the pedal is off and then gradually increasing the force in response to pedal operation, while lifting limits once a target force is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive unit is reactivated during coasting with the accelerator pedal operated, then the driving force rapidly recovers, but the driving force changes abruptly making the vehicle difficult to control
Solution Approach 1:
The patent applies dynamics by making the accelerator opening degree change dynamically over time rather than remaining static. Specifically, the accelerator opening degree is set to increase gradually from an initial value to a target value over a predetermined period after reactivation, rather than jumping immediately to the target value. This dynamic adjustment allows the driving force to recover smoothly while maintaining vehicle controllability.
Solution Approach 2:
The patent applies preliminary action by pre-setting the accelerator opening degree to a specific initial value (e.g., 1/4 to 1/2 of the target value) at the moment of reactivation, before gradually increasing it to the final target value. This preliminary setting prevents sudden full-power activation and allows for controlled, progressive engagement of the drive unit, resolving the contradiction between quick reactivation and smooth controllability.
2Speed
If the accelerator opening degree is increased immediately upon reactivation, then the driving force recovers quickly, but the sudden change in driving force creates safety issues
Solution Approach 1:
The patent applies beforehand cushioning by introducing a gradual increase period for the accelerator opening degree after reactivation. Instead of immediately setting the accelerator opening to its target value, the system allows it to increase progressively over a predetermined time period. This cushioning effect prevents sudden driving force changes that could harm vehicle stability and safety, while still achieving relatively quick reactivation.
Solution Approach 2:
The patent uses dynamics to transition the accelerator opening degree from a static immediate-setting approach to a dynamic gradual-increase approach. The accelerator opening degree changes over time according to a predetermined profile, smoothing out the driving force transition and eliminating harmful sudden changes while maintaining acceptable reactivation speed.
Data Source
AI summary
A vehicle includes a drive unit that generates a driving force for driving a driving wheel, and an accelerator pedal. In the vehicle, the driving force generated by the drive unit is controlled on the basis of an operation amount of the accelerator pedal, which is operated by a user. It is determined whether or not the vehicle carries out coasting with the drive unit unactivated. It is determined whether a predetermined condition that an activation command for the drive unit be received from the user with the accelerator pedal operated is fulfilled during the coasting. An actual driving force that is transmitted from the drive unit to the driving wheel is limited with respect to a driving force that is required by the user, in comparison with a case where the vehicle travels in a state other than the coasting, if the predetermined condition is fulfilled.