Vehicle Driving Force Arbitration for Fuel-Cut Vibration Suppression
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Solution Overview
Problem
When transitioning from fuel cut to a non-implemented state, there is a delay in the vehicle's driving force following the driving force lower limit set by the powertrain actuator, leading to driveshaft twisting and vibrations, especially in vehicles with long driveshafts, due to requests for driving force exceeding the powertrain actuator's capability.
Innovation Solution
A control device with an electronic control unit that arbitrates requests from the driving assistance system, calculating a second request that does not exceed the driving force lower limit of the powertrain actuator, ensuring the actual driving force generated by the vehicle does not surpass this limit until reaching the powertrain actuator's capability, thereby preventing driveshaft twisting and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If requests for driving force exceeding the powertrain actuator's capability are allowed during fuel cut recovery, then the vehicle can respond quickly to driving assistance system requests, but driveshaft twisting and vibrations occur due to the delay in actual driving force following the requested driving force
Solution Approach 1:
The control device applies preliminary anti-action by detecting when the actual driving force lags behind the requested driving force during fuel cut recovery, and proactively suppressing subsequent requests for driving force that would exceed the powertrain actuator's capability. This prevents driveshaft twisting and vibrations before they occur, rather than reacting after the problem manifests.
Solution Approach 2:
The control device uses feedback by continuously monitoring the relationship between requested driving force and actual driving force during fuel cut recovery. When it detects that actual driving force has not yet caught up to requested driving force, it adjusts subsequent control commands to prevent exceeding the powertrain actuator's capability, thereby eliminating driveshaft twisting and vibrations.
2Use of energy by moving object
If the clutch is disengaged during coasting control, then fuel efficiency is improved, but torque fluctuation on the drivetrain causes shock and vibrations
Solution Approach 1:
The control device applies preliminary action by waiting for torque fluctuation to converge before disengaging the clutch during coasting control. This preparatory timing ensures that the drivetrain is stable when the clutch disengages, preventing shock and vibrations while still achieving fuel efficiency benefits from coasting control.
Solution Approach 2:
The control device uses parameter changes by monitoring torque fluctuation characteristics and using this information to determine the optimal timing for clutch disengagement. By changing the timing parameter based on torque fluctuation convergence, the system achieves both fuel efficiency and vibration suppression.
Data Source
AI summary
A control device installed in a vehicle comprising an electronic control unit configured to: accept a plurality of first requests from a driving assistance system; arbitrate the first requests; calculate a second request that is a physical amount that differs from the first requests based on a result of arbitration in which the first requests are arbitrated; and distribute the second request to at least one of a plurality of actuator systems, wherein the electronic control unit is configured to, when there is the first request requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, perform arbitration such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio.