Vehicle ECU Driving Force Variation Control
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Solution Overview
Problem
When the limitation on driving force is canceled, the variation in driving force corresponding to the accelerator pedal stroke amount can cause discomfort to the occupant due to unintended driving force variations.
Innovation Solution
The vehicle's Electronic Control Unit (ECU) limits the increase rate of driving-related physical amounts when the second CD mode is canceled, ensuring a controlled transition and minimizing driving force variation by adjusting the running power target value based on the requested power and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the limitation on driving force is canceled, then the requested amount of driving force can be increased according to accelerator pedal stroke, but driving force variation occurs that causes discomfort to the occupant
Solution Approach 1:
The patent applies dynamics by switching between different running modes (first running mode and second running mode) based on accelerator pedal stroke amount. When the pedal stroke exceeds a threshold, the system transitions from the first running mode with driving force limitation to the second running mode without limitation, enabling adaptive power delivery that responds to driver intent while maintaining comfort
Solution Approach 2:
The patent changes the parameter of driving force limitation based on accelerator pedal stroke amount. By detecting when the pedal stroke exceeds a predetermined threshold, the system modifies the running mode to alter the driving force characteristics, thereby eliminating unwanted variations while preserving the ability to deliver requested power
2Speed
If the requested amount of driving force is varied with accelerator pedal stroke, then driving responsiveness is improved, but unintended driving force variation occurs when limitation is canceled
Solution Approach 1:
The system dynamically adjusts the relationship between accelerator pedal stroke and requested driving force by implementing two distinct running modes. The transition between modes occurs at a predetermined pedal stroke threshold, allowing the system to maintain stable driving force characteristics during normal operation while enabling responsive power delivery when the driver demands higher acceleration
Data Source
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AI summary
An ECU 200 executes a program including the steps of, when the selection of a second CD mode has been canceled and there is a difference between a current value of running power and a target value of the running power after the cancellation of the selection of the second CD mode (YES in S100), turning on a limitation request flag for limiting an increase rate of running power Ptrv (S102), when there is not a difference between the current value and the target value (NO in S104), turning off the limitation request flag (S106), and when the limitation request flag is ON (YES in S108) and a stroke amount of an accelerator pedal has been increased (YES in S110), turning on an increase-in-stroke-amount determination flag for relaxing the limitation on the increase rate of the running power.