Hybrid Vehicle Driving Force Control for Mode Transition Shock
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Solution Overview
Problem
Conventional hybrid vehicles without a differential rotation absorbing element experience mode transition shock when transitioning from EV mode to HEV mode due to sudden increases in driving force, causing discomfort for drivers, especially when vehicle speed changes.
Innovation Solution
A driving force control device that limits the driving force transmitted to the wheels in the HEV mode according to the maximum outputable driving force in the EV mode during mode transitions, ensuring a smooth transition by controlling the hybrid vehicle's driving force control unit within the range of the maximum outputable driving force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the internal combustion engine is started and mode transitions from EV mode to HEV mode while traveling, then the driving force of the internal combustion engine is added to the driving force of the electric motor, but the total driving force transmitted to the drive wheels is suddenly increased, causing mode transition shock
Solution Approach 1:
The control device limits the driving force of the internal combustion engine at the moment of mode transition from EV mode to HEV mode. This preliminary restriction prevents the sudden increase in total driving force that would otherwise occur when the engine is started, thereby suppressing mode transition shock before it can affect the drive wheels.
Solution Approach 2:
The control device dynamically adjusts the driving force of the internal combustion engine based on the operating mode. During mode transition, the driving force is restricted to a predetermined value or below a predetermined threshold, and this restriction is maintained until the vehicle speed changes by a predetermined amount, creating a dynamic control strategy that adapts to changing operating conditions.
2Speed
If the mode transitions from EV mode to HEV mode because of a change in vehicle speed, then the driver's sensitivity to shock is high, but the driver is likely to experience discomfort
Solution Approach 1:
The control device anticipates mode transition by detecting changes in vehicle speed and preemptively restricting the internal combustion engine's driving force to a predetermined value or below a predetermined threshold. This preliminary action occurs before the actual mode transition, preventing shock from reaching the driver when their sensitivity is high due to speed changes.
Solution Approach 2:
The control device continuously monitors vehicle speed and uses this feedback to determine when to apply or release the driving force restriction. When vehicle speed changes by a predetermined amount, the control device adjusts the engine driving force accordingly, creating a closed-loop control system that responds to real-time operating conditions and prevents driver discomfort.
Data Source
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AI summary
To provide a driving force control device for a hybrid vehicle that does not have a differential rotation absorbing element, wherein shock that occurs when the mode transitions from the EV mode to the HEV mode is less likely to be felt, when the driver's sensitivity to shock is high. In a hybrid vehicle that does not have a differential rotation absorbing element in the drive system, a hybrid control module (21), which controls the driving force to the drive wheels (19) in accordance with the required driving force within the range of the maximum outputable driving force of the traveling drive source, limits the driving force transmitted to the drive wheels (19) in the HEV mode in accordance with the maximum outputable driving force in the EV mode at the time of the mode transition, when the mode transitions from an EV mode, in which only a first motor/generator (MG1) is used as the traveling drive source, to an HEV mode, in which the first motor/generator (MG1) and an internal combustion engine (ICE) are used as traveling drive sources, accompanying a change in the vehicle speed.