Hybrid Vehicle Charging Control for Low-Torque Drivability
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Solution Overview
Problem
The existing control apparatus for vehicles, particularly in hybrid electric vehicles, experiences reduced drivability due to fluctuations in drive power during automatic drive control, especially at low speeds, as the engine torque increases significantly, leading to discomfort for the driver and potential noise issues.
Innovation Solution
The control apparatus adjusts the charging amount based on the requested drive torque, setting it to a smaller amount when the torque is small and larger when it's high, and switches between basic and variable charging amounts depending on the vehicle's speed and charged state, while using creep torque at low speeds to reduce engine rotational speed and torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the charging amount is increased to improve charging performance, then the charging efficiency is improved, but the drive power fluctuation increases causing reduced drivability
Solution Approach 1:
The charging amount is dynamically adjusted based on the requested drive torque. When the requested drive torque is small, the charging amount is limited to a smaller value. When the requested drive torque is large, the charging amount can be increased. This dynamic adjustment resolves the contradiction by making the charging system adaptive to real-time driving conditions rather than using a fixed charging strategy.
Solution Approach 2:
The control apparatus changes the parameter of charging amount based on the parameter of requested drive torque. By establishing a relationship where charging amount varies with drive torque levels, the system optimizes both charging efficiency and drivability simultaneously - achieving higher charging when drive torque is available while preventing drive power fluctuation when drive torque is small.
2Quantity of substance
If the engine torque is increased to compensate for charging control, then the charging amount is improved, but the drive power fluctuation causes discomfort to the driver
Solution Approach 1:
The system takes preliminary anti-action by proactively limiting the charging amount when the requested drive torque is small, before the drive power fluctuation can occur. Instead of compensating after fluctuation happens, the control apparatus prevents the fluctuation by adjusting the charging amount in advance based on the drive torque conditions, thereby eliminating the harmful effect before it affects drivability.
3Ease of operation
If the rate of change of charging amount is reduced to suppress drive power fluctuation, then drivability is improved, but the charging performance is insufficient
Solution Approach 1:
Rather than uniformly reducing the rate of change of charging amount, the system dynamically adjusts the charging amount based on the requested drive torque. This allows the charging rate to be high when drive torque is large (maintaining charging performance) while being limited when drive torque is small (maintaining drivability), thus resolving the contradiction through conditional dynamic control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces drivability issues by minimizing drive power fluctuations, ensuring efficient charging performance, and preventing electric power insufficiency, while maintaining comfort and reducing noise during automatic driving.
Implementation Method 1
a rotating machine serving as at least an electric power generator... to cause the rotating machine to generate an electric power by driving and rotating the rotating machine by the engine
Data Source
AI summary
A control apparatus for a vehicle that includes an engine as a drive power source, a rotating machine as an electric power generator, and an electric storage device. The control apparatus executes an automatic drive control for automatically controlling a torque of the drive power source in accordance with a requested drive torque without requiring an acceleration/deceleration operation by a driver of the vehicle. During an engine running of the vehicle, the rotating machine is rotated by the engine to generate an electric power, and a charging amount, by which the electric storage device is to be charged, is controlled by controlling the electric power generated by the rotating machine. The control apparatus is configured, during an automatic driving of the vehicle, to set the charging amount such that the charging amount is smaller when the requested drive torque is small than when the requested drive torque is large.