Vehicle Drive Device Uphill Reverse Suppression Control
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Solution Overview
Problem
Hybrid vehicles experience unintended vehicle reversal on uphill roads due to insufficient torque suppression when the capacitor is fully charged, making it difficult to prevent the vehicle from moving backward against the driver's intention.
Innovation Solution
A drive device with a control unit that estimates when the vehicle is reversing on an uphill road and discharges electric power from the capacitor to maintain an electrically chargeable state, allowing the rotating electric machine to generate increased torque for suppressing the vehicle's rotation by charging both the capacitor and secondary battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the capacitor is fully charged before reverse occurs, then the suppressing torque is reduced, but the vehicle reversal is not suppressed
Solution Approach 1:
The control unit performs preliminary discharging of the capacitor when reverse is predicted to occur (based on uphill road detection and brake release timing), ensuring the capacitor is in a chargeable state before the reverse happens. This preliminary action prevents the capacitor from being fully charged at the critical moment, maintaining the ability to generate sufficient suppressing torque.
Solution Approach 2:
The control unit continuously monitors the vehicle's operating conditions (road gradient, brake status, capacitor charge state) and adjusts the capacitor discharge timing based on feedback from these sensors. When the system predicts reverse will occur, it triggers capacitor discharge to maintain optimal charge state for torque suppression.
2Force
If the capacitor charges the generated electric power during reverse, then the suppressing torque increases, but the capacitor becomes fully charged and cannot accept more power
Solution Approach 1:
The system performs preliminary discharging of the capacitor before the reverse occurs, creating space in the capacitor to accept the regenerative energy that will be generated during reverse. This ensures the capacitor remains in a chargeable state throughout the reverse process, maximizing energy recovery while maintaining torque suppression.
Solution Approach 2:
The system temporarily discards some stored energy in the capacitor by discharging it before reverse, in order to recover the regenerative energy generated during reverse. This cyclic discarding and recovering process ensures the capacitor can continuously accept energy during reverse events while maintaining the electrical load needed for torque suppression.
3Quantity of substance
If the capacitor is in a fully charged state, then the energy storage is maximized, but the rotating electric machine cannot generate sufficient torque for reverse suppression
Solution Approach 1:
The control unit performs preliminary discharging of the capacitor when reverse is predicted (based on uphill road detection and brake release timing), ensuring the capacitor is in a chargeable state before the reverse happens. This maintains the electrical load necessary for the rotating electric machine to generate sufficient suppressing torque while still preserving overall energy storage capacity.
Solution Approach 2:
The system dynamically adjusts the capacitor's charge state based on real-time driving conditions. The capacitor transitions between charged and dischargeable states depending on whether reverse is predicted, allowing the system to optimize between energy storage and torque generation capabilities as conditions change.
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
The solution effectively increases the torque generated by the rotating electric machine, enabling better suppression of the vehicle's reverse motion on uphill roads by ensuring the capacitor remains in an electrically chargeable state and utilizing both the capacitor and secondary battery for power generation, thus preventing unintended vehicle reversal.
Implementation Method 1
a rotating electric machine for traveling the vehicle, connected to the drive shaft, for generating electric power with rotation of the drive shaft
Implementation Method 2
a capacitor connected to the rotating electric machine, for electrically charging electric power generated by the rotating electric machine
Data Source
AI summary
An object of the present invention is to suppress reverse of a vehicle on an up-hill road against an intention of a driver. A drive device for a vehicle according to the present invention includes: an estimator for estimating whether or not reverse of the vehicle occurs on an up-hill road; a rotating electric machine for generating electric power by rotation of a drive wheel in the vehicle when the vehicle reverses; a capacitor for electrically charging the electric power generated by the rotating electric machine; and a battery connected in parallel to the capacitor, wherein the estimator estimates that the reverse of the vehicle occurs when a current traveling road is an up-hill road and a vehicular speed is smaller than a threshold whereas the electric power of the capacitor is electrically discharged to the battery when the reverse of the vehicle is estimated and the amount of electric energy of the capacitor is greater than a certain threshold.