Capacitor-Based Torque-Down Control for Vehicle Gear Shift Shocks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle control systems face challenges in managing surplus power generated during torque-down control in automatic transmissions, leading to potential gear shift shocks and durability issues due to restricted torque-down rates, especially when using batteries with low charging/discharging rates.
Innovation Solution
A control device that includes an electronic control unit to determine if the automatic transmission is in a pre-gear shift state before torque-down control, using a rapid power storage device like a capacitor to absorb surplus power, thereby securing a predetermined free capacity and relaxing the restrictions on torque-down control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the down amount or the decrease rate of the electric motor torque is restricted to absorb surplus power in a battery with low charging/discharging rate, then surplus power can be absorbed, but gear shift shock may occur or gear shift time may be extended causing damage to durability of frictional members
Solution Approach 1:
The power storage device is segmented into two distinct components: a battery with large power storage capacity but slow charging/discharging rate, and a rapid power storage device (capacitor) with small power storage capacity but very fast charging/discharging rate. Each component handles different aspects of power management, with the capacitor specifically absorbing surplus power during torque-down control to prevent gear shift shocks while the battery provides overall energy storage.
Solution Approach 2:
The rapid power storage device (capacitor) acts as an intermediary between the electric motor and the battery. During torque-down control, when surplus power is generated, the capacitor quickly absorbs this power before it can cause damage to the transmission system. This intermediary component protects the frictional members from shock while enabling faster torque-down rates.
2Speed
If a rapidly chargeable/dischargeable capacitor is used to quickly absorb surplus power, then surplus power can be absorbed quickly, but the power storage capacity of the capacitor is small limiting its effectiveness
Solution Approach 1:
The power storage system is divided into two segments with complementary characteristics: the battery provides large power storage capacity for overall energy management, while the capacitor provides fast charging/discharging capability for immediate surplus power absorption. This segmentation allows each component to optimize its strengths without being constrained by the other's limitations.
Solution Approach 2:
The battery and rapid power storage device (capacitor) are merged into a hybrid power storage system that combines their respective advantages. The battery's large capacity compensates for the capacitor's limited storage, while the capacitor's fast response compensates for the battery's slow charging/discharging rate, creating a synergistic system that addresses both requirements simultaneously.
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 allows for quick absorption of surplus power without restricting torque-down rates, reducing the risk of gear shift shocks and extending the durability of frictional members, while minimizing the use restrictions of the rapid power storage device.
Implementation Method 1
The rapid power storage device is chargeable and dischargeable rapider than the battery, and is a capacitor, a flywheel power storage device, or the like
Implementation Method 2
Since the battery is a secondary battery, such as a lead battery, a lithium-ion battery, or a nickel-hydrogen battery, and is charged or discharged using a chemical reaction
Data Source
AI summary
It is determined whether or not an automatic transmission is in a pre-gear shift state determined in advance prior to a power-ON gear shift in which torque-down control is performed. When the automatic transmission is in the pre-gear shift state, since a required free capacity is secured in a capacitor, torque-down control of a second motor generator is performed in a gear shift, and even if surplus power is generated in a power supply circuit due to the torque-down control, the surplus power can be quickly absorbed using the capacitor. Since a required free capacity is secured in the capacitor by determining whether or not the automatic transmission is in the pre-gear shift state, a predetermined free capacity does not need to be secured constantly, normal capacitor storage control focusing on drivability or the like can be performed normally, and use restriction of the capacitor is minimized.