Hybrid Vehicle Creep Torque Control for Shift Quality
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Solution Overview
Problem
Hybrid electric vehicles experience deteriorated shift feel and increased fuel consumption due to torque variations when controlling creep torque, particularly during shifting from high to low gear stages and at low vehicle speeds.
Innovation Solution
A method and apparatus for controlling creep torque in hybrid electric vehicles by detecting vehicle speed and shift stage, applying creep torque factors based on shift stage and brake amount, and adjusting motor output to maintain creep torque at or below zero during shifting and low-speed conditions, while gradually increasing torque after shifting is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If creep torque is increased to improve shift feel during shifting, then shift quality improves, but fuel consumption deteriorates due to excessive torque output
Solution Approach 1:
The patent implements dynamic creep torque control by continuously adjusting torque output based on real-time detection of vehicle speed, shift stage, and brake amount. The control strategy transitions from static predetermined torque values to dynamic adjustment, optimizing the balance between shift feel and fuel consumption during different driving conditions.
Solution Approach 2:
The patent changes key operating parameters (creep torque magnitude, vehicle speed threshold, shift stage detection) to optimize performance. By modifying torque output parameters according to detected driving conditions, the system achieves improved shift feel while preventing excessive fuel consumption.
2Use of energy by moving object
If creep torque is sharply decreased at low speed to improve fuel consumption, then fuel efficiency improves, but shift feel deteriorates due to torque variation and driver discomfort
Solution Approach 1:
The patent applies different creep torque control strategies for different driving conditions (local conditions). Specifically, it distinguishes between low-speed conditions and shifting conditions, applying appropriate torque levels for each scenario rather than a uniform control approach, thereby maintaining fuel efficiency while preventing shift feel deterioration.
Solution Approach 2:
The patent detects shift stage changes in advance and prepares appropriate creep torque levels before the shift is complete. By anticipating the shift event and pre-adjusting torque output, the system prevents sudden torque variations that would cause driver discomfort while maintaining fuel efficiency.
3Reliability
If creep torque is increased before stopping to maintain vehicle motion, then vehicle stopping performance improves, but shift feel deteriorates due to torque variation during shifting
Solution Approach 1:
The patent implements dynamic adjustment of creep torque based on real-time detection of shift stage and vehicle speed. During the shifting process, the system dynamically reduces torque output to prevent variations that would deteriorate shift feel, while maintaining adequate torque for stopping performance when shifting is not in progress.
Data Source
AI summary
An apparatus and a method for controlling a creep torque of a hybrid electric vehicle that outputs the creep torque to improve shift feel and fuel consumption of the hybrid electric vehicle, may include the method for controlling a creep torque of a hybrid electric vehicle that may include detecting data of the hybrid electric vehicle for controlling the creep torque, determining whether a vehicle speed is greater than or equal to a predetermined speed and the hybrid electric vehicle is shifting from a current shift stage to 1 stage when the current shift stage is 3 stage or 2 stage, applying a creep torque factor depending on a shift stage and a brake amount when the hybrid electric vehicle is shifting from 3 stage or 2 stage to 1 stage, and controlling a motor to output the creep torque to which the creep torque factor is applied.