Hybrid Engine Torque Control for Idle-Stop Response Delay

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Hybrid electric vehicles experience a delay in vehicle start after releasing the idle-stop state due to the time required to generate engine RPM and transmission oil pressure for clutch control.

Innovation Solution

A method for controlling engine torque in hybrid electric vehicles involves transmitting torque restriction information based on engine coolant temperature to the engine control unit, restricting torque until clutch operation, and releasing it after a predetermined time if the clutch does not engage, allowing immediate clutch control hydraulic pressure formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine is restarted after idle-stop state, then the vehicle can resume operation, but there is a delay in vehicle start due to time required to generate engine RPM and transmission oil pressure

Engineering Contradiction:

Improvevehicle start speedVSAvoidvehicle start delay time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-generating clutch control hydraulic pressure using the clutch control hydraulic pressure generator before clutch engagement is actually needed. This advance preparation eliminates the delay that would otherwise occur while waiting for oil pressure to build up, allowing the clutch to engage immediately when the engine restarts after idle-stop state.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clutch control hydraulic pressure generator acts as an intermediary device that provides hydraulic pressure specifically for clutch control independently of the main transmission oil pressure system. This intermediary system ensures that clutch engagement can occur immediately without being constrained by the slower oil pressure generation process of the main transmission system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If torque restriction is applied based on engine coolant temperature, then engine durability is protected during cold start, but torque output is reduced during the restriction period

Engineering Contradiction:

Improveengine durabilityVSAvoidengine torque output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The torque restriction is implemented dynamically based on real-time engine coolant temperature conditions. The engine control unit continuously monitors temperature and adjusts torque output accordingly - applying restriction when temperature is low to protect the engine, and releasing restriction when temperature reaches optimal levels. This dynamic adjustment allows the system to balance engine protection with performance requirements at different operating conditions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7828696B2Method for controlling engine torque of hybrid electric vehicle with electronic throttle control

Publication Date: 2010.11.09 HYUNDAI MOTOR CO LTD

AI summary

A method for controlling engine torque of a hybrid electric vehicle with an electronic throttle control when an engine is restarted after an idle-stop state includes: transmitting torque restriction information to an engine control unit, outputting a restricted torque from the engine control unit using the torque restriction information, transmitting an input torque of the engine to a continuously variable transmission by a clutch operation according to a control of the engine control unit, and supplying a clutch control hydraulic pressure based on the input torque.