Hybrid Engine Start Torque Control During Starter Failure

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Solution Overview

Problem

Hybrid electric vehicles experience acceleration disconnection sensations during engine start due to torque shocks when the starter motor fails, particularly during rapid acceleration, as existing methods fail to compensate for engine clutch load effectively.

Innovation Solution

A method and system that predict and adjust the driving motor's torque by subtracting the engine clutch load from its maximum torque to prevent torque shocks, ensuring smooth engine start by controlling the engine clutch pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine clutch is connected during rapid acceleration when the starter motor fails, then the engine can be started using the driving motor, but torque shocks and acceleration disconnection sensations occur due to uncompensated engine clutch load

Engineering Contradiction:

Improveengine starting capabilityVSAvoidacceleration linearity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The controller predicts the engine clutch load before connecting the engine clutch during rapid acceleration. By calculating the required load compensation in advance based on driving conditions, the system prepares the appropriate torque adjustment value before the clutch engagement occurs, preventing torque shocks and acceleration disconnection sensations while ensuring reliable engine starting

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller dynamically adjusts the driving motor's torque output by changing the torque command value in real-time. During rapid acceleration when the engine clutch is connected, the system modifies the torque parameter to compensate for the engine clutch load, maintaining smooth acceleration and preventing disconnection sensations while enabling engine starting capability

Inventive Principle:

Principle #35Parameter changes

2Power

If the driving motor outputs maximum torque during rapid acceleration to start the engine, then the engine can be started, but the engine clutch load causes abrupt vehicle stop sensation and deteriorates acceleration linearity

Engineering Contradiction:

Improvedriving motor torqueVSAvoidacceleration smoothness

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The controller continuously monitors driving conditions and calculates the engine clutch load based on real-time parameters such as vehicle speed, acceleration rate, and driving motor torque output. This feedback mechanism allows the system to dynamically adjust the torque command value to compensate for engine clutch load, maintaining acceleration smoothness and preventing abrupt vehicle stop sensations while ensuring the driving motor has sufficient power to start the engine

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9162683B2Method and system for starting engine during failure of starter motor of hybrid electric vehicle

Publication Date: 2015.10.20 HYUNDAI MOTOR CO LTD

AI summary

A method of starting an engine when a starter motor of a hybrid electric vehicle has a failure includes identifying a request for starting the engine in a state where the starter motor has the failure. When the request for starting the engine is made in the state where the starter motor has the failure, a torque or a load of an engine clutch and a pressure of the engine clutch are determined. A torque of a driving motor is set to a smaller torque between a driving motor demanded torque and a torque obtained by subtracting the torque of the engine clutch from a maximum torque of the driving motor. The engine starts with the set torque of the driving motor while controlling the engine clutch.