Engine Disconnect Clutch Torque Schedule Control

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Solution Overview

Problem

Hybrid vehicles face challenges in efficiently managing the torque of the engine disconnect clutch during engine starting events, particularly when the actual engine start time exceeds predetermined thresholds, affecting fuel efficiency and performance.

Innovation Solution

A controller is programmed to adjust the engine start torque apply schedule for the clutch to ensure the actual engine start time falls within target time ranges for subsequent engine start events, thereby optimizing the engine start process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine disconnect clutch uses a fixed torque apply schedule, then the control system is simple, but the actual engine start time may exceed target time ranges affecting fuel efficiency

Engineering Contradiction:

Improveengine start time consistencyVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The controller monitors the actual engine start time and compares it to target time ranges. When the actual start time falls outside the target range, the controller automatically adjusts the torque apply schedule for subsequent engine start events. This closed-loop feedback mechanism ensures consistent engine starting within target time ranges while maintaining fuel efficiency, without requiring complex manual intervention or system redesign.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The torque apply schedule is made dynamic rather than fixed. The controller modifies the torque apply schedule based on actual engine start performance, creating an adaptive control system. This dynamic adjustment allows the system to optimize engine start times for fuel efficiency while accommodating variations in operating conditions, resolving the contradiction between simplicity and reliability.

Inventive Principle:

Principle #15Dynamics

2Speed

If the engine disconnect clutch applies high torque during engine start, then the engine starts faster, but fuel efficiency may be compromised

Engineering Contradiction:

Improveengine start speedVSAvoidfuel efficiency

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The controller adjusts the torque apply schedule by modifying torque magnitude and timing parameters based on actual engine start performance. When engine start time exceeds target ranges, the controller optimizes the torque apply profile to achieve faster starting while minimizing fuel consumption. This parameter optimization resolves the contradiction between fast engine starting and fuel efficiency by finding the optimal torque application curve.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9950705B2Hybrid vehicle and method of controlling an engine disconnect clutch for engine start-up

Publication Date: 2018.04.24 FORD GLOBAL TECH LLC

AI summary

A vehicle includes an engine, a transmission, a clutch, and a controller. The clutch is configured to couple the engine and transmission during engine starts. The controller is programmed to alter an engine start torque apply schedule for the clutch such that the actual engine start time is less than the upper threshold time for a next engine start event. The controller may be further programmed to, in response to the actual engine start time being less than a lower threshold time for the engine start event, alter the engine start torque apply schedule for the clutch such the actual engine start time is greater than the lower threshold time for a next engine start event.