Driveline Disconnect Clutch Control During Hybrid Engine Pull-Up

Solution Overview

Problem

The torque transferring capacity of the driveline disconnect clutch in hybrid vehicles is inconsistent during engine pull-up requests, particularly when the torque converter impeller speed is low and the electric transmission fluid pump is activated, leading to driveline torque disturbances.

Innovation Solution

Deactivating the electric transmission fluid pump in response to an engine pull-up request allows for more consistent fluid pressure delivery to the driveline disconnect clutch, improving the torque transfer capacity and reducing driveline torque disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the electric transmission fluid pump is activated to supply sufficient capacity to cool the electric machine, then the cooling capacity is improved, but the torque transfer capacity of the driveline disconnect clutch becomes inconsistent

Engineering Contradiction:

Improveelectric machine cooling capacityVSAvoidtorque transfer capacity consistency

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The system dynamically controls the operation state of the electric transmission fluid pump based on real-time detection of engine pull-up requests. The controller receives the pull-up request signal and adjusts the pump's operation accordingly, transitioning from a static always-on state to a dynamic controlled state that adapts to engine starting conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller deactivates the electric transmission fluid pump in advance upon receiving an engine pull-up request, before the engine actually starts. This preliminary action prevents the pump from interfering with clutch engagement during the critical engine starting phase, ensuring consistent torque transfer capacity from the outset.

Inventive Principle:

Principle #10Preliminary action

2Stress or pressure

If the electric transmission fluid pump is activated, then fluid pressure capacity is improved, but driveline torque disturbances occur during engine start

Engineering Contradiction:

Improvefluid pressure capacityVSAvoiddriveline torque disturbances

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The controller deactivates the electric transmission fluid pump in advance upon receiving an engine pull-up request, before the engine actually starts. This preliminary action prevents the pump from interfering with clutch engagement during the critical engine starting phase, ensuring consistent torque transfer capacity from the outset.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The electric transmission fluid pump is temporarily removed from the active system during engine starting operations. By deactivating the pump when a pull-up request is detected, the system extracts the potential source of torque disturbances from the driveline, allowing clean engine starts without pump-induced fluctuations.

Inventive Principle:

Principle #2Taking out (Extraction)

3Quantity of substance

If the electric transmission fluid pump operates during engine pull-up, then fluid supply capacity is improved, but engine start repeatability decreases

Engineering Contradiction:

Improvefluid supply capacityVSAvoidengine start repeatability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The controller deactivates the electric transmission fluid pump in advance upon receiving an engine pull-up request, before the engine actually starts. This preliminary action prevents the pump from interfering with clutch engagement during the critical engine starting phase, ensuring consistent torque transfer capacity from the outset.

Inventive Principle:

Principle #10Preliminary action

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 results in more repeatable engine starts, reduced driveline torque disturbances, simplified torque capacity control for the driveline disconnect clutch, and improved vehicle drivability.

Implementation Method 1

fluid pressure that builds in the driveline disconnect clutch and is supplied by a mechanically driven transmission fluid pump

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

the electric transmission fluid pump may be activated to supply sufficient capacity to cool an electric machine

Methodology Applied

Scientific EffectFluid cooling: Heat Exchanger

Data Source

PatentUS12304457B2System and method for starting an engine

Publication Date: 2025.05.20 FORD GLOBAL TECH LLC

AI summary

Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, an electrically driven transmission fluid pump may be deactivated in response to an engine pull-up request so that a driveline disconnect clutch may provide more consistent torque transfer capacity during closing of the driveline disconnect clutch.