Vehicle Drive Control Device Slipping Engagement Torque Management

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Solution Overview

Problem

In electric vehicle mode, existing control devices require a narrower torque region due to the need to secure separate torque for starting the internal combustion engine, limiting the torque that can be transferred from the rotary electric machine to the wheels.

Innovation Solution

A control device that executes second slipping control on the second engagement device and first slipping control on the first engagement device, lowering the rotational speed of the rotary electric machine, allowing torque conversion and transfer of inertia torque to the internal combustion engine, thereby reducing the torque needed from the rotary electric machine for engine start and expanding the electric mode's torque region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If torque is secured separately for starting the internal combustion engine in electric mode, then the internal combustion engine can be started reliably, but the torque region in which the electric mode is executable becomes narrower

Engineering Contradiction:

Improvereliability of internal combustion engine startVSAvoidtorque region for electric mode

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The first engagement device is controlled into a slipping engagement state before the internal combustion engine starts, allowing the rotary electric machine's rotational energy to be converted into torque through engagement pressure. This preliminary action enables torque transfer to the internal combustion engine side during the starting process, reducing the need to reserve torque separately for engine start in electric mode.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The engagement pressure of the first engagement device is controlled to adjust the torque transfer characteristics during the starting process. By varying the engagement pressure, the system can optimize the balance between torque transfer to the internal combustion engine and torque available for wheel drive in electric mode, thereby expanding the executable torque region.

Inventive Principle:

Principle #35Parameter changes

2Power

If maximum torque is transferred from the rotary electric machine to the wheels in electric mode, then the vehicle acceleration performance is improved, but insufficient torque remains to start the internal combustion engine

Engineering Contradiction:

Improvetorque transfer to wheelsVSAvoidcapability to start internal combustion engine

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The torque transfer path is segmented into two separate paths: one through the first engagement device to the internal combustion engine, and another through the second engagement device to the wheels. This segmentation allows the rotary electric machine to simultaneously transfer torque to both the internal combustion engine (for starting) and the wheels (for drive), enabling maximum torque utilization in electric mode while ensuring reliable engine start capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first engagement device acts as an intermediary mechanism that enables torque transfer from the rotary electric machine to the internal combustion engine during starting. By controlling this intermediary device into a slipping engagement state, the system can transfer torque to the engine without compromising the torque available for wheel drive, thus resolving the contradiction between maximum power transfer and engine start capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration enables the transfer of larger torque to the wheels during electric mode operation, extending the torque region in which the electric mode is executable and allowing earlier engine start while maintaining vehicle acceleration.

Implementation Method 1

the first engagement device which has been in a disengaged state is controlled into a slipping engagement state

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

Inertia torque as a reaction force against the reduction in rotational speed of the rotary electric machine is transferred to the internal combustion engine side via the first engagement device

Methodology Applied

Scientific EffectInertia: Inertia

Data Source

PatentUS10279687B2Control device for vehicle drive device

Publication Date: 2019.05.07 AISIN AW CO LTD

AI summary

A control device that includes an electronic control unit that is programmed such that, when the internal combustion engine is started by the rotary electric machine while output torque from the rotary electric machine is transferred to the wheels in a state in which rotation of the internal combustion engine has been stopped, the electronic control unit: executes second slipping control in which the second engagement device is controlled into a slipping engagement state, executes first slipping control in which the first engagement device which has been in a disengaged state is controlled into a slipping engagement state during execution of the second slipping control, and controls an engagement pressure of the first engagement device so as to lower a rotational speed of the rotary electric machine in the first slipping control.