Power Split Device for Hybrid Vehicle Auxiliaries

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Solution Overview

Problem

Existing drive arrangements for auxiliary equipment in vehicles fail to efficiently operate when the internal combustion engine is shut down, particularly when the vehicle is moving or stopped, leading to inefficiencies and the need for oversized electrical systems.

Innovation Solution

A drive arrangement featuring a power split device with three separate couplings, including an auxiliary electric machine connected to one coupling, allowing torque delivery to auxiliary equipment, and means to disconnect the input shaft from the gearbox, enabling operation during engine shutdown and vehicle movement or stoppage without interfering with the driveline.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If auxiliary equipment is mechanically driven by the internal combustion engine, then the equipment operates reliably, but the vehicle cannot move with the engine shut down and electrical systems must be oversized

Engineering Contradiction:

Improvevehicle operation modesVSAvoidelectrical system size

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The power split device enables the auxiliary equipment to be driven by multiple power sources (internal combustion engine through input shaft, or electric machine through output shaft), making the drive system universal and adaptable to different operating conditions including engine shutdown scenarios

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If electrical drive is used for auxiliary equipment, then the vehicle can move with engine shut down, but the electrical system must be oversized due to safety issues and low efficiency

Engineering Contradiction:

Improveengine shutdown operationVSAvoidelectrical system capacity

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The power split device acts as an intermediary mechanism that allows torque from either the input shaft (engine) or output shaft (electric machine) to be transmitted to the auxiliary equipment, enabling efficient power transfer without requiring an oversized electrical system

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If a differential is used to drive auxiliary equipment from both input and output shafts, then simultaneous drive is achieved, but torque cannot be delivered when the engine is shut down and vehicle is stopped

Engineering Contradiction:

Improveauxiliary equipment drive capabilityVSAvoidoperation during shutdown

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The power split device separates the drive paths into distinct couplings (first coupling to input shaft, second coupling to output shaft, third coupling to auxiliary equipment), allowing selective engagement of different power sources based on operating conditions including engine shutdown scenarios

Inventive Principle:

Principle #1Segmentation

4Reliability

If an auxiliary electric machine is added to the power split device, then torque can be delivered during engine shutdown, but the device complexity increases

Engineering Contradiction:

Improveoperation during shutdownVSAvoidpower split device structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary electric machine is integrated into the existing power split device architecture, merging its function with the differential mechanism to provide torque delivery during engine shutdown without creating a completely separate drive system

Inventive Principle:

Principle #5Merging (Combining)

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

Enables efficient operation of auxiliary equipment using either the internal combustion engine or electric machine, reducing the need for oversized electrical systems and allowing downsizing of the electric machine, while maintaining normal driveline operation.

Implementation Method 1

an auxiliary electric machine connected to one of the couplings of the power split device, adapted to deliver torque to said at least one auxiliary equipment

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a power split device having no more than three separate input/output couplings, wherein a first coupling is connected to the input shaft, a second coupling is connected to the output shaft, and a third coupling is connected to said at least one auxiliary equipment

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS9556942B2Drive arrangement for vehicle auxiliaries

Publication Date: 2017.01.31 VOLVO TRUCK CORP

AI summary

A drive arrangement for a least one auxiliary equipment of a hybrid vehicle includes a gearbox having at least one input shaft connected to a drive internal combustion engine and one output shaft connected to driven wheels of the vehicle. The drive arrangement includes a power split device having no more than three separate input/output couplings, with a first coupling connected to the input shaft, a second coupling connected to the output shaft, and a third coupling connected to the at least one auxiliary equipment. The drive arrangement includes an auxiliary electric machine connected to one of the couplings of the power split device, and adapted to deliver torque to the at least one auxiliary equipment. The drive arrangement further includes an arrangement to disconnect the first coupling from the input shaft of the gearbox.