Electric PTO System Decoupling Engine and Shaft Speed

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Solution Overview

Problem

Conventional power take-off (PTO) systems in vehicles are limited by the need for mechanical coupling to the internal combustion engine, restricting engine efficiency at partial loads, maximum torque, and ground speed, and limiting PTO shaft placement.

Innovation Solution

A PTO system utilizing an energy storage device and electrical drive systems to supply independent mechanical power to PTO shafts, decoupled from the engine, allowing for independent control of rotational speed and direction, and energy recapture during braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine is mechanically coupled to the PTO shaft via clutch and gearbox to provide fixed PTO shaft speed, then the PTO shaft rotation speed is controlled, but the engine efficiency is reduced at partial load operation and the maximum torque or power that can be supplied is limited

Engineering Contradiction:

ImprovePTO shaft rotation speedVSAvoidengine efficiency

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical coupling system (clutch and gearbox) with an electrical coupling system. The engine drives a generator that converts mechanical energy to electrical energy, which is then stored in an energy storage device and used to power an electric motor that drives the PTO shaft. This substitution allows independent control of engine speed and PTO shaft speed, resolving the contradiction by enabling the engine to operate at optimal efficiency points while the PTO shaft maintains required rotation speeds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary electrical energy storage system between the engine and PTO shaft. The generator converts engine mechanical energy to electrical energy, the energy storage device stores and regulates this energy, and the electric motor converts it back to mechanical energy for the PTO shaft. This intermediary system acts as a buffer that decouples the engine speed from PTO shaft speed, allowing each to operate independently at their optimal points.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the PTO shaft is mechanically coupled to the engine, then the PTO system can be implemented, but the number of locations where the PTO system can be employed is limited by engine location

Engineering Contradiction:

ImprovePTO shaft placement flexibilityVSAvoidmechanical coupling arrangement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical coupling arrangement with an electrical energy transmission system. Electrical energy can be transmitted through wires to any location on the vehicle, eliminating the constraint of engine location on PTO shaft placement. This substitution dramatically increases adaptability and versatility, allowing PTO shafts to be positioned anywhere on the vehicle without complex mechanical linkages.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If a clutch and gearbox arrangement is used to couple the PTO shaft to the engine, then the PTO shaft speed is controlled, but the device complexity increases and the number of components increases

Engineering Contradiction:

ImprovePTO shaft rotation speedVSAvoidclutch and gearbox arrangement

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical clutch and gearbox arrangement with a simpler electrical energy conversion system. The generator, energy storage device, and electric motor provide speed control through electrical regulation rather than mechanical gear changes, significantly reducing device complexity while maintaining or improving speed control capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution enhances engine efficiency, allows for flexible PTO shaft placement, and improves fuel efficiency by enabling independent operation of the engine speed from PTO shaft speed, while also recapturing energy during braking.

Implementation Method 1

each of the at least one electrical drive systems configured to convert the electrical power to a desired mechanical power

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

an energy storage device configured to supply electrical power

Methodology Applied

Scientific EffectElectrical energy storage: Electrical Accumulator

Data Source

PatentUS8115334B2Electrically driven power take-off system and method of manufacturing same

Publication Date: 2012.02.14 BUNKER HILL TECHNOLOGIES LLC

AI summary

A system and method for operating power take-off (PTO) systems aboard hybrid and electric systems and vehicles is disclosed. The PTO system includes an energy storage device configured to supply electrical power and at least one electrical drive system electrically connected to the energy storage device to receive the electrical power, with each of the at least one electrical drive systems configured to convert the electrical power to a desired mechanical power. The PTO system also includes at least one PTO shaft mechanically connected to each of the at least one electrical drive systems that is driven by the mechanical power to generate a mechanical output, with the mechanical output of each of the at least one PTO shafts being independently controllable from the mechanical output of other PTO shafts.