Hydrostatic Transmission Valve Layout for Low-Loss Energy Management

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Solution Overview

Problem

Existing hydraulic transmission systems for work vehicles are costly and inefficient due to their complex design with a large number of components and valves, leading to significant pressure drops and reduced efficiency.

Innovation Solution

A hydraulic energy management system for hydrostatic transmission that uses a reduced number of components, including a pump, hydraulic motors, accumulators, and a hydraulic connection module with electro-actuated proportional ON-OFF valves, to manage fluid flow and torque, optimizing operations while minimizing pressure drops and component complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a high number of valves and components are used to manage hydraulic operations, then multiple operations (forward/reverse motion, boost, energy recovery) can be achieved, but the system becomes costly and bulky with significant pressure drops

Engineering Contradiction:
Improvemultiple operations capabilityVSAvoidnumber of components and valves
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single electro-hydraulic unit that performs multiple functions previously requiring separate valves and components. The unit integrates directional control, pressure regulation, and flow management capabilities into one compact device, enabling forward/reverse motion, power boost, and energy recovery operations without needing a high number of separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple hydraulic control functions into a single electro-hydraulic unit. By combining what were previously separate valves (directional control valve, pressure relief valve, flow control valves) into one integrated component, the system reduces overall component count, minimizes connection points, and decreases pressure drops while maintaining full operational versatility.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a high number of valves are used to control hydraulic circuit, then multiple operations can be managed, but pressure drops increase and efficiency decreases

Engineering Contradiction:
Improveoperation control capabilityVSAvoidpressure drops
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

By merging multiple valve functions into a single electro-hydraulic unit with integrated internal passages, the patent eliminates numerous external connections and junctions where pressure drops occur. The integrated design reduces flow path length and minimizes turbulence, thereby reducing energy losses while maintaining the ability to control multiple operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the essential control functions from a complex array of separate valves and consolidates them into one unit. By taking out only the necessary control capabilities and implementing them in a streamlined integrated design, the system achieves operation control with minimal pressure drops, removing unnecessary intermediate components that caused energy losses.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If a hydro-electrical manifold with many components is used, then multiple operations can be managed, but the system becomes costly and bulky

Engineering Contradiction:
Improveoperation management capabilityVSAvoidsystem bulk and cost
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The electro-hydraulic unit is designed as a universal component that handles multiple operations (directional control, pressure regulation, flow management) that previously required a bulky hydro-electrical manifold with many separate components. This multi-functional design reduces system bulk and cost while maintaining full operation management capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By merging the functions of multiple separate components (valves, accumulators, manifolds) into a single integrated electro-hydraulic unit, the patent significantly reduces system bulk and component count. The integrated design eliminates the need for a large hydro-electrical manifold while maintaining the ability to manage all required operations.

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

The system achieves efficient energy management with fewer components, reducing costs and pressure drops, enabling multiple operating modes with improved efficiency and versatility for various vehicles.

Implementation Method 1

hydraulic energy, stored in a working fluid in form of pressure

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

electro-actuated proportional ON-OFF valves, to manage fluid flow and torque

Methodology Applied
Scientific EffectFluid flow control: Valve

Implementation Method 3

a first accumulator (4) and a second accumulator (5), fluidly connected together

Methodology Applied
Scientific EffectHydraulic accumulator: Hydraulic Accumulator

Implementation Method 4

a pump (2), connected to an engine (7)... transform a hydraulic energy, stored in a working fluid in form of pressure, into mechanical energy

Methodology Applied
Scientific EffectHydraulic pump: Pump

Implementation Method 5

hydraulic motors which are used for a plurality of operation such as movement of the vehicle; such hydraulic motors transform a hydraulic energy, stored in a working fluid in form of pressure, into mechanical energy

Methodology Applied
Scientific EffectHydraulic motor: Turbine

Data Source

PatentEP3830453B1Hydraulic energy management system for hydrostatic transmission
Publication Date: 2024.01.31 CNH IND ITALIA SPA
  • EP3830453B1 patent drawingFigure 1
  • EP3830453B1 patent drawingFigure 2
  • EP3830453B1 patent drawingFigure 3

AI summary

Hydraulic energy management system for hydrostatic transmission for a work vehicle, comprising - a pump (2) carried by an engine (7) and at least a hydraulic motor (3), pump (2) d said motor (3) being configured so operate with a fluid in pressure passing through themselves, - a first and a second accumulator (4, 5) configured to store fluid in pressure, - a hydraulic connection module (6) fluidly connecting together pump (2), motor (3) and first and second accumulators (4, 5), the module comprising at least seven ON-OFF valves and a peculiar layout configured to allow a versatile control of the hydraulic transmission.