Hybrid Wheel Loader Power Management

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Solution Overview

Problem

Conventional wheel loaders face power deficiencies during excavating work, especially when engine revolution speed is low, leading to inefficient excavation and potential fuel consumption increases due to extra fuel injection to raise engine speed in time for excavating motions.

Innovation Solution

A hybrid wheel loader system that includes a motion detector and control device to estimate output power, increasing electric power from an electricity storage device to the traveling motor and accelerating the engine to ensure sufficient power for excavating work, thereby raising engine revolution speed before contact with the excavation object, reducing the likelihood of power deficiencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the engine revolution speed is raised in advance to ensure sufficient power for excavating work, then the power availability during excavation is improved, but the fuel consumption increases due to extra fuel injection

Engineering Contradiction:
Improvepower availability during excavationVSAvoidfuel consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The control device detects motion indicating approach to excavation object and performs preliminary engine acceleration before excavation begins. This preliminary action ensures the engine reaches required revolution speed in time for power-intensive excavation operations, avoiding power deficiency during actual work while managing fuel consumption through timely, targeted acceleration rather than continuous high-speed operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The motion detector provides real-time feedback about the vehicle's approach to the excavation object. The control device uses this feedback to dynamically adjust engine acceleration timing and magnitude, optimizing the balance between ensuring sufficient power availability and minimizing unnecessary fuel consumption by accelerating only when and to the extent needed

Inventive Principle:
Principle #23Feedback

2Productivity

If the vehicle velocity is maintained at high level during approach, then the operating efficiency is improved, but the engine revolution speed cannot follow up the velocity variations, causing power deficiency at excavation moment

Engineering Contradiction:
Improveoperating efficiencyVSAvoidpower availability at excavation
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

Based on motion detection feedback indicating approach to excavation object, the control device performs preliminary engine acceleration before the excavation moment. This allows the engine to reach required revolution speed in advance, ensuring power availability when excavation begins, while the vehicle can maintain high approach velocity for operational efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device dynamically adjusts engine acceleration based on real-time motion detection feedback. When approach to excavation object is detected, the system activates engine acceleration control; when approach is complete or work mode changes, the control is adjusted. This dynamic response allows the engine to adapt its revolution speed to match the varying power demands during different phases of the excavation cycle

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3093399B1Hybrid wheel loader
Publication Date: 2020.09.23 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3093399B1 patent drawingFigure 1~2
  • EP3093399B1 patent drawingFigure 3
  • EP3093399B1 patent drawingFigure 4~5

AI summary

A hybrid wheel loader includes a control device (200) that estimates output power of an engine (1) and an electricity storage device (11) when the hybrid wheel loader is inferred on the basis of output values of detectors (62, 63) to be traveling towards an object of excavation in order to perform an excavating work, and then, if the output power is less than target power considered necessary for the excavating work, accelerates the engine (1) to a target revolution speed while increasing the electric power supplied from the electricity storage device to a traveling motor (9). Accordingly, power necessary for excavation can be drawn from the engine even when the engine revolution speed is low and there is a fear of power deficiency occurring at the time of the excavating work.