Tractor Hybrid Power System for Fuel Savings and Engine Efficiency
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Solution Overview
Problem
Agricultural tractors face challenges in reducing emissions and improving efficiency due to different power demand characteristics compared to automotive vehicles, and existing hybrid systems are not effectively adapted for tractors, leading to inefficiencies in power transmission and engine sizing.
Innovation Solution
A hybrid power system for tractors incorporating an internal combustion engine, an electrical generator, and electrical motors, with a battery-connected motor/generator system that allows for both mechanical and electrical power transmission, enabling efficient power delivery to wheels and implements through serial and parallel hybrid technologies, optimizing engine operation around maximum torque for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a traditional mechanical transmission system is used to deliver power from the engine to the wheels, then the power transmission is direct and simple, but the engine cannot operate continuously at optimal efficiency points and the system lacks adaptability to varying power demands
Solution Approach 1:
The patent replaces the traditional mechanical transmission system with an electrical transmission system. The engine drives a generator that produces electrical energy, which is then used to power electric motors connected to the wheels. This substitution allows the engine to operate at constant optimal efficiency points while the electrical system provides flexible power delivery to meet varying demands.
2Object-generated harmful factors
If the engine is downsized to reduce emissions, then the emissions are reduced, but the engine cannot meet the maximum power output demands during high-load operations
Solution Approach 1:
The patent combines a downsized engine with an electrical energy storage system (battery). The battery compensates for the reduced power output of the smaller engine by providing additional electrical energy during high-load operations. This merging allows the engine to be downsized for reduced emissions while the battery ensures sufficient maximum power output is available when needed.
3Use of energy by moving object
If a diesel-electric system with infinitely variable power transmission is used for wheel propulsion, then the propulsion efficiency is improved, but the PTO shaft cannot maintain constant speed for optimal efficiency
Solution Approach 1:
The patent segments the power transmission system into two independent paths: one for wheel propulsion and one for the PTO shaft. The wheel propulsion uses a diesel-electric system with a generator and electric motor for infinitely variable power transmission and improved propulsion efficiency. The PTO shaft maintains a direct mechanical connection to the engine, allowing it to rotate at constant speed for optimal efficiency with attached implements.
4Productivity
If a hybrid system with both mechanical and electrical power paths is implemented, then the system can handle transient overloads and improve fuel efficiency, but the system complexity and cost increase
Solution Approach 1:
The patent implements a hybrid system where the first motor/generator serves multiple functions: it acts as a generator during normal operation to drive the electric motor for wheel propulsion, and it can also operate as a motor to provide additional power to the PTO shaft during transient overload conditions. This multi-functionality allows the system to handle various operating conditions and improve fuel efficiency while managing complexity through component versatility.
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 system achieves fuel savings of 5-20% depending on the implement, maintains optimal engine efficiency, and handles transient overloads by utilizing electrical energy, while reducing the need for traditional mechanical transmissions and allowing for efficient power distribution to both wheels and PTO shafts.
Implementation Method 1
an electrical generator drivingly connected to the engine
Implementation Method 2
at least one electrical motor arranged to deliver a propulsion force to the wheels or tracks, the at least one electrical motor being electrically connected to, and powered by, the electrical generator
Implementation Method 3
a battery connected to the electrical generator and to the electrical motor
Data Source
AI summary
A tractor (100) comprises an internal combustion engine (107) for delivering torque, wheels (101-104) or tracks for imparting a propulsive force to the ground, and a power takeoff shaft (110) for delivering torque to implements attached thereto. The power takeoff shaft is driven by a mechanical drive connection to the engine. An electrical motor/generator (115) is drivingly connected to the engine, and at least one electrical motor (121-124) is arranged to deliver a propulsion force to the wheels or tracks. The motor is electrically connected to, and powered by, the electrical motor/generator. A battery (120) is connected to the electrical motor/generator and to the electrical motor so that electrical energy can be passed therebetween. The motor/generator can also operate as a motor so that the power takeoff shaft is at least partially powered by electrical energy from the battery.