Selectable Four-Wheel Drive System for Utility Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Utility vehicles, such as ride-on mowers, face challenges in operating effectively on severe terrain and slopes due to the lack of efficient four-wheel drive systems that can seamlessly integrate electric and conventional drive assemblies, requiring complex control systems and lacking stability and control in varying conditions.
Innovation Solution
A selectable four-wheel drive system that pairs an electric front-wheel drive assembly with a conventional rear-wheel drive assembly, utilizing a combination of manual and electronic controls, including an accelerator pedal with mechanical and electronic linkages, position sensors, and processors to coordinate the drive systems, allowing for operator-controlled activation between two-wheel and four-wheel modes, and incorporating features like independent electric motors and differentials for enhanced stability and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-time four-wheel drive system is used, then vehicle control and stability on severe terrain is improved, but device complexity and energy consumption increase
Solution Approach 1:
The system dynamically switches between two-wheel drive and four-wheel drive modes based on terrain conditions and operator input. The selectable four-wheel drive system allows the vehicle to operate in two-wheel drive mode under normal conditions, then engage four-wheel drive only when needed for severe terrain or slope operation, thereby maintaining reliability when required while reducing overall system complexity and energy consumption during typical operation.
2Reliability
If an electric front-wheel drive assembly is added to a conventional rear-wheel drive assembly, then four-wheel drive capability is improved, but device complexity increases
Solution Approach 1:
The drive system is segmented into two independent drive assemblies: a conventional rear-wheel drive assembly powered by a prime mover and an electric front-wheel drive assembly powered by a battery pack and electric motor. This segmentation allows each assembly to be optimized independently and enables selective engagement of four-wheel drive capability without requiring complete system redesign, thereby improving four-wheel drive capability while managing overall system complexity.
3Reliability
If hybrid systems alternate or combine power delivery from combustion engine and electric motor, then four-wheel drive performance is improved, but control system complexity increases
Solution Approach 1:
The patent extracts and separates the control functions for the electric front-wheel drive assembly from the conventional rear-wheel drive control system. Independent controls include an accelerator pedal with position sensor for electric motor control, a brake pedal with position sensor for regenerative braking control, and a selectable four-wheel drive switch. This extraction of control functions simplifies the overall control architecture by allowing independent optimization of electric drive control without complicating the conventional drive control system.
4Ease of operation
If manual and electronic controls are combined for coordination, then vehicle control precision is improved, but device complexity increases
Solution Approach 1:
The system employs an intermediary controller that receives inputs from both manual controls (accelerator pedal position sensor, brake pedal position sensor, selectable four-wheel drive switch) and automatically coordinates the electric front-wheel drive assembly with the conventional rear-wheel drive assembly. This intermediary control unit acts as a mediator that translates operator inputs into coordinated actions of both drive systems, improving vehicle control precision while managing the complexity of coordinating multiple drive sources through a centralized control logic.
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 provides improved vehicle control and stability on severe terrain by coordinating electric and conventional drive systems, enabling precise control of axle speeds and steering, reducing the risk of skidding and scuffing, and optimizing energy management through selective four-wheel drive operation.
Implementation Method 1
an electric motor having a through-shaft that drives both front wheels
Implementation Method 2
an electric transaxle complete with reduction gearing and a differential engaged to a pair of axles
Data Source
AI summary
A drive system for a vehicle having a rear drive assembly powered by a first power source, a front drive assembly in selective electrical communication with a second power source, a selector switch to selectively permit or prevent electrical communication between the front drive assembly and the second power source, and an output capacity sensor to detect an output of the first power source, where the rear drive assembly drives the vehicle when the selector switch is in a first position and both the rear and front drive assemblies drive the vehicle when the selector switch is in a second position and the output capacity sensor detects that the output of the first power source meets a threshold output.