Infinitely Variable Transmission Rim-Pull Control for Work Vehicles
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Solution Overview
Problem
Conventional powertrains with fixed discrete ratios lead to excessive wear on service brakes and inefficient fuel consumption due to repetitive operations in work vehicles, and operators lack customizable powertrain characteristics to suit their preferences and job requirements.
Innovation Solution
An operator selectable transmission system with a variable drivetrain and torque control, allowing selection between hydrostatic, torque converter, and direct drive modes, along with adjustable contour relationships between ground speed and rim-pull, reducing the need for service brake usage and optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional powertrains with fixed discrete ratios are used, then the structure is simple and reliable, but service brake wear increases and fuel efficiency decreases due to repetitive operations
Solution Approach 1:
The patent implements an infinitely variable transmission (IVT) that dynamically adjusts the rim-pull to ground speed ratio continuously, replacing fixed discrete ratios. This dynamic adjustment allows the powertrain to optimize braking energy recovery and reduce service brake wear while improving fuel efficiency through continuous adaptation to operating conditions.
Solution Approach 2:
The system changes the operational parameters by introducing operator-selectable powertrain characteristics including different transmission modes (hydrostatic, torque converter, direct drive) and adjustable contour relationships between rim-pull and ground speed. These parameter changes enable customization for different work environments and operator preferences while optimizing energy efficiency and brake life.
2Adaptability or versatility
If conventional powertrains with fixed discrete ratios are used, then the device complexity is low, but the adaptability to different work environments and operator preferences is limited
Solution Approach 1:
The patent creates a universal powertrain system that can replicate multiple transmission types (hydrostatic, torque converter, direct drive) through software-controlled contour relationships within the IVT. This multi-functionality allows a single transmission system to adapt to different work environments and operator preferences without requiring multiple specialized transmissions, thereby managing complexity while maximizing versatility.
Solution Approach 2:
The system uses dynamic, operator-selectable contour relationships that can be adjusted in real-time to match different work environments and operator preferences. This dynamic adaptability allows the powertrain to optimize performance for various conditions (loading, hauling, dumping, reversing) without requiring complex mechanical reconfiguration.
3Productivity
If service brakes are used for repetitive stop-start operations, then the vehicle can stop and reverse efficiently, but excessive wear occurs on the service brakes
Solution Approach 1:
The patent converts the harmful effect of kinetic energy during deceleration into a beneficial force by using the IVT to create rim-pull that opposes vehicle motion. This transmission braking recovers kinetic energy and converts it to useful work, reducing reliance on service brakes while improving productivity in repetitive stop-start operations.
Solution Approach 2:
The system replaces the mechanical service brake system with a transmission-based braking mechanism. The IVT uses rim-pull control to create decelerating force during vehicle operation, substituting the need for frequent service brake application and extending brake life while maintaining operational efficiency.
Data Source
AI summary
An operator selectable transmission and method for a vehicle with variable drivetrain and torque control. The operator selectable transmission includes a plurality of transmission modes, each mode including a plurality of selectable contour relationships between vehicle ground speed and transmission rim-pull, an operator mode selector for selecting transmission mode, and an operator contour selector for selecting a contour for the selected mode. There can be hydrostatic, torque converter, direct drive and other transmission modes. An operator interface can display the currently selected mode, and its affects on performance, fuel consumption, and brake wear. The contour selector can be a foot pedal, hand lever or other device. The method includes reading a selected mode, contour and ground speed; determining a rim-pull command based on the readings; calculating a torque command for the transmission based on the rim-pull command and vehicle parameters; and sending the calculated torque command to the transmission.