Vehicle Speed Control via Powershift Transmission Ratio
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Solution Overview
Problem
Conventional vehicle speed control systems are limited by the number of gear ratios in the transmission, failing to provide enough speed ranges for operators to tailor vehicle performance to specific conditions and unable to maintain speed under changing loads.
Innovation Solution
A control system that includes a control unit to receive signals for vehicle speed and power plant output speed, determining a desired power plant output speed to maintain a desired vehicle speed independently of load magnitude, providing more speed ranges than available gear ratios and adapting to changing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of gear ratios in the transmission is increased to provide more speed ranges, then the adaptability to different operating conditions is improved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by making the transmission ratio continuously variable rather than fixed at discrete steps. The powershift transmission enables smooth transition between ratios, allowing the system to adapt to different operating conditions without adding multiple fixed gear stages, thus improving adaptability while avoiding increased mechanical complexity
Solution Approach 2:
The patent changes the parameter of transmission ratio from discrete fixed values to continuously variable values. By controlling the powershift transmission to provide infinite ratio steps within a range, the system achieves multiple speed ranges without adding physical gear components, resolving the contradiction between adaptability and complexity
2Reliability
If conventional transmission control is used, then the device complexity is kept simple, but the ability to maintain vehicle speed under changing loads is lost
Solution Approach 1:
The patent implements feedback control by continuously monitoring vehicle speed and transmission ratio, then automatically adjusting the transmission ratio to maintain desired speed. The control system receives speed signals, compares them with target values, and modifies the powershift transmission ratio accordingly, enabling reliable speed maintenance under varying loads through closed-loop control
Solution Approach 2:
The control system performs self-service by automatically adjusting transmission ratio based on real-time speed feedback without requiring manual intervention. The system monitors its own performance and makes corrective adjustments to maintain optimal operation, achieving reliable speed control through autonomous operation
3Ease of operation
If more speed ranges are provided than transmission gear ratios, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical system of multiple fixed gear ratios with a controlled powershift transmission system. Instead of adding physical gears and shafts to create multiple speed ranges, the invention uses electronic control to vary the transmission ratio continuously, achieving unlimited speed selection flexibility without increasing mechanical complexity
Data Source
AI summary
A system is provided for controlling the speed of a vehicle having a powertrain including a power plant operably coupled to a transmission. The system includes a control unit configured to receive a signal indicative of vehicle speed, receive a signal indicative of power plant output speed, and determine a desired power plant output speed based on the signal indicative of vehicle speed and the signal indicative of power plant output speed. The control unit is further configured to send a signal to the power plant such that the power plant operates at the desired power plant output speed, and maintain a desired vehicle speed in a manner substantially independent of a magnitude of load on the powertrain.