Dynamic Powertrain Control to Prevent Switching Shock in Work Vehicles
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Summary
Problems
Existing continuously variable powertrain devices for work vehicles experience switching shock due to workload variations when changing shift levels, as the fixed switching point is not adaptable to changing hydraulic static transmission efficiency.
Innovation solutions
A continuously variable powertrain device with a pressure detector to monitor hydraulic pressure, a powertrain controller to adjust the hydraulic static transmission and planetary transmission based on real-time velocity and pressure data, and a switching timing changer to dynamically adjust the shift level switching point, incorporating threshold characteristics for stable clutch operation.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a fixed switching point is used for planetary transmission shift levels, then the control logic is simple, but switching shock occurs when volumetric efficiency of the HST varies due to workload changes
Why choose this principle:
The patent applies dynamics by making the switching point variable rather than fixed. The switching timing is dynamically adjusted based on the detected hydraulic pressure in the closed circuit of the HST. When the hydraulic pressure indicates reduced volumetric efficiency, the switching point is shifted to prevent premature shifting that would cause switching shock. This dynamic adaptation resolves the contradiction by maintaining simple control logic while eliminating the harmful switching shock through real-time parameter adjustment.
Principle concept:
If a fixed switching point is used for planetary transmission shift levels, then the control logic is simple, but switching shock occurs when volumetric efficiency of the HST varies due to workload changes
Why choose this principle:
The patent implements feedback by using a pressure detector to monitor the hydraulic pressure in the HST closed circuit and feeding this information back to the planetary clutch controller. The controller uses this feedback to determine the appropriate switching timing, adjusting the switching point based on the actual volumetric efficiency conditions. This feedback mechanism allows the system to adapt to workload changes and prevent switching shock while maintaining relatively simple control logic.
Application Domain
Data Source
AI summary:
A continuously variable powertrain device with a pressure detector to monitor hydraulic pressure, a powertrain controller to adjust the hydraulic static transmission and planetary transmission based on real-time velocity and pressure data, and a switching timing changer to dynamically adjust the shift level switching point, incorporating threshold characteristics for stable clutch operation.
Abstract
A continuously variable powertrain device for a work vehicle includes a hydraulic static transmission to output a continuously shifted motive power while continuously varying a velocity of a motive power received from an engine, a planetary transmission to receive the motive power from the engine and the continuously shifted motive power and to output a compound motive power, a pressure detector to detect a hydraulic pressure in a closed circuit of the hydraulic static transmission, a planetary clutch mechanism to switch a shift level of the planetary transmission, and a powertrain controller to control actuation of the hydraulic static transmission and the planetary transmission based on a shift command.