Hydrostatic Transmission Control for Engine Load Management
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Solution Overview
Problem
Existing vehicle drive systems fail to efficiently manage engine power and fuel consumption while maintaining engine performance under varying load conditions, particularly in hydrostatic transmissions, which can lead to engine overload or stalling.
Innovation Solution
A control arrangement that synchronizes engine speed with hydrostatic transmission, using load sensing data to adjust pump and motor displacement, preventing engine overload by maintaining optimal pressure and displacement within the engine's capability, and employing a learning algorithm to adjust engine speed based on past driving cycles for improved fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hydrostatic transmission operates at maximum pressure to maintain vehicle speed, then the power transmission capability is improved, but the engine may be overloaded or stall
Solution Approach 1:
The control system continuously monitors engine speed, load conditions, and transmission pressure, using feedback signals to dynamically adjust pump displacement and pressure control. This closed-loop control prevents engine overload by reducing pressure when engine speed drops below threshold values, while maximizing power transmission when engine conditions are favorable.
Solution Approach 2:
The system dynamically adjusts the displacement of the hydrostatic pump based on real-time engine operating conditions. By varying pump displacement according to engine speed and load demands, the system optimizes the balance between power transmission capability and engine protection, allowing maximum pressure operation only when the engine can sustain it.
2Use of energy by moving object
If the engine speed is controlled to maintain fuel efficiency, then the fuel consumption is reduced, but the engine may not have enough power to handle sudden load increases
Solution Approach 1:
The control system anticipates load increases by monitoring engine operating conditions and pre-adjusts pump displacement and pressure settings. When the engine operates in favorable conditions, the system prepares by building up hydraulic pressure and optimizing pump displacement, so that when sudden load peaks occur, the transmission is already positioned to deliver maximum power without causing engine stall.
Solution Approach 2:
The system continuously varies key parameters including pump displacement, transmission pressure, and engine speed setpoints based on operating conditions. By dynamically changing these parameters, the system maintains fuel efficiency during steady-state operation while ensuring power availability during transient load conditions, resolving the contradiction between fuel economy and power responsiveness.
3Reliability
If the maximum pressure is increased to prevent engine stalling, then the engine protection is improved, but the fuel consumption increases
Solution Approach 1:
The control system dynamically adjusts transmission pressure based on real-time engine speed and load conditions rather than maintaining a fixed maximum pressure. When engine conditions indicate risk of stalling, pressure is increased to protective levels. When engine conditions are favorable, pressure is reduced to optimize fuel consumption, thus resolving the contradiction between engine protection and fuel efficiency.
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 solution ensures the engine operates within its torque-producing capabilities, minimizing fuel consumption and preventing stalling, while allowing the hydrostatic transmission to operate at maximum pressure without causing engine speed to drop excessively, thus enhancing fuel efficiency and power output across a defined engine speed range.
Implementation Method 1
a hydrostatic transmission (14) having a pump (24) and a motor (26)
Implementation Method 2
the maximum pressure is selected considering the torque and the speed (rpm) of the engine at a given point on the engine characteristics curve
Implementation Method 3
adjusting a maximum pressure or displacement of a pump and motor in the hydrostatic transmission
Data Source
AI summary
A control arrangement for use in a drive arrangement of a vehicle includes an engine, a hydrostatic transmission, a load sensing means configured to detect a load on the engine, and an engine speed controller for controlling the engine. The arrangement further includes a pressure control means configured to act on a pressure in the hydrostatic transmission and a drive controller. The load sensing means generates a first signal, and based on the first signal, the drive controller generates a second signal for the engine speed controller and the pressure control means.