Power Train Controller Engine Speed Override
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Solution Overview
Problem
Existing transmission control systems struggle to prevent engine speed from exceeding a maximum desirable speed during propulsion direction changes, as they may not respond quickly enough to reduce fueling rate when downshifting is initiated, leading to potential engine speed spikes.
Innovation Solution
A power train system with a controller that overrides an operator's target engine speed request by lowering the current engine speed to a modified target speed, allowing the fuel system to stop supplying fuel and prevent engine speed spikes during propulsion direction changes, thereby maintaining engine speed within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the fueling rate is reduced to prevent engine speed from exceeding the maximum desirable speed, then the engine speed is controlled, but the fueling system cannot respond quickly enough during propulsion direction changes
Solution Approach 1:
The controller proactively adjusts the target engine speed to a modified target speed before the engine speed spike occurs during downshifting. This preliminary action eliminates the need for rapid fueling system response by preventing the condition that would trigger excessive engine speed in the first place.
Solution Approach 2:
The controller prepares the engine speed control by lowering the target engine speed to a modified target speed in advance of the downshifting event. This beforehand cushioning creates a buffer that prevents the engine speed from exceeding maximum desirable speed even though the fueling system response is delayed.
2Reliability
If the controller waits until the operator requests an engine speed exceeding the threshold before overriding, then the override action is taken, but the engine speed has already exceeded the threshold during the rapid increase
Solution Approach 1:
The controller detects the initiation of propulsion direction change and proactively lowers the target engine speed to a modified target speed before the engine speed can exceed the maximum desirable threshold. This preliminary action ensures threshold compliance by acting in advance of the harmful effect.
Solution Approach 2:
The controller continuously monitors operator requests and engine operating conditions to detect when a propulsion direction change is being initiated. This feedback enables the controller to proactively adjust the target engine speed to a modified target speed at the appropriate moment, ensuring the engine speed remains within desirable limits throughout the transition.
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 effectively prevents engine speed from exceeding the maximum desirable speed during propulsion direction changes by overriding the operator's request and adjusting the engine speed proactively, ensuring safe and controlled transitions.
Implementation Method 1
adjusting the transmission (e.g. downshifting) thereby using parasitic losses to slow the machine down
Data Source
AI summary
A power train is provided having an engine operably coupled to a transmission. The power train also has at least one operator interface device, each operator interface device being configured to generate an operator request. In addition, the power train has a controller configured to, in response to a first operator request, override a second operator request for a desired target engine speed by lowering a current engine speed to a modified target engine speed below the desired target engine speed.