Variable Displacement Pump Stator Control for Rapid Engine Brake Activation
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Solution Overview
Problem
Variable displacement pumps used in mid-range/high-powered engines for heavy vehicles experience delays in increasing oil flow and pressure, which hampers quick activation of the engine brake and increases stress on internal engine components.
Innovation Solution
A control system and method for a variable volume positive displacement rotary pump that includes a movable stator with a first and second thrust chamber, a filter causing a localized pressure drop, and a three-way valve for fluid flow control, allowing the pump to adjust its configuration to meet demanding operating conditions by altering the fluid supply path and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed displacement pump is used to ensure adequate lubrication at low speeds, then lubrication is improved at low speeds, but flow rate becomes excessive at higher speeds requiring greater engine consumption and imposing higher pressures and stress on the circuit
Solution Approach 1:
The patent applies a variable displacement pump mechanism where the stator can move between multiple positions (first, second, and third positions) to dynamically adjust the pump's displacement volume. This allows the system to optimize flow rate according to operating conditions - providing adequate lubrication at low speeds while reducing flow rate and energy consumption at higher speeds, thereby resolving the contradiction between lubrication adequacy and energy loss.
2Loss of energy
If a variable displacement pump is used to optimize flow rate at higher speeds, then energy consumption is reduced, but there is a marked delay in increasing flow rate/pressure for quickly activating the engine brake
Solution Approach 1:
The patent incorporates a first thrust chamber that can be pre-pressurized using fluid from the supply line before the engine brake activation is needed. This preliminary action stores pressurized fluid in the thrust chamber, enabling rapid flow rate increase when the brake is activated, thus eliminating the delay in flow rate response while maintaining energy efficiency during normal operation.
Solution Approach 2:
The patent introduces a control valve that acts as an intermediary between the supply line and the first thrust chamber. This valve can redirect fluid flow to pre-pressurize the thrust chamber or to provide direct flow to the load, enabling rapid pressure and flow rate increase for brake activation while maintaining optimized energy consumption during normal pump operation.
3Productivity
If the stator is positioned to provide maximum displacement, then flow rate is maximized, but pressure distribution and fluid flow control become less optimized for demanding operating conditions
Solution Approach 1:
The patent implements a dynamic stator positioning system with multiple discrete positions (first, second, and third positions) that can be selected based on operating conditions. The stator can be positioned in the first position for normal operation, moved to the second position for demanding conditions requiring pre-pressurization, and positioned in the third position for maximum flow rate requirements, thereby providing both adaptability and high productivity.
Solution Approach 2:
The patent divides the stator's operational range into distinct positional segments (first, second, and third positions), each optimized for specific operating conditions. This segmentation allows the system to select the appropriate position based on demand - normal operation, pre-pressurization preparation, or maximum flow rate requirements - thereby achieving both adaptability and high productivity across different conditions.
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
Enables rapid increase in fluid flow rate and pressure to meet more demanding engine operating conditions, such as activating the engine brake, while minimizing stress on engine components and ensuring consistent lubrication.
Implementation Method 1
a positive displacement pump (2), which is of the variable volume rotary type
Implementation Method 2
an element (4) that defines a localized pressure drop
Implementation Method 3
a first thrust chamber (214) for thrusting the stator (20)... The movement of the stator determines a variation in the output of the pump
Data Source
Figure 1
Figure 2
AI summary
A control system comprising: - a variable volume positive displacement rotary pump (2), in turn comprising: i) a stator (20) that is movable so as to determine a variation in the volume of the pump (2); ii) a first thrust chamber (21 ) for thrusting the stator (20) and designed to be filled with a fluid processed by the pump so as to determine a movement of the stator (20) and a variation in the volume of the pump (2); -a supply line (3) for supplying the fluid processed by the pump (2) to a load; -an element (4) that defines a localized loss in load, said element (4) being located along said supply line (3); -control means (5) for controlling the flow of the fluid supplying said first chamber (21 ), said control means (5) being able to assume at least a first and a second configuration; -a first branch (31, which, in the first configuration of the control means (5), allows for collecting the fluid to be directed into the first thrust chamber (21 ) from said supply line (3), downstream of said element (4); -a second branch (32), which, in the second configuration of the control means (5), allows for collecting the fluid to be directed into the first thrust chamber (21 ) from said supply line (3), upstream of said element (4); with respect to the first configuration, said second configuration enabling functioning of the load under more demanding conditions.