Active Vent Valve Control for HPDI Fuel Pressure Bias
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Solution Overview
Problem
Existing fluid control systems for multi-fueled engines face challenges in maintaining consistent fuel pressure and preventing leakage between gaseous and liquid fuels, leading to unnecessary venting and potential contamination, especially when the engine transitions between fueling modes or experiences pressure fluctuations.
Innovation Solution
A fluid control system with an actively controllable vent valve and pressure regulator that adjusts fluid pressures dynamically based on measured differentials, using sensors and an electronic control unit to manage pressure bias and minimize venting, while integrating components to reduce space and potential leak points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive venting mechanism is used to maintain pressure bias between gaseous and liquid fuels, then gaseous fuel leakage into liquid fuel supply lines is prevented, but unnecessary venting of gaseous fuel occurs during normal operation
Solution Approach 1:
The patent replaces the static passive venting mechanism with a dynamic actively controlled vent valve that responds to real-time pressure differential measurements. The vent valve is controlled by an electronic control unit that receives signals from pressure sensors, allowing the system to adapt venting actions to actual operating conditions rather than relying on fixed mechanical thresholds.
Solution Approach 2:
The system implements a feedback control loop where pressure sensors continuously monitor the pressure differential between gaseous and liquid fuel supply lines, and this information is fed back to the electronic control unit. The ECU uses this feedback to intelligently control the vent valve, opening it only when the pressure differential exceeds a threshold indicating actual leakage risk, and closing it during normal operation to prevent unnecessary venting.
2Loss of substance
If pressure sensors and electronic control components are added to reduce unnecessary venting, then gaseous fuel loss is minimized, but device complexity increases
Solution Approach 1:
The electronic control unit serves multiple functions: it monitors pressure differential signals from sensors, determines when venting is necessary by comparing against threshold values, controls the vent valve actuator, and can interface with the engine control system for coordinated fuel management. This multi-functionality consolidates control logic into a single component rather than requiring separate dedicated circuits for each function.
Solution Approach 2:
The patent replaces the purely mechanical passive venting mechanism with an electro-mechanical system that uses electronic sensors and control logic. Pressure sensors substitute for mechanical pressure-sensing elements, and electronic control replaces mechanical linkages and fixed thresholds, allowing for more precise and adaptable control of the vent valve.
3Loss of substance
If an actively controlled vent valve is used instead of passive venting, then unnecessary venting is reduced, but the risk of high back pressure damaging components increases
Solution Approach 1:
The system performs preliminary monitoring of the pressure differential between gaseous and liquid fuel lines using pressure sensors. By detecting pressure reversals before they can cause damage, the electronic control unit can proactively activate the vent valve to relieve excessive back pressure, preventing damage to the pressure regulator and other components before it occurs.
Solution Approach 2:
The actively controlled vent valve acts as an intermediary safety mechanism between the gaseous and liquid fuel supply systems. When the electronic control unit detects abnormal pressure conditions that could lead to component damage, it activates the vent valve to provide a controlled release path, mediating the pressure conflict between the two fuel systems and protecting vulnerable components.
Data Source
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AI summary
Disclosed are a fluid control system and method for controlling delivery of two variable pressure fluids to maintain a pressure bias between the two fluids within an end use device. The system employs an actively controlled vent valve which can be integrated into a fluid control module in preferred embodiments and is actuated to an open position to decrease fluid pressure in a first fluid supply line when a determined pressure differential reversal exceeds a predetermined threshold pressure differential reversal. The disclosed system is particularly useful in a high pressure direct injection (HPDI) multi-fueled engine system where the first fluid is a gaseous fuel and the second fluid is a liquid fuel. The fluid control system and method of controlling it provide for improved control of venting along with protecting system components from high back pressure and cross contamination of fluids.