Liquid LPG Direct Injection Pressure Control for Low-Emission Engines
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Solution Overview
Problem
Current LPG injection systems fail to maintain LPG in a liquid state, especially in cold conditions, leading to inefficient combustion, increased emissions, and non-compliance with stringent emissions standards like EURO VI E.
Innovation Solution
An LPG-only engine system with Liquid Phase Direct Injection (LPDI) that keeps fuel in liquid form until injection, using a fuel pump, pressure rail, and closed-loop circulation system to ensure precise delivery and recirculation of unused LPG, combined with an exhaust gas treatment element to reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LPG is converted to gaseous state prior to injection, then injection can be performed, but combustion efficiency decreases and emissions increase
Solution Approach 1:
The patent changes the physical state parameter of LPG from gaseous to liquid form during injection. By maintaining LPG in liquid state through pressure control and direct injection into the combustion chamber, the system achieves better atomization and combustion efficiency while reducing harmful emissions compared to traditional gaseous injection methods.
Solution Approach 2:
The patent employs hydraulic principles by using high-pressure liquid injection similar to diesel fuel systems. The liquid LPG is injected directly into the combustion chamber under controlled pressure, enabling precise fuel delivery and efficient combustion without the need for vaporization, thereby reducing emissions and improving productivity.
2Measurement precision
If LPG is stored and transported in liquid state, then fuel delivery precision improves, but maintaining liquid state in cold conditions becomes difficult
Solution Approach 1:
The system performs preliminary heating of the fuel tank and fuel lines before cold weather operation to prevent LPG from freezing or losing its liquid state. This preliminary action ensures that the fuel remains in liquid form throughout the injection system, maintaining both delivery precision and reliability in cold conditions.
Solution Approach 2:
The patent adjusts temperature and pressure parameters dynamically to maintain LPG in liquid state across varying environmental conditions. By controlling the physical parameters of the fuel storage and delivery system, the patent ensures reliable liquid state maintenance while preserving precise fuel delivery capability.
3Productivity
If LPG is injected in liquid form directly into combustion chamber, then combustion efficiency improves, but system complexity increases
Solution Approach 1:
The patent designs the liquid LPG injection system to serve multiple functions: fuel delivery, atomization, and combustion control all through a single high-pressure injection mechanism. This multi-functionality reduces the need for separate vaporization and injection systems, thereby managing complexity while maintaining high combustion efficiency.
Solution Approach 2:
The patent introduces a high-pressure pump and control unit as intermediary components that enable liquid LPG injection. These intermediaries manage the complexity by centralizing the control functions and simplifying the overall system architecture compared to traditional gaseous injection methods that require vaporization chambers and complex timing mechanisms.
4Loss of energy
If fuel circulation system is implemented to recirculate unused LPG, then fuel efficiency improves, but system complexity increases
Solution Approach 1:
The patent merges the fuel circulation function with the existing injection system by integrating a recirculation line that returns unused LPG from the injection system back to the fuel tank. This combined approach allows fuel efficiency improvement through recirculation while avoiding the complexity of a completely separate circulation system.
Solution Approach 2:
The fuel circulation system is designed to automatically recirculate unused LPG back to the tank without requiring external intervention or complex control mechanisms. The system self-regulates the fuel flow, improving efficiency while maintaining simplicity by eliminating the need for additional pumps or complex control logic.
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
Achieves precise fuel delivery, improved combustion efficiency, and compliance with EURO VI E standards by maintaining LPG in liquid form, reducing emissions and fuel wastage.
Implementation Method 1
a fuel pump configured to transfer LPG from the fuel tank to at least one pressure rail
Implementation Method 2
The pressure rail can accumulate LPG and provide a constant pressure
Implementation Method 3
at least one fuel injector, configured to inject LPG in liquid form directly from the pressure rail into a respective combustion chamber of the engine
Implementation Method 4
an exhaust gas treatment element can be configured to treat exhaust gases from the engine
Data Source
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AI summary
A system for operating and controlling an LPG-only engine with Liquid Phase Direct Injection, LPDI. The system (100) comprising the LPG-only engine (1); a fuel tank (2), configured to store LPG in a liquid state; a fuel pump (3), configured to transfer LPG from the fuel tank (2) to at least one pressure rail (4). Wherein the pressure rail (4) is configured to accumulate LPG and provide a constant pressure, comprising an inlet for receiving LPG from the fuel pump (3) and an outlet for returning a portion of unused LPG back to the fuel tank (2). The system (100) further comprising at least one fuel injector (9), configured to inject LPG in liquid form directly from the pressure rail (4) into a respective combustion chamber of the engine (1). The system (100) further comprising an electronic control unit (6), ECU, configured to control the operation of the fuel injector (9) based on operating conditions, at least including the amount of LPG injected and the timing of the injections. The system (100) further comprising a fuel circulation system (7), configured to circulate LPG between the pressure rail (4) and the fuel tank (2), wherein unused liquid LPG returns to the fuel tank (2) for recirculation, wherein the fuel circulation system (7) comprises a pressure regulation element (13) in a return path of the fuel circulation system (7) between the pressure rail (4) and the fuel tank (2). The system (100) further comprising an exhaust gas treatment element (8), configured to treat exhaust gases from the engine (1).