Dual LP Gas Injection Control for Cold Starts and High Load
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Solution Overview
Problem
Liquid LP gas injection systems face issues such as unintended vaporization, pressure fluctuations, pump failure, and inefficiency due to air displacement, while vapor LP gas systems struggle with cold starts and reduced efficiency at high loads.
Innovation Solution
A dual LP gas injection system that selectively delivers both vapor and liquid LP gas based on engine conditions, using a fuel pump for liquid delivery and a fuel pressure regulator for vapor delivery, controlled by a controller that adjusts based on temperature, load, and fuel level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid LP gas injection is used, then volumetric efficiency is improved, but unintended vaporization occurs causing lean combustion
Solution Approach 1:
The fuel injection system is segmented into two independent pathways: a liquid injection system with injectors positioned to deliver liquid fuel directly into the combustion chamber, and a vapor injection system with separate injectors for vapor fuel. This segmentation allows selective delivery of liquid or vapor phases based on operating conditions, preventing unintended vaporization in the fuel rail while maintaining volumetric efficiency when liquid injection is used.
2Productivity
If liquid LP gas injection is used, then volumetric efficiency is improved, but fuel pump overheating occurs at low fuel levels
Solution Approach 1:
The system changes the physical state parameter of the fuel by offering both liquid and vapor injection modes. When fuel levels are low and the risk of pump overheating exists, the system switches to vapor injection mode, which eliminates the need for a fuel pump to draw liquid from the tank, thereby protecting the pump from thermal damage while maintaining engine operation.
3Reliability
If vapor LP gas injection is used, then reliability is improved, but volumetric efficiency decreases at high engine speeds
Solution Approach 1:
The injection system dynamically adapts its operation mode based on real-time engine conditions. The controller monitors engine speed, load, and temperature parameters, then dynamically switches between liquid injection mode (for high volumetric efficiency at high speeds), vapor injection mode (for reliability at low speeds or cold conditions), or a combination of both modes, optimizing performance across the entire operating range.
4Device complexity
If vaporizer is used in vapor LP gas system, then fuel delivery is simplified, but cold start capability is lost
Solution Approach 1:
The fuel delivery system achieves multi-functionality by incorporating both vapor and liquid injection capabilities. The liquid injection pathway enables cold start operation by delivering liquid fuel that can be rapidly vaporized in the combustion chamber, while the vapor injection pathway handles normal operating conditions. This universal system replaces the need for gasoline auxiliary systems and maintains functionality across all temperature conditions.
5Productivity
If liquid LP gas is used, then air charge is improved, but ice formation damage occurs from flash freezing
Solution Approach 1:
The system performs preliminary vaporization by providing a vapor injection pathway that delivers pre-vaporized fuel to the combustion chamber. This preliminary action prevents the flash freezing phenomenon that occurs when liquid fuel rapidly vaporizes in the intake manifold, thereby avoiding ice formation that could damage engine components while maintaining the air charge efficiency benefits of liquid injection.
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
Enhances engine efficiency by stabilizing tank pressure, eliminating cold start reliance on gasoline, and minimizing reliability issues, while maintaining efficient air charge at varying engine loads.
Implementation Method 1
a fuel pressure regulator configured to adjust the pressure of liquid LP gas released from the fuel tank such that the released liquid LP gas is converted to vapor LP gas
Implementation Method 2
a fuel pump configured to displace liquid LP gas fuel from the fuel tank to the plurality of liquid injectors
Implementation Method 3
a plurality of liquid injectors each configured to inject liquid LP gas into a respective cylinder of the internal combustion engine
Implementation Method 4
a plurality of vapor injectors each configured to inject vapor LP gas into a respective cylinder of the internal combustion engine
Data Source
AI summary
A liquefied petroleum (LP) gas fuel system includes a fuel source to store liquid LP gas and a fuel supply system to draw liquid LP gas from the fuel source and selectively deliver vapor LP gas and liquid LP gas into a plurality of cylinders of an internal combustion engine. The fuel supply system includes a plurality of liquid LP gas injectors, a plurality of vapor LP gas injectors, a fuel pump to drive liquid LP gas fuel from the fuel source to the plurality of liquid injectors, and a fuel pressure regulator to deliver vapor LP gas to the plurality of vapor injectors. The fuel system includes a controller to actuate the fuel pressure regulator to deliver vapor LP gas to the plurality of vapor injectors and actuate the fuel pump to deliver liquid LP gas to the plurality of liquid injectors.