Flexible-Fuel Engine Dual Injector Control System
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Solution Overview
Problem
Existing bi-fuel and flexible-fuel engines face challenges in efficiently delivering and managing both liquid and gaseous fuels, leading to suboptimal performance and emissions due to limited cooperation between original engine systems and aftermarket conversion kits, particularly with natural gas, which requires high pressure injection systems that are technically challenging and costly.
Innovation Solution
An apparatus and method that includes a computer-controlled system with a gaseous fuel direct injector and a liquid fuel port injector, regulating fuel pressures and injection timing to optimize fuel delivery based on various engine parameters, allowing for flexible operation between gaseous, liquid, and dual-fuel modes to improve efficiency and emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high pressure injection systems are used for natural gas delivery, then fuel delivery precision is improved, but device complexity and cost increase
Solution Approach 1:
The fuel delivery system is segmented into separate gaseous fuel injection system and liquid fuel injection system, each optimized for its fuel type. The gaseous fuel system uses port injection at lower pressures while the liquid fuel system uses direct injection at higher pressures, avoiding the need for a single complex high-pressure system for both fuels.
Solution Approach 2:
The system dynamically switches between gaseous fuel port injection and liquid fuel direct injection modes based on operating conditions. The computer selectively activates appropriate injectors to match engine load, speed, and fuel availability, optimizing performance without requiring continuously high-pressure capability for all operations.
2Quantity of substance
If gaseous fuel is stored at high pressure, then fuel energy density is improved, but safety and infrastructure requirements worsen
Solution Approach 1:
The system changes the physical state parameter of the fuel by storing gaseous natural gas in compressed form at high pressure in the fuel tank, then delivering it at reduced pressures through port injection. This allows high energy density storage while using lower pressure delivery systems that are safer and less complex.
3Temperature
If liquid fuel is used to cool the engine, then engine temperature control is improved, but emissions increase
Solution Approach 1:
The system applies different fuel types to different locations and functions: gaseous fuel is used for combustion in the cylinder, while liquid fuel is selectively applied to the intake valve for cooling purposes. This localized application provides cooling where needed without requiring large amounts of liquid fuel that would increase emissions.
Solution Approach 2:
The liquid fuel serves as an intermediary cooling medium that absorbs heat from the intake valve without being fully combusted. This allows thermal management function to be separated from the primary combustion function, reducing the amount of liquid fuel needed and thus lowering emissions while maintaining temperature control.
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
This solution enhances fuel delivery precision and engine performance by optimizing fuel ratios and injection timing, reducing emissions and extending fuel range while maintaining engine integrity, thereby addressing the limitations of current bi-fuel engine technologies.
Implementation Method 1
a first fuel injector to directly inject the gaseous fuel into the combustion chamber
Implementation Method 2
combustion of liquid fuels
Implementation Method 3
inject the liquid fuel into the intake charge upstream of the intake valve
Implementation Method 4
Mix Gas
Implementation Method 5
regulating fuel pressures and injection timing to optimize fuel delivery
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A flexible-fuel internal combustion engine apparatus comprises a combustion chamber, an intake valve, a first fuel injector, a second fuel injector, and a computer. The intake valve is operable to admit an intake charge into the combustion chamber. The first fuel injector injects a gaseous fuel directly into the combustion chamber. The second fuel injector injects a liquid fuel into the intake charge upstream of the intake valve. The computer is operatively connected with the first fuel injector and the second fuel injector to actuate injection of fuel respectively therefrom. The computer is programmed to command a gaseous-to-liquid fuel ratio as a function of at least one operating parameter from a group comprising gaseous fuel pressure, gaseous fuel mass, engine speed, engine torque, inlet air temperature, inlet air humidity, knock detection, operating history, torque command, and emissions.