Fuel Vapor Injection Control for Cold-Start Combustibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern fuel-injected vehicle engines face challenges with cold-start combustibility due to liquid fuel injection, leading to decreased emission efficiency and potential engine failure, as fuel in the fuel rail can evaporate, resulting in a lean Air/Fuel ratio and rough engine performance.
Innovation Solution
An injection control system that utilizes purge vapors from a canister to assist engine start by controlling a controllable valve to deliver fuel vapors into the intake manifold, with an electronic control unit determining the fuel state in the liquid fuel line and adjusting the valve to ensure accurate vapor delivery, reducing the need for increased fuel line pressure and minimizing evaporative emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid fuel is injected during start-up, then the fuel injection system is simple to operate, but the combustibility decreases due to cold fuel being harder to vaporize
Solution Approach 1:
The system changes the physical state parameter of the fuel from liquid to vapor by utilizing evaporated fuel from the fuel tank through the charcoal canister purge system, thereby improving combustibility during start-up without complicating the injection operation
Solution Approach 2:
The charcoal canister purge system acts as an intermediary between the fuel tank and the intake manifold, capturing evaporated fuel and delivering it to the engine during start-up, thus resolving the combustibility issue without requiring direct modification of the liquid fuel injection system
2Measurement precision
If fuel line pressure is increased to prevent fuel evaporation, then fuel delivery accuracy is improved, but evaporative emissions increase due to increased leakage
Solution Approach 1:
The system converts the harmful effect of fuel evaporation (which causes emissions) into a beneficial resource by capturing the evaporated fuel in the charcoal canister and utilizing it as a fuel source during start-up, thereby eliminating emissions while maintaining accurate fuel delivery without requiring increased line pressure
3Reliability
If purge vapour is used to assist engine start, then combustibility is improved, but the Air/Fuel ratio control becomes inaccurate due to inability to control vapor delivery
Solution Approach 1:
The existing purge control valve, originally designed for emission control, is repurposed to also control fuel vapor delivery during start-up. By integrating the dual function of emission purging and fuel delivery control into a single valve system, the patent achieves both improved combustibility and accurate Air/Fuel ratio control without adding separate control mechanisms
4Reliability
If pre-combustion heating is applied to improve vaporization, then combustibility is improved, but system complexity and cost increase
Solution Approach 1:
The system utilizes the natural evaporation process of fuel in the fuel tank, driven by heat from the engine and ambient temperature, to produce fuel vapor for combustion. This self-service approach eliminates the need for external heating systems, maintaining simplicity while improving combustibility through the use of naturally evaporated fuel captured by the charcoal canister
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 engine start and after-start performance by ensuring the correct Air/Fuel ratio, reducing the risk of engine failure, and minimizing evaporative emissions by accurately delivering fuel vapors when the fuel in the rail is evaporated, while maintaining efficient combustion quality.
Implementation Method 1
The evaporated fuel collects in the fuel tank and is periodically removed by the purge vapour control system. The fuel vapours from the tank are initially collected and stored in a vapour canister.
Implementation Method 2
a purge valve is opened permitting the engine to draw the fuel vapours from the purge canister into the engine for combustion
Implementation Method 3
Prior to delivery the fuel is contained in a fuel rail upstream of the injectors which is held under pressure
Implementation Method 4
determining the state of a fuel in a liquid fuel line... When the state of the fuel has been determined the electronic control unit decides to use the canister purge vapours to assist engine start
Data Source
AI summary
A method and a system for improved control of fuel supply to an internal combustion engine are presented. The system, in addition to a liquid fuel injector, includes a fuel vapor injector disposed in an engine air intake manifold. The method includes determining the state of fuel in the liquid fuel line, and adjusting the amount purge fuel vapors injected into engine air intake manifold accordingly. Thus, improved engine performance is achieved.