Variable Injection Timing for Direct Injection Engine Cold Start
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Solution Overview
Problem
Direct injection gasoline engines face challenges during cold start, including incomplete combustion and increased emissions due to variations in injection rail pressure and limited air-fuel mixing, with existing methods like intake stroke injection leading to fuel deposition on combustion chamber walls and compression stroke injection resulting in uncontrolled fuel clouds missing the spark plug.
Innovation Solution
A method involving direct fuel injection into the cylinder at least twice during the compression stroke for the first combustion event, with varying injection numbers and timing based on engine events to optimize combustion performance and emission control, using a control system to adjust parameters such as injection timing, fuel amount, and spark timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fuel is injected during the intake stroke, then fuel delivery occurs, but fuel travels across the combustion chamber and deposits on the opposite wall where it does not combust
Solution Approach 1:
The patent applies preliminary action by injecting fuel during the compression stroke before the combustion event, allowing the fuel to be positioned and mixed with air in advance of the spark ignition. This timing ensures the fuel is ready for complete combustion when the spark occurs, preventing unburnt hydrocarbons from escaping.
Solution Approach 2:
The patent applies local quality by targeting the fuel injection toward the spark plug location during the compression stroke. This creates a localized fuel cloud in the specific region where combustion will occur, ensuring concentrated fuel delivery to the correct location rather than distributing fuel across the entire combustion chamber.
2Quantity of substance
If fuel is injected during the compression stroke, then fuel is delivered to the cylinder, but the fuel cloud is not repeatably and tightly controlled and may miss the spark plug
Solution Approach 1:
The patent applies dynamics by adjusting the injection timing relative to the compression stroke based on engine operating conditions. The injection timing is dynamically controlled to account for variations in compression timing and duration, ensuring the fuel cloud consistently reaches the spark plug location across different engine speeds and loads.
Solution Approach 2:
The patent applies feedback by using sensor data from the engine management system to adjust injection parameters. The control system monitors engine conditions and modifies the injection timing and duration to maintain precise fuel cloud positioning at the spark plug, compensating for variations in real-time.
3Productivity
If multiple injections are used during the first combustion event, then combustion efficiency improves, but injection timing and fuel amount control complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the fuel injection into multiple separate injection events during the first combustion cycle. This includes an initial injection followed by additional injection(s), allowing each injection to be optimized for specific combustion phases and improving overall combustion efficiency through staged fuel delivery.
Solution Approach 2:
The patent applies periodic action by implementing multiple injections at specific intervals during the first combustion event. The injection system delivers fuel in periodic pulses rather than a single continuous injection, with each pulse timed to correspond to specific points in the compression and combustion process.
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 approach improves combustion efficiency and reduces emissions by ensuring fuel is accurately delivered to the spark plug, enhancing engine starting and stabilization, particularly during cold starts, by optimizing injection strategies based on engine conditions.
Implementation Method 1
directly injecting fuel to the cylinder at least twice, where each of said two injections at least partially occur during a compression stroke
Implementation Method 2
ensuring fuel is accurately delivered to the spark plug, enhancing engine starting and stabilization
Data Source
AI summary
A method for starting an internal combustion engine having direct fuel injection into a cylinder, comprising of only for a first combustion event under selected conditions during an engine start, directly injecting fuel to the cylinder at least twice, where each of said two injections at least partially occur during a compression stroke.