Multi-Stroke Fuel Injection for SIDI Engine Emissions
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Solution Overview
Problem
Spark ignition direct injection (SIDI) engines generate more hydrocarbons during startup and cranking due to insufficient fuel-air mixing, leading to increased hydrocarbon emissions when cold, as the fuel has less time to mix with air before ignition.
Innovation Solution
Implementing a multi-fuel injection combustion cycle mode with multiple fuel injections during a combustion cycle, controlled by a temperature sensor to optimize fuel-air mixing, including a first injection during the intake stroke and a second injection during the compression stroke, reducing the number of fuel injections based on temperature signals to improve burn efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fuel is injected directly into the combustion chamber once per combustion cycle, then fuel economy and power are improved, but hydrocarbon emissions increase during cold startup and cranking
Solution Approach 1:
The single fuel injection per combustion cycle is segmented into multiple injections: a first injection during the intake stroke and a second injection during the compression stroke. This segmentation allows the fuel to be delivered in stages, ensuring better mixing during cold conditions while maintaining efficiency during normal operation.
Solution Approach 2:
The fuel injection system dynamically adjusts the number of injections based on engine temperature conditions. During cold startup and cranking, multiple injections are performed to enhance mixing. Once the engine reaches operating temperature, the system transitions to a single injection per cycle, optimizing for fuel economy and power.
2Power
If fuel is injected directly into the combustion chamber, then power and efficiency are improved, but fuel-air mixing time is insufficient during cold operation
Solution Approach 1:
The first fuel injection occurs during the intake stroke, before the compression stroke begins. This preliminary injection allows fuel to be introduced into the combustion chamber earlier, providing additional time for fuel-air mixing to occur during the intake and early compression phases, particularly important when engine temperature is low.
Solution Approach 2:
By dividing the fuel delivery into two separate injection events, the system ensures that fuel is introduced at optimal moments during the combustion cycle, extending the effective mixing time without compromising the power output associated with direct injection.
3Stability of the object's composition
If multiple fuel injections are performed during a combustion cycle, then fuel-air mixing is improved, but device complexity increases
Solution Approach 1:
The existing fuel injection system, originally designed for single injection per cycle, is enhanced to perform multiple injections by adding temperature-based control logic. The same hardware infrastructure is utilized, but the control module now executes conditional logic to determine whether to perform one or two injections based on engine temperature, avoiding the need for additional injection hardware.
Solution Approach 2:
The control module uses temperature sensor feedback to determine the appropriate injection strategy. When the engine temperature indicates cold operation, the system activates the second injection during compression stroke. This feedback-based control adds minimal complexity while achieving improved mixture homogeneity when needed.
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 enhances air/fuel mixture burn in the cylinder, reducing engine-out hydrocarbons during cranking and startup without requiring additional fuel injection hardware, thereby improving emissions and engine efficiency.
Implementation Method 1
A SIDI engine includes a high pressure fuel injection system that sprays fuel directly into a combustion chamber
Implementation Method 2
A temperature sensor generates a temperature signal indicative of a temperature of a portion of the exhaust system
Implementation Method 3
At the end of the compression stroke the air/fuel mixture is ignited to provide a power stroke
Data Source
AI summary
The fuel injection system includes a fuel injector that injects fuel directly into a combustion chamber of a cylinder of an engine. The control module initiates multiple fuel injections in a combustion chamber during a combustion cycle of the cylinder via the fuel injector.