Engine Cylinder Selection for Starting via Dual Fuel Injection
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Solution Overview
Problem
Engines that frequently stop and restart face challenges in maintaining consistent starting positions, leading to degraded engine emissions and extended run-up times due to varying stopping locations, making it difficult and costly to adjust engine actuators for consistent engine stopping.
Innovation Solution
A method is developed to select a cylinder for engine starting by providing two fuel injections during the compression stroke, with the ratio of fuel between the injections adjusted based on intake valve closing timing, to improve combustion stability and reduce engine emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the engine is stopped at different positions each time, then the engine can be restarted without complex positioning mechanisms, but engine emissions degrade and run-up time increases
Solution Approach 1:
The system changes fuel injection parameters (timing, duration, ratio between first and second injections) based on the detected engine stopping position. The ECU selects different fuel injection strategies depending on which cylinder is nearest to TDC, thereby adapting to varying stop positions while maintaining consistent emissions performance and run-up characteristics.
2Object-generated harmful factors
If engine actuators are adjusted to achieve consistent engine stopping position, then emissions and run-up time improve, but device complexity and cost increase
Solution Approach 1:
The system uses the existing starter motor to rotate the engine and automatically detects the stopping position using existing sensors (crankshaft position sensor). The ECU then self-adjusts fuel injection parameters based on detected position, eliminating the need for additional actuators or complex positioning mechanisms while maintaining consistent starting performance.
3Reliability
If fuel injection timing is optimized for specific cylinder positions, then combustion stability improves, but control system complexity increases
Solution Approach 1:
The control system dynamically adjusts fuel injection timing and duration based on the real-time engine stopping position. The ECU selects different fuel injection strategies depending on which cylinder is nearest to TDC, thereby adapting to varying stop positions while maintaining consistent starting performance and combustion stability without requiring complex mechanical adjustments.
4Reliability
If two fuel injections are provided during compression stroke, then combustion stability and starting robustness improve, but energy consumption increases
Solution Approach 1:
The fuel injection is divided into two separate injections during the compression stroke: a first injection that establishes initial combustion conditions and a second injection that enhances combustion stability. This segmentation allows for optimized fuel distribution timing, ensuring reliable starting while managing energy consumption through precise control of each injection event based on cylinder position.
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 engine starting consistency, reduces misfires, improves emissions, and enhances driver perception by optimizing fuel injection timing and ratio relative to the engine's position and operating conditions.
Implementation Method 1
providing two fuel injections during a compression stroke of the cylinder for a first combustion event since engine stop
Implementation Method 2
first combustion event since engine stop
Data Source
AI summary
A method and system for improving starting of an engine is presented. In one example, the method selects a first cylinder to receive fuel since engine stop the cylinder's position relative to the cylinder's top-dead-center compression stroke. The method also describes adjusting a number of fuel injections for a first combustion event since engine stop.