Internal Combustion Engine Cylinder Group Segmentation for Reliable Cold Start
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Solution Overview
Problem
Large gas engines operated with fuel gas face difficulties in starting reliably, especially at low temperatures, due to the dilution of the gas/air mixture by compressed air, which prevents ignition.
Innovation Solution
Preheating the prechambers of at least one group of cylinders to a defined temperature, blowing compressed air into all cylinders until a breakaway speed is reached, then disabling air supply to the first group and introducing self-igniting pilot fuel to ignite the gas/air mixture, while continuing compressed air supply to the second group until a starting speed is reached, and finally stopping air supply to all cylinders for ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If compressed air is supplied to all cylinders during starting, then the engine can overcome breakaway torque, but the gas/air mixture is diluted and ignition is prevented
Solution Approach 1:
The cylinders are divided into two groups: a first group that receives only compressed air for overcoming breakaway torque, and a second group that receives the gas/air mixture for ignition. This segmentation allows the starting process to be separated into two functional zones, resolving the contradiction between needing compressed air for torque and needing undiluted mixture for ignition.
Solution Approach 2:
The harmful dilution effect of compressed air is extracted and isolated to only those cylinders that need it for breakaway torque. By taking out the compressed air supply from the ignition-critical cylinders, the patent preserves the integrity of the gas/air mixture where ignition is required.
2Speed
If compressed air is supplied continuously to all cylinders, then the engine can reach starting speed, but the gas/air mixture concentration is reduced below ignition threshold
Solution Approach 1:
Cylinders are segmented into those receiving compressed air and those receiving gas/air mixture. This allows the system to achieve the necessary starting speed through air-compressed cylinders while preserving sufficient fuel concentration in mixture-supplied cylinders for reliable ignition.
Solution Approach 2:
Different cylinder groups are assigned different air supply qualities: one group receives pure compressed air for mechanical force, while the other group receives the fuel-containing gas/air mixture for combustion. This local differentiation resolves the contradiction between speed achievement and mixture concentration.
3Reliability
If compressed air supply is interrupted early, then ignition can occur in first group cylinders, but the engine cannot reach sufficient starting speed
Solution Approach 1:
The starting process is segmented into two phases with different cylinder group activations. The first phase uses compressed air cylinders to build up speed, then the second phase activates mixture-supplied cylinders for ignition. This temporal and spatial segmentation allows both speed achievement and reliable ignition.
Solution Approach 2:
Compressed air is supplied to the first group of cylinders in advance to overcome breakaway torque and initiate rotation before the gas/air mixture is supplied to the second group for ignition. This preliminary action sequence ensures both speed threshold is reached and ignition can occur.
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
Enables reliable starting of the internal combustion engine by overcoming breakaway torque and achieving ignition in both groups of cylinders, ensuring consistent engine startup even at low temperatures.
Implementation Method 1
preheating of prechambers of at least a first group of cylinders to a defined preheating temperature
Implementation Method 2
blowing compressed air into all cylinders of the first and second group of cylinders at the beginning of the starting process
Implementation Method 3
introducing self-igniting pilot fuel into the antechambers of the first group of cylinders when the breakaway speed is reached and igniting the gas/air mixture in the cylinder spaces of these cylinders using the self-igniting pilot fuel
Data Source
Figure 1
AI summary
The method involves forming burnable gas/air mixture in an admission system (I) in a gas mixer (9). Pre-combustion chambers of a group of cylinders (2, 3, 6) are pre-heated to a defined pre-heating temperature. A self-igniting pilot fuel is introduced into the pre-combustion chambers of the cylinders when a defined rotational speed is reached. The gas/air mixture is ignited in cylinder chambers of another group of cylinders (1, 4, 5) by the fuel. The supply of pressurized air to the respective cylinders is stopped after the ignition of the gas/air mixture that is blown into the chambers. An independent claim is also included for an internal combustion engine comprising an internal combustion system.