Diesel Engine Quantitative Combustion NOx Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current diesel engines face challenges in reducing nitrogen oxide (NOx) emissions, which increase with combustion temperatures and lean conditions, making it difficult to achieve high efficiency and low NOx levels across varying engine loads.
Innovation Solution
Implementing a 4-stroke diesel engine with quantitative combustion, where the amount of fuel is continuously adapted to match the air volume, maintaining a consistent compression ratio and using freely operated inlet valves to regulate air intake, minimizing NOx formation by avoiding lean conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If qualitative combustion is used with varying fuel injection amounts, then power demand can be adjusted, but air excess varies causing NOx formation
Solution Approach 1:
The invention changes the fundamental combustion parameter from varying fuel amount (qualitative) to varying air amount (quantitative). By adjusting the air excess ratio while maintaining constant fuel injection, the system achieves both power control and NOx reduction. The air excess is optimized for each operating point to minimize thermal NOx formation while maintaining efficient combustion.
Solution Approach 2:
Instead of controlling power by varying fuel amount (conventional approach), the invention inverts the approach by controlling power through varying air amount. This inversion allows the fuel-to-air ratio to remain optimal for low NOx formation across all load conditions, while power output is adjusted by changing the total air mass intake.
2Use of energy by moving object
If high compression ratio is used, then engine efficiency is improved, but combustion temperature increases causing more NOx
Solution Approach 1:
The invention changes the air excess ratio parameter across different operating points rather than maintaining constant high compression ratio. By optimizing air excess for each load condition, the system achieves efficient combustion at lower peak temperatures, reducing thermal NOx formation while maintaining high overall engine efficiency through quantitative combustion optimization.
3Object-generated harmful factors
If air excess is reduced to minimize NOx, then combustion temperature decreases improving emissions, but engine efficiency is compromised
Solution Approach 1:
The invention dynamically adjusts the air excess ratio according to the specific operating point and power demand. Rather than using a fixed air excess, the system optimizes the air-to-fuel ratio for each operating condition, achieving the minimum air excess needed for complete combustion at each load level. This dynamic optimization maintains high efficiency while minimizing NOx formation across the entire operating range.
Solution Approach 2:
The system uses feedback from operating point sensors to continuously optimize the air excess ratio. Based on measured parameters such as load, speed, and temperature, the control system adjusts the air intake to maintain optimal combustion conditions, ensuring both high efficiency and low NOx emissions are achieved adaptively across varying operating conditions.
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 results in reduced NOx emissions and high engine efficiency across all engine loads, allowing for effective exhaust treatment and improved combustion pressures and temperatures.
Implementation Method 1
the air is compressed, is varied via the engine control system in relation to said selected volume of air depending on the demand of the power/engine load and which is loaded through the free operated valves during the intake stroke
Implementation Method 2
a selected volume of air is compressed to essentially the same end pressure cycle after cycle
Implementation Method 3
After the compression the amount of fuel is injected that produces the minimum of NOx
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a procedure to minimize NOx during varying engine loads in a 4-stroke diesel engine comprising at least one cylinder with a cylinder head (1), a reciprocating first piston (2) mounted on a connecting rod (3), one actuator (4) mounted on the cylinder-head and one of the actuator operated second piston (5) which can be locked via a hydraulic circuit (6) in various positions in a combustion chamber (7), at least one of the cylinder head existing outlet valves (8) for exhaust gas evacuation, at least one on the cylinder head existing free controlled inlet valve (10) for the supply of combustion air, at least one to the combustion chamber (7) connected injector (9) for injection of fuel in said chamber. The procedure is characterized in that the second piston (5), at the latest during the current compression stroke is actuated by the actuator (4) and is locked by the hydraulic circuit (6) at a position in the combustion chamber (7), where it by the first piston (2) introduced air is compressed in a predetermined compression ratio to meet an existing engine load wherein the free operated inlet valve (10) is brought to close the inlet stroke at a piston position where the volume of the combustion air as introduced at the end of the compression stroke gives the predetermined compression ratio and that the injector (9) injects the stated amount of fuel.