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Redesigning the COOPER-BESSEMER® GMV to meet 2008 emissions regulations using advanced in-cylinder combustion

CFD and experimental methodsFebruary 6 & 7, 2013

Reasoning and Concept

Analysis and Methods

Conclusions

Why the GMV, why now?

• The GMV family represents the largest percentage of large-bore, 2-cycle, COOPER-BESSEMER® engines and we had access to a GMVH-6 test stand during design.

• 2008 regulations for emissions would put the GMVs out of service as large overhauls were undertaken.

2008 Regulations

• EPA New Source Performance Standards (NSPS) in 2008 regulated:• NOx – 1 g/bhp·h• CO – 2 g/bhp·h• Volatile Organic Compounds (VOCs) - 0.7 g/bhp·h

• See 40 CFR 60 Subpart JJJJ (Spark Ignited Engines).

Concept

• The original design was based upon the GMVH-6C2.• The pre-chamber was redesigned and repositioned to

provide for more efficient and faster combustion.• The head and piston were redesigned to provide for better

scavenging and, again, to increase combustion speed.

Baseline New

Reasoning and Concept

Analysis and Methods

Conclusions

Experimentation

• Used in two ways:• To provide data from the original design to initialize the

simulation and help set boundary conditions.• After a design has been settled upon and parts made, to

test the parts and compare test data to simulation results and adjust simulation inputs to test data and refine results.

• Primary performance parameters evaluated:• Emissions (NOx and CO)• Combustion speed• Fuel Consumption• Combustion Stability

Computational Fluid Dynamics (CFD)

• CFD can now model:Flow structures ScavengingCombustionEmissions

• This tool is now predictive.• Virtual prototyping and virtual design cycles are now routine.

Baseline New

Reasoning and Concept

Analysis and Methods

Conclusions

CFD Results

• Scavenging analysis shows that the new design has an increase of 10% scavenging efficiency over the baseline.

• Mixing in the new design shows a more uniform distribution of fuel in the main chamber, eliminating pockets of fuel.

• Indicated a faster heat release and uniform combustion in the main chamber.

• Showed a decrease in emissions, both NO and formaldehyde (CH2O).

NOx and CO Emissions

Unburned Hydrocarbon Emissions

Fuel Consumption

Conclusions

• Test results agreed with the analysis results.• NOx, CO, and unburned hydrocarbon

emissions were reduced by up to 60%.• Fuel consumption was improved by 6%.• Analysis allowed for redesign without having to

make multiple prototypes, thus minimizing cost.