Ford 2011 6.7L Power Stroke® Diesel Engine Combustion System Development Ford Motor Company

Format:

Conference/Event

Author/Creator:

Styron, Styron, author.

Contributor:

Baldwin, Brian

Fulton, Brien

Ives, David

Ramanathan, Subramanian

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

A new diesel engine, called the 6.7L Power Stroke® V-8 TurboDiesel, and code named "Scorpion," was designed anddeveloped by Ford Motor Company for the full-size pickup truck andlight commercial vehicle markets. The combustion system includesthe piston bowl, swirl level, number of nozzle holes, fuel sprayangle, nozzle tip protrusion, nozzle hydraulic flow, andnozzle-hole taper. While all of these parameters could be exploredthrough extensive hardware testing, 3-D CFD studies were utilizedto quickly screen two bowl concepts and assess their sensitivitiesto a few of the other parameters. The two most promising bowlconcepts were built into single-cylinder engines for optimizationof the rest of the combustion system parameters.1-D CFD models were used to set boundary conditions at intakevalve closure for 3-D CFD which was used for the closed-cycleportion of the simulation. The critical C100 operating conditionfor the dynamometer-certified engine was chosen to evaluate howwell each combination of parameters utilized the limited availableoxygen in the cylinder. A fractional-factorial Designed Experiment(DoE) was developed that assessed three shape parameters in eachbowl concept as well as two swirl levels, and three fuel sprayangles. Two bowl shapes were selected based on a multi-objectiveoptimization which sought to simultaneously minimize fuelconsumption and NOx and soot emissions. The DoE also allowed anassessment of sensitivities to variations in the other parameterswhich could be important for robustness considering manufacturingvariation. Analysis of the mixing structures from the 3-D CFDproved beneficial to help explain some of the trends.Each piston bowl was built into a single-cylinder engine block.Two cylinder heads, each with a different swirl level, were alsoprepared. A suite of injectors was built to vary the number ofinjector holes, fuel spray angle, hydraulic flow, and nozzle-holetaper. For each injector, copper washers of varying thickness wereused to fine tune injector targeting. For each hardwarecombination, EGR sweeps were performed at four different operatingconditions (C100, A100, A25, and 1500 rpm/3 bar BMEP) to allow acomplete assessment of emissions and fuel economy performance. Thetwo higher load points are critical for dynamometer-certifiedemissions compliance. The two lower load points are critical totypical driving fuel economy and chassis-certified emissionscompliance. Analysis of the EGR sweeps proved useful for selectingall of the combustion system parameters that now form the heart ofthe 2011 6.7L Power Stroke® V-8 Turbo Diesel.Glow plugs were chosen as the primary cold-starting aid. CFDstudies were performed to find an optimum location that couldenhance cold-start ability, cylinder head strength, and glow plugdurability. The recommended location and several depths shorter andlonger were tested in multi-cylinder engines to verify function andprovide data for determination of the final glow plug location. Theproduction location, outside of the valve bridge area, maximizesinteraction of vapor-phase fuel with the glow plug while minimizingimpingement of liquid phase fuel

Notes:

Vendor supplied data

Publisher Number:

2011-01-0415

Access Restriction:

Restricted for use by site license