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  • Interview: Tim Britt, Chief Engineer and Elma Avdic, Technical Project Leader, Cummins 5.0L V-8

Interview: Tim Britt, Chief Engineer and Elma Avdic, Technical Project Leader, Cummins 5.0L V-8

Claiming the Space

Gary Witzenburg
Feb 11, 2016
Photographers: courtesy of Nissan, Courtesy of Cummins
Despite very different backgrounds, Tim Britt and Elma Avdic share much in common.
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Growing up on a small farm in southwestern Virginia, Tim showed early mechanical talent. "From the age of eight, I was taking apart and repairing lawnmowers and dirt bikes," Tim says. Aspiring to be an engineer, he went to Virginia Polytechnic Institute (Virginia Tech) while co-opting at a nearby Volvo Truck facility during all five terms. He joined Cummins following graduation with a bachelor of science in mechanical engineering in 1992.
Elma grew up in Sarajevo, Bosnia, and Herzegovina, and came to the U.S. for her senior year at West Potomac High School in Fairfax County, Virginia, before moving on to study electrical engineering, also at Virginia Tech, in 2000. "As a child growing up in Bosnia," she says, "my dad was an engineer and a hands-on guy. He didn't have any boys, so I was like his little boy. I did some hands-on work with him growing up and developed a love for math, science, and engineering." She interned twice at Cummins while at Virginia Tech and joined full-time in 2004 as a senior engineer for electronic engine control module development.
Tim has advanced through a variety of responsibilities ranging from R&D to product development to production support on the full range of Cummins engines. He was technical project leader for the Tier-3 industrial version of the 6.7L turbodiesel before joining the 5.0L V-8 team in 2006 as base engine development leader. He was named chief engineer in 2013.
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Elma moved up to Engine Controls team leader for the Dodge Ram pickup version of the 6.7L turbodiesel six in 2007 and technical product leader for the medium-duty version in 2011. She joined the 5.0L V-8 team in 2013 as overall technical project leader.
What do they have in common beyond engineering degrees from VT, a love of diesel technology, and their partnership on the leadership team for the new 5.0L turbo-diesel V-8 now available in the ’16 Nissan Titan XD pickup? Both also earned their masters degrees in engineering from Purdue University: Tim in 1999 and Elma a decade later in 2009.
Truck Trend: The 6.7L turbodiesel six is a veteran that's been updated through the years.
Tim Britt: We know that many customers look for the Cummins logo, which is one reason why we're really excited about this new 5.0L V-8 in the Nissan truck. We believe our badge on its side will be a real selling point.
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TT: Was there debate around V-8 versus I-6?
TB: This program started as R&D in the early ’90s. The U.S. Department of Energy offered grant money to pursue alternatives to large V-8 and V-10 gas engines in pickups and vans, looking for major fuel economy improvement. So Cummins put together a proposal and received that grant, and that led to some of the early decisions around the architecture.
When I came to the program in 2006, the directive was to provide a diesel equivalent that would fit in the same "space claim" as a V-8 gas product. A V-8 is shorter in height than an inline-six and a lot shorter in length, so it was mostly space claim that led to the V-8 decision.
TT: Was Chrysler your first intended customer?
TB: Yes, but when Chrysler unfortunately went into bankruptcy in 2008-09, that opened the door for us to pursue other OEMs.
TT: There was a joint venture between Chrysler and Nissan to share their next-generation pickup, but following the bankruptcy, Nissan started over with its own new truck. So it was a natural progression for Nissan to become your OEM customer?
TB: There was a gap in time between Chrysler backing away and Nissan committing, but Cummins was committed to this product and convinced that it would be a hit in the American pickup market. We stayed the course, took a step back ,and made some significant improvements. We're really excited about the way it has turned out with Nissan.
Truck Trend: Are you contractually bound not to sell it to any other OEM?
Elma Avdic: The base engine can be sold to other customers, but this particular calibration and tuning was developed specifically for Nissan and is not available to other OEMs. TT: What were its design objectives?
TB: One primary goal was to make it fit wherever a gas V-8 would. Other key objectives consistent with replacing gasoline products were weight and NVH (noise, vibration and harshness). It's not as light as a gas V-8 but significantly lighter than our inline-six, and we made it as much like a gasoline product as possible when it comes to NVH. TT: Was it challenging to design it to fit where a gas V-8 would?
TB: We made decisions around the bore and stroke, the valvetrain, and the air handling systems to make it fit. It wasn't extremely difficult, but it absolutely influenced our design decisions as we were laying out the architecture.
EA: As we chose the lightweight design, we had to keep the strength and durability expected of a Cummins engine. As we innovated new technologies and integrated them, we held ourselves to the same validation standards as for the 6.7L and other Cummins products.
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TT: Was meeting U.S. emissions especially difficult?
EA: Some decisions and technologies we chose were for emissions requirements. We chose high-pressure common-rail Bosch piezo fuel injection with very precise multiple-pulse injections for both emissions and NVH. Our "M-squared" turbocharger is two-stage but acts as a series turbo for emissions and to avoid turbo lag in acceleration.
TT: How difficult was achieving the balance of emissions, fuel efficiency, and output?
EA: We must meet emissions while optimizing fuel economy and power. It's a trade-off that fits in the white space between heavy-duty pickups and light-duty gas engines.
TB: We benchmarked other products to make sure we understand what they are doing, but we have taken many opportunities to innovate. The engine is sized and designed to fill this niche between a half-ton and a 3/4-ton pickup, and the design of our turbocharger and the way we're using the advanced fuel system are unique to Cummins.
EA: We haven't talked about cold weather performance.
TB: We worked with Nissan to establish a one-touch starting system. Step on the brake, press the start button, take your finger off, and the engine will crank and start. There's a very short period for the glow plugs to energize. We're really excited about the way it's performing in that situation because a lot of customers will be making the transition from gasoline to diesel, and a lot of traditional diesel products take a little longer to start than gasoline engines.
TT: What technology enables that performance?
TB: Ceramic glow plugs in each cylinder instead of a single grid heater in the intake. We've also paid a lot of attention to tuning the engine and dialing in the fuel-injection events and air-handling controls to improve cold-start performance.
AE: Another benefit is that electrical requirements on the vehicle are greatly reduced, since the grid heater requires large cables and fuses and a lot more energy from the battery compared to the glow plugs.
TT: Engineers are never satisfied. Is there room for improvement in future generations?
TB: At Cummins, we never stop trying to make improvements to our products, and this one will not be an exception. We're excited about this engine as we're launching it, but we will continue to work very closely with Nissan to recognize and pursue improvements.



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