Volvo Trucks is introducing a next generation 13-liter turbo compound engine, the D13TC. John Bartel, Volvo Trucks director, product strategy-driveline, discusses the engine enhancements and what they mean for fleets. Q: What makes the D13TC different from other turbo compound engines? A: “You have two choices when you make a turbo compound engine. Most prior applications used the compound turbine to create additional horsepower, to make a 500 hp engine a 520 hp engine, for instance. We’re not doing that, but instead using it to gain efficiency. We are getting the same horsepower but burning less fuel. Because we’re capturing that energy out of the exhaust, we can put a little less fuel in each cylinder.” Q: What applications are best for the D13TC? A: “Any application that needs fuel efficiency and drivability, combined with good power and peak torque. Sleepers or daycabs that run a lot of highway miles, that’s where the TC really shines. e TC is nice for fleets running decent loads for significant miles and trying to get their best fuel efficiency. It’s effective over a much broader range of applications than our first generation of TC engines.” Q: What will drivers notice with the new engines? A: “It’s much better on the driver. It’s better on the inside acoustics than a typical engine goig down to 900 rpm. You would expect a normal 13-liter engine on lower numerical ratio to be a 2.64 rear axle ratio. e D13TC would be a 2.47 rear axle ratio equivalent. And with the turbo compound, as exhaust is constantly coming through the unit and the recovered power is going directly back to the crankshaft , it’s much more of a constant energy stream to the crankshaft , so it’s smoother running. at creates a lot less stress on the driver. Drivers get used to it—so much so that when they get into a different truck, they notice more noise.” Q: What’s different about this engine from the first generation of Volvo turbo compounds? A: “In our first generation TC engines, we knew what applications would be good and which wouldn’t and we tried to keep the applications as limited as possible. Now, we have further optimized the engine so it’s no longer the case that you have to be in a very specific duty cycle to get the maximum bene t out of it. We also optimized it with our I-Shift transmission to enable control of the shift points and keep it within fuel-efficient rpms at all times. We can downspeed the engine and save fuel.” D13TC Fact Box (to go beside the Q&A) The next generation D13TC is up to 6% more efficient than Volvo’s current 2020 D13. It is 11% more efficient than the 2015 model. The Volvo D13TC uses two turbines in series. The first is the turbocharger turbine; the second is part of the turbo compound unit and is geared back to the crankshaft.