Volvo Fuel Efficiency and the Turbo D13TC Compound Engine

Volvo Trucks has a new D13TC engine for their popular Volvo VNL line of Class 8 semis. According to Volvo, this new engine is 6% more efficient than the 2020 model, 11% more efficient than the 2015 model, and up to 16% less fuel than earlier trucks reaching the end of their service lives. The design is built for more than straight fuel efficiency in a laboratory setting. By changing how it delivers power, owners should find lower fuel consumption for any hauling task, including steep grades and heavy loads.

At the center of this new design is a compound turbo. A regular turbo has two turbines connected by a shaft. One turbine is spun by exhaust gases exiting the engine, while the other turbine pushes air into the engine. This compound turbo has an extended shaft that connects to the crankshaft using a series of gears. This lets the flow of exhaust gas power the truck directly while increasing the amount of air in the cylinders. This combination of power delivery allows Volvo to use a fixed geometry turbo without compromising power. That means the engine has fewer moving parts for better reliability. Inside the engine, most of the design is unchanged, aside from the pistons. They are now dished in a way that reflects fuel from the injector toward the center of the cylinder, improving burn efficiency.
This new version of the D13TC engine produces more torque at low RPM than its predecessor. This keeps engine speeds lower during operation, even in severe-duty applications. Operators should expect a longer engine life and lower fuel consumption. The D13TC can be paired with several versions of Volvo’s I-Shift automated manual transmission, including a severe duty model with crawler gears for heavy loads, steep grades, and precision maneuvers. Volvo’s I-See has been updated to take advantage of this new engine. This predictive cruise control is self-learning to judge the right gear and RPM for the current terrain and load.
Volvo says the fixed geometry turbo is designed to meet the 1.2 million mile B50 life of the engine.