The Anatomy of Volvo's Triple Charged Engine

By: Grattan R.

First, let us start with the basics, turbochargers and superchargers are both methods of adding more horsepower to cars by the means of forced induction. In simple terms, turbochargers and superchargers compress more air and send it into the combustion chamber of an engine for rapid power increase- aka forced induction. A turbo is driven by an impeller which has to spool and a supercharger is driven by two screws that both spin opposite each other to create a compression effect. The forced air from both of these applications means the engine can cycle much quicker, but it also means lots of stress on an engine.

This is where Volvo’s magic comes in, for example the amount of air being compressed by a forced induction application is measured in boost pressure, or psi. So, for example if a turbo is making 24 psi, it is forcing 24 pounds of compressed air simultaneously into the engine block. This is relevant because usually just to handle one supercharger or turbo an engine has to be reinforced internally to withstand the massive pressures of boost. Volvo however has managed to fit two turbochargers and one supercharger onto an engine, making a huge horsepower number for a 2 liter 4 cylinder, all while still retaining fuel economy, reliability, and keeping price reasonable.

One more factor affects engines with forced induction: lag. While an economy turbo car with a fist-sized turbo may not have to worry about lag, Volvo is clearly going for performance with their new line of engines. Lag is the time from when you push the pedal down to when the forced induction application has spooled to a quick enough speed to produce boost. Lag is the killer of forced induction engines, many of them produce much less power until boost kicks in. While Volvo isn’t the first to do the method of using an anti-lag supercharging system to eliminate lag for two turbochargers, they are the first to offer it on a production car. Anti-lag means at any rpm; you will be able to have boost pressure. This is achieved by a supercharger creating boost pressure constantly when the pedal is pressed so that once power is needed, boost pressure for the turbochargers to utilize has already been generated.

What Volvo has done is revolutionary and risky at the same time. They have enabled anyone who can afford it to have a compound supercharged system their car (until now if you wanted a compound supercharger system you would have to do a custom job yourself), as well as save people money and change the sports car market. This is risky because of the decline of sports cars in the early 2000’s to 2013 ish, but the market is coming back stronger and I think Volvo will continue to innovate as such; I just hope they make their new car in manual.

Sources Cited

George, Patrick. “How Volvo Will Crank 450hp Out of Just 4 Cylinders”. Jalopnik.com. Jalopnik. Web. 20 February 2016.

Perkins, Chris. “Report: Volvo Polestars May Use 450-HP Triple-Charged Four-Cylinder”. Road&Track.com. Hearst Digital Media. Web. 20 February 2016.

Picture Sources

http://jalopnik.com/how-volvo-will-crank-450-hp-out-of-just-four-cylinders-1643311981

http://roa.h-cdn.co/assets/16/07/980x490/landscape-1455987134-158312-volvo-s60-and-v60-polestar-model-year-2016.jpg