It’s a common problem: You’re off to Le Mans with your new 400 bhp engine and you discover that it won’t fit in the airplane's overhead compartment. This week, Nissan showed off the answer to this traveler’s nightmare with its ultralight DIG-T R 1.5 liter, three-cylinder petrol engine that is small enough to fit in carry-on luggage and boasts a power-to-weight ratio better than the engine of a Formula 1 racer.

The new engine is the other half of a hybrid powerplant for Nissan's Zero Emission On Demand Racing Car (ZEOD RC), which is set to become the first entry to complete a lap of the Circuit de la Sarthe at Le Mans solely under electric power this June.

The DIG-T R’s base engine is 500 mm tall x 400 mm long x 200 mm wide (19.68 x 15.74 x 7.78 in), but it puts out power like a fire hose at 400 bhp (298 kW) and 380 Nm (280 ft-lb) of torque. Nissan points out though this is small enough to fit inside the luggage guides found at check in, at 40 kg (88 lb), the DIG-T R is too heavy to be considered as a carry-on. That works out to 10 bhp per kilo, which Nissan says is better than the new engines approved for the FIA Formula 1 World Championship this year.

The engine is an example of how Nissan is approaching the ZEOD RC with an eye towards reducing size while increasing efficiency. The ZEOD RC is also part of an effort to develop a more efficient petrol/electric hybrid engine that can switch on or off on demand.

As part of the design strategy, both the petrol and electric parts of the powerplant go through the same five-speed gearbox. However, Nissan says that the real problem in developing the DIG-T R for the ZEOD RC was cutting down friction, since the less of it there is, the less the engine needs to deal with its consequences. To help with this, Nissan worked closely with French lubricants manufacturer Total to come up with better fuels and lubricants to take care of internal friction.

After the ZEOD RC finished dyno testing, Nissan took to the track last week, where it tested both the electric and petrol components. It will undergo further testing for the next four months, then in June it will take part in the Le Mans 24 Hour, where it will occupy “Garage 56.” which is reserved for new technology demonstrators by the Automobile Club de l‘Ouest. The ZEOD RC will do one lap of each roughly hour-long fuel stint of the competition using only electric power, then the DIG-T R will take over for the rest of the run. Lessons from the ZEOD RC will be used in Nissan’s entry in the LM P1 class of the FIA World Endurance Championship in 2015.

"Nissan will become the first major manufacturer to use a three-cylinder engine in major international motorsport,” says Darren Cox, Nissan's Global Motorsport Director. “We're aiming to maintain our position as industry leaders in focusing on downsizing. Lessons learned from the development of the engine will be seen in Nissan road cars of the future.

The video below explains the development of the new engine.

Source: Nissan