Honda builds V3 engine with electric supercharger

At this year's iteration of the EICMA motorcycle show, Honda is presenting a radical drive concept: a very slim V3 engine in a tubular steel bridge frame. An electrically driven compressor applies air pressure to the airbox. According to Honda, the V3 compressor concept is intended to address the question of what the next generation of highly efficient engines for motorcycle use could look like. In Honda's words, the result was "a liquid-cooled three-cylinder V-four-stroke engine with a cylinder angle of 75 degrees for machines with a larger displacement".

Unfortunately, the "larger displacement" is not specified. Visually, some colleagues estimate it at around 900 cm³. The V3 arrangement of the cylinders, with a very narrow bank of 2 cylinders at the front and one cylinder at the rear, is a real attention-grabber at the motor show. Honda and other motorcycle manufacturers successfully used V3 engines as two-strokes in the 500cc championships in the 1980s. With the Honda NS400 R in 1985, Honda even brought out a road version of the motorcycle with which Freddie Spencer won the 500cc world championship title in 1983. Although a V3 could also be built as a four-stroke, it does not seem likely that Honda would do this, as the concept would have hardly any advantages over the V4, as successfully built in series by Honda, Aprilia and Ducati, for example, but would have some disadvantages. However, the second part of the drive concept is a completely different story: the compressor.

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V3 mit Kompressor: das Konzept in Bildern (12 Bilder)

Electrically compressed

In the concept, Honda places a small compressor above the cylinder bank at the front. Unlike Kawasaki's H2 series, this is not mechanically driven directly by the engine, but by an electric motor. This approach completely decouples the compressor speed and thus the boost pressure from the engine speed. Honda's aim is to improve engine torque, particularly at low and medium engine speeds, and thus potentially also efficiency in the partial load range. Firstly, electric compressors can be controlled independently of the engine speed (conventional compressor) and exhaust gas pressure (turbocharger) and secondly, they only need a few hundredths of a second for speed jumps, which enables very precise timing of the required pressure and thus reduces the need for electrical drive energy.

Turbochargers with electric auxiliary drive have now become established in the automotive sector. Honda has deliberately chosen a different technology because it is easier to integrate into the very limited installation space on the motorcycle. The supercharger does not require charge air cooling and does not have to be resistant to high temperatures. In the concept, Honda shows it mounted in front of the airbox in the front frame triangle. However, it could also be located at the rear on vehicles with an airbox at the rear. So although a V3 would be cool but is unlikely, electric superchargers could actually become a feature of upcoming Honda production engines.

(cgl)