H engine

A hydrogen engine is a combustion engine with a cylinder arrangement in which the cylinders or even cylinder banks, as viewed in the direction of the crankshaft to look like a lying, large H. An H- motor may, accordingly, two superposed 180 ° V - motors can be seen. The " two" engines have their own crankshaft, which are connected to the engine end to which the force is removed with gears, respectively.

Pros and Cons

The above cylinder arrangement enables the full balancing of free mass forces already at four cylinders without balance shafts, however, a worse power to weight ratio results than variants with a single crankshaft. In aircraft it has the advantage that you can build flatter and also compact engines with the same number of cylinders as compared to radial engines. This allows for better aerodynamics.


Because of the few advantages over many drawbacks H motors were used very rarely.

H engines in the motorcycle

H engines in automobiles

  • B.R.M. H -16 Formula 1 engine. The engine was a flop because it was too heavy and too unreliable, and too little torque and had a high center of gravity. Jackie Stewart is said to have said about the engine " This piece of metal you should be better than ship's anchor instead use as an engine ."

H engines in aircraft

  • Napier Rapier, Dagger and Sabre aircraft engines. In contrast to the BRM engine Sabre was a successful design. Pratt & Whitney developed the X - 1800's.

H engines in ships

  • In the early 1970s, the German and the French Navy developed in cooperation a 40 -cylinder H engine ( 40 H 672 ) for marine technical specialty applications. For the V- angle of a standard 20 - cylinder four- stroke diesel engine was enlarged to 180 ° and combined two such units to an engine. The two counter-rotating crankshafts transferred their performance to a common output shaft. To conserve fuel an engine half could be turned off. It remained, however, in an attempt engine.

Designated incorrect "H " engines

Subaru has irritating, water- cooled 4 - and 6- cylinder boxer engines marketed as H -4 and H-6, although the cylinder assembly has nothing to do with a real H- engine. It would be correct, the term B4 and B6 (B for Boxer ).

Saab uses the term "H - Motor" (H engine) for a conventional four-cylinder in-line engine, which is available with 2 and 2.3 liters (type designation B205 and B235 respectively ).