Engine vibration

Much effort is put into improving the comfort for driver and passenger. Two areas that this affects are engine vibration and noise, both the result of the basic engine design. Combustion of fuel, where chemical energy is transformed into mechanical energy, creates gas forces that act on the piston crowns. The reciprocating motion of the pistons and connecting rods create inertial forces that make the engine vibrate in different ways.

At low engine speeds, these gas forces are greater than the inertial forces, while the opposite applies at high engine speeds. The most influential forces arise periodically once or twice per crankshaft revolution and are said to be of the first and second order respectively. Inertial forces of the first order are fully balanced because the crankshaft is balanced and the two pairs of pistons 1--4 and 2--3 turn simultaneously in opposite directions.