1. Variable distribution

Table 1 summarizes some of the key dates in the evolution of the internal combustion engine, highlighting the technologies behind variable valve timing.

The first patent on variable valve timing was filed in 1902 by Louis Renault. 1954 saw the appearance of Alfa Romeo's first mass-produced phase shifter, which remained in production until 1993. Another pioneer in this field was Honda, who introduced the famous VTEC system in 1989.

Since then, a multitude of variable valve timing systems have been developed. In 2001, BMW introduced the Valvetronic-Vanos system, which allows production engines to operate without throttle valves.

In 2009, a real innovation introduced on production vehicles was Fiat's electrohydraulic MultiAir valve timing, which is now available...