We’ve been learning a lot about variable valve timing and the technology behind the various systems over the last year here at ELTA. Variable valve timing is a key process used by many vehicle manufacturers to meet increasing strict emission regulations. The methods used vary but the fundamentals remain the same. By gaining more control of valve lift depending on engine speed and conditions, greater efficiency can be achieved. There have been many milestone vehicles since its introduction but here are some of the most significant and iconic.
1903 Cadillac Runabout and Tonneau
Surprisingly, the first use of variable valve timing was on the 1903 Cadillac Runabout and Tonneau. This is believed to be the first Patent for automotive use. Patent 767,794 “INLET VALVE GEAR FOR INTERNAL COMBUSTION ENGINES” filed August 3rd, 1903, and granted August 16th, 1904.
1980 Alfa Romeo Spider 2000 – VVT
It would be many years until variable valve timing became commonplace on our cars. Several manufacturers filed patents including Porsche in 1958 and Fiat in the late 60s. But it was Alfa Romeo who became the first manufacturer to use a variable valve timing system in a production car. Whilst the fuel injected 1980 Alfa Romeo Spider 2000 had a mechanical VVT system; All other Alfa Romeo Spider models (1983 on) used electronic systems.
1989 Nissan 300zx (Z32) – N-VTC
Nissan introduced their ground-breaking N-VTC system in 1987 on their VG30DE and VG20DET engines. These engines featured in many Nissan production, prototype and even race cars. Arguably the most iconic and respected being the 1989 Nissan 300zx (Z32)
1989 Honda Civic – VTEC
Arguably one of the most recognisable systems, Honda released the VTEC system in 1989. Whilst earlier Nissan systems altered the phasing of the camshaft, the VTEC system switches to a separate cam profile at high engine speeds resulting in improved peak power. The first VTEC engine was the B16A used in the Integra, CRX, and Civic hatchback.
1992 Porsche 968 – VarioCam
Porsche’s VarioCam system in 1992 was the first system to provide continuous adjustment (rather than discrete adjustment). The Porsche 968 was the first to use this system which operated on the intake valves only.
1992 BMW E34 520i & 525i – VANOS
BMW introduced their first variable valve timing system in 1992.
The system named VANOS (an abbreviation of the German words for variable camshaft timing) was first used by BMW in the Straight-6 M50 engine of the E34 520i and 525i.
2000 Toyota Celica – VVT-i
Another of the most recognisable systems to date; Toyota launched VVT-i in 1995, and it was first seen on the 1998 Lexus LS 400 and the more familiar 2000 Toyota Celica. VVT-i stands for Variable Valve Timing-Intelligence, which is Toyota still use today in most of its internal combustion engines.
2001 BMW 316ti – Valvetronic
In 2001 BMW introduced a sophisticated system called Valvetronic. Whilst VANOS controlled timing of the lift, Valvetronic controlled the amount of lift. It was first used on the 2001 316ti compact. Valvetronic has since featured in many of BMW’s engines. The first use of this technology in a turbocharged engine was another BMW milestone as used in the N55 engine.
2001 Peugeot 307 – VTi
As variable valve timing became more common place, it began to filter into more ‘everyday’ vehicles rather than sports or prestige models. Perhaps the most renown of these systems is the VTi Engine (Variable Valve Lift and Timing injection) created jointly by PSA Peugeot Citroën and BMW. It was based around the BMW VALVETRONIC concept and Peugeot claimed a potential reduction in fuel consumption on a 2001-2008 Peugeot 307 by more than 10%. The system is still in use on Peugeot and Citroën models today.
2010 Mitsubishi Lancer 1.8L – First Diesel VVT
In 2010 the first variable valve timing system for diesel passenger vehicles was introduced by Mitsubishi when mass production of the 4N13 1.8 L DOHC I4 engine began. The Mitsubishi Lancer 1.8L 4N13 turbo diesel I4 was one of the first of its kind to market.