9/10/2023 0 Comments Bmw variable valve timingAt high revs, oil pressure forced a metal pin to connect the active finger-follower to its inactive neighbour, bringing all the valves into operation. In the REV system, each valve was operated via finger-follower that sat on top of the valve stem and below the camshaft but the cam lobes only acted directly on half of them – one exhaust and one intake for each cylinder. Unlike a true variable valve timing system, REV involved taking a four-valve-per-cylinder engine and turning it into a two-valve-per-cylinder motor at low revs. The first was Honda’s REV (above) setup back in 1983. The Mitsubishi Lancer 1.8L 4N13 turbo diesel I4 was one of the first of its kind to market.So far, motorcycles have seen three distinct types of variable valve control. 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. 2010 Mitsubishi Lancer 1.8L – First Diesel VVT The system is still in use on Peugeot and Citroën models today. 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%. 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. 2001 Peugeot 307 – VTiĪs variable valve timing became more common place, it began to filter into more ‘everyday’ vehicles rather than sports or prestige models. The first use of this technology in a turbocharged engine was another BMW milestone as used in the N55 engine. Valvetronic has since featured in many of BMW’s engines. It was first used on the 2001 316ti compact. Whilst VANOS controlled timing of the lift, Valvetronic controlled the amount of lift. In 2001 BMW introduced a sophisticated system called Valvetronic. VVT-i stands for Variable Valve Timing-Intelligence, which is Toyota still use today in most of its internal combustion engines. 2000 Toyota Celica – VVT-iĪnother 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. 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. 1992 BMW E34 520i & 525i – VANOSīMW introduced their first variable valve timing system in 1992. The Porsche 968 was the first to use this system which operated on the intake valves only. Porsche’s VarioCam system in 1992 was the first system to provide continuous adjustment (rather than discrete adjustment). ![]() The first VTEC engine was the B16A used in the Integra, CRX, and Civic hatchback. 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. Arguably the most iconic and respected being the 1989 Nissan 300zx (Z32) 1989 Honda Civic – VTECĪrguably one of the most recognisable systems, Honda released the VTEC system in 1989. These engines featured in many Nissan production, prototype and even race cars. ![]() Nissan introduced their ground-breaking N-VTC system in 1987 on their VG30DE and VG20DET engines. 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. But it was Alfa Romeo who became the first manufacturer to use a variable valve timing system in a production car. Several manufacturers filed patents including Porsche in 1958 and Fiat in the late 60s. It would be many years until variable valve timing became commonplace on our cars. Patent 767,794 “INLET VALVE GEAR FOR INTERNAL COMBUSTION ENGINES” filed August 3rd, 1903, and granted August 16th, 1904. This is believed to be the first Patent for automotive use. ![]() Surprisingly, the first use of variable valve timing was on the 1903 Cadillac Runabout and Tonneau. There have been many milestone vehicles since its introduction but here are some of the most significant and iconic. By gaining more control of valve lift depending on engine speed and conditions, greater efficiency can be achieved. The methods used vary but the fundamentals remain the same. Variable valve timing is a key process used by many vehicle manufacturers to meet increasing strict emission regulations. We’ve been learning a lot about variable valve timing and the technology behind the various systems over the last year here at ELTA.
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