typical opening variation was 37%. Alfa Romeo was the first manufacturer to use a variable valve timing system in production cars (US Patent 4,231,330). The fuel injected models of the 1980 Alfa Romeo Spider 2000 had a mechanical VVT system. The system was engineered by Ing Giampaolo Garcea in the 1970s. All Alfa Romeo Spider models from 1983 onward used electronic VVT. In 1989, Honda released the VTEC system. While the earlier Nissan NVCS alters the phasing of the camshaft, VTEC switches to a separate cam profile at high engine speeds to improve peak power. The first VTEC engine Honda produced was the B16A which was installed in the Integra, CRX, and Civic hatchback available in Japan and Europe. In 1992, Porsche first introduced VarioCam, which was the first system to provide continuous adjustment (all previous systems used discrete adjustment). The system was released in the Porsche 968 and operated on the intake valves only. Motorcycles Variable valve timing has been applied to motorcycle engines but was considered a non-useful "technological showpiece" as late as 2004 due to the system's weight penalty. Since then, motorcycles including VVT have included the Kawasaki 1400GTR/Concours 14 (2007), the Ducati Multistrada 1200 (2015), the BMW R1250GS (2019) and the Yamaha YZF-R15 V3.0 (2017), the Suzuki GSX-R1000R 2017 L7. Marine Variable valve timing has begun to trickle down to marine engines. Volvo Penta's VVT marine engine uses a cam phaser, controlled by the ECM, which continuously varies advancement or retardation of the camshaft timing. Diesel In 2007, Caterpillar developed the C13 and C15 Acert engines which used VVT technology to reduce NOx emissions, to avoid the use of EGR after 2002 EPA requirements. In 2010, Mitsubishi developed and started mass production of its 4N13 1.8 L DOHC I4, the world's first passenger car diesel engine that features a variable valve timing system. Automotive nomenclature Manufacturers use many different names to describe their implementation of the various types of variable valve timing systems. These names include: AVCS (Subaru) AVLS (Subaru) CPS (Proton) CVVTCS (Nissan, Infiniti) (developed by Hyundai and Kia, but it can also be founded on Geely, Iran Khodro and Volvo) DCVCP - dual continuous variable cam phasing (General Motors) DVT (Desmodromic variable timing, Ducati) DVVT (Daihatsu, Perodua, Wuling) FSI, TFSI, TSI, SI (Volkswagen Group) MIVEC (Mitsubishi) MultiAir (FCA) VCT (Ford) N-VCT (Nissan) S-VT (Mazda) Ti-VCT (Ford) VANOS (Variable Nockenwellen Steuerung) - 'camshaft timing' without