Двигатель Quad 4: История и особенности американского четырехцилиндрового мотора

Quad 4 is the name of a family of principally DOHC inline four cylinder engines produced by General Motors' Oldsmobile division between 1987 and 2002; a single SOHC version was built between 1992 and 1994. Its name was derived from the engine's four valve, four cylinder layout. Introduced with a displacement of , the engine was a modern design for its time, using a cast iron block and an aluminum head. Even though belts were more popular for this purpose on OHC engines at the time, chains were used to time the camshafts to the crankshaft. The water pump is also driven by the timing chain. The Quad 4 was the first wholly domestic regular production DOHC four cylinder engine designed and built by GM; the only prior DOHC four cylinder engine offered by GM was the Cosworth Vega, which featured a DOHC head designed by Cosworth in England. In addition to the DOHC versions, there was also both a short lived SOHC variant, the "Quad OHC", available from 1992 to 1994, and the Twin Cam from 1996 to 2002. All engines in the Quad 4 family were produced at the Lansing Engine Plant (plant five) in Delta Township near Lansing, Michigan. The Twin Cam was the last engine that was engineered and produced solely by Oldsmobile; the Aurora V8 and Shortstar V6 shared architecture with the Cadillac Northstar V8. First released to the public as a regular production option for the 1988 Oldsmobile Cutlass Calais and Pontiac Grand Am, the engine's availability expanded to Buick in late 1988 and Chevrolet in 1990, after which it became a mainstay in GM's lineup until its cancellation after the 2002 model year. It was replaced by the Ecotec for the 2003 model year.

Simultaneous to the engine's release in 1988, Oldsmobile attempted to further the Quad 4 name through highly publicized events featuring such cars as the Oldsmobile Aerotech. Another such event was the 1988 Indianapolis 500, when Oldsmobile was chosen to pace the race with a convertible version of their Cutlass Supreme, and a pre production turbocharged Quad 4 was the engine of choice for their pace car. Although it was publicized in 1988 that the Quad 4 was forthcoming in a "HO", as well as a turbocharged version (the same engine that was in the pace car that year), GM never released the turbocharged version as a publicly available option. Although the engine in Oldsmobile Aerotech was a purpose built, turbocharged example; it was solely meant to showcase the capability of the engine's design. After the first few years of positive reviews of the Quad 4, the automotive press began to criticize it for its noise, vibration, and harshness (NVH) levels. At the time, the Quad 4 was generally compared to turbocharged four cylinders, V6s, and occasionally V8s. The first changes of the Quad 4 to address its NVH were two rounds of exhaust port size reductions, followed by the addition of balance shafts in 1995. Further changes were made for the 1996 model year when the engine's bore and stroke were changed, and the engine was subsequently redubbed "Twin Cam". In recent years, the design has gained a minor following in hot rodding circles as a period style engine because it looks similar to a 1930s Offenhauser DOHC design (once you remove the ribbed aluminum cover, exposing the tall "cam towers" and the deep valley between them holding the spark plugs).

The LD9 Twin Cam was a Quad 4 variant with balance shafts, and a redesigned cylinder head which debuted in 1996. In the mid nineties, these engines, like their earlier 2.3L counterparts, were known for timing chain failures, as well as water pump failures, in which the water pumps were often difficult and costly to access and replace. They also had very small oil passages, making for less than adequate lubrication, and costly engine repairs if not maintained properly. Bore was decreased from and stroke increased from for better torque. Power came in at This engine received a minor update halfway through the 1999 model year that eliminated the exhaust gas recirculation, increased the compression ratio from 9.5:1 to 9.7:1, and switched from low impedance fuel injectors to high impedance. For increased reliability this engine also saw other minor updates in the 2000s towards the end of its use in General Motors vehicles. In 2001, changes included a smaller knock sensor, flat top pistons instead of dished, new oiling passages, newer stronger timing chain, a newer designed water pump, a redesigned starter motor and a higher capacity catalytic converter. An improved belt tensioner was introduced in 2002.