Information AboutMulti-valve |
| CATEGORIES ABOUT MULTI-VALVE | |
| engine technology | |
| engine valves | |
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All tappet-valve, four-stroke Internal Combustion Engine s have at least two valves per cylinder — one for ''intake'' of air and fuel, and another for ''exhaust'' of combustion products. Adding more valves improves the flow of intake and exhaust gases, potentially improving combustion efficiency, power, and performance. Most multivalve engines use an recently introduced a 3-valve version of its Generation IV V8 which uses Pushrod s to actuate forked rockers, and Cummins makes a 4-valve pushrod Straight-6 Diesel , the Cummins 600 . HISTORY The first multivalve engine was built by Peugeot in 1912 for Grand Prix racing. The technology was also attempted by Bugatti , Bentley , and Stutz , but it was not until the 1970s that this technology became widespread. The first was Jensen in the 1972 Jensen Healey roadster. This used a Lotus developed version of a GM design which resulted in a 1973 cc (2.0 L) DOHC engine that delivered 140 hp. Others, including Cosworth (on the 1975 Chevrolet Vega 's 2300 Engine ), Lotus Cars (on the 1976 Esprit — which used a 160 hp version of the same engine first seen in the Jensen Healey), and BMW (on the 1979 M1 's M88 Engine ). Triumph also introduced a Single Overhead Cam 16-valve head on the '' Slant-4 '' in their Dolomite Sprint . Ferrari followed Lotus and GM in to the multivalve designs with their ''Quattrovalve'' 308 . From there, Honda and Toyota rapidly spread the technology to their mainstream models in the 1980s . MODERN MULTIVALVE ENGINES Today, multivalve engines are used by nearly all manufacturers. They are common among the Japan ese and Europe an makers. The US manufacturers have lagged, though improvements to their pushrod designs have caused some to question the benefits of multivalve engines. V8 from the Corvette ZR-1 and the 3.4 L LQ1 V6 . Pushrod engines are still the norm at GM, however. Ford 's DOHC success came with their (multivalve-optional) Modular V8 , SHO V6 , and Mazda-developed B-family of I4 engines. Their Duratec family consists entirely of multivalve engines, and is used across the product line. DaimlerChrysler 's Mercedes-Benz used 3-valve SOHC engines for many years, but recently switched to 4-valve designs. Their American Chrysler operation has developed a number of successful multivalve OHC I4 and V6 engines, but relies on pushrod V8s. VAG companies like Volkswagen and Audi now use 5-valve engines in many of their vehicles after acquiring the technology from Bugatti who developed it for their EB110 Supercar . EDIT: Toyota also use 5-valve heads in their 4A-GE power plants. Sk 'silver top' 4.gen 160ps(hp) and 'black top' 5.gen 165ps(hp). Built from ~1991 to 1999. In dyno tests they are claimed to not give more than 150hp or so. Ferrari has 5-valve tech as well. |
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