Multi-valve
In automotive engineering a multi-valve or multivalve engine is one where each cylinder has more than two valves. A multi-valve engine has better breathing and may be able to operate at higher revolutions per minute (RPM) than a two-valve engine, delivering more power.[1][2]
Multi-valve rationale
Multi-valve engine design
A multi-valve engine design has three, four, or five
- Three-valve cylinder head
This has a single large exhaust valve and two smaller intake valves. A three-valve layout allows better breathing than a two-valve head, but the large exhaust valve results in an RPM limit no higher than a two-valve head. The manufacturing cost for this design can be lower than for a four-valve design. The three-valve design was common in the late 1980s and early 1990s; and from 2004 the main valve arrangement used in
- Four-valve cylinder head
This is the most common type of multi-valve head, with two exhaust valves and two similar (or slightly larger) inlet valves. This design allows similar breathing as compared to a three-valve head, and as the small exhaust valves allow high RPM, this design is very suitable for high power outputs.
- Five-valve cylinder head
Less common is the five-valve head, with two exhaust valves and three inlet valves. All five valves are similar in size. This design allows excellent breathing, and, as every valve is small, high RPM and very high power outputs are theoretically available. Although, compared to a four-valve engine, a five-valve design should have a higher maximum RPM, and the three inlet ports should give efficient cylinder-filling and high gas turbulence (both desirable traits), it has been questioned whether a five-valve configuration gives a cost-effective benefit over four-valve designs. The rise of direct injection may also make five-valve heads more difficult to engineer, as the injector must take up some space on the head. After making five-valve Genesis engines for several years, Yamaha has since reverted back to the cheaper four-valve design.
Examples of the five-valve engines are the various 1.8 L 20vT engines manufactured by AUDI AG, the later versions of the Ferrari Dino V8, and the 1.6 L 20-valve 4A-GE engine made by Toyota in collaboration with Yamaha.
- Beyond five valves
For a cylindrical bore and equal-area sized valves, increasing the number of valves beyond five decreases the total valve area. The following table shows the effective areas of differing valve quantities as proportion of cylinder bore. These percentages are based on simple geometry and do not take into account orifices for spark plugs or injectors, but these voids will usually be sited in the "dead space" unavailable for valves. Also, in practice, intake valves are often larger than exhaust valves in heads with an even number of valves-per-cylinder:
- 2 = 50%
- 3 = 64%
- 4 = 68%
- 5 = 68%
- 6 = 66%
- 7 = 64%
- 8 = 61%
Alternative technologies
Cars and trucks
Before 1914
The 1908 Ariès VT race cars had 1.4 litre supercharged single cylinder engines with four valve per cylinder desmodromic systems. (Source: [1])
The 1910 Isotta-Fraschini Tipo KM had a 10.6 litre inline 4 with single overhead camshaft and four valves per cylinder and it had one of the first engines with fully enclosed overhead valve gear (source: Isotta Fraschini Tipo KM [1] and [2])
The first motorcar in the world to have an engine with two overhead camshafts and four valves per cylinder was the 1912 Peugeot L76 Grand Prix race car designed by Ernest Henry. Its 7.6-litre monobloc straight-4 with modern hemispherical combustion chambers produced 148 bhp (110 kW) (19.5 HP/Liter(0.32 bhp per cubic inch)). In April 1913, on the Brooklands racetrack in England, a specially built L76 called "la Torpille" (torpedo) beat the world speed record of 170 km/h.[1] Robert Peugeot also commissioned the young Ettore Bugatti to develop a GP racing car for the 1912 Grand Prix. This chain-driven Bugatti Type 18 had a 5-litre straight-4 with SOHC and three valves per cylinder (two inlet, one exhaust). It produced appr. 100 bhp (75 kW; 101 PS) at 2800 rpm (0.30 bhp per cubic inch) and could reach 99 mph (159 km/h). The three-valve head would later be used for some of Bugatti's most famous cars, including the 1922 Type 29 Grand Prix racer and the legendary Type 35 of 1924. Both Type 29 and Type 35 had a 100 bhp (75 kW) 2-liter SOHC 24-valve NA straight-8 that produced 0.82 bhp (0.61 kW) per cubic inch.
Between 1914 and 1945
In 1916 US automotive magazine Automobile Topics described a four-cylinder, four-valve-per-cylinder car engine made by Linthwaite-Hussey Motor Co. of Los Angeles, CA, USA: "Firm offers two models of high-speed motor with twin intakes and exhausts.".[5]
Early multi-valve engines in
Multi-valve engines continued to be popular in racing and sports engines. Robert M. Roof, the chief engineer for Laurel Motors, designed his multi-valve Roof Racing Overheads early in the 20th century. Type A 16-valve heads were successful in the teens, Type B was offered in 1918 and Type C 16-valve in 1923. Frank Lockhart drove a Type C overhead cam car to victory in Indiana in 1926.[12][13]
Bugatti also had developed a 1.5-liter OHV straight-4 with four valves per cylinder as far back as 1914 but did not use this engine until after World War I. It produced appr. 30 bhp (22.4 kW) at 2700 rpm (15.4 kW/liter or 0.34 bhp/cid). In the 1920 Voiturettes Grand Prix at Le Mans driver Ernest Friderich finished first in a Bugatti Type 13 with the 16-valve engine, averaging 91.96 km/h. Even more successful was Bugattis clean sweep of the first four places at Brescia in 1921. In honour of this memorable victory all 16-valve-engined Bugattis were dubbed Brescia. From 1920 through 1926 about 2000 were built.
Peugeot had a triple overhead cam 5-valve Grand Prix car in 1921.[14]
Bentley used multi-valve engines from the beginning. The Bentley 3 Litre, introduced in 1921, used a monobloc straight-4 with aluminium pistons, pent-roof combustion chambers, twin spark ignition, SOHC, and four valves per cylinder. It produced appr. 70 bhp (0.38 bhp per cubic inch). The 1927 Bentley 4½ Litre was of similar engine design. The NA racing model offered 130 bhp (0.48 bhp per cubic inch) and the 1929 supercharged 4½ Litre (Blower Bentley) reached 240 bhp (0.89 bhp per cubic inch). The 1926 Bentley 6½ Litre added two cylinders to the monobloc straight-4. This multi-valve straight-6 offered 180-200 bhp (0.45-0.50 bhp per cubic inch). The 1930 Bentley 8 Litre multi-valve straight-6 produced appr. 220 bhp (0.45 bhp per cubic inch).
In 1931 the Stutz Motor Company introduced a 322 cid (5.3-liter) dual camshaft 32-valve straight-8 with 156 bhp (116 kW) at 3900 rpm, called DV-32. The engine offered 0.48 bhp per cubic inch. About 100 of these multi-valve engines were built. Stutz also used them in their top-of-the-line sportscar, the DV-32 Super Bearcat that could reach 100 mph (160 km/h).[15][16]
The 1935 Duesenberg SJ Mormon Meteor's engine was a 419.6 cid (6.9-liter) straight-8 with DOHC, 4 valves per cylinder and a supercharger. It achieved 400 bhp (298.3 kW) at 5,000 rpm and 0.95 bhp per cubic inch.[17][18]
The 1937 Mercedes-Benz W125 racing car used a supercharged 5.7-liter straight-8 with DOHC and four valves per cylinder. The engine produced 592-646 bhp (441.5-475 kW) at 5800 rpm and achieved 1.71-1.87 bhp per cubic inch (77.8-85.1 kW/liter). The W125 top speed was appr. 200 mph (322 km/h).
After 1945
The 1967
Debuting at the 1968 Japanese Grand Prix in the original 300 PS (221 kW; 296 hp) 3.0-liter version the Toyota 7 engine participated in endurance races as a 5.0-liter (4,968 cc) non-turbo V8 with DOHC and 32-valves. It produced 600 PS (441 kW; 592 hp) at 8,000 rpm (88.8 kW/liter) and 55.0 kg⋅m (539 N⋅m; 398 lb⋅ft) at 6,400 rpm.
There is much discussion about which was the first 'mass-produced' car to use an engine with four valves per cylinder. For six cylinder engines, and considering special versions of mass-produced cars, the first appears to have been the 1969
For a four cylinder engine, the first mass-produced car using a four valves per cylinder engine was the British
The 1975 Chevrolet Cosworth Vega featured a DOHC multi-valve head designed by Cosworth Engineering in the UK. This 122-cubic-inch straight-4 produced 110 bhp (82 kW; 112 PS) at 5600 rpm (0.90 bhp/cid; 41.0 kW/liter) and 107 lb⋅ft (145 N⋅m) at 4800 rpm.[19]
The 1976 Fiat 131 Abarth (51.6 kW/liter), 1976 Lotus Esprit with Lotus 907 engine (54.6 kW/liter, 1.20 bhp/cid), and 1978 BMW M1 with BMW M88 engine (58.7 kW/liter, 1.29 bhp/cid) all used four valves per cylinder. The BMW M88/3 engine was used in the 1983 BMW M635CSi and in the 1985 BMW M5.
The 1978
In 1985 Lamborghini released a Countach Quattrovalvole, producing 455 PS (335 kW; 449 hp) from a 5.2-liter (5167 cc) Lamborghini V12 engine (64.8 kW/liter).
The
Saab introduced a 16-valve head to their 2.0-liter (1985 cc) straight-4 in 1984 and offered the engine with and without turbocharger (65.5 kW/liter and 47.9 kW/liter respectively) in the Saab 900 and Saab 9000.
The 2.0-liter Nissan
Following Nissan's lead, Toyota released the 1.6-liter (1,587 cc)
In 1986 Volkswagen introduced a multi-valved Golf GTI 16V. The 16-valve 1.8-liter straight-4 produced 139 PS (102 kW; 137 bhp) or 56.7 kW/liter, almost 25% up from the 45.6 kW/liter for the previous 8-valve Golf GTI engine.
The
Three valves
The 1975 Honda Civic introduced Honda's 1.5-liter SOHC 12-valve straight-4 engines. Nissan's 1988–1992 SOHC KA24E engine had three valves per cylinder (two intakes, one exhaust) as well. Nissan upgraded to DOHC after 1992 for some of their sports cars, including the 240SX.
In 1988, Renault released a 12 valve version of its Douvrin 4 cylinder 2.0l SOHC.
Mercedes and Ford produced three-valve V6 and V8 engines, Ford claiming an 80% improvement in high RPM breathing without the added cost of a DOHC
The 1989 Citroën XM was the first 3-valve diesel-engined car.
Four valves
Examples of SOHC four-valve engines include the Honda F-series engines, D-series engines, all J-series engines, the R-series engines, the Mazda B8-ME, and the Chrysler 3.5 L V6 engine.
The V12 engines of many World War II fighter aircraft also used a SOHC configuration with four valves for each cylinder.
The 1993 Mercedes-Benz C-Class (OM604 engine) was the first 4-valve diesel-engined car.
Five valves
Peugeot had a triple overhead cam five-valve Grand Prix car in 1921.[14]
In April 1988 an
Mitsubishi were the first to market a car engine with five valves per cylinder, with the 548 cc 3G81 engine in their Minica Dangan ZZ kei car in 1989.[23][24]
Yamaha designed the five-valve cylinder head for the 20-valve 4A-GE engines made by Toyota for use in some Toyota Corolla models in Japan in 1991. Yamaha also developed five-valve Formula One engines, the 1989 OX88 V8, 1991 OX99 V12, 1993 OX10 V10 and 1996 OX11 V10, but none of these were very successful. For their YZ250F and YZ450F motocross bikes, Yamaha developed five-valve engines.
) have all produced five-valve-engined vehicles.Six valves
In 1985, Maserati made an experimental 2.0-liter turbo V6 engine with six valves per cylinder (three intakes, three exhaust). It achieved 261 bhp (195 kW; 265 PS) at 7,200 rpm (97.5 kW/liter).[25]
Pushrod
Although most multi-valve engines have
Turbocharged
The 1980 Lotus Essex Turbo Esprit (with type 910 2.2-liter inline four engine) was the first production car to use a multi-valve turbocharged engine.
Motorcycles
Examples of motorcycles with multivalve-engines include:
- 1914 Peugeot Grand Prix racer, 500 cc DOHC 8-valve parallel twin (top speed over 122 km/h).[28]
- 1915 Indian board track racer, 61-cid (1.0-liter) OHV 8-valve V-twin.[29]
- 1921 Triumph Ricardo 499 cc OHV 4-valve single-cylinder machine, copied by Rudge-Whitworth with their 1924 Rudge Four 350 cc OHV 4-valve single-cylinder machine, and 1929 Rudge Ulster 500 cc OHV 4-valve single-cylinder machine.
- 1923 Morgan three-wheelers and McEvoymotorcycles
- 1972 Honda XL250 "pent-roof" SOHC 4-valve single-cylinder machine (the first mass-produced 4-valve motorcycle).
- 1973 Yamaha TX500 "pent-roof" 500cc DOHC 8-valve parallel-twin (the first mass-produced DOHC 4-valve per cylinder motorcycle)[30]
- 1977 Honda CB400 SOHC 6-valve parallel-twin.
- 1978 CX500 Turbo was the first factory multi-valve turbochargedmotorcycle.
- 1978 Honda CBX1000, a 1,047 cc DOHC 24-valve straight-6 (105 bhp (78 kW; 106 PS)).
- 1979 -1992: Honda NR series, racing & production motorcycles with 8-valve-per-cylinder "oval-piston" V4 engines (actually 32-valve V8s with adjoining cylinders merged).
- 1985 Yamaha FZ750 motorcycle with DOHC 20-valve straight-4 Yamaha "Genesis" engine.
- 1991-2010 parallel twinmotorcycles with 5 valves per cylinder
- 1998–2006 superbike with redesigned (more compact) "Genesis" engine. 2006 model delivered 180 bhp (134 kW; 182 PS) at 12,500 rpm (130.3 kW/liter).
The
Aircraft
Ettore Bugatti designed several multi-valve aircraft engines. The 1916 Bugatti U-16 1484.3 cid (24.32 L) SOHC 16-cylinder, consisting of two parallel 8-cylinder banks, offered 410 bhp (305 kW) at 2,000 rpm (12.5 kW/liter or 0.28 bhp/cid). Each cylinder had two vertical inlet valves and a single vertical exhaust valve, all driven by rocking levers from the camshaft. Other advanced World War I aircraft engines, such as the 1916 Maybach Mb.IVa that produced 300 bhp (224 kW; 304 PS) at altitude and the 1916 Benz Bz.IV with aluminium pistons and the 1918 Napier Lion (a 450 bhp 24-liter DOHC 12-cylinder), used two intake valves and two exhaust valves.
Long after the King-Bugatti "U-16" aviation engine used them, shortly before World War II, the Junkers aviation firm began production of the Third Reich's most-produced military aviation engine (68,000+ produced), the 1936-designed, 35-litre displacement, inverted-V12, liquid-cooled Junkers Jumo 211, which used a three-valve cylinder head design[31] inherited from Junkers' first inverted V12 design, the 1932-origin Junkers Jumo 210[32] — this was carried through into the later, more powerful 1940-origin Junkers Jumo 213, produced through 1945, the production versions of which (the Jumo 213A and -E subtypes) retained the Jumo 211's three-valve cylinder head design.[33]
The V12 engines of many World War II fighter aircraft used a SOHC configuration with four valves for each cylinder.
An example of a modern multi-valve piston-engine for small aircraft is the Austro Engine AE300. This liquid-cooled turbocharged 2.0-liter (1,991 cc) DOHC 16-valve straight-4 diesel engine uses common rail direct fuel injection and delivers 168 bhp (125 kW; 170 PS) at 3,880 rpm (62.0 kW/liter). The propeller is driven by an integrated gearbox (ratio 1.69:1) with torsional vibration damper. Total power unit weight is 185 kg (408 lb).
Boats
In 1905 car builder
An example of modern multi-valve engines for small boats is the Volvo Penta IPS Series. These joystick-operated seawater-cooled inboard diesel engines use combined charging (turbo and supercharger, except IPS450) with aftercooler, common rail fuel injection and DOHCs with hydraulic 4-valve technology. Propshaft power ranges from 248 to 850 bhp (185 to 634 kW; 251 to 862 PS) (highest efficiency 59.7 kW/liter for IPS400 3.7-liter straight-4 diesel). Multiple units can be combined.
References
- ^ a b Kevin Clemens. "An Echo of the Past: The history and evolution of twin-cam engines (European Car, February, 2009)". Archived from the original on 2014-01-11. Retrieved 2011-12-23.
- ^ a b Dan McCosh. "Auto Tech 88: 4-valves (Popular Science, May 1988, pp. 24, 37-40)". Archived from the original on 2013-06-02. Retrieved 2011-12-23.
- ^ a b In direct injection engines - such as diesels and later petrol engines - fuel is delivered to the chamber directly via the injector rather than through a valve. In carburetted engines and indirect-injection engines the fuel is mixed with the air outside of the cylinder and both enter together via the intake valve.
- ^ "Alfa Designers". velocetoday.com. Retrieved 2011-12-30.
- ^ Mort Schultz (January 1985). Engines: A Century of Progress (Popular Mechanics, Jan 1985, pp. 95-97, 120, 122). Retrieved 2011-12-26.
- ^ Sports Car Market. "1918 Stutz Series S Roadster (Sportscarmarket.com, Friday, 31 March 2000)". Archived from the original on 16 January 2012. Retrieved 2011-12-23.
- ^ Classic Car Database. "1918 Stutz S Series Roadster Standard Specifications (Classic Car Database)". Retrieved 2011-12-23.
- ^ PaulFreehill. "16-valve Stutz block (YouTube.com video, May 6, 2010)". YouTube. Archived from the original on 2021-12-22. Retrieved 2011-12-23.
- ^ RM Auctions. "1919 Pierce-Arrow Model 48 Dual-Valve Four-Passenger (RM Auctions, Phoenix, AZ, USA)". Archived from the original on 2012-01-12. Retrieved 2011-12-23.
- ^ Classic Car Database. "1919 Pierce Arrow 48-B-5 Series Touring Standard Specifications (Classic Car Database)". Retrieved 2011-12-23.
- ^ Conceptcarz.com. "1919 Pierce Arrow Model 48 Specifications (Conceptcarz.com)". Retrieved 2011-12-23.
- ^ Northwest Vintage Speedsters. "Roof Alphabetical Index and Images (nwvs.org)". Retrieved 2011-12-23.
- ^ Model T Ford Club of America. "Robert M. Roof (MTFCA.com)". Retrieved 2011-12-23.
- ^ a b Sports Car Market. "1921 Peugeot 3-liter Racer (Sportscarmarket.com, 30 June 1999)". Archived from the original on 24 October 2011. Retrieved 2011-12-27.
- ^ Donald Osborne. "Honoring the Original American Sports Cars (New York Times, August 12, 2011)". Retrieved 2011-12-23.
- ^ Classic Car Database. "1932 Stutz CD DV 32 Series Super Bearcat Standard Specifications (Classic Car Database)". Retrieved 2011-12-23.
- ^ Richard Owen. "1935 Duesenberg SJ Mormon Meteor (Supercars.net)". Retrieved 2011-12-22.
- ^ Daniel Vaughan. "1935 Duesenberg SJ Special Mormon Meteor (Conceptcarz.com, March 2011)". Retrieved 2011-12-22.
- ^ "1975 Cosworth Vega advertisement (Motor Trend Magazine, 1975)". Retrieved 2011-12-23.[permanent dead link]
- ^ Mike Allen (February 1988). Quad 4: The Inside Story (Popular Mechanics, February 1988, pp.62-65). Retrieved 2011-12-23.
- ^ D. Sherman (January 1990). Five valves for Audi (Popular Science, Jan 1990, pp. 35, 37). Retrieved 2011-12-30.
- ^ Brunn Racing. "AUDI 200 N6000 - WORLD RECORD PROTOTYPE (Brunnracing.com, Dec 2011)". Retrieved 2011-12-30.
- ^ "A baby that sprints: tiny Mitsubishi engine blasts off with five valves". Ward's Auto World (April 1989).
- ^ Michael Knowling. "Mighty Minica ZZ-4 (Autospeed Issue 353, 19 October 2005)". Retrieved 2011-12-26.
- ^ Ermanno Cozza & George Lipperts. "Maserati Sei Valvole (Enrico's Maserati Pages, 2002–2004)". Retrieved 2011-12-26.
- ^ Bennett, Jay (2016-08-29). "Milwaukee Eight Multi-Valve". Popular Mechanics. HEARST DIGITAL MEDIA. Retrieved 16 August 2017.
- ^ Cook, Marc. "HD Pushrods". Motorcyclist Online. Bonnier Corporation. Retrieved 16 August 2017.
- ^ Yves J. Hayat & Bernard Salvat. "Peugeot Racers - Part 1 (The Best Motorcycle, Jan 26, 2010)". Retrieved 2011-12-27.
- ^ Yesterdays.nl. "1915 Indian 8 Valve Boardtrack Racer (YouTube.com video, Mar 18, 2010)". YouTube. Archived from the original on 2021-12-22. Retrieved 2011-12-27.
- ^ "YAMAHA TX500/750: A QUESTION OF BALANCE". Tobyfolwick.com. Archived from the original on 2016-03-04. Retrieved 2015-12-23.
- ^ German language illistration of Jumo 211 three-valve design
- ^ "Flight Magazine, September 9, 1937". flightglobal.com. Flightglobal Archive. September 9, 1937. p. 265. Retrieved March 15, 2017.
At the recent international meeting at Zürich, several of the successful German machines were fitted with the new Junkers 210 petrol engine...Three valves per cylinder are provided, two inlets and one exhaust, operated by push rods and rockers from a single camshaft.
- ^ Culy, Doug (April 4, 2012). "The Junkers Jumo 213 Engine". enginehistory.org. Aircraft Engine Historical Society. Archived from the original on December 21, 2016. Retrieved March 15, 2017.
The Jumo 213 had a three-valve head, but a four-valve head was in development for the "J" version. However, the Jumo 213A is documented as itself having superior high altitude performance at that particular point in time, although the DB 603 was later developed with equal or better features.
- ISBN 9780760304648. Retrieved 2011-12-23.
External links
- Kinematic Models for Design Digital Library (KMODDL) - Movies and photos of hundreds of working mechanical-systems models at Cornell University. Also includes an e-book library of classic texts on mechanical design and engineering.