General Motors Rotary Combustion Engine

Last updated
A General Motors rotary engine at the Ypsilanti Automotive Heritage Museum Ypsilanti Automotive Heritage Museum May 2015 062 (GM rotary engine).jpg
A General Motors rotary engine at the Ypsilanti Automotive Heritage Museum

The General Motors Rotary Combustion Engine (GMRCE) is an internal combustion Wankel engine which uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons. In November 1970, GM paid $50 million, ($348,886,033 in 2021 dollars [1] ), for initial licenses to produce their version of the Wankel rotary engine, and GM President Ed Cole initially projected its release in three years. Chevrolet, with impetus from Pete Estes and John DeLorean, as well as Ed Cole worked on the Wankel. Bob Templin was the chief executive in charge of rotary-engine research at the GM Tech Center in Warren, Michigan, but Ed Cole would leave his office in Detroit twice a week for the trip to Warren, taking charge of the program. [2] The engine was initially targeted for an October 1973 introduction as a 1974 Chevrolet Vega option. Its mediocre fuel economy and the ill-timed Arab oil embargo were contributing factors to end the GM rotary program.

Contents

History of Development

1972 GM Rotary engine cutaway shows twin-rotors 1974 GM Rotory engine.jpg
1972 GM Rotary engine cutaway shows twin-rotors

Popular Science magazine in the May 1972 article "GM Rotary Engine for the 1974 Vega", an illustration of the Wankel installed in a 1974 Vega hatchback showed a different grille, a lower, more sloped hood line, and a "GM Rotary" badge and Wankel crest on the rear quarter panel. They stated the Vega-rotary would be sold as a package with performance items, including mag-styled wheels, radial tires, and rally stripes. [3]

The Wankel had so far proven more reliable than four, six, and eight-cylinder engines – GM-rotary engines were run up to 500,000 miles (800,000 km) showing only minimal wear, and the engine's fewer moving parts assured its reliability. [4] The final design General Motors Rotary Combustion Engine (GMRCE) was fixed when responsibility for the power plant's manufacture was turned over to General Motors Hydra Matic Division in August 1972 – two rotors displacing 206 cubic inches (3.38 L), twin distributors and coils, and a switch to aluminum housing construction. Iron couldn't match the heat-dissipating qualities of aluminum. In addition, there was also a rotor tip-seal problem in the cast-iron configuration, especially after 15,000 miles (24,000 km). [5] RC2-206 Wankels were installed in 1973 Vegas for cold weather testing performed in Canada.

Fuel economy vs reliability and meeting emissions

1974 Vega RC2-206 Wankel '74 GM Rotary engine.jpg
1974 Vega RC2-206 Wankel

Early in 1973, progress on the generation I Wankel engine had progressed to the point where GM felt it had a good chance to meet '75 emissions standards. To meet those standards GM had to scrap the design theory of widely spaced dual spark plugs and move them closer to the rotor chamber, Mazda fashion. That helped lower emissions but did not improve fuel economy, and GM was unwilling to face gas mileage criticism that Mazda withstood.

In April 1973, the Environmental Protection Agency (EPA) relaxed emission standards for '75, and GM tuned the engine to provide better mileage at a sacrifice to exhaust emissions by reverting to the earlier layout. Other refinements improved mileage to 20  mpg ‑ US (12  L/100 km ; 24  mpg ‑ imp ), according to GM, but with the fuel breakthrough came related side-effect problems. Durability under the "hot" set-up began to deteriorate. Higher temperatures and pressures affected both apex seals and the chrome-on-steel-on-aluminum coating of the trochoid surface. The surface plating tended to crack and flake away around the exhaust port, blamed by GM engineers on sudden cooling after hard, hot running.

Motor Trend magazine, in the July 1973 article "The '75 Vega Rotary" quoted: "GM saw the rotary engine's future as probably much greater than they do today...mileage will be in the 16–18 mpg‑US (15–13 L/100 km; 19–22 mpg‑imp) range. Compared to the normal piston (engine) Vega's 20 to 26 mpg‑US (11.8 to 9.0 L/100 km; 24 to 31 mpg‑imp), the whole rotary deal begins to look just a little less attractive, with what the price of gasoline skyrocketing, but that's another matter." [6]

By November, 1973 the side-effect troubles were intense. No immediate solutions were being revealed by engineers working all but around the clock, their backs to the two walls of production tooling requirements and the need to freeze a design to begin emission certification. Ed Cole and his top engineer Frank Winchell, had taken personal charge of the project and had stopped work on all other GM-rotaries to focus on the problems of the Vega RC2-206 Wankel. A month later it was clear the Wankel would not be ready for either production or emissions certification in time for the start of the 1975 model year. A new model had now been planned to showcase the engine; The 1975 Vega-based Monza 2+2. [7] On December 21, 1973, when GM paid another $10 million against its rotary licence fees, the company announced the first postponement. [8]

Motor Trend in April 1974 predicted the outcome: "If the GM rotary engine hasn't made a place for itself in the company's lineup by fall, and if by then it hasn't been locked into the '75 model range - somewhere - the odds will increase that it may never go into production."

End of rotary program

The Wankel cycle Wankel Cycle anim.gif
The Wankel cycle

On September 24, 1974, Ed Cole postponed the Wankel engine, ostensibly due to emissions difficulties. He retired the same month. [7] The rotary's emissions problem was mentioned with no specifics. GM admitted fuel economy for the rotary was sub-standard and postponed production in favor of further development. Pete Estes succeeded Ed Cole as GM President and never showed any special interest in the Wankel or in the perpetuation of Cole's ideas. [9] As General Motors managers were cancelling the Wankel project, the R&D team partly released the results of their most recent research, which claimed to have solved the fuel economy problem, and reliable engines with a lifespan above 530,000 miles. These findings were not taken into account when the cancellation order was issued. The General Motors' abandonment of the rotary engine affected American Motors, who had an agreement to purchase power rotary plants from General Motors. The 1975 AMC Pacer was designed to utilize GM's new rotary engine, however AMC was forced to market the car with an inline six engine. [10]

Rotary vs GM V8 engine

206 cu in (3,380 cc) Wankel vs. 307 cu in (5,030 cc) V8 engine

See also

Related Research Articles

<span class="mw-page-title-main">Wankel engine</span> Combustion engine using an eccentric rotary design

The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion. It was invented by German engineer Felix Wankel, and designed by German engineer Hanns-Dieter Paschke. The Wankel engine's rotor, which creates the turning motion, is similar in shape to a Reuleaux triangle, with the sides having less curvature. The rotor rotates inside an oval-like epitrochoidal housing, around a central output shaft. The rotor spins in a hula-hoop fashion around the central output shaft, spinning the shaft via toothed gearing.

<span class="mw-page-title-main">Chevrolet Caprice</span> Motor vehicle

The Chevrolet Caprice is a full-sized automobile produced by Chevrolet in North America for the 1965 to 1996 model years. Full-size Chevrolet sales peaked in 1965 with over a million sold. It was the most popular car in the U.S. in the 1960s and early 1970s, which, during its lifetime, included the Biscayne, Bel Air, and Impala.

<span class="mw-page-title-main">NSU Ro 80</span> Motor vehicle

The NSU Ro 80 is a four-door, front-engine executive sedan manufactured and marketed by the West German firm NSU from 1967 until 1977.

<span class="mw-page-title-main">Chevrolet Vega</span> Subcompact automobile

The Chevrolet Vega is a subcompact automobile that was manufactured and marketed by GM's Chevrolet subdivision from 1970 to 1977. Available in two-door hatchback, notchback, wagon, and sedan delivery body styles, all models were powered by an inline four-cylinder engine with a lightweight, aluminum alloy cylinder block. The Vega first went on sale in Chevrolet dealerships on September 10, 1970. Variants included the Cosworth Vega, a short-lived limited-production performance model, introduced in the spring of 1975.

<span class="mw-page-title-main">Chevrolet Monza</span> Motor vehicle

The Chevrolet Monza is a subcompact automobile produced by Chevrolet for the 1975 through 1980 model years. The Monza is based on the Chevrolet Vega, sharing its wheelbase, width, and standard inline-four engine. The car was designed to accommodate the GM-Wankel rotary engine, but due to mediocre fuel economy and emissions-compliance issues the engine was cancelled, and a V8 engine option was substituted. The Monza name has also been used for several other cars.

<span class="mw-page-title-main">Mazda Wankel engine</span> Motor vehicle engine

The Mazda Wankel engines are a family of Wankel rotary combustion car engines produced by Mazda.

<span class="mw-page-title-main">Mazda diesel engines</span> Motor vehicle engine

Mazda has a long history of building its own diesel engines, with the exception of a few units that were built under license.

<span class="mw-page-title-main">Ford Power Stroke engine</span> Motor vehicle engine

Power Stroke is the name used by a family of diesel engines for trucks produced by Ford Motor Company and Navistar International for Ford products since 1994. Along with its use in the Ford F-Series, applications include the Ford E-Series, Ford Excursion, and Ford LCF commercial truck. The name was also used for a diesel engine used in South American production of the Ford Ranger.

<span class="mw-page-title-main">Buick V8 engine</span> Motor vehicle engine

The Buick V8 is a family of V8 engines produced by the Buick division of General Motors between 1953 and 1981. The first version replaced the Buick straight-eight. Displacements vary from 215 cu in (3.5 L) to 455 cu in (7.5 L) for its last big block in 1976. All are naturally aspirated OHV pushrod engines, except for an optional turbocharged version of the short-lived 215 used in the 1962-63 Oldsmobile Jetfire.

The Ford Motor Company produced straight-six engines from 1906 until 1908 and from 1941 until 2016. In 1906, the first Ford straight-six was introduced in the Model K. The next was introduced in the 1941 Ford. Ford continued producing straight-six engines for use in its North American vehicles until 1996, when they were discontinued in favor of more compact V6 designs.

<span class="mw-page-title-main">Detroit Diesel V8 engine</span> Motor vehicle engine

General Motors introduced a line of Diesel V8 engines for their C/K pickup trucks in 1982. This engine family was produced by GM through 2000, when it was replaced by the new Duramax line. AM General's subsidiary General Engine Products (GEP) still produces a military variant of this engine for the HMMWV.

<span class="mw-page-title-main">Honda R engine</span> Motor vehicle engine

The Honda R engine is an inline-four engine launched in 2006 for the Honda Civic (non-Si). It is fuel injected, has an aluminum-alloy cylinder block and cylinder head, is a SOHC 16-valve design and utilizes Honda's i-VTEC system. The R series engine has a compression ratio of 10.5:1, features a "drive by wire" throttle system which is computer controlled to reduce pumping losses and create a smooth torque curve.

<span class="mw-page-title-main">Chevrolet Aerovette</span> Motor vehicle

The Chevrolet Aerovette was a concept car created by Chevrolet, beginning life as Experimental Project 882 (XP-882) in the late 1960s. It had a mid-engine configuration using a transverse mounting of its V8 engine. Zora Arkus-Duntov's engineers originally built two XP-882 prototypes during 1969, but John DeLorean, Chevrolet's general manager, canceled the program believing it to be impractical and costly. However, when Ford announced plans to sell the DeTomaso Pantera through Lincoln-Mercury dealers, DeLorean ordered that one XP-882 prototype be cleaned up for display at the 1970 New York Auto Show.

<span class="mw-page-title-main">Chevrolet Cosworth Vega</span> Motor vehicle

The Chevrolet Cosworth Vega is a subcompact four-passenger automobile produced by Chevrolet for the 1975 and 1976 model years. It is a limited-production version of the Chevrolet Vega, with higher performance.

The MidWest AE series are lightweight, liquid-cooled, single- and twin-rotor Wankel engines, with dual ignition, designed for light aircraft. They were produced by Mid-West Engines Ltd. at Staverton Airport, Gloucestershire, UK.

Skyactiv is a brand name for a series of automobile technologies developed by Mazda that increase fuel efficiency and engine output. The initial announcement of the Skyactiv technologies included new engines, transmissions, body, and chassis, which appeared in Mazda products from 2011 onwards.

<span class="mw-page-title-main">Mazda HR-X</span> Motor vehicle

The Mazda HR-X was the first hydrogen powered concept car produced by Mazda. The car was unveiled at the Tokyo Motor Show in 1991. The car seated four people in a plastic shell and was powered by a two rotor Wankel engine which propelled it to 130 km/h (81 mph). The hydrogen was stored in a cooled metal hydride tank and 3.32 kilograms (7.3 lb) provided a range of 190 km (120 mi). It was the first in a series of demonstration hydrogen internal combustion engine vehicles produced by Mazda.

Wankel Diesel engine describes the idea of using the Diesel principle in a Wankel rotary engine. Several attempts to build such an engine have been made by different engineers and manufacturers in the 1960s and 1970s. Due to technical problems and the general disadvantages of the Wankel design, the Wankel Diesel engine never left the prototype stage, and designing a Wankel Diesel engine capable of running under its own power is thus considered unfeasible.

<span class="mw-page-title-main">GM Whirlfire engine</span> Motor vehicle engine

The GMWhirlfire gas turbine engines were developed in the 1950s by the research division of General Motors Corporation and fitted to concept vehicles, including the Firebird concept cars, Turbo-Cruiser buses, and Turbo-Titan trucks through the 1960s. They are free-turbine turboshaft machines with two spools: one compressor/gasifier turboshaft and one power/output turboshaft sharing a common axis without a mechanical coupling between them. Fuel consumption of the first-generation GT-300 was high compared to piston engines, so thermal wheel regenerators were added to the second-generation GT-304, cutting consumption by approximately 1⁄2.

References

  1. ↑ 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–" . Retrieved April 16, 2022.
  2. ↑ Automotive News Article date:May 21, 2001
  3. ↑ Popular Science-May 1974
  4. ↑ Popular Science May 1972 p. 100
  5. ↑ Motor Trend-July 1973 p.52
  6. ↑ quote-Motor Trend-July 1973-p.52
  7. 1 2 Motor Trend, Mar. 1975, v. 29, n. 3, pg. 53
  8. ↑ Motor Trend, International report, p.24-April 1974
  9. ↑ Estes had previously decided to let the Corvair expire, another Cole project — well before the celebrated attacks of Ralph Nader. Motor Trend, April 1974
  10. ↑ Hinckley, Jim; Robinson, Jon G. (2005). The Big Book of Car Culture: The Armchair Guide to Automotive Americana. MBI Publishing. p. 122. ISBN   978-0-7603-1965-9 . Retrieved 2011-12-11.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.