Engineering:Single-cylinder engine

From HandWiki
Short description: Piston engine with one cylinder
DKW RT 250 (1952–1953) motorcycle engine

A single-cylinder engine, sometimes called a thumper, is a piston engine with one cylinder. This engine is often used for motorcycles, motor scooters, go-karts, all-terrain vehicles, radio-controlled vehicles, portable tools and garden machinery (such as lawnmowers, cultivators, and string trimmers). Single-cylinder engines are made both as 4-strokes and 2-strokes.

Characteristics

Villiers engine in a 1959 Bond Minicar

Compared with multi-cylinder engines, single-cylinder engines are usually simpler and compact.[1] Due to the greater potential for airflow around all sides of the cylinder, air cooling is often more effective for single cylinder engines than multi-cylinder engines. This reduces the weight and complexity of air-cooled single-cylinder engines, compared with liquid-cooled engines.

Drawbacks of single-cylinder engines include a more pulsating power delivery through each cycle and higher levels of vibration.[2] The uneven power delivery means that often a single-cylinder engine requires a heavier flywheel than a comparable multi-cylinder engine, resulting in relatively slower changes in engine speed. To reduce the vibration level, they often make greater use of balance shafts than multi-cylinder engines,[3] as well as more extreme methods such as a dummy connecting rod (for example the Ducati Supermono).[4][5] These balancing devices can reduce the benefits of single-cylinder engines regarding lower weight and complexity.

Most single-cylinder engines used in motor vehicles are fueled by petrol (and use a four-stroke cycle),[6][7][8] however diesel single-cylinder engines are also used in stationary applications (such as the Lombardini 3LD and 15LD).

A variation known as the split-single makes use of two pistons which share a single combustion chamber.

Uses

Yamaha SRX600 (1985–1997) motorcycle engine

Early motorcycles, automobiles and other applications such as marine engines all tended to be single-cylinder. The configuration is almost exclusively used in portable tools, along with garden machinery such as lawn mowers.[9] Single cylinder engines also remain in widespread use in motorcycles, motor scooters, go-karts, auto rickshaws, and radio-controlled models. From 1921 to 1960, the Lanz Bulldog tractor used a large horizontally-mounted single cylinder two-stroke engine.[10] However they are rarely used in modern automobiles and tractors, due to developments in engine technology.

Single cylinder engines remain the most common engine layout in motor scooters and low-powered motorcycles. The Honda Super Cub (the motor vehicle with the highest overall sales since its introduction in 1958) uses a 49 cc (3.0 cu in) four-stroke single-cylinder engine. There are also several single-cylinder sportbikes (such as the KTM 690 Duke R), dual-sport motorcycles (such as the BMW G650GS) and the classic-styled Royal Enfield 500 Bullet.[11][12]

The Moto3 class in the MotoGP World Championship have used four-stroke 250 cc (15.3 cu in) single cylinder engines since the class replaced 125cc two-strokes in 2012.

Other single-cylinder engines

Engines of other sorts, like the beam engine and certain types of Stirling engine, operate using one cylinder and thus can also be considered single-cylinder engines.

References

  1. "Single Cylinder Engines". Archived from the original on 2019-12-17. https://web.archive.org/web/20191217103057/https://www.thebikemarket.co.uk/advice/single-cylinder-engines. 
  2. "How to Balancing a Single Cylinder Engine Crankshaft and Piston/Connecting Rod Assembly and Flywheel to Reduce Dangerous Vibration". http://gardentractorpullingtips.com/balance.htm. 
  3. "Engine Science: The Balancing Act of Single Cylinder Engines" (in en). https://isavetractors.com/articles-1/engine-science-the-balancing-act-of-single-cylinder-engines/. 
  4. Methods of Balancing Single Cylinder Engines. Joseph R. Harkness. SAE Transactions. Vol. 77, Section 3: Papers 680436–680591 (1968), pp. 2329-2338
  5. Suzuki's Supermono Engine Design. A second con-rod without a piston. Ben Purvis. April 26, 2019
  6. "5 of the funkiest single-cylinder street bikes" (in en). 5 March 2009. https://www.motorcyclenews.com/news/first-rides-tests/2009/march/mar0609-5-of-the-best-funky-singles/. 
  7. "The Single Life: 6 of the best thumpers" (in en). https://www.bennetts.co.uk/bikesocial/news-and-views/advice/biking-tips/the-single-life-6-of-the-best/. 
  8. "The 16 Best Retro Motorcycles Make Bikes Great, Again". 9 August 2016. https://www.thecoolist.com/best-retro-motorcycles/. 
  9. "How Car Engines Work" (in en). 5 April 2000. https://auto.howstuffworks.com/engine2.htm. 
  10. "The Lanz Bulldog" (in en). December 1988. https://www.gasenginemagazine.com/tractors/the-lanz-bulldog. 
  11. "690 Duke: The essence of motorcycling". http://www.ktm.com/gb/naked-bike/690-duke-ausuk.html. 
  12. David Blasco. "Royal Enfield Motorcycles". Royalenfields.com. http://www.royalenfields.com/.