A camless or free-valve piston engine is an engine that has poppet valves operated by means of electromagnetic, hydraulic, or pneumatic actuators instead of conventional cams. Actuators can be used to both open and close valves, or to open valves closed by springs or other means.

Camshafts normally have one lobe per valve, with a fixed valve duration and lift. The camshaft rotates at half the rate of the crankshaft. Although many modern engines use camshaft phasing, adjusting the lift and valve duration in a working engine is more difficult. Some manufacturers use systems with more than one cam lobe, but this is still a compromise as only a few profiles can be in operation at once. This is not the case with the camless engine, where lift and valve timing can be adjusted freely from valve to valve and from cycle to cycle. It also allows multiple lift events per cycle and, indeed, no events per cycle—switching off the cylinder entirely.

Camless development

Camless valve trains have long been investigated by several companies, including Renault, BMW, Fiat, Valeo, General Motors, Ricardo, Lotus Engineering, Ford, Jiangsu Gongda Power Technologies and Koenigsegg's sister company FreeValve.[1][2][3][4][5] Some of these systems are commercially available, although not yet in engines in production road vehicles. In the Spring of 2015, Christian von Koenigsegg told reporters that the technology pursued by his company is "getting ready for fruition", but said nothing specific about his company's timetable.[6][7]

In November 2016, Chinese automobile manufacturer Qoros Auto displayed the Qoros 3 hatchback at the 2016 Guangzhou Motor Show, which showcased a new Qoros ‘Qamfree’ engine. The engine's Swedish designer FreeValve claims that the 1.6-litre (98 cu in) turbocharged engine will produce 170 kW (230 hp) and 320 N⋅m (240 lb⋅ft) of torque. They also claim that, compared to a similar traditional engine, it offers a 50% reduction in size (including a 50 mm (2.0 in) lower height), 30% reduction in weight, 30% improvement in power and torque, 30% improvement in fuel economy, and a 50% reduction in emissions.[8] Christian Koenigsegg claims in a video that the Qamfree engine with the PHEA camless technology is based on an existing Qoros engine that was "...developed in Germany and Austria five, six years ago...".[9]

Christian Koenigsegg also claims that the PHEA camless technology allows the elimination of the pre-catalytic converter, because the standard catalytic converter can be brought up to temperature quickly by manipulating the exhaust cycle.[9]

Camless engines in marine and power stations

Advantages

Because camless engines have no camshaft, they may have fewer moving parts. In these systems, the camshaft rollers and pushrods have been replaced by an electro-hydraulic actuator system which uses the existing fuel pumps, thus reducing development risks of the new system by employing existing technology.[10] Direction changing on older B&W MC engines was engaged by changing the direction of the cam roller, whereas with the new camless engine, it is controlled by a computer. This eliminates the risk of mechanical failures that could damage the engine if there was a malfunction while changing directions. Additionally, because there is no chain connection between the crank shaft and the camshaft, the engine is lighter with fewer points of failure. The absence of a camshaft also means that the parasitic load on the engine is lower, which is particularly useful in large marine engines, as it can equate to a large amount of power savings. With a camless engine, fuel injection and exhaust timing are directly controlled by an engine control unit and can be constantly changed and adjusted without stopping the engine. This allows for the engine to run at a lower RPM, a feature useful in ships as it allows better low speed maneuvering while docking. Additionally, when a ship is maneuvering, the computer controlled fuel injection and valve timing allows for faster RPM control, hence faster stopping in emergency situations.

Emissions

Camless engines are able to produce less emissions than their equivalent camshaft counterparts because they are able to more precisely control the combustion procedure, allowing for more complete combustion of all hydrocarbons. The computer is able to sense when not all of the fuel is being consumed and immediately relax valve timings to supply less fuel to a cylinder. The ECU can constantly adjust valve timing, height and fuel/air mixtures to optimize efficiency for a given RPM/torque load. It can sense when there is a high amount of NOx and SOx (Sulfur oxide) emission and change the timing to make the exhaust gas hotter or cooler. Since the engine is run electronically and not mechanically, camless engines can be updated to meet new emission regulations without mechanical modifications.

Fuel Injection

Camless engines can further reduce NOx emissions with the use of fuel staging. Instead of simply injecting a constant stream of fuel, fuel staging injects the fuel at the optimal time for the most complete combustion. Fuel injection can shut off when there is sufficient pressure and add more fuel when there is less pressure allowing the engines to run closer to a perfect diesel cycle. This allows the engine to run as efficiently as the environment and heat capacity of the metal will allow.

Long term effects

Because these new engines can diagnose themselves and run efficiently without an operator changing settings, these engines require less crew to maintain them when at sea. This crew reduction equates to cheaper shipping for companies and hence more and cheaper global trade[11].

Camless engines in cars

The British company Camcon Technology[12] is developing a camless engine for passenger vehicles based on their proprietary Intelligent Valve Actuation (IVA) system. Camcon has collaborated with Jaguar Land Rover to fit IVA onto an Ingenium 2.0l 4 cylinder petrol engine and they jointly published results at the 2017 Aachen Kolloquium[13]; their paper is available on the Camcon website [12]. Camcon also discussed features and benefits in an article and video that was published in Autocar magazine [14] "New Valve Technology gives Petrols the Efficiency of Diesels"

The Swedish company Freevalve AB (formerly Cargine), a sister company to Koenigsegg Automotive AB, is developing a camless system on an existing SAAB car engine.[15][16][17][18]

In April 2016, the Chinese car manufacturer Qoros presented a concept car incorporating Freevalve technology.[19]

See also

References

  1. ^ "United States Patent: 6871618". Patft.uspto.gov. Retrieved 2009-10-02.
  2. ^ "Valeo tests camless system for gas engines; supplier hopes to produce fuel-saving technology by '08: AutoWeek Magazine". Autoweek.com. 2009-02-06. Archived from the original on 2011-05-22. Retrieved 2009-10-02.
  3. ^ "View Item : » Managed Content » Lotus". Grouplotus.com. Archived from the original on 2008-08-20. Retrieved 2009-10-02.
  4. ^ "Cargine". Cargine. Archived from the original on 2009-07-17. Retrieved 2009-10-02.
  5. ^ Lou, Zheng David; Deng, Qiangquan; Wen, Shao; Zhang, Yunhai; Yu, Mengjin; Sun, Ming; Zhu, Guoming (2013). "Progress in Camless Variable Valve Actuation with Two-Spring Pendulum and Electrohydraulic Latching," SAE Int. J. Engines 6(1):319-326, 2013, doi:10.4271/2013-01-0590". SAE International Journal of Engines. 6: 319–326. doi:10.4271/2013-01-0590.
  6. ^ Noah Joseph. "Koenigsegg planning four-door model, camless engine". Autoblog. Retrieved 2017-06-24.
  7. ^ "Get ready for the 4-door Koenigsegg". Top Gear. 2015-03-04. Retrieved 2017-06-24.
  8. ^ 2016-10-30 (2016-10-30). "Koenigsegg camless engine wins PopSci award". Msn.com. Retrieved 2017-06-24.
  9. ^ a b "Freevalve Update Camless Engine - /INSIDE KOENIGSEGG". YouTube. 2016-11-09. Retrieved 2017-06-24.
  10. ^ [1], MAN B&W Diesel Engines. (2003). Camless two stroke main propulsion engine. Camless two stroke main propulsion engine.
  11. ^ [2], A. (2016, July 21). New Generation Engines - The Intelligent Engines.
  12. ^ a b "Camcon Auto Ltd, reducing CO2 and NOX emissions from vehicles through innovative actuators".
  13. ^ "Home".
  14. ^ "New engine valve tech gives petrols the efficiency of diesels | Autocar".
  15. ^ Kurt Ernst (2013-02-20). "Inside Koenigsegg Looks At Future Engine Technology: Video". Motorauthority.com. Retrieved 2017-06-24.
  16. ^ Travis Okulski (26 February 2014). "What It's Like To Ride In A Car With The Camless Engine Of The Future". Jalopnik. Retrieved 5 June 2016.
  17. ^ http://kth.diva-portal.org/smash/get/diva2:542744/FULLTEXT01
  18. ^ Video on YouTube
  19. ^ "Freevalve technology unveiled at Beijing Motor Show in Qoros Qamfree concept car". Koenigsegg. 26 April 2016. Archived from the original on 2016-06-11. Retrieved 2016-06-11.

External links

  • "EVIC Engine Home Page". David Bowes. 2011-01-20. Retrieved 2011-01-20.
  • "Valeo tests camless system for gas engines; supplier hopes to produce fuel-saving technology by '08". AutoWeek. Archived from the original on September 29, 2007. Retrieved October 14, 2005.
  • "Advanced Actuators Research Group, Department of Mechanical Engineering, University of South Carolina".
  • "Valeo signs up 'several global automakers' for camless engine".
  • "Study of a Pneumatic Hybrid aided by a FPGA Controlled Free Valve Technology System".[permanent dead link]
  • "ME Engines – the New Generation of Diesel Engines" (PDF).