Camless piston engine

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

As a camshaft normally has only one lobe per valve, the valve duration and lift is fixed. 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[edit]

Camless engines are not without their problems. Common issues include high fuel consumption, accuracy at high speed, temperature sensitivity, weight and packaging, high noise, high cost, and unsafe operation if there are electrical problems in the vehicle.

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] Camless 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 the time-table.[6][7]

In November 2016, Chinese automobile manufacturer Qoros Auto displayed a Qoros 3 hatchback at the 2016 Guangzhou Motor Show showcasing a new Qoros ‘Qamfree’ engine. The engine's Swedish designer FreeValve claims that the 1.6-litre turbocharged engine will produce 230bhp and 320Nm of torque. They also claim that, compared to a similar traditional engine, it offers a 50% reduction in size (including a 50 mm 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 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. [10]

Camless engines in marine and power stations[edit]


Because there is no camshaft, there are less major parts less parts. There cam shaft rollers and push rods have been replaced by an electro-hydraulic actuator system this system allows for the same fuel pumps to be used but was actuates them has changed. This is combining the new system and keeping a proven and tested system still in use [11]. Direction changing on older B&W MC engines were changed by changing the direction of the cam roller. With the new cam-less engine it is controlled by a computer. This gets rid of mechanical failures that can damage the engine if there is a malfunction in the engine when changing directions. Also, there is no chain connection between the crank shaft and the cam shaft the engine can be lighter and less chance for failure. Since there is connection between the crank shaft and the cam shaft there is less of a parasitic load on the engine output. When this parasitic load is taken away in large marine engines that are producing up to almost 100 megawatts it can be noticeable amount of power saving. With a cam-less engine fuel injection and exhaust timing are directly controlled by an Engine control unit and it can be constantly changed and adjusted without stopping the engine. This allows for the engine to run at lower RPM when maneuvering to have even slower ship speeds to be more safe and precise when docking. Also, when a ship is maneuvering the computer controlled Fuel injection will decrease the time it takes to speed up the engine making it safer in emergency situations.


The new engines can be safer for the environment compared the older models because when the engine is burning to much fuel and not having enough oxygen then engine will produce black smoke and not meeting Emission standard. The computer will sense when this is happening and immediately make the injectors supply a little bit less fuel to the engine cylinder. Also, the computers have economy setting where the computer figures out the best and most fuel-efficient timing for a given sea speed. The computers can also sense when there is a high amount of NOx and SOx (Sulfur oxide) pollution is happening and can change the timing to have the Exhaust gas be hotter or cooler. Since the engine is run by a computer and not mechanical timing parts as emission regulations change over time the engines can be updated to meet the new regulations and not have to have major overhauls on the engine to keep it up to date.

Fuel Injection[edit]

The new cam-less engines can use fuel staging. This is where you aren’t just putting a constant stream of fuel in the cylinder you are adding fuel when needed. This is a major advantage with the MAN B&W ME engine because of its long stroke. Fuel injection can be shut off when there is sufficient pressure and add more fuel when there is less pressure making the engines 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. The computers can be constantly updated and this prolongs the life of the marine diesel engines. The expected life the new Burmeister & Wain diesel engines are 2 years of continuous running at the average sea speed. That’s the equivalent of running your car engine out to 1.6 million miles. Because these engines have a computer controlling them it can sense when it is in RPM ranges that can damage the engine or if there is too much load on the engine it can slow its self-down or move the engine RPM through those speed ranges faster to prevent damage to the engine [12].

Long Term Effects[edit]

Because if these new engines being able to diagnose themselves and run efficiently without and operator changing its settings. These engines require less crew to maintain them when out at sea. This allows for less crew to be on the ship and making it cheaper for companies to ship more goods around the world improving global trade[13].. Also, the computer software can be constantly updated and allow for the engine to be updated and prolonging the life of the engine.

Camless engines in cars[edit]

The Swedish company Freevalve AB (formerly Cargine), a sister company to Koenigsegg Automotive AB, are developing a camless system and have successfully implemented the system on an existing SAAB car engine.[14][15][16][17] In April 2016 the Chinese car manufacturer Qoros presented a concept car incorporating Freevalve technology.[18]

See also[edit]


  1. ^ "United States Patent: 6871618". Retrieved 2009-10-02. 
  2. ^ "Valeo tests camless system for gas engines; supplier hopes to produce fuel-saving technology by '08: AutoWeek Magazine". 2009-02-06. Retrieved 2009-10-02. 
  3. ^ "View Item : » Managed Content » Lotus". Retrieved 2009-10-02. 
  4. ^ "Cargine". Cargine. Retrieved 2009-10-02. 
  5. ^ "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.". 
  6. ^
  7. ^
  8. ^
  9. ^
  10. ^
  11. ^ [1],MAN B&W Diesel Engines. (2003). Camless two stroke main propulsion engine. Camless two stroke main propulsion engine.
  12. ^ [2], MAN Diesel & Turbo 2017.
  13. ^ [3],A. (2016, July 21). New Generation Engines - The Intelligent Engines.
  14. ^
  15. ^ 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. 
  16. ^
  17. ^ Video on YouTube
  18. ^ "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. 

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