What Is the ‘Atkinson’ Cycle? Simply put, the Atkinson cycle aims to use all of the energy in the cylinder. It does this by leaving the intake valve open longer, creating a shorter compression stroke. In the Prius engine, the net result is an effective compression ratio of 8:1, while the expansion ratio is about 13:1.
What did James Atkinson invent?
James Atkinson of Hampstead was a British engineer who invented several engines with greater efficiency than the Otto cycle. The Atkinson cycle engines were named the “Differential 1882”, “Cycle 1887” and “Utilite 1892”. The most well-known of Atkinson’s engines is the “Cycle 1887”, patented in 1887.
What is the efficiency of Otto cycle?
7.4. Variation of the normalized power output and the thermal efficiency of the irreversible Otto cycle with the compression ratio, γ = 1.4, ηcom = 0.85, and ηexp = 0.90.
What is the Atkinson engine cycle?
Atkinson “Cycle Engine” The next engine designed by Atkinson in 1887 was named the “Cycle Engine” This engine used poppet valves, a cam, and an over-center arm to produce four piston strokes for every revolution of the crankshaft.
What is a miller capable engine?
In engineering, the Miller cycle is a thermodynamic cycle used in a type of internal combustion engine. The Miller cycle was patented by Ralph Miller, an American engineer, US patent 2817322 dated Dec 24, 1957. The engine may be two- or four-stroke and may be run on diesel fuel, gases, or dual fuel.
Who invented the Atkinson cycle engine?
A thermodynamically more efficient version of modern Otto-cycle engines, the Atkinson-cycle engine was invented way back in 1887 by British engineer James Atkinson. As a refresher, a standard Otto-cycle engine operates in four strokes: the intake, compression, power/expansion and exhaust stroke.
What is the difference between Miller and Atkinson cycle?
An Atkinson-cycle engine differs from a Miller-cycle engine in that the Miller-cycle engine uses some device to push air into the system – a supercharger or turbocharger – while the Atkinson-cycle engine is naturally aspirated.
What type of IC engine is used in Toyota Prius?
The Prius has a 1497 cubic centimetre (approximately 1.5 litre) displacement gasoline internal combustion engine which produces all power for the car.
Who makes Atkinson engines?
Honda engineers update an established engine design with leading-edge technology to create an extremely fuel-efficient powerplant. The Feature: The CR-V Hybrid engine makes for excellent efficiency as well as responsive power output.
How does the Atkinson cycle work?
The pistons are powered by gasoline, sprayed into the engine and detonated by the spark plug. The piston moves four times in each cycle: down to draw in gasoline vapour, up to compress it, down when the vapour ignites and explodes, and then up to push out the exhaust.
What is the difference between Atkinson cycle and Otto cycle?
An Atkinson cycle has a greater work output and a higher thermal efficiency than the Otto cycle at the same operating condition. The compression ratios that maximize the work of the Otto cycle are always found to be higher than those for the Atkinson cycle at the same operating conditions.
Who uses Miller cycle engine?
This type of engine was first used in ships and stationary power-generating plants, but in the 1990s, it was adapted by Mazda for use in the Mazda Millennia. To be effective, the Miller cycle turbocharger or supercharger must be able to compress the air with less energy than with the engine’s pistons.
Are Atkinson engines good?
The Atkinson cycle is ideal for hybrids because their electric motor(s) make up for the lost low-speed output. Compression and expansion ratios are the same in an Otto engine. Atkinson wins on efficiency because its expansion ratio is significantly larger than its compression ratio.
How much more efficient is the Atkinson cycle?
The end result is a maximum thermal efficiency of 37 percent and a fuel efficiency improvement of “approximately 30 percent over current vehicles” – that’s the difference between 60 mpg (US) and 78 mpg (US) and it’s an astonishing improvement.
Why is there a Miller cycle?
In diesels, Miller cycle has been used primarily to control NOx emissions at high engine load. In spark-ignited engines, the benefits of the Miller cycle include reduced pumping losses at part load and improved efficiency, as well as knock mitigation.
Why Toyota is using the Atkinson cycle engine in all hybrid cars?
The final return stroke of the cycle evacuates the spent gases via the exhaust valve so that the process can begin again. This revelation allowed Toyota to build the world’s first Otto cycle engine with a simulated Atkinson-type valve action to significantly improve fuel efficiency.
Is Prius a GDI?
The Prius has exceeded all of the G21 goals established in 1993 except for the use of gasoline direct fuel injection (GDI), but Toyota just announced a new GDI hybrid engine earlier this year, so more changes are on their way.
What cars use the Miller cycle engine?
The Miller-cycle system was most famously used in production by Mazda’s Millenia, with its KZ-JEM 2.3-liter V-6, which ceased production in 2004. Mazda has kept an eye on the technology, though, and applied it recently on the Mazda 2.
What is the most complex engine in modern cars?
Most Amazingly Complicated Engines Of All Time Saab Variable Compression. Lancia-Abarth Triflux. Cadillac V-8-6-4. Volkswagen W8. H16 BRM. Cizeta V16. Bugatti W16. Camcon Automotive Intelligent Valve Actuation. Cylinder deactivation and variable compression engines are now out in the real world.
How does the Miller cycle engine work?
A Miller-cycle engine leaves the intake valve open during part of the compression stroke, so that the engine is compressing against the pressure of the supercharger rather than the pressure of the cylinder walls. The effect is increased efficiency, at a level of about 15 percent.
Can you turbo an Atkinson engine?
The VC-Turbo can switch between both Atkinson and regular combustion cycles without interruption, enabling greater efficiency and performance as it transforms. Under the Atkinson cycle, air and fuel intakes overlap, allowing the fuel in the combustion chamber to expand to larger volumes for greater efficiency.
Is the Toyota 2.5 a good engine?
Overall, the 2AR-FE 2.5L engine is one of the most reliable engines we’ve written about. If you’re simply looking for a solid engine and car to get you from A to B the 2AR-FE RAV4 and Camry are among the best out there.
What engine is in a 2010 Prius?
1.8 L 4-cylinder.