What is the Atkinson combustion cycle?
The Atkinson-cycle engine is a type of internal combustion engine invented by James Atkinson in 1882. The Atkinson cycle is designed to provide efficiency at the expense of power density. A variation of this approach is used in some modern automobile engines.
What are characteristics of the Atkinson cycle?
An Atkinson-cycle engine works the same way, but with a twist. In a regular engine, the intake valve stays closed when the piston moves up on its compression stroke, creating pressure in the cylinder. In an Atkinson-cycle engine, the valve stays open slightly longer.
How much more efficient is 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.
What is the difference between Otto cycle and Atkinson 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.
What is a Miller and Atkinson cycle engine?
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 are the 4 steps of combustion?
An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust.
Why is Atkinson cycle more efficient?
The Atkinson cycle delays the intake valve’s closing until the piston has completed 20 to 30 percent of its upward travel on the compression stroke. Atkinson wins on efficiency because its expansion ratio is significantly larger than its compression ratio.
What did James Atkinson invent?
Atkinson cycle engines
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.
Why is Atkinson more efficient than Otto?
The key advantage is higher efficiency than is achievable in an Otto engine, albeit with some loss of 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.
Who makes the Atkinson engine?
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.
Why do Hybrids cars use Atkinson cycle engines?
The Atkinson cycle is ideal for hybrids because their electric motor(s) make up for the lost low-speed output. The Atkinson cycle delays the intake valve’s closing until the piston has completed 20 to 30 percent of its upward travel on the compression stroke.
Who uses Miller cycle engine?
Mazda
This type of engine was first used in ships and stationary power-generating plants, and is now used for some railway locomotives such as the GE PowerHaul. It was adapted by Mazda for their KJ-ZEM V6, used in the Millenia sedan, and in their Eunos 800 sedan (Australia) luxury cars.