What is the Atkinson cycle in a gasoline engine?

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.

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 an Atkinson cycle engine?

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.

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.

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 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 Atkinson engines?

Why does Toyota use Atkinson cycle engines? Until the late 20th Century, most production vehicles fitted with a spark ignition internal combustion engine adopted a traditional Otto-type four-stroke piston cycle.

What is the main difference between Miller and Atkinson cycle engines?

How does an Atkinson cycle engine save fuel?

An Atkinson-cycle engine works the same way, but with a twist. In an Atkinson-cycle engine, the valve stays open slightly longer. Since there’s now less pressure in the cylinder, the piston doesn’t have to work as hard to overcome friction, which in turn improves fuel efficiency.

What cars use the Miller cycle engine?

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.

How do Atkinson engines 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.

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.

What is an Atkinson-cycle gasoline engine?

While it’s a very old technology, the Atkinson-cycle gasoline engine has made a comeback thanks to its fuel-saving operation. It’s a perfect fit for hybrids, where the vehicle’s electric motor helps to overcome the Atkinson’s shortcomings.

Why is the Atkinson cycle so efficient?

Atkinson wins on efficiency because its expansion ratio is significantly larger than its compression ratio. American engineer Ralph Miller chimed in with another useful patent in 1957. His cycle was intended for use with two- and four-stroke engines running on gasoline, diesel, or gaseous fuels such as propane.

What is the difference between the Otto and Atkinson cycle?

In the Otto cycle, some of the force during the power stroke goes to pushing the piston down, but more force is produced than needed. That extra force is essentially wasted energy, the Atkinson cycle adjustment reduces that wasted energy and by doing so makes the engine more efficient. There’s a clear downside to this method: less power.

When did Henry Atkinson invent the thermodynamic engine?

The engine he patented in 1882 had variable stroke lengths provided by a multilink connecting rod between the piston and the flywheel. While Atkinson’s engines weren’t successful, his thermodynamic cycle is still in wide use, mainly in gas-electric hybrids.