Internal Combustion Engine Miller Cycle, Miller Cycle Engine Benefits

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To explain why the Miller cycle is based on the Otto cycle, let's first talk about the gasoline engine and the diesel engine (the gasoline engine is similar to the Alto cycle, and the diesel engine is similar to the Diesel cycle). The gasoline engine has a low compression ratio, so the thermal efficiency is low (compared to the diesel engine), but because of the high power density and low noise, the gasoline engine is often used in cars. In order to improve the thermal efficiency of the gasoline engine, the early closing of the intake valve (i.e., the Miller cycle) is adopted, which has the advantage that the expansion ratio becomes larger (greater than the compression ratio, and the Alto cycle compression ratio is equal to the expansion ratio), and the thermal efficiency is improved.

So, the Miller cycle has nothing to do with the Diesel cycle.

The other type of Atkinson cycle (late intake valve closure or complex mechanics) is similar to the Miller cycle in that it allows the expansion ratio to be greater than the compression ratio, which is based on the Diesel cycle.

What exactly is the Miller cycle of a car engine, what are the advantages and disadvantages, there are cars to take a look.

A standard four-stroke engine is known as an Otto cycle engine. The Otto cycle engine is named after Nicholas Otto, who invented this type of engine in 1867.

In the forties of the twentieth century, Ralph Miller patented the Miller cycle engine, which is very similar to the Otto cycle engine. The Miller cycle engine, like the Otto cycle engine, uses components such as pistons, valves, spark plugs, etc. So the Miller cycle is based on the Otto cycle.

But there are two major differences between a Miller-cycle engine and an Otto-cycle engine: 1: A Miller-cycle engine relies on a supercharger.

2: During the compression stroke of the Miller cycle engine, the intake valve remains open, so the engine will compress the pressure of the supercharger and not the pressure of the cylinder wall. This will result in an efficiency increase of about 15%.

This in turn makes the two engines interdependent, but absolutely different.

1. Miller cycle engines rely on superchargers. 2. The intake valve remains open during the compression stroke of the Miller cycle engine, so the engine will compress the pressure of the supercharger, and the pressure of the cylinder wall will not be compressed by slippage. This will result in an efficiency increase of about 15%.

The compression ratio of the Alto cycle is equal to the expansion ratio, which means that the compression ratio increases at the same time as the expansion ratio, which causes the engine to knock to increase. The Miller cycle is a low-temperature cycle, which can effectively reduce the tendency of engine knocking and effectively improve the thermal efficiency of the engine. The Miller cycle is characterized by the fact that the effective compression ratio of the engine is less than the expansion ratio.

The Miller cycle actually changes the moment the intake valves close, which changes the actual compression ratio of the engine. The separation of the compression ratio and the expansion ratio of the engine increases the expansion work and effectively suppresses the engine knocking. The Miller cycle not only suppresses engine knocking, but also reduces NOx emissions.

The advantage of the Miller cycle is also reflected in the fact that the load control is achieved at partial load by delaying the intake valve closing angle, replacing the throttle. The pump gas loss of the engine is reduced, and the geometric compression ratio is increased to improve the economy of the natural gas engine.

Therefore, the Miller cycle has the advantages of reducing part-load pump gas loss, increasing expansion work, improving engine thermal efficiency, reducing combustion temperature in the cylinder, reducing heat charge, and reducing NOx emissions.