Cycles Related to Internal Combustion Engines

Summary:

The passage discusses various air-standard cycles in internal combustion engines, including the Carnot, Atkinson, Stirling, Ericsson, and Miller cycles. The Carnot Cycle, invented by Sadi Carnot, serves as the basis for all ideal and actual cycles, achieving the highest possible efficiency by depending only on the sink and source temperatures. James Atkinson’s Atkinson Cycle features a longer intake valve opening during compression, enhancing fuel efficiency and economy, making it popular in hybrid vehicles like the Toyota Prius. Robert Stirling’s Stirling Cycle, a closed-cycle regenerative heat engine, can use any heat source and employs a double-effect piston with a regenerator for improved efficiency.

Excerpt:

Cycles Related to Internal Combustion Engines

INTERNAL COMBUSTION ENGINE

V. Carnot, Atkinson, Stirling, Ericsson, and Miller

A. THE OTHER AIR-STANDARD CYCLES
Air-standard cycles include other known cycles such as Carnot, Atkinson, Stirling, Ericsson, and Miller. In this chapter on Internal Combustion Engine, we will discuss them.

1. Carnot Cycle – The best-known reversible cycle was created by a French engineer named Nicolas Leonard Sadi Carnot in 1824; this cycle is the standard and the basis of all ideal and actual cycles created because it is only a function of the sink and source temperature only whilst the other cycles including the previously stated (Otto, Diesel, and Dual) required several ratios, which means the Carnot Engine achieves the highest and possible efficiency of any real engine. The piston and cylinder are completely insulated in this cycle, so no heat is gained or lost during adiabatic processes.
2. Atkinson Cycle – This was created by a British engineer named James Atkinson in 1882. In an Atkinson Engine, the inlet valve stays open a little bit longer during compression, creating lesser pressure which means the piston won’t have to worry about friction which improves fuel efficiency and fuel economy since gas vapour is pulled back in, making it very popular in hybrid vehicles as secondary power such as Toyota Prius. The longer opening time for the intake valve allows the increase in efficiency in exchange for power density, and reduction in displacement while keeping the expansion ratio the way it is.