# What is constant pressure cycle?

## What is constant pressure cycle?

In addition, a diesel engine operates on what is referred to as a theoretical “constant pressure cycle,” where fuel is presumed to be supplied as the piston moves down the cylinder on its power stroke at a rate such that the cylinder pressure remains constant during the combustion process.

What is a constant cycle called?

Otto cycle
The Otto cycle consists of isentropic compression, heat addition at constant volume, isentropic expansion, and rejection of heat at constant volume.

What is constant in Otto cycle?

Otto cycle Thermodynamics. 1. an ideal thermodynamic combustion cycle, as follows: a compression at constant entropy; a constant-volume heat transfer to the system; an expansion at constant entropy; and a constant-volume heat transfer from the system.

### What is the most efficient thermodynamic cycle?

The most efficient heat engine cycle is the Carnot cycle, consisting of two isothermal processes and two adiabatic processes. The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws.

What is auto cycle and diesel cycle?

Otto cycle is used for petrol or spark ignition engine while diesel cycle is used for diesel or compression ignition engine. The main difference between Otto cycle and Diesel cycle is that in Otto cycle heat addition takes place at constant volume and in diesel cycle heat addition takes places at constant pressure.

What is the most efficient thermodynamic cycle and why?

Classical thermodynamics indicates that the most efficient thermodynamic cycle operating between two heat reservoirs is the Carnot engine [1] , and a basic theorem expresses that any reversible cycle working between two constant temperature levels should have the same efficiency as a Carnot cycle [2].

## Is the pressure in the Diesel cycle constant?

The Diesel cycle is assumed to have constant pressure during the initial part of the combustion phase ( to in the diagram, below). This is an idealized mathematical model: real physical diesels do have an increase in pressure during this period, but it is less pronounced than in the Otto cycle.

What should the pressure ratio of a Brayton cycle be?

In most common designs, the pressure ratio of a gas turbine ranges from about 11 to 16. The power output of a Brayton engine can be improved by:

How is the isentropic process of the Otto cycle constructed?

The Otto cycle is constructed from: The isentropic process of compression or expansion implies that there will be no inefficiency (loss of mechanical energy), and there be no transfer of heat into or out of the system during that process. Hence the cylinder, and piston are assumed impermeable to heat during that time.

### How is the compression stroke in the Otto cycle reversible?

Mechanically this is the isentropic compression of the air/fuel mixture in the cylinder, also known as the compression stroke. This isentropic process assumes that no mechanical energy is lost due to friction and no heat is transferred to or from the gas, hence the process is reversible.