Calculation and investigation of ideal cycle of internal combustion engine

Министерство образования и науки Республики Казахстан

ТОО «Высший колледж АРЕС PetroTechnic»

«Допущена к защите»

Председатель ЦМК

специальных дисциплин

_____________________

КУРСОВАЯ РАБОТА

По дисциплине: Основы гидравлики и теплотехники

На тему: Calculation and investigation of ideal cycle of internal combustion engine

Выполнил: Sabit Orynbassaruly student                        

                    group of INTT-2.3

________________________________

Проверил: Bakitzhan Murynov

________________________________

Атырау, 2017 г.

Content

Introduction.............................................................................................................3

1. Calculation of initial parameters.............................................................................5

1.  Molar mass of the mixture...............................................................................5
2.  Gas constant of working fluid..........................................................................5
3.  Mass heat capacities of the mixture.................................................................5
4.  The adiabatic exponent....................................................................................6

1. Determining the parameters of the working fluid at the points of the cycle...........7
2. Calculation of the cycle process.............................................................................11

1.  Adiabatic compression process.......................................................................11
2.  Heat addition at constant volume....................................................................11
3.  Heat addition at constant pressure...................................................................12
4.  Adiabatic expansion process............................................................................12
5.  Heat rejection at constant volume....................................................................13

1. Calculation of cycle characteristics.........................................................................14
2. Investigation of the cycle.........................................................................................16

1.  Effect of the compression ratio on the thermal efficiency of the cycle............16
2.  Effect of the pressure increase on the thermal efficiency of the cycle.............16
3.  The influence of the degree of isobaric expansion on the thermal efficiency of the cycle..............................................................................................................17

1. Analysis....................................................................................................................18

References................................................................................................................19

Introduction

The thermal engine is a machine for converting thermal energy into mechanical work. In the heat engine, gas expansion takes place, which presses the piston, causing it to move, or to the turbine wheel blades, imparting rotation to it. Examples of reciprocating engines are steam engines and internal combustion engines such as carburettor and diesel engines.                        

The internal combustion engine is a heat engine in which the heat is supplied to the working fluid by burning fuel inside the engine itself. The working body in such engines is at the first stage air or a mixture of air with flammable fuel, and in the second stage - combustion products. In such engines, the working fluid can be regarded as an ideal gas.

         At present, the internal combustion engine is the main type of automobile engine.

Purpose of the work is

Task

1 - Calculate the ideal cycle of an ICE with a mixed heat supply, which, in accordance with Figure 1, includes the following thermodynamic processes of changing the state of the working fluid:

a) 1-2 - adiabatic compression;

b) 2-3 –heat additionat constant volume;

c) 3-4 – heat addition at constant pressure;

d) 4-5 - adiabatic expansion;

e) 5-1 – heat rejection at constant volume.

[pic 1]

Calculate:

1.1 gas constant of the working fluid;

1.2. The value of pressure, specific volume, temperature and entropy at all points of the cycle;

1.3 for each of the processes making up the cycle, changing the internal energy and enthalpy, heat capacity, heat and workflow values;

1.4 cycle characteristics, in general: the amount of heat input and output, average pressure and thermal efficiency.

2 - Investigate the influence of the degree of compression, the degree of pressure increase and the degree of preliminary (isobaric) expansion on the thermodynamic efficiency of the cycle.

Explore:

2.1 the effect of the degree of pressure increase on the thermal efficiency;

2.2 effects of compression ratio on thermal efficiency;

2.3 the influence of the degree of isobaric expansion on the thermal efficiency.

Initial data for calculations of the ICE cycle.

1. Calculation of initial parameters

1.1 Molar mass of gas mixture

μ=Σri*μi        (1)

where n – number of components of the working fluid, n=4;

ri - the volume fraction of the i-th component in the composition of the mixture;

μi - the molar mass of the i-th component, kg / kmol.

Calculate the molar mass of each component of the mixture:

μСО2 = 12 + 16 * 2 = 44 kg / kmol

μСО = 12 + 16 = 28 kg / k mol

μN2 = 14 * 2 = 28 kg / k mol

μH2O = 1 * 2 + 16 = 18 kg / kmol

Substituting the molar masses of each component in formula (1), we obtain the total molar mass for the gas mixture: