Thermal and dynamic calculation of diesel engine without pressurization

Contents

Contents

Introduction

1 Job

2 Thermal calculation of engine operating cycle

3 Calculation of engine external speed characteristic

4 Dynamic calculation of crank mechanism

Conclusion

List of sources used

Appendix A

Appendix B

Introduction

The basis of any vehicle, including ground, is a power plant - an engine that converts various types of energy into mechanical work. The successful design, development of new designs and the creation of prototypes of internal combustion engines were largely provided by serious research work in the field of engine workflow theory.

Modern land transport modes owe their development mainly to the use of piston internal combustion engines as power plants. It is ICE pistons that are until now the main type of power plants, mainly used on cars, tractors, agricultural, road transport and construction machines. This trend continues today and will continue in the near future.

The purpose of this course design is to calculate the designed automobile engine.

The object of this course design is a diesel engine without pressurization with a liquid cooling system. During the project execution:

- thermal and dynamic calculations of the engine;

- calculations of engine main parts;

- calculation of liquid cooling system;

Conclusion

During the course design, the skills of calculation of KSM parts for strength, engine liquid cooling systems, engine working processes, thermal balance, external speed characteristic, dynamic characteristics of the crank gear were acquired.

In the second point, the calculation of the thermal process of the engine working cycle was made, which includes the calculation of all the main processes of the cycle (intake, compression, combustion, expansion, exhaust) and the determination of the parameters of the working medium (volume, pressure) at the characteristic points of the cycle (a, c, z, "z b, r). Based on these calculations, an indicator diagram is built in the p-v coordinate system.

In the third point, the calculation was carried out for the external speed characteristic of the diesel engine (without pressurization). It is the dependence of the power and torque on the shaft of the engine on its speed .

To calculate the external speed characteristic of the engine, it is necessary to take the technical characteristics of the key point values.

1. Maximum engine power: Nmax, kW. Shaft speed corresponding to maximum power: nN, rpm.

2. Maximum engine torque: Memax, kN· m. The shaft speed corresponding to the maximum torque: nM, rpm.

Graphs of change of external speed characteristic are built according to specified values of key points

1) power change curve

2) engine torque change curve

3) extremum of moment function.

Dynamic calculation is used to determine the forces and moments acting on the parts of the crank gear during the operation of the diesel engine. Knowledge of forces and moments is required to calculate the parts of the designed engine for strength, analyze the reliability and durability of units and parts in operation, evaluate the engine balance and compare its load with similar operated diesel engines.

In this course design, the relationship of thermal calculation with dynamic calculation is clearly expressed, as well as the influence of dynamic indicators on the parts of the crank gear .

This course project includes the graphic part in the form of:

1) a sheet containing an indicator diagram, diagrams based on the results of dynamic calculation, a scheme of action of forces in KSM.

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