Design Spread Calculation - Drawings

Contents

Content.

Introduction

Accept and select source data

Inlet Process Parameters

Compression Process Parameters

Combustion process parameters

Extension Process Settings

Release Process Parameters

Calculation of qualitative parameters and determination of engine dimensions

Engine heat balance

Building an Indicator Chart

Construction of external speed characteristic

Camshaft Calculation

Conclusion

Literature

Introduction

An internal combustion engine (abbreviated ICE) is a type of engine, a thermal machine in which the chemical energy of a fuel (usually liquid or gaseous hydrocarbon fuel is used) burned in the working zone is converted into mechanical work.

Despite the fact that ICE are a relatively imperfect type of heat machine (bulkiness, heavy noise, toxic emissions and the need for a removal system, relatively small life, the need for cooling and lubrication, high complexity in design, manufacture and maintenance, complex ignition system, large number of wear parts, high fuel consumption, etc.), due to its autonomy (the fuel used contains much more energy than the best electric batteries), ICE is very widespread - for example, in transport.

The specifics of engine production technology and the increase in requirements for engine quality with an increasing volume of their production made it necessary to create specialized engine plants. The successful application of internal combustion engines, the development of experimental designs and the improvement of power and economic indicators became possible to a large extent due to the research and development of the theory of working processes in internal combustion engines.

Performing the tasks of production and operation of transport engines requires specialists to have a deep knowledge of the working process of engines, knowledge of their designs and calculation of internal combustion engines.

Consideration of individual processes in engines and their calculation make it possible to determine the estimated cycle parameters, power and economy, as well as the pressure of gases acting in the above-piston space of the cylinder, depending on the angle of rotation of the crankshaft. According to the calculation, you can establish the main dimensions of the engine (cylinder diameter and piston stroke) and check the strength of its main parts.

Accept and select source data

Initial data are given in the task for thermal calculation of the engine or accepted and selected using existing data in the literature and in accordance with the prototype of the engine.

1.1 Necessity of thermal calculation of the engine.

Thermal calculation of the engines allows to determine the values of the working mixture state, which develops in a cycle, in order to construct an indicator diagram. Using thermal calculation, you can determine the main dimensions, improvement and economy of the engine. At the same time, the necessary data are provided for the dynamic calculation of the crank gear, based on the forces used in calculating the engine resistances in the final.

1.2 Prototype engine.

The prototype of the engine is accepted in accordance with the purpose, operating conditions, the method of formation of the combustible mixture and the type of fuel supply system specified in the calculation task.

1.3 Rated engine power Pn.

In automobile and tractor engines, the rated power Pn is equal to the maximum power Pemax at the rated crankshaft speed. Acceptance and selection of rated power is carried out depending on the purpose of the engine (for cars or trucks, tractors), its type (gasoline-carburetor or engine with electronic fuel injection, gas, diesel), operating conditions, etc. The effective rated engine power can be specified in the task or accepted within - 15... 800 kW.

In the absence of power in the task, the maximum engine power is determined based on the initial data: the maximum speed of the car Vmax, the coefficient of rolling resistance fo and the useful weight (number of passengers) of the car.