Thermal calculation of the internal combustion engine of the Ford Focus2 car

Contents

Contents

SECTION 1. THERMAL CALCULATION OF THE ENGINE

1. Calculation of basic parameters of actual engine processes

1.1. Calculation of parameters of "inlet" and "outlet" cycles

1.2. "Compression" stroke and fresh charge combustion process

1.3. Expansion Process (Stroke)

1.4. Identification of the main indicators characterizing the performance of re-

aln engine

1.5. Calculation of ICE theoretical cycle

1.6. Calculation of working medium state parameters at characteristic points

theoretical cycle

1.7. Engine heat balance

1.8. Determination of engine main parameters

1.9. Building an Indicator Chart

1.10. Calculation and construction of the external speed characteristic of the gasoline engine

SECTION 2. KINEMATIC AND DYNAMIC CALCULATION

ENGINE

2.1. Kinematics of crank mechanism

2.1.1. Determining the Piston Travel Path

2.1.2. Calculation of piston speed and acceleration

2.2.1. Calculation of connecting rod kinematics

2.2. Dynamic engine calculation

2.2.1. Calculation of forces acting on crank mechanism

2.3. Create an expanded diagram of the total forces acting on the piston

2.3.1. Order of total forces diagram

2.4. Plotting Tangential Forces

2.5. Torque uniformity and travel uniformity

2.6. Determining the Weight of the Flywheel

2.7. Polar diagram of forces acting on crankshaft crankshaft

2.8. Build an expanded polar chart

SECTION 3. CALCULATION OF ICE MECHANISMS AND SYSTEMS

3.1. Piston pin strength calculation

Conclusion

List of Recommended Literature

2.3. Build an expanded chart

total forces acting on piston

The expanded force diagram is drawn from the angle of rotation of the crankshaft in the section from

00 to 720 ° for a 4-stroke engine, and 360 ° for a two-stroke engine.

2.3.1. Order of total forces diagram

Plotting a diagram of the total force P. on the axis of abscissa O - α we apply a scale at the scale γ = 15 °/1 cm with an interval of 15 ° of crankshaft rotation. We take as the maximum value of the abscissa axis the curve of change of inertia forces.

By making measurements with a circulus solution between the curve of inertia forces and the intake line on the indicator diagram at the points of piston movement corresponding to the successive rotation of the crankshaft for every 15 °, we will construct a total force P1 during the intake. By measuring the distances between the inertia force line and the compression, expansion and exhaust lines, we obtain P1 for compression, working stroke and exhaust processes, respectively.

This takes into account the following sign rule: the direction of force to the center of the crankshaft is considered positive, from the center - negative. The scale of forces P1 remains unchanged from the scale of gas pressure forces in the indicator diagram.

Section 3. calculation of mechanisms and systems of engines

It is difficult to calculate the strength of the engine parts due to the fact that during the operation of the engine all parts are subjected to a variable load, varying not only in size, but for some, parts and by sign. Significant difficulties also arise due to the fact that most of the engine parts work at a variable temperature, which cha hundred reaches such values ​ ​ at which the indicators characterizing the strength of the material change significantly, and, in addition, due to the complexity of the shape of many parts, the effect of forces on them is difficult to take into account.

When calculating engine parts for strength, static material is widely used in terms of operability of parts of a large number of engines of various types. Comparison of the design material with the statistical processing data, rational design, and then refinement of the prototype engines after versatile testing of the engines allows designers to create modern, quite modern internal combustion engines.

When designing an engine, a significant part of the time is devoted to determining the rational design shape of both the engine as a whole and its individual parts. The design of the engine is largely determined by its purpose (automobile, tractor, ship, etc.) or the requirements of the customer. A clear idea of the purpose of the engine, its place of work and working conditions greatly facilitates the work of the designer in finding the perfect design forms of the engine and ensuring the necessary strength of its parts.

Conclusion

Internal combustion engines are the most common type of power plant. The idea of ​ ​ burning fuel inside the cylinder of a piston machine arose at the end of the 18th century, but only in 1859 the French mechanic E. Lenoir managed to create the first internal combustion engine. More than 150 years have passed since then, and scientists and engineers continue to improve these power plants. The best co-temporary ICE have an indicator efficiency of not more than 60%, and an effective one - not more than 50%. These figures indicate that modern power units are far from perfect and require further improvements.

The development of methods for calculating transport power plants will allow students to better understand the principles of ICE operation and design, but also understand the reasons leading to the deterioration of their technical and economic indicators and in the future develop a set of new design and operational measures that ensure increased reliability, fuel economy and improved environmental friendliness of engines.

A training manual aimed at studying the basics of design and calculation of internal combustion engines will be useful not only for students studying this course, but will also contribute to the formation of them as future specialists who can independently solve any engineering problems.

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