Calculation of KrAZ truck performance - 255L1

Contents

Table of contents

Introduction

Analysis and justification of prototype selection

Initial data for the course work performance

1 Construction of traction-dynamic characteristic

1.1 Calculation of required engine power

1.2 Selection of engine and its characteristics

Engines are in demand due to high reliability, high repairability, distribution of spare parts and low price compared to foreign counterparts

1.3 Construction of external speed characteristic

1.4 Calculation of transmission gear ratios

1.5 Construction of traction characteristic

1.6 Construction of dynamic characteristic

2 Construction and calculation of speed characteristics

2.1 Construction of acceleration characteristics

2.2 Construction of acceleration characteristics

3. Power balance of the car

4. Construction and calculation of fuel economy characteristics

4.1 Construction of fuel characteristic of steady-state motion

4.2 Construction of fuel and economic characteristics

5. Construction and calculation of braking characteristics

5.1 Construction of brake diagram

Conclusion

List of literature

Introduction

A motor vehicle (PBX) is a trackless vehicle whose traction force is created by the operation of an engine (power source) and the interaction of driving wheels with a supporting surface. The theory of the operational properties of a car is a science that studies groups of properties that characterize the possibility of effective use of the car in certain operating conditions and allow you to assess the extent to which its design meets these conditions. Knowledge of the theory of the operational properties of the car is necessary when designing and refining new models, for rational selection and use in given operating conditions. Increasing the productivity of cars and reducing the cost of transportation is impossible without studying the operational properties of the car.

The theory of the car considers its operational properties directly related to movement. Modern society is difficult to imagine without transport networks, thanks to a number of advantages, road transport has become the most widely used and has become a mass product. However, the accelerated pace of motorization has a number of drawbacks, primarily the problems of ecology and resource saving.

The market of automotive and tractor equipment is represented by the widest range and various models. Nevertheless, every day new and new tasks appear in the national economy, and the demand and fashion of consumers of the private market is changing, in this regard, the design of cars, based on operational and consumer properties, remains one of the main tasks of the industry.

In this course project, the KrAZ car is considered - 255L1. For this car, it is necessary to calculate the required engine power, select the engine, and find transmission ratios. For the selected engine, build an external speed characteristic. It is also necessary to construct a dynamic and traction characteristic, acceleration characteristic and braking diagram, acceleration characteristic, fuel characteristic, fuel-economic characteristic and power balance.

The traction-speed properties of the car characterize its ability to carry goods or passengers with the maximum possible average speed at given road conditions. The engine power, transmission gear ratios, and transmission efficiency have the greatest influence on traction and speed properties.

Fuel economy characterizes a set of properties that determine fuel consumption when a car performs transport work in various operating conditions.

Analysis and justification of prototype selection

The KrAZ - 255L1 car was chosen as a prototype since this car is Durable and hanged cross-country, which is not of little importance for military equipment. It is also worth noting that this car is used to transport goods, personnel, military installations and is not afraid of obstacles and off-road. The load capacity of the model increased by 20%, speed - by 11%, operational life - by 95%, fuel consumption decreased by 6%. The tractor cabin was moved forward, which allowed to increase the cargo platform and load capacity. The length of the hood decreased, which positively affected the review.

Conclusion

During the course project, knowledge and skills were gained in solving problems related to calculating and determining the operational and consumer properties of cars and tractors. They also learned to choose, based on the indicators found, the main parameters of vehicles. Skills of creation of a number of characteristics of the car are received: external high-speed characteristic, dynamic and traction characteristics, characteristics of acceleration, dispersal and braking, fuel economic characteristics and fuel characteristic of the established movement.