Test bench for investigation of turbocompressor of ICE pressurizing unit

Contents

Contents

Introduction

Status of the question

Mixing in diesel engines

Fuel spraying

Film and volume-film mixing methods

Adjustment characteristics of fuel supply system

Goals and objectives of graduation work

Special part

Design features of HPV and their impact on

indicators of fuel supply process

Dynamic and efficient performance of MMZ engines

Thermal calculation of the engine

Kinematic calculation

crank mechanism

Piston movement

Piston speed

Piston acceleration

Dynamic calculation

crank mechanism

Force of gas pressure on piston

Inertia force reciprocating

moving masses of KSM

Total force acting on piston pin

Forces loading the connecting rod neck

Definition of tangential force

Determining Radial Force

Determine the resulting force

Definitions of normal force

Loading of connecting rod neck and

determining its dimensions

Forces acting on engine supports

Design Development

with performance of working drawings and strength calculations

Calculation of bolted connections

Conclusions

List of used literature

Introduction

According to domestic and foreign forecasts, the piston internal combustion engine will remain as the main power plant of self-propelled vehicles. Preference will be given to the most economical engines - diesel engines.

Due to the large economic role of diesel engines in the CIS and abroad, work is constantly underway to improve them in the following areas:

- Improving fuel economy by using direct fuel injection chambers; increase of pressurizing pressures; introduction of adiabateness elements with transition to turbocharged and compound engines; increase of efficiency of fuel mixing and combustion processes due to pressure increase; increase of mechanical efficiency of engine and turbocompressors; optimum control of fuel supply process depending on operation modes, environmental conditions, physical and mechanical properties of fuels; changes in the engine state during operation using flexible, up to adaptive, electronically controlled systems;

- increase of specific power and decrease of specific mass indices of engines by increase of average effective pressures with simultaneous increase of permissible maximum cycle pressures;

- reduction of emissions of toxic combustion products and smoke due to improvement of fuel supply, mixing and combustion processes of fuel - optimal combination of schemes of combustion chambers, gas-dynamic situation in them and parameters of fuel injection process by application of fuel supply systems with electronic control;

- improving the reliability (service life) of diesel engines due to improving the manufacturing technology, using new materials (plastics, composites, ceramics, special lubricants, etc.), improving methods for calculating strength and reliability;

- automation and remote control of diesel engines, power plants and vehicles in general using microprocessor technology;

- adaptation of diesel engines to work on various alternative non-petroleum fuels, liquefied and compressed gases, as well as on oil fuel of light and heavy fractional composition.

Consumer qualities of fuel equipment are evaluated by technical level indicators, which are divided into:

- parameters determining injection conditions (injection characteristic; mean and maximum pressure; starting point of fuel supply and minimum duration of supply);

- stability indicators of fuel equipment parameters;

- reliability indicators;

- maintenance and repair costs;

- processability indicators;

- overall - mass indicators.

At the same time, all indicators in one fuel system cannot be met. Modern systems with electronic control have the maximum capabilities for this.

Status of the question

1.1 Mixing in diesel engines

Unlike engines with forced ignition of a combustible mixture, where mixing processes usually occupy a significant part of the working cycle, very short periods of time are allocated to mixing in diesel engines, corresponding to only 20-40 ° of crankshaft rotation. At the same time, the process of mixing in time coincides with the supply of fuel to the cylinders and with the development of the combustion process. The qualitative preparation of a fuel-air mixture with a uniform distribution of fuel over the volume of the combustion chamber in these conditions is a very difficult task, the more or less successful solution of which is possible only through the use of special fuel equipment, as well as the appropriate design forms of combustion chambers and inlet pipelines. In order to obtain the necessary composition of the mixture in accordance with the mixing methods, the fuel equipment, the design of the combustion chamber and the inlet duct should provide:

- strict conformity of the shape of the combustion chamber with the shape, quantity and direction of the fuel flares;

- The formation of fuel droplets at the inlet of the fuel of a size sufficiently complete evaporation of the fuel and uniform distribution over the volume of the combustion chamber;

- creation of an organized charge movement in the combustion chamber, which allows to perform sufficiently complete and perfect mixing of vapors and droplets of fuel with air.

Depending on the nature of evaporation, mixing with air charge and introduction of the main mass of fuel injected into cylinders into the combustion zone, diesel engines distinguish between volumetric, film and volumetric-film mixing methods.

In volumetric mixing, the fuel is introduced in a finely sprayed droplet-like state directly into the air charge of the combustion chamber, where then it, evaporating and mixing with air, forms a fuel-air mixture.

In the case of film mixing, the bulk of the fuel is injected onto the walls of the combustion chamber and, under the influence of the organized charge movement, is stretched into the thin film over its surface. Subsequently, due to intensive evaporation of this film, the fuel is mixed with air and sequentially introduced into the combustion zone.

During volume-film mixing, the fuel-air mixture is prepared simultaneously by both volume and film methods. This method of producing a combustible mixture practically takes place in all diesel engines and can be considered as a general case of mixing in general. Depending on how much fuel is introduced into the fuel-air mixture from the spray state or from the fuel film, it can accordingly be converted into a bulk or film mixing method.

1.2 Fuel spraying

With volumetric and from part of volumetric-film methods of mixing, perfection of fuel-air mixture preparation is determined mainly by quality of fuel spraying during injection.

The spraying process is a very complex phenomenon and consists in breaking the fuel jet into small droplets under the influence of aerodynamic drag forces of the medium to which the fuel is introduced, as well as initial disturbances in the flow that occur when the fuel flows through the nozzles of the sprayer.

In order to ensure that all subsequent fuel injection processes in the engines proceed normally, the fuel droplets generated during spraying must be sized. With too large drops, the fuel will not be able to evaporate at the necessary speeds, which will lead to an abnormal combustion process, an increase in fuel flooding and a deterioration in engine performance. In the case of very small droplets, the evaporation of the fuel can be completely completed in the immediate vicinity of the nozzle of the atomizer and will not penetrate into the remote volumes of charge, which will impair the distribution of the fuel through the combustion chamber and create some difficulties for the effective use of the air therein. Therefore, the main purpose of the spraying is to form droplets of such a size that their total total surface is sufficient to evaporate the fuel at the necessary speeds, and their mass ensures the penetration of the fuel to the entire depth of the combustion chamber, thereby creating the prerequisites for its uniform distribution over the air charge.

The fineness and uniformity of spraying, as well as the quality of mixing in general, are determined by a number of different factors, the most interesting of which are: injection pressure, back pressure of the medium, the number of revolutions of the pump shaft, fuel properties and design features of the sprayer.

As the injection pressure increases, the rate of fuel flow through the sprayer channel and the rate of fuel flow from the sprayer to the environment increases. In this regard, firstly, disturbances in the fuel jet are increased, leading to vortex movements within the jet and on its periphery, and secondly, due to the increased effect of aerodynamic forces on the surface of the jet at higher flow rates, the crushing effect of the medium into which the fuel is injected is increased. As a result of the joint influence of these factors, the decay of the fuel jet is significantly facilitated and the production of smaller and more uniform fuel droplets is ensured, that is, the fineness and uniformity of spraying are improved. (Figure 1 (a)).

List of used literature

Selivanov N.I. Tractors and cars. Course and Diploma Design. Cras. State agrarian. unt.- Krasnoyarsk 2005156 s.

Krokhotin Yu. M. Diesel power systems. Voronezh 1999-336 p.

Orlin A. S., Kruglov M. G. The theory of piston and combined engines. M.: Engineering, 1983-372 s.

Kolchin A.I., Demidov V.P. Calculation of automobile and tractor

engines. M.: Vysh. school, 1980 400 p.

Khovakh M. S. Automobile engines. Mechanical engineering, 1997 -336 s.

Kulchitsky A.R. Toxicity of automobile and tractor

engines. Textbook - 2 ed. M.: Academic Project, 2004 -

400 pages.

Selivanov N.I., Kirin. V. S. Fuel equipment of auto-tractor diesel engines. Maintenance and repair. Textbook - Krasnoyarsk 2002 112 s.

Tractors "Belarus" MTZ100; MTZ-102 Technical description and operating manual:. Minsk. 1984.

Belyavtsev A.V., Protserov A.S., Fuel equipment of auto-tractor diesel engines: design features and operation. M: Rosagropromizdat, 1988.223s.

Patrahaltsev N.N., Savastenko A.A. Forcing internal combustion engines with supercharging: -M.: Legion - Avtodata, 2004 - 176s.

Belov P.M., Buryachko V.R., Akatov E.I. Engines of army vehicles. Part one. Theory. -M.: Military building, 1991 - 512s.

Fuel equipment of tractor and combine engines: Handbook/V.G. Kislov et al. -M.: Engineering, 1981-208 p.

Pisarenko G.S., Yakovlev A.P., Matveev V.V. Handbook on Resistance of Materials. -M.: "Naukova Dumka" Kiev 1975.704s.

Novichikhina L.I. Handbook of Technical Drawing. - Mn.: Bookhouse, 2004.320s.

Conclusions

1. Design changes of the type 77 TNVD make it possible to realize the tendency to further increase to 70 MPa created by the plunger pair.

2. Design changes of TNHD type 77 ensure stability of parameters affecting qualitative and quantitative parameters of its operation.

3. The advance angle of fuel injection in MMZ engines with volume-film mixing affects mainly the rigidity of the engine.

4. Dynamic calculation determines the laws of change, maximum values ​ ​ of forces and acting on KSM parts and the engine support and connection mechanism.