Turbo Charger and Compressor - Part One

Turbo charger

Turbo charger

Turbo? This term is used in addition to motoring and energy in other areas and is often used as a synonym for something that is better, better, faster. This text explains terms such as turbocharger, turbocharger. In this text, we compare the two approaches to increasing power and explain the auxiliary aggregates for both systems.

Introduction

For people who do not deal with the topic of cars, the term "turbo" has for the past ten years generally referred to them as diesel engines. The so-called “turbo” era ended in the late 90s and from then until the present day, the turbo is really what in most cases is a good hint that it is a diesel engine.

The first thing we need to emphasize in this text is the name differences: The turbocharger is most commonly referred to as just the turbo, and in English the name used is "turbocharger", While a turbocharger may also be called a compressor (Mercedes uses this name, for example), charger (G charger - VW) while in English literature, turbo compressors are called "supercharger".

Turbines are used in the energy, aerospace and auto industries and what sets them apart is, of course, performance since their tasks are different, but what definitely connects them is the same look and principle of operation. In the auto industry there are several ways of so-called "eating" (a term used in the textbooks of our Faculty of Mechanical Engineering) ie. extra compaction more air than natural pressure allows. The engine combines a mixture of air and fuel, and that air enters the engine through a suction branch of the engine withdrawn from the surrounding atmosphere by the difference in pressure the engine generates. In order to increase the power of the air, artificial modes such as: turbochargers, mechanical compressors and so-called are used. "Ram Air" system. This text for the topic is the work of a turbocharger and turbocharger, while the principle of operation of "Ram Air" system will be explained in the next few sentences.

Ram Air

This system, or in free translation, a natural turbine, is a system used by race cars, and it boils down to the simple principle that the intake manifold (with the help of appropriate filters) be brought directly somewhere to the outside of the car facing the direction of travel, thereby increasing the speed of the car in proportion increases the pressure of air entering the engine. For example, F1 cars have a suction directly above the driver's head, GT cars have "humps" on the hood that directly inject air into the car's engine, and this pressure is directly proportional to the speed of the car.

Ferrari Maranello 575 - A typical example of a GT car with a "Ram Air" system

Ferrari Maranello 575 - A typical example of a GT car with a "Ram Air" system

How to make more power

Four options with one thing in common

When it comes to ways to increase engine power, the common goal, of course, is to burn as much of the fuel / air mixture in a unit of time as possible. There are, practically, four fundamentally different ways of doing this.

1. Make an efficient engine so that as much air and fuel as possible is introduced into it by reducing the intake and exhaust manifold restrictions, reducing the mass rotating inside the engine, increasing the energy generated by the spark plug and fine-tuning the engine timing. These are the goals of all the "performance" parts that increase engine power - air filters, ignition programmers, exhaust systems, etc. These modifications are very popular because they add strength, look good and sound good. The problem with such modifications is that they bring small gains, and often these gains in power are insignificant and cannot be felt. Today's modern engines are fairly well tuned upon leaving the factory and are not equipped with overly restrictive intake or exhaust branches that would reduce fuel consumption. In other words, if you are looking for moderate power gains, you need to go deeper than such modifications, which aim only at a slight increase in engine efficiency.

2. The power of the engine can be increased by accelerating it, ie. the engine will rotate at a higher speed. This technique is effective when insisting on maintaining low weight and compactness of the engine, and at the same time requires more power. Of course all race cars have engines that achieve high speeds. The only drawback of this approach is that if you want to allow the engine to rotate at a very high speed, you need very high quality (and expensive) parts that will be able to withstand operation in such conditions. The increased number of revolutions significantly increases the wear of the material, which reduces the reliability of the engine and reduces its service life. Most normal cars have a red field between 6000 - 7000 rpm precisely for this reason to increase engine life. Turning the engine faster than anticipated is a risk to the engine.

3. Another way to increase engine power is very obvious. Using a larger engine. Larger engines can burn more air and fuel and thus generate more power. Of course, if it were that simple everyone would have V12 engines under the hood. Increasing the engine can easily be done by drilling (increasing the diameter) of the cylinders and placing larger pistons, or by increasing the stroke of the piston, but such engine increases are very limited since the design of the engine does not allow too much increase in these parameters. To increase the engine significantly, it is necessary to have a physically larger multi-cylinder engine, but it delivers larger dimensions, more weight and less fuel efficiency.

4. The last way to increase power is to introduce a larger amount of a mixture of fuel and air before it burns, and the result is a power that is adequate to a classic engine with a larger volume. The problem with this technique is that it is not enough to say that the engine should suck more mixture, the pressure is conditioned by the atmospheric pressure of 1 bar at 0 m above sea level. As the height increases, the air becomes thinner and thus the engine has less and less power. This is where turbochargers or turbochargers come into play. The compressor, as its name suggests, compresses the air and fuel into the cylinder chamber under a pressure higher than atmospheric and thus practically gets the effect of increasing the power as if the engine is larger in volume than it is. Secondly, the small engine retains all its features - light, compact, efficiently consumes fuel, and again, with the help of a compressor, it gives more power. It can additionally be controlled when the compressor is running so that if you do not press the accelerator pedal to the floor, the engine is running at its normal performance and more importantly consumes very little fuel.

In reality, there are far more than the above four ways to increase power, but these are the most conventional. You could, for example, use more calorie fuel, which is the idea behind the guidance of systems using Nitro Oxide - better known as NOS or other Top Fuel systems.

The golden “turbo” era

Turbochargers were first introduced in a large-scale passenger car in the early 1960s. The model was a Chevrolet Corvair manufactured by General Motors - GM. The car had a bad reputation for having poor performance at low speeds, and the huge turbo lag made running liquid in this car virtually impossible.

Turbo lag was a major problem for the automotive industry and prevented cars that used the turbocharger from being practical at the time. Turbochargers were used extensively in auto sports at that time - from the iconic BMW 2002 turbo model to the endurans and finally Formula One, however race car drivers managed to cope with the rather awkward turbocharged engines at the time, but it was not a solution for everyday driving and the normal driver. The turbines of that era were very large and heavy and therefore very inert. Such turbines could not rotate below 1 rpm, so the engine operating range up to 3500 rpm was very weak given that it was 3500: 6,5 at the time of turbo engine compression to avoid overheating of the cylinder head.

Porsche is a pioneer when it comes to relatively practical turbo cars. In 1975, the 911 Turbo 3.0 appeared, using a solution that came from Poresh's engineers. The mechanism was based on the use of so-called "recirculating" hoses that allowed the turbine to spin before starting work, thus reducing lag. The 1978 Porsche 911 Turbo 3.3 model that succeeded the 3.0 Turbo introduced another novelty - an intercooler that further reduced lag and added to the engine's power output.

During the 80s, turbocharger manufacturing technology evolved towards more cultured operation. In recent years, turbocharged cars have used another turbo lag reduction system - electronic turbine pressure control. Early turbochargers used primitive mechanical solutions with a "west gate" valve to avoid too much pressure and too much turbine speed. In the late 80's and early 90's, with the development of electronics, fine pressure control of the turbine was enabled, so that, for example, the turbo could deliver 1,4 bar below 3000 rpm, 1,6 bar from 3000 to 4500 rpm, and 1,8 , 4500 bar above XNUMX rpm. Such fine control resulted in a linear increase in power, which added to the fluid feel of the ride.

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