Engine V8: characteristic, photo, circuit, device, volume, weight. Cars with V8 engine

Currently, there are several options for power units, depending on the layout and number of cylinders. The V8 engine belongs to the top-level engines for passenger cars, as they are equipped with sports and elite models. Therefore, they are not very common, but are in demand.

Definition

Engine V8 is a power unit with a V-shaped arrangement of cylinders in two rows of four and a common crankshaft.

Prerequisites for creation

At the beginning of the last century there was no direct connection between the volume of the engine and the number of cylinders. However, over time, factors such as increased turnover and power, as well as a desire to reduce costs, led to the introduction of the average volume of the cylinder. In addition, there was such a thing as a liter capacity. Thus, they related the engine power to the number of cylinders. That is, each cylinder has a certain volume, and from a specific volume value a certain capacity is removed. Moreover, these characteristics are optimized, that is, it is unprofitable to go beyond them for mass production. Thus, small mass models began to be equipped with small-volume motors with a small number of cylinders, and to achieve high power it was required to create multi-cylinder power units of a larger volume.

History

The first V8 engine was put into production in 1904. It was developed two years earlier by Leon Levasser. However, it was not used for cars, but was installed on airplanes and small ships.

The first car engine V8 in volume of 3536 sm ^{3 was} issued by firm Rolls-Royce. However, she built only 3 cars equipped with it.

In 1910, 7773 cm ³ V8 was introduced by the manufacturer De Dion-Bouton. And although the cars equipped with it were also produced quite a bit, in 1912 it was presented in New York, provoking great interest. After this, American manufacturers started to create such engines.

The first relatively mass production of cars with a V8 engine was the company Cadillac in 1914. It was a lower-valve engine with a volume of 5429 cm ³ . There is an opinion that its design was copied from the above-mentioned French power unit. In the first year, about 13,000 cars were equipped with them.

In 2 years, its version of the V8 with a volume of 4 liters was presented by Oldsmobile.

In 1917, Chevrolet also started production of 4.7 liters of V8, however, the following year the manufacturer became part of GM, the units of which were the two firms mentioned above. However, Chevrolet, unlike them, focused on the production of fuel-efficient cars, which were supposed to install simpler engines, so the production of V8 stopped.

All the engines discussed above were installed on expensive models. For the first time in the mass segment, they were moved by Ford in 1932 to Model 18. Moreover, this power unit had a significant technical innovation. It was equipped with cast cast-iron block of cylinders, although before that the production of such parts was considered to be technically impossible, so the cylinders were separated from the crankcase, which complicated and made their manufacture more expensive. To create a solid part, it was necessary to improve the casting technology. The new power unit was named Flathead. It was produced until 1954.

In the US, V8 engines were especially widely used in the 1930s. They became so popular that such power units were equipped with all classes of cars, except subcompact. A car with a V8 engine by the end of the 1970s accounted for 80% of all manufactured in the US. Therefore, many of the terms associated with these power units are of American origin, and V8 is still associated with many American cars.

In Europe, these engines have not gained such popularity. So, in the first half of the last century they were equipped only with piece-produced elite models. Only in the 50's began to appear the first serial eight-cylinder engines or cars with a V8 engine. And then some of the latter were equipped with US power units.

Layout

At the beginning of the last century there were very unusual schemes for engines, for example, seven-cylinder, in-line eight-cylinder and star-shaped.

With the ordering of the motor structure, thanks to the introduction of the above principles, the number of cylinders has now been determined for the engines, depending on their power. And further, the question arose about their optimal arrangement.

First appeared the simplest version of the layout - in-line arrangement of the cylinders. This kind assumes their installation in a row one after another. However, this arrangement is relevant for engines with a number of cylinders of no more than six. In this case, the most common four-cylinder options. Two- and three-cylinder engines are relatively rare, although they appeared as early as the beginning of the 20th century. Five-cylinder engines are also not very common, besides they were developed only in the mid-70's. Six-cylinder in-line motors are currently losing popularity. The layout of the eight-cylinder engines was no longer used in the 1930s.

The use of a V-shaped circuit for motors with a large number of cylinders is due to layout considerations. If you use a row layout for multi-cylinder power packs, they will be too long, and there is a problem with their placement under the hood. Now the most common is the lateral layout, and it's very difficult to place a row even a six-cylinder power unit. In this case, the biggest problems arise with the placement of the gearbox. That's why such engines lost in the prevalence of V6. The latter can be arranged both longitudinally and transversely.

Application

The considered scheme is most often used on large-volume engines. They are installed mainly on sports and premium models among cars, as well as heavy SUVs, trucks, buses, tractors.

Characteristics

The basic parameters of V8 include volume, power, camber angle, balance.

Scope

This parameter is one of the main for any internal combustion engine. At the beginning of the history of ICE there was no connection between the volume of the engine and the number of cylinders, and the average volume was much higher than now. So, 10 liters single-cylinder engine and 23 liters six-cylinder are known.

However, later the cylinder volume specifications mentioned above and the relationship between volume and capacity were introduced.

As it was said, the considered layout is used mainly for multi-liter power packs. Therefore, the volume of the V8 engine is usually at least 4 liters. The maximum values of this parameter for modern engines of cars and SUVs are 8.5 liters. On trucks, tractors and buses install more voluminous power units (up to 24 liters).

Power

This characteristic of the V8 engine can be determined based on a specific liter capacity. For a gasoline atmospheric engine, it is 100 hp. Thus, a 4 liter engine has an average power of 400 hp. Consequently, the options of a larger volume are more powerful. In the case of some systems, especially supercharging, liter capacity is significantly increased.

The angle of disintegration

This parameter is relevant only for V-shaped engines. By it is meant the angle between the rows of cylinders. For most powertrains it is 90 °. The prevalence of this arrangement of the cylinders is explained by the fact that it allows to achieve a low level of vibration and optimal ignition of the mixture and to create a low and wide engine. The latter favorably affects the controllability, since such a power unit helps to reduce the center of gravity.

Somewhat less often there are motors with an angle of collapse of 60º. Much less motors with an even smaller angle. This allows you to reduce the width of the engine, however, in such cases it is difficult to damp the vibration.

There are engines and with an unfolded camber angle (180º). That is, their cylinders are located in a horizontal plane, and the pistons move towards each other. However, such motors are not called V-shaped, but opposite, and are denoted by the letter B. They provide a very low center of gravity, so that such engines are installed mainly on sports models. However, they differ in a large width, so the opposite motors are rare because of the complexity of placement.

Vibrations

In any case, these phenomena are manifested when the piston engine is operating. However, designers are trying to minimize them as they not only affect comfort, but also at an excessive level can lead to damage and destruction of the engine.

In its functioning, multidirectional forces and moments operate. To reduce vibrations, it is necessary to balance them. One solution to this is to design the engine in such a way that the moments and forces are equal and multidirectional. On the other hand, it is enough to refine only the crankshaft. So, you can change the location of its necks and install counterweights on it or use balancing shafts of anti-rotation.

Equilibrium

First of all, it should be noted that among the common engines only two types are balanced: in-line and opposed, and six-cylinder. Motors of other layouts differ in this indicator.

As for the V8, they are very well balanced, and especially the variants with a right angle of the collapse of the cylinders and cranks located in perpendicular planes. In addition, the smoothness is achieved due to the possibility of uniform alternation of flares. Such engines have only two unbalanced moments on the cheeks of the outer cylinders, which can be completely compensated by two counterweights on the crankshaft.

Benefits

V-shaped engines differ from motors with in-line layout with increased torque. This is facilitated by the motor circuit V8. In contrast to the in-line motor, where the direction of forces is directly perpendicular, in the engine under consideration they act on the shaft from both sides along the tangent. Due to this, a much greater inertia is created, giving the shaft dynamic acceleration.

In addition, the crankshaft V8 is highly stiff. That is, this element is stronger, therefore it is more durable and effective when operating in limit modes. And also it extends the range of engine operating frequencies and allows faster gaining momentum.

Finally, V-shaped motors are more compact in comparison with in-line ones. And they are not only shorter, but also lower, as can be seen from the photo of the V8 engine.

disadvantages

The motors of the layout in question are characterized by a complex construction, which causes a high cost. In addition, with relatively small length and height, they are wide. Also, the weight of the V8 engine is large (from 150 to 200 kg), which causes problems with the weighting. Therefore, they are not installed on small cars. In addition, such motors have a significant level of vibration and are difficult to balance. Finally, they are costly to operate. Firstly, this is due to the fact that the device of the V8 engine is very complicated. In addition, it has a large number of details. Therefore, repair of the V8 engine is complicated and expensive. Secondly, such engines are characterized by high fuel consumption.

Modern development

In the development of all internal combustion engines, there has recently been a trend towards greater efficiency and profitability. This is achieved by reducing the volume and application of various systems such as direct fuel injection, turbo charging, variable valve timing, etc. This has led to the fact that large engines, including V8, are gradually losing popularity. Many-liter motors are now replaced by turbocharged engines of a smaller volume. This particularly applies to the V12 and V10 versions, which are replaced by the inflatable V8, and the latter - by V6. That is, the average volume of motors is reduced, which is partly due to the increase in efficiency, the index of which is liter capacity.
However, sports and luxury cars still use powerful multi-liter power packs. And their productivity has also significantly increased in comparison with the past due to the use of modern technologies.

Prospects

Despite the prospects of replacing the engine with electric and other environmentally friendly engines, they still have not lost relevance. In particular, V-shaped variants are considered very promising. By now, designers have developed ways to eliminate their shortcomings. In addition, in their opinion, the potential of such power units is not fully disclosed, so they simply modernize.