Currently, there are several options for power units depending on the layout and number of cylinders. The V8 engine belongs to the highest level engines for passenger cars, as it is equipped with sports and luxury models. Therefore, they are not very common, but in demand.
Definition
The V8 engine is a power unit with a V-shaped arrangement of cylinders in two rows of four and a common crankshaft.
Creation Background
At the beginning of the last century, there was no direct relationship between the volume of the engine and the number of cylinders. However, over time, factors such as an increase in speed and power, as well as the desire to reduce the cost, led to the introduction of the average cylinder volume. In addition, a concept such as liter capacity appeared. Thus, they linked the engine power to the number of cylinders. That is, each cylinder has a certain volume, and a certain power is removed from a specific volume value. Moreover, these characteristics are optimized, that is, it is unprofitable to go beyond their scope in mass production. Thus, small mass models began to be equipped with small-volume engines with a small number of cylinders, and to achieve high power it was necessary to create multi-cylinder power units of a larger volume.
Story
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 automobiles, but was installed on airplanes and small vessels.
The first 3536 cm 3 V8 car engine was launched by 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 there were also very few cars equipped with it, in 1912 it was introduced in New York, causing great interest. After that, the creation of such engines was taken up by American manufacturers.
The first relatively mass-produced car with a V8 engine was Cadillac in 1914. It was a 5429 cm 3 low valve motor. There is an opinion that its design was copied from the French power unit mentioned above. In the first year, approximately 13,000 vehicles equipped with it were produced.
After 2 years, Oldsmobile introduced its 4-liter version of the V8.
In 1917, Chevrolet also began producing 4.7 liters of V8, however, the next year the manufacturer became part of GM, the divisions of which were the two above-mentioned companies. However, Chevrolet, unlike them, focused on the production of fuel-efficient cars, which were supposed to install simpler engines, so the production of V8 was stopped.
All the engines discussed above were installed on expensive models. For the first time they were transferred to the mass segment by Ford in 1932 on Model 18. Moreover, this power unit had a significant technical innovation. It was equipped with a cast-iron cast-iron cylinder block, although before that it was considered technically impossible for some to manufacture such parts, so the cylinders were separated from the crankcase, which made their manufacture more complicated and expensive. To create an integral part, it was necessary to improve the casting technology. The new powertrain was called Flathead. It was produced until 1954.
In the USA, V8 engines became especially widespread in the 30s. They became so popular that all classes of cars, except for the subcompact, were equipped with such power units. A car with a V8 engine by the end of the 1970s accounted for 80% of all manufactured in the United States. Therefore, many terms associated with these powertrains are of American origin, and many V8 are still associated with 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-wise elite models. Only in the 50s the first production eight-cylinder engines or cars with a V8 engine began to appear. And then some of the latter were equipped with American-made power units.
Layout
At the beginning of the last century, engine schemes very unusual for modernity were encountered, for example, seven-cylinder, in-line eight-cylinder and star-shaped ones.
With the streamlining of the design of the engines, thanks to the introduction of the above principles, the number of cylinders was now determined for engines depending on their power. And further, the question arose about their optimal location.
The first appeared the simplest layout option - in-line arrangement of cylinders. This view involves their installation in a row one after another. However, this arrangement is relevant for engines with no more than six cylinders. In this case, four-cylinder options are most common. Two- and three-cylinder engines are relatively rare, although they appeared at the beginning of the XX century. Five-cylinder engines are also not very common, in addition, they were developed only in the mid-70s. Six-cylinder in-line motors are currently losing popularity. The inline arrangement of eight-cylinder engines was no longer used in the 1930s.
The use of a V-shaped circuit for engines with a large number of cylinders is due to layout considerations. If you use the in-line layout for multi-cylinder power units, then they will turn out too long, and there is a problem with their placement under the hood. Now the most common transverse layout, and to place an inline even six-cylinder power unit in this way is very difficult. In this case, the biggest problems arise with the placement of the gearbox. That is why such engines are inferior in the prevalence of V6. The latter can be arranged both longitudinally and transversely.
Application
The considered circuit is most often used on large-volume engines. They are installed mainly on sports and premium models among cars, as well as on heavy SUVs, trucks, buses, tractors.
Characteristics
The basic parameters of V8 include volume, power, camber angle, balance.
Volume
This parameter is one of the main parameters for any internal combustion engine. At the beginning of the ICE history, 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 liter single-cylinder engine and 23 liter six-cylinder are known.
However, later the above mentioned cylinder volume standards and the relationship between volume and power were introduced.
As was said, the configuration in question is used mainly for multi-liter power units. 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 reach 8.5 liters. Trucks, tractors and buses are equipped with more voluminous power units (up to 24 liters).
Power
This characteristic of the V8 engine can be determined based on the specific liter power. For a gasoline atmospheric engine, it is 100 hp. Thus, a 4 liter engine has an average power of 400 hp. Consequently, larger options are more powerful. In the case of some systems, especially boost, the liter capacity increases significantly.
Camber angle
This parameter is relevant only for V-engine engines. By it is meant the angle between the rows of cylinders. For most powertrains, it is 90 °. The prevalence of this arrangement of cylinders is due to the fact that it allows you to achieve a low level of vibration and optimal ignition of the mixture and create a low and wide engine. The latter favorably affects handling, since such a power unit helps to reduce the center of gravity.
Motors with a camber angle of 60º are somewhat less common. Significantly fewer engines with an even more minimal angle. This allows to reduce the width of the engine, however, on such options it is difficult to dampen the vibration.
There are engines with a wide angle of camber (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 opposed and are marked with the letter B. They provide a very low center of gravity, as a result of which such engines are mainly installed on sports models. However, they are large in width, so boxer motors are rare because of the difficulty of placement.
Vibrations
In any case, these phenomena occur during the operation of a piston internal combustion engine. However, designers seek to reduce them as much as possible, as they not only affect comfort, but even at an excessive level can lead to damage and destruction of the engine.
During its functioning, multidirectional forces and moments act. To reduce vibrations, it is necessary to balance them. One solution to this is to design the engine so that the moments and forces are equal and multidirectional. On the other hand, it’s enough to refine only the crankshaft. So, you can change the location of its necks and install counterweights on it or use counterbalanced balancing shafts.
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 by this indicator.
As for the V8, they are very well balanced, and especially options with a right angle to the collapse of the cylinders and cranks located in perpendicular planes. Additionally, smoothness is given due to the possibility of ensuring uniform alternation of flashes. Such engines have only two unbalanced moments on the cheeks of the extreme cylinders, which can be fully compensated by two counterweights on the crankshaft.
Benefits
V-engines are distinguished from engines with an in-line layout with increased torque. This contributes to the V8 engine circuit. Unlike an in-line motor, where the direction of the forces is directly perpendicular, in the engine in question, they act on the shaft from two sides tangentially. Due to this, a significantly greater inertia is created, giving the shaft dynamic acceleration.
In addition, the V8 crankshaft is characterized by increased rigidity. That is, this element is stronger, therefore it is more durable and effective when working in extreme conditions. And also it extends the range of operating frequencies of the engine and allows you to gain speed faster.
Finally, V-shaped motors are more compact compared to in-line ones. Moreover, they are not only shorter, but also lower, as can be seen from the photo of the V8 engine.
disadvantages
The motors of the configuration in question are distinguished by a complex design, which leads to a high cost. In addition, with a 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 weight distribution. 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 design of the V8 engine is very complex. In addition, it has a large number of details. Therefore, repairing a 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 in recent years there has been a tendency to increase efficiency, efficiency. This is achieved by reducing the volume and application of various systems such as direct fuel injection, turbocharging, variable valve timing, etc. This has led to the fact that large engines, including the V8, are gradually losing popularity. Multi-liter engines are now being replaced with smaller turbocharged engines . This is especially true for versions V12 and V10, which are replaced by supercharged V8, and the latter - on V6. That is, the average volume of motors is reduced, which is partly due to the increase in efficiency, an indicator of which is the liter capacity.
However, on sports and luxury cars they still use powerful multi-liter power units. Moreover, their productivity has also increased significantly in comparison with the past due to the use of modern technologies.
Prospects
Despite the prospects of replacing ICE with electric and other environmentally friendly engines, they still have not lost their relevance. In particular, V-shaped options are considered very promising. To date, designers have developed ways to eliminate their shortcomings. In addition, in their opinion, the potential of such power units is not fully disclosed, so it’s easy to upgrade them.