Inline engine: types, device, advantages and disadvantages

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Inline internal combustion engine is one of the simplest engines. These units are called such because the cylinders are arranged in a row. Pistons make one crankshaft rotate when the engine is running. The in-line engine was one of the first to be installed on cars. They were designed and built at the dawn of the automotive industry.

How did it all start?

The ancestor of the modern in-line internal combustion engine was a single-cylinder engine. Designed and built by Etienne Lenoir in 1860. It is generally accepted that this is so, although there were attempts to obtain a patent for this engine even before Lenoir. But it is precisely its development that is as similar as possible to those designs that are currently installed under the hoods of most budget serial passenger cars.

The motor had only one cylinder, and its power was equal to 1.23 horsepower, huge at that time. For comparison, the modern "Oka" 1111 has two cylinders and its power is from 30 to 53 horsepower.

Bigger and more powerful

Lenoir's idea turned out to be brilliant. Many engineers and inventorsspent years and effort trying to improve the engine as much as possible (of course, at the level of the technical capabilities that existed at that time). The main emphasis was placed on increasing power.

In the beginning, attention was concentrated on a single cylinder - they tried to increase its size. Then it seemed to everyone that by increasing the size, you can get more power. And the increase in volume was then the easiest. But one cylinder was not enough. I had to greatly increase the rest of the details - connecting rod, piston, block.

All those engines turned out to be very unstable, had a large mass. During the operation of such a motor, there was a huge difference in time between the ignition cycles of the mixture. Literally every detail in such a unit rattled and shook, which forced the engineers to think about a solution. And they equipped the system with a balancer.

Dead end road

It soon became clear to everyone that the research had reached a dead end. The Lenoir engine could not work normally and correctly, since the ratio of power, weight and size was terrible. A lot of additional energy was needed to increase the volume of the cylinder again. Many began to consider the idea of \u200b\u200bcreating an engine a collapse. And people would still ride horses and carts, if not for one technical solution.

Designers began to realize that it is possible to rotate the crankshaft not only with one piston, but with several at once. The simplest was the manufacture of an in-line engine - they added a few more cylinders.

The world could see the first four-cylinder unit at the end of the 19th century. It is impossible to compare its power with a modern engine. However, in terms of efficiency, it was higher than all its other predecessors. Power was increased due to the increased working volume, that is, by adding cylinders. Pretty quickly, specialists from various companies were able to create multi-cylinder engines up to 12-cylinder monsters.

Operation principle

How does ICE work? Apart from the fact that each engine has a different number of cylinders, an inline engine with six or four cylinders works the same way. The principle is based on the traditional characteristics of any internal combustion engine.

All cylinders in the block are arranged in one row. The crankshaft, driven by pistons due to the energy of fuel combustion, is the only one for all parts of the cylinder-piston group. The same applies to the cylinder head. It is the only one for all cylinders. Of all existing in-line engines, balanced and unbalanced designs can be distinguished. We will consider both options below.

Balance

It is important because of the complex design of the crankshaft. The need for balancing depends on the number of cylinders. The more of them in a particular ICE, the greater the balance should be.

An unbalanced engine can only be that design, where there are no more than four cylinders. Otherwise, vibrations will appear during operation, the force of which will be able to destroy the crankshaft. Even cheap six-cylinder engineswith a balancer will be better than expensive inline fours without balancer shafts. So, to improve balance, an inline four-piston engine may sometimes also require the installation of stilling shafts.

Motor position

Traditional four-cylinder units are usually mounted longitudinally or transversely under the hood of a car. But the six-cylinder unit can only be installed longitudinally and nothing more (with the exception of some Volvo models and Chevrolet Epica cars).

The in-line internal combustion engine, which has an asymmetric design with respect to the crankshaft, also has features. Often the shaft is made with compensating castings - these castings must dampen the inertia force resulting from the operation of the piston system.

Inline-six today already has less popularity - all the fault of significant fuel consumption and large overall dimensions. But even despite the long cylinder block, the engine is perfectly balanced.

Advantages and disadvantages of the unit

Apart from a few nuances, in-line internal combustion engines have the same advantages and the same disadvantages as most V-engines and motors of other designs. The four-cylinder engine is the most common, is the simplest and most reliable. The mass is relatively light, the repair costs are relatively low. The only drawback is the lack of balance shafts in the design. This is the best internal combustion engine for modern cars, even the middle class. There are also small-capacity in-line engines with lessthe number of cylinders. As an example, the two-cylinder economical SeAZ Oka 1111.

Six-cylinder units have a perfect balance and here the lack of a "four" is compensated. But there is a price to pay for balance. Therefore, despite the significantly better characteristics compared to the "four", these internal combustion engines with an in-line arrangement of cylinders in the engine are less common. The crankshaft is long, the production cost is quite high, and the dimensions are relatively large.

Technical limit

Now it's not the 19th century, but modern power units are still far from technical perfection. And even modern turbines and high-octane fuel will not help here. The efficiency of an internal combustion engine is about 20%, and all other energy is spent on friction, inertia and detonation. Only a fifth of gasoline or diesel will go to useful work.

Already developed the basic properties of motors with the greatest efficiency. At the same time, the combustion chambers and the piston group have significantly smaller volumes and dimensions. Due to the compact size, the parts have less inertia - this reduces the likelihood of damage due to detonation.

The design features of compact pistons introduce certain limitations. With a high degree of compression, due to the small size, the transmission of piston pressure to the connecting rod is reduced. If the pistons have a larger diameter, then it is impossible to get an accurate balanced work due to the enormous complexity. Even a modern BMW engine has theseshortcomings, although it was developed by German engineers.

Conclusion

Unfortunately, engine building has reached its technological limit. It is unlikely that scientists will make serious technical discoveries and achieve greater efficiency from an internal combustion engine. So all hope that the era of electric vehicles will come.