The reciprocating internal combustion engine has been known for over a century, and almost as many, or rather since 1886, it has been used in cars. The fundamental solution to this type of engine was found by German engineers E. Langen and N. Otto in 1867. It turned out to be quite successful in order to provide this type of engine with a leading position that has been preserved in the automotive industry to this day. However, the inventors of many countries tirelessly sought to build a different engine capable of surpassing the piston internal combustion engine in terms of the most important technical indicators. What are these indicators? First of all, this is the so-called effective coefficient of performance (COP), which characterizes how much heat that was in the consumed fuel is converted into mechanical work. The efficiency for a diesel internal combustion engine is 0.39, and for a carburetor - 0.31. In other words, the effective efficiency characterizes the efficiency of the engine. Specific indicators are no less significant: specific occupied volume (hp / m3) and specific gravity (kg / hp), which indicate compactness and lightness of the design. Equally important is the ability of the engine to adapt to various loads, as well as the complexity of manufacturing, the simplicity of the device, the noise level, and the content of toxic substances in the combustion products. With all the positive aspects of a particular concept of a power plant, the period from the beginning of theoretical development to its introduction into mass production sometimes takes a very long time. Thus, the creator of the rotary piston engine, the German inventor F. Wankel, took 30 years, despite his continuous work, in order to bring his unit to an industrial design. By the way, it will be said that it took almost 30 years to introduce a diesel engine on a production car (Benz, 1923). But it was not technical conservatism that caused such a long delay, but the need to exhaustively work out a new design, that is, to create the necessary materials and technology to enable its mass production. This page contains a description of some types of non-traditional engines, but which have proven their viability in practice. A piston internal combustion engine has one of its most significant drawbacks - it is a rather massive crank mechanism, because the main friction losses are associated with its operation. Already at the beginning of our century, attempts were made to get rid of such a mechanism. Since that time, many ingenious designs have been proposed that convert the reciprocating motion of a piston into the rotational motion of a shaft of this design.
Connecting rodless engine S. Balandin
The transformation of the reciprocating motion of the piston group into rotational motion is carried out by a mechanism based on the kinematics of the "exact straight line". That is, two pistons are rigidly connected by a rod acting on a crankshaft rotating with gear rims in the cranks. A successful solution to the problem was found by the Soviet engineer S. Balandin. In the 1940s and 1950s, he designed and built several models of aircraft engines, where the rod that connected the pistons to the converting mechanism did not oscillate. Such a connecting rodless design, although to some extent more complicated than the mechanism, occupied a smaller volume and provided less friction losses. It should be noted that an engine similar in design was tested in England at the end of the twenties. But the merit of S. Balandin is that he considered the new possibilities of a transforming mechanism without a connecting rod. Since the rod in such an engine does not swing relative to the piston, then it is also possible to attach a combustion chamber on the other side of the piston with a structurally simple seal of the rod passing through its cover.
Rotary piston engine F. Wankel
It has a trihedral rotor, which makes a planetary movement around the eccentric shaft. The changing volume of the three cavities formed by the walls of the rotor and the internal cavity of the crankcase allows the operating cycle of the heat engine with the expansion of gases to be carried out. Since 1964, on mass-produced cars in which rotary piston engines are installed, the piston function is performed by a trihedral rotor. The movement of the rotor required in the housing relative to the eccentric shaft is provided by a planetary-gear matching mechanism (see figure). Such an engine, with equal power to a piston engine, is more compact (has a 30% smaller volume), 10-15% lighter, has fewer parts and is better balanced. But at the same time, it was inferior to a piston engine in terms of durability, reliability of seals in working cavities, it consumed more fuel, and its exhaust gases contained more toxic substances. But, after many years of fine-tuning, these shortcomings were eliminated. However, mass production of cars with rotary piston engines is currently limited. In addition to the design of F. Wankel, numerous designs of rotary piston engines by other inventors (E. Cauertz, G. Bradshaw, R. Seyrich, G. Ruzhitsky, etc.) are known. However, objective reasons did not give them the opportunity to leave the experimental stage - often due to insufficient technical merit.
Gas twin-shaft turbine
From the combustion chamber, gases rush to two turbine impellers, each connected to independent shafts. A centrifugal compressor is driven from the right wheel, and power directed to the wheels of the car is taken from the left. The air injected by it enters the combustion chamber passing through the heat exchanger, where it is heated by the exhaust gases. A gas turbine power plant with the same power is more compact and lighter than a piston internal combustion engine, and is also well balanced. Less toxic and exhaust gases. Due to the peculiarities of its traction characteristics, a gas turbine can be used on a car without a gearbox. The technology for the production of gas turbines has long been mastered in the aviation industry. For what reason, taking into account the experiments with gas turbine machines that have been going on for over 30 years, do they not go into mass production? The main reason is the low effective efficiency and low efficiency in comparison with piston internal combustion engines. Also, gas turbine engines are quite expensive to manufacture, so that they are currently only found on experimental cars.Steam piston engine
Steam is alternately supplied to the two opposite sides of the piston. Its supply is regulated by a spool that slides over the cylinder in the steam distribution box. In the cylinder, the piston rod is sealed with a sleeve and connected to a fairly massive crosshead mechanism, which converts its reciprocating motion into rotational.R. Stirling engine. External combustion engine
Two pistons (lower - working, upper - displacing) are connected to the crank mechanism by concentric rods. The gas located in the cavities above and below the displacement piston, being heated alternately from the burner in the cylinder head, passes through the heat exchanger, cooler and back. A cyclic change in the temperature of the gas is accompanied by a change in volume and, accordingly, an effect on the movement of the pistons. Similar engines ran on fuel oil, wood, coal. Their advantages include durability, smooth operation, excellent traction characteristics, which makes it possible to do without a gearbox at all. The main disadvantages: the impressive mass of the power unit and low efficiency. Experimental developments of recent years (for example, the American B. Lear and others) made it possible to design closed-cycle units (with complete condensation of water), to select the compositions of vapor-forming liquids with indicators more favorable than water. Nevertheless, not a single plant has dared to mass-produce cars with steam engines in recent years. The hot-air engine, the idea of which was proposed by R. Stirling back in 1816, belongs to external combustion engines. In it, the working fluid is helium or hydrogen, which is under pressure, alternately cooled and heated. Such an engine (see figure) is simple in principle, has a lower fuel consumption than internal combustion reciprocating engines, does not emit gases that have harmful substances during operation, and also has a high effective efficiency equal to 0.38. However, the introduction of the R. Stirling engine into mass production is hindered by serious difficulties. It is heavy and very bulky, slowly gaining momentum compared to a reciprocating internal combustion engine. Moreover, it is technically difficult to ensure reliable sealing of working cavities. Among non-traditional engines, ceramic stands apart, which does not differ structurally from a traditional four-stroke piston internal combustion engine. Only its most important parts are made of a ceramic material that can withstand temperatures 1.5 times higher than metal. Accordingly, the ceramic engine does not require a cooling system and thus there are no heat losses that are associated with its operation. This makes it possible to design an engine that will operate on the so-called adiabatic cycle, which promises a significant reduction in fuel consumption. Meanwhile, similar work is being carried out by American and Japanese specialists, but so far they have not left the stage of searching for solutions. Although there is still no shortage of experiments with a variety of non-traditional engines, the dominant position in cars, as noted above, is retained and, possibly, will remain for a long time to be reciprocating four-stroke internal combustion engines.The history of the creators of the most powerful internal combustion engine in the world. How to increase the efficiency of the motor by several times, what is the difference between the new unit and the well-known rotary engines and what is the advantage of Soviet education over American - in the material of the department of science.
Technology is constantly evolving. You can read about how to protect your electrical wiring on the website of the Electric Shop online store.
A native of the USSR, living in the USA, together with his son invented, patented and tested the most powerful and efficient internal combustion engine in the world. The new motor will be many times superior to the existing ones in terms of efficiency and yield in weight.
In 1975, shortly after graduating from the Kyiv Polytechnic Institute, the young physicist Nikolai Shkolnik left for the United States, where he received a scientific degree and became a theoretical physicist - he was interested in applications related to general and special relativity. After working in the field of nuclear physics, the young scientist opened two companies in the United States: one dealing with software, the other developing walking robots. He later took up consulting for troubled tech innovation companies for ten years.
However, as an engineer, Shkolnik was constantly worried about one question - why are modern car engines so uneconomical?
Indeed, despite the fact that mankind has been improving the piston internal combustion engine for a century and a half,
The efficiency of gasoline engines today does not exceed 25%, diesel - about 40%.
Meanwhile, Shkolnik's son Alexander entered MIT and received a doctorate in computer science, becoming a specialist in system optimization. Thinking about increasing the efficiency of the engine, Nikolai Shkolnik developed his own thermodynamic cycle of the engine HEHC (High-efficiency hybrid cycle), which became a key step in the realization of his dream.
“The last time this happened was in 1892, when Rudolf Diesel proposed a new cycle and created his own engine,” Shkolnik Jr. explained in an interview.
The inventors settled on a rotary engine, the principle of which was proposed in the middle of the 20th century by the German inventor Felix Wankel. The idea of a rotary engine is simple. Unlike conventional piston engines, in which there are many rotating and moving parts that reduce efficiency, the Wankel rotary engine has an oval chamber and a triangular rotor rotating inside it, which, by its movement, forms various sections in the chamber where the intake, compression, combustion and exhaust of fuel take place. .
Pluses of the engine - power, compactness, absence of vibrations. However, despite the higher efficiency and high dynamic characteristics, rotary engines have not found wide application in technology for half a century. One of the few examples of serial installation
The weak points of such motors were unreliability associated with low wear resistance of seals, due to which the rotor is tightly adjacent to the walls of the chamber, and low environmental friendliness.
Already working in the company LiquidPiston, the founders of which they became, the Schoolchildren created their own, completely new reincarnation of the idea of rotary motors.
The fundamental thing about it was that in the Shkolnikov engine it was not a chamber, but a rotor that resembled a walnut in shape, which rotated in a triangular chamber.
This made it possible to solve a number of insurmountable problems of the Wankel engine. For example, the notorious seals can now be made of iron and fixed to the walls of the chamber. In this case, the oil is supplied directly to them, while earlier it was added to the air itself and, burning, created a dirty exhaust, and lubricated poorly.
In addition, during the operation of the Shkolnikov engine, the so-called isochoric combustion of fuel occurs, that is, combustion at a constant volume, which increases the efficiency of the motor.
The inventors created one after another five models of a fundamentally new motor, the last of which was tested for the first time in June - it was put on a sports kart. The tests met all expectations.
The miniature engine is the size of a smartphone, weighing less than 2 kg and has a power of only 3 hp. The engine is high-speed, operates at a frequency of 10 thousand rpm, but can reach 14 thousand. The efficiency of the motor is 20%. This is a lot, considering that a conventional piston engine of the same volume of 23 “cubes” would have an efficiency of only 12%, and a piston engine of the same mass would give only 1 hp.
But most importantly, the efficiency of such motors increases dramatically with an increase in their volume.
Thus, the next Shkolnikov engine will be a 40 hp diesel engine, while its efficiency will already be 45%, which is higher than the efficiency of the best diesel engines of modern trucks.
It will weigh only 13 kg, despite the fact that its piston counterparts of the same power today weigh under 200 kg.
This motor is already planned to be put on a generator that will rotate the wheels of a diesel-electric car. “If we build an even bigger engine, we can achieve an efficiency of 60%,” explains Shkolnik.
In the future, Shkolnikov's compact, revving and powerful motors are planned to be used where these properties are especially important - in the design of light drones, manual chainsaws, lawn mowers and electric generators.
While the motor was being driven for 15 hours, however, according to the standards, in order to go into production, it must work continuously for 50 hours. At the same time, the automotive industry requires engine reliability for 100,000 miles, which is still a dream, the designers admit.
“This is the most economical, powerful engine not only among rotary, but also among all internal combustion engines.
This is shown by our measurements, and what we get on larger motors, we have already simulated on computers,” Shkolnik Jr. rejoices.
The fact that the announced figures are not fantasies of inventors confirms the seriousness of investors' intentions. Today, $18 million in venture investments have already been invested in the startup, $1 million of which was given by the American advanced research agency DARPA.
The interest of the military here is understandable. The fact is that the US military in aviation mainly uses JP-8 fuel. And the military wants all army equipment to run on this type of fuel, which, by the way, diesel engines can also run on.
But modern diesel engines are bulky, which is why DARPA is eyeing Shkolnikov's development so actively.
Alexander believes that the education that his father received back in the USSR helped to create such a revolutionary engine. “He thinks differently, not like an ordinary engineer in the US. His imagination is limited only by physics. If physics says - something is possible, then he believes that it is so, and only thinks how it can be done, ”added Alexander.
Nikolai Shkolnik himself tells the story of his success and the benefits of Soviet education in his own way.
“In the USA, I was worried that, having a specialty in mechanical engineering, I would not have a sufficient background in physics and, especially, mathematics.
These fears turned out to be in vain thanks to the excellent training I received in the Soviet school.
This solid educational background still helps me here in our work with the new rotary engine. From my point of view, there are two big differences between American engineers and those educated in Russia. First, American engineers are incredibly efficient at what they do. It usually takes two or three Russian engineers to replace one American. However, Russians have a broader view of things (related to education, at least in my time) and the ability to achieve goals with a minimum of resources, as they say, on the knee, ”Nikolai Shkolnik shared his thoughts.
Engineers came up with a new engine back in 2003. By 2012, the first prototype was built, which was written about in the Popular Mechanics magazine. In 2015, the company not only signed a contract with DARPA, but also began developing a mini version of the engine.
It doesn’t matter what these were made for, in an attempt to create the most economical motor, or vice versa, the most powerful. Another fact is important - these engines were created and they exist in real working copies. We are happy about this and invite our readers to take a look with us at the 10 craziest car engines that we managed to find.
To compile our list of 10 crazy car engines, we followed some rules: only power plants of mass-produced cars got into it; no racing motors or experimental models, because they are unusual, by definition. We also did not use engines from the category of "very-most", the largest or the most powerful, exclusivity was calculated according to other criteria. The immediate purpose of this article is to highlight the unusual, sometimes crazy, engine design.
Gentlemen, start your engines!
8.0 liters, over 1000 hp The W-16 is the most powerful and difficult to manufacture engine in history. It has 64 valves, four turbochargers, and enough torque to change the direction of the Earth's rotation - 1,500 Nm at 3,000 rpm. Its W-shaped, 16-cylinder, essentially multi-engine combo, never existed before, and on, no other model than the new car. By the way, this engine is guaranteed to work its entire service life without breakdowns, the manufacturer assures of this.
Bugatti Veyron W-16 (2005-2015)
The Bugatti Veyron is the only car to date to see the W-shaped monster in action. Bugatti opens the list (pictured is 2011 16.4 Super Sport).
At the beginning of the last century, automotive engineer Charles Knight Yale had an epiphany. Traditional poppet valves, he reasoned, were too complicated, return springs and pushrods too inefficient. He created his own kind of valves. His solution was dubbed the "spool valve" - a shaft-driven sliding sleeve around the piston that opens the intake and exhaust ports in the cylinder wall.
Knight Sleeve Valve (1903-1933)
Surprisingly, it worked. Spool valve engines offered high displacement, low noise, and no risk of valve sticking. There were few drawbacks, these included increased oil consumption. Knight patented his idea in 1908. Subsequently, it began to be used by all brands, from Mercedes-Benz to Panhard and Peugeot cars. Technology became a thing of the past when classic valves were better able to handle high temperatures and high RPMs. (1913-Knight 16/45).
Imagine, in the 1950s, you are an automaker trying to develop a new car model. Some German guy named Felix comes to your office and tries to sell you the idea of a triangular piston rotating inside an oval box (special profile cylinder) to fit on your future model. Did you agree to this? Probably yes! The operation of this type of engine is so mesmerizing that it is difficult to tear yourself away from contemplating this process.
An integral minus of everything unusual is complexity. In this case, the main difficulty was that the engine must be incredibly balanced, with precisely fitted parts.
Mazda/NSU Wankel Rotary (1958-2014)
The rotor itself is triangular with convex edges, three of its corners are vertices. As the rotor rotates inside the housing, it creates three chambers that are responsible for the four phases of the cycle: intake, compression, power stroke and exhaust. Each side of the rotor, when the engine is running, performs one of the stages of the cycle. No wonder the rotary piston type of engine is one of the most efficient internal combustion engines in the world. It is a pity that normal fuel consumption from Wankel engines could not be achieved.
Unusual motor, isn't it? And you know what's even weirder? This motor was in production until 2012 and it was put on a sports car! (1967-1972 Mazda Cosmo 110S).
The Connecticut Eisenhuth Horseless Vehicle Company was founded by John Eisenhuth, a New York City man who claimed to have invented the gasoline engine and had a nasty habit of getting lawsuits from his business associates.
His Compound models of 1904-1907 were distinguished by their three-cylinder engines, in which the two outer cylinders were driven by ignition, the middle "dead" cylinder was powered by the exhaust gases of the first two cylinders.
Eisenhuth Compound (1904-1907)
Eisenhuth promised a 47% improvement in fuel efficiency over standard engines of the same size. The humane idea fell out of favor at the beginning of the 20th century. At that time no one thought about saving. The result is bankruptcy in 1907. (pictured 1906 Eisenhuth Compound Model 7.5)
Leave the opportunity for the French to develop interesting engines that look ordinary at first glance. The well-known Gali manufacturer Panhard, mostly remembered for its eponymous Panhard jet rod, installed a series of air-cooled boxer engines with aluminum blocks in its post-war cars.
Panhard Flat-Twin (1947-1967)
The volume varied from 610 to 850 cm3. Power output was between 42 hp. and 60 hp, depending on the model. The best part of cars? The Panhard twin has ever won the 24 Hours of Le Mans. (pictured 1954 Panhard Dyna Z).
A strange name, sure, but the engine is even weirder. The 3.3-litre Commer TS3 was a supercharged, flat-piston, three-cylinder, two-stroke diesel engine. Each cylinder has two pistons facing each other, with one central candle located in one cylinder. It didn't have a cylinder head. A single crankshaft was used (most boxer engines have two).
Commer/Rootes TS3 "Commer Knocler" (1954-1968)
Rootes Group came up with this engine for its Commer brand of trucks and buses. (Bus Commer TS3)
Lanchester Twin-Crank Twin (1900-1904)
The result was 10.5 hp. at 1,250 rpm and no noticeable vibrations. If you've ever wondered, take a look at the engine in this car. (1901 Lanchester).
Like the Veyron, the limited-edition Cizeta (née Cizeta-Moroder) V16T supercar is defined by its engine. The 560 horsepower 6.0-liter V16 in the womb of the Cizeta was one of the most hyped engines of its time. The intrigue was that the Cizeta engine, in fact, was not a true V16. In fact, it was two V8 engines combined into one. For two V8s, a single block and a central timing were used. What doesn't make it any more insane is the location. The engine is mounted transversely, the central shaft supplies power to the rear wheels.
Cizeta-Moroder/Cizeta V16T (1991-1995)
The supercar was produced from 1991 to 1995, this car had a manual assembly. Initially, it was planned to produce 40 supercars a year, then this bar was lowered to 10, but in the end, in almost 5 years of production, only 20 cars were produced. (Photo 1991 Cizeta-16T Moroder)
The Commer Knocker engines were actually inspired by the family of these opposed-piston French engines that were produced in two, four, six cylinders until the early 1920s. Here's how it works in the two-cylinder version: two rows of pistons opposite each other in common cylinders so that the pistons of each cylinder move towards each other and form a common combustion chamber. The crankshafts are mechanically synchronized, and the exhaust shaft rotates ahead of the intake shaft by 15-22 °, power is taken from either one or both of them.
Gobron-Brillié Opposed Piston (1898-1922)
Serial engines were produced in the range from 2.3-liter "twos" to 11.4-liter sixes. There was also a monstrous 13.5-liter four-cylinder racing version of the engine. In a car with such a motor, the racer Louis Rigoli first reached a speed of 160 km / h in 1904 (1900 Nagant-Gobron)
Adams-Farwell (1904-1913)
If the idea of a rear-spinning engine doesn't faze you, then Adams-Farwell vehicles are perfect for you. True, not all of them rotated, only the cylinders and pistons, because the crankshafts on these three- and five-cylinder engines were static. Arranged radially, the cylinders were air-cooled and acted as a flywheel once the engine was fired and started to run. The motors were light for their time, 86 kg weighed 4.3 liter three-cylinder engine and 120 kg - 8.0 liter engine. Video.
Adams-Farwell (1904-1913)
The cars themselves were rear-engined, with the passenger compartment in front of the heavy engine, the layout ideal for getting the maximum damage from the occupants in an accident. At the dawn of the automotive industry, high-quality materials and reliable construction were not thought of; in the first self-propelled carriages, wood, copper, and occasionally metal, of not the highest quality, were used in the old fashioned way. It was probably not very comfortable to feel the work of a 120 kg motor spinning up to 1,000 rpm behind your back. However, the car was produced for 9 years. (Photo 1906 Adams-Farwell 6A Convertible Runabout).
Thirty cylinders, five blocks, five carburettors, 20.5 liters. This engine in Detroit was developed specifically for the war. Chrysler built the A57 as a way to fill an order for a tank engine for World War II. Engineers had to work in a hurry, making the most of the available components as much as possible.
BONUS. Incredible non-production engines: Chrysler A57 Multibank
The engine consisted of five 251cc straight-sixes from passenger cars arranged radially around a central output shaft. The output turned out to be 425 hp. used in the M3A4 Lee and M4A4 Sherman tanks.
The second bonus is the only racing engine included in the review. 3.0-liter engine used by BRM (British Racing Motors), 32-valve H-16 engine, combining essentially two flat eights (H-shaped engine - an engine whose cylinder block configuration is the letter "H" in a vertical or horizontal arrangement. An H-engine can be considered as two opposed engines, one on top of the other or one next to the other, each of which has its own crankshafts). The power of the sports engine of the late 60s was more than high, more than 400 hp, but the H-16 was seriously inferior to other modifications in terms of weight and reliability. saw the podium once, at the U.S. Grand Prix, when Jim Clark won in 1966.
BONUS. Incredible non-production engines: British Racing Motors H-16 (1966-1968)
The 16-cylinder engine wasn't the only one the guys at BRM were working on. They also developed a supercharged 1.5 liter V16. It revs up to 12,000 rpm and produces approximately 485 hp. It would probably be cool to install such an engine on the Toyota Corolla AE86, enthusiasts from all over the world have thought about this more than once.
Another cycle
At the beginning of the twentieth century, quiet valveless motors were installed on many prestigious models. For example, under the hood of this chic “Daimler Double Six 40/50” was just such an engine.
“Mazda Millenia/Xedos 9” is one of the few mass-produced cars that was equipped with an Atkinson engine.
A CONVENTIONAL 4-stroke engine operates according to a cycle invented back in 1876 by the German engineer Nikolaus Otto: certain processes alternately occur in the cylinder under certain conditions - intake, compression, power stroke and exhaust. In 1886, the British engineer James Atkinson tried to improve this scheme.
At first glance, its engine differed little from its progenitor - the same order of cycles, a similar principle of operation ... However, in fact, there were many differences. For example, due to a special crankshaft with displaced attachment points, Atkinson managed to reduce friction losses in the cylinder and increase the compression ratio of the engine.
Also in such engines there are other valve timing. If on a conventional internal combustion engine the intake valve closes almost immediately after the piston passes the bottom dead center, then in the Atkinson cycle the intake stroke is much longer - the valve closes only halfway to the top dead center of the piston, when the compression stroke is already in full swing in the Otto cycle.
What did it give? Most importantly, better filling of the cylinders due to the reduction of so-called pumping losses. Without going into technical details, let's just say that as a result, the Atkinson engine is about 10% more efficient (and more economical) than a conventional internal combustion engine.
However, on production cars, motors operating according to the Atkinson scheme have not been encountered until recently. The fact is that such an engine can work correctly and give good performance only at high speeds. And at idle, on the contrary, he strives to stall. To solve the problem of filling the cylinders at low speeds, mechanical superchargers have to be installed on such motors (such a scheme is sometimes not quite rightly called the “Miller engine”), which further complicates and increases the cost of the design. In addition, the compressor drive losses practically negate the advantages of an unusual motor.
Therefore, mass-produced cars with Atkinson engines can be counted on the fingers of one hand. A typical example is the Mazda Xedos 9 / Millenia, which was produced from 1993 to 2002 and was equipped with a 210-horsepower 2.3-liter V6.
But in its purest form, Atkinson engines proved to be very suitable for hybrid models like the famous "Toyota Prius" or the latest "Mercedes-Benz" S-Class, which will soon go into mass production. After all, at low speeds, such cars move mainly on electric traction, and the gasoline engine is connected only during acceleration or under heavy loads. This scheme, on the one hand, allows you to level the inherent shortcomings of the Atkinson motor, and on the other hand, to make the most of its positive qualities.
Silent spools
Due to their high fuel economy, Atkinson cycle engines are increasingly used today in hybrid vehicles like the Toyota Prius.
The valve timing is one of the most complex and noisy in a traditional engine. Therefore, many inventors tried to completely get rid of it, or at least significantly modernize it.
Perhaps the most successful alternative design was the motor, created by the American engineer Charles Knight in the early twentieth century. There were no familiar valves and their bulky drive in this engine - they were replaced by special spools in the form of two sleeves placed between the cylinder and the piston. With the help of the original drive, the spools moved up and down and, at the necessary moment, opened windows in the cylinder wall, through which a fresh combustible mixture entered and exhaust gases were removed into the atmosphere.
Such a motor was difficult to manufacture and quite expensive, but it was very quiet, almost silent by the standards of that time. Therefore, many executive car companies began to install Knight engines in their models. Buyers were ready to overpay for the sake of high comfort. At the beginning of the last century, such motors were used by such well-known companies as Daimler, Mercedes-Benz, Panhard-Levassor ..
However, the initial delight at the quiet operation of Knight's engines soon gave way to disappointment. The design turned out to be unreliable, besides, it was distinguished by increased consumption of gasoline and oil due to the high friction between the spools and the cylinder walls, which increased several times with an increase in crankshaft speed. Therefore, a characteristic gray haze always curled behind cars with such engines.
The era of Knight engines ended in the 30s, when engines with an improved valve timing mechanism appeared on the market, which almost got rid of excessive noise. Nevertheless, now and then there are reports of various prototypes of valveless engines, so it is possible that in the future we will still see such motors on production cars.
Variable compression ratio
The compression ratio is one of the most important characteristics of an engine. The larger this parameter, the higher the maximum power, economy and efficiency of the gasoline engine. However, it is impossible to increase the compression ratio indefinitely - detonation will occur in the cylinders, that is, explosive, uncontrolled combustion of the working mixture, leading to increased wear of parts and mechanisms.
This problem is even more acute when creating supercharged engines, which have recently become more widespread. The fact is that the parts of such motors work in more severe conditions, so they heat up more, and the risk of detonation is higher. So the compression ratio has to be reduced. At the same time, the efficiency of the engine decreases accordingly.
Ideally, the compression ratio should change smoothly depending on the mode of operation of the motor. To get the most out of it, it must be increased when the load on the engine is small, and then gradually decrease as the resistance to movement increases.
The first projects of engines with a variable compression ratio appeared in the second half of the twentieth century, but the complexity of the design does not yet allow for widespread use on mass models. Nevertheless, many automakers are working on improving this scheme.
For example, in 2000 SAAB introduced an experimental in-line 5-cylinder SVC engine (“Saab Variable Compression”), which, due to a variable compression ratio, with a modest displacement of 1.6 liters, produces a decent 225 hp. The Swedish engine is horizontally divided into two parts, hinged to each other on one side. The lower one contains the crankshaft, connecting rods and pistons, and the upper one combines the cylinders and their heads in a single monoblock. A special hydraulic drive can slightly tilt the monoblock, varying the compression ratio from 14 units at idle to 8 units at high speeds when the drive compressor is turned on. This design turned out to be effective, but very expensive, so soon after the premiere, the SVC project was closed until better times.
According to experts, another scheme looks more viable. Such an engine is practically indistinguishable from a conventional one, with the exception of the original crank mechanism. The crankshaft is connected to the piston through a special rocker. It, in turn, is fixed on a special shaft, which can be rotated using an electric or hydraulic drive. When the rocker is tilted, the position of the piston in the cylinder changes, and hence the compression ratio. The advantages of this arrangement are in relative simplicity - in principle, it can be created on the basis of almost any motor.
Thus, modern technologies already make it possible to build an engine with a variable compression ratio. It remains only to solve the problem of the high cost of such projects.
Not the hybrid
Perhaps in the near future we will see engines on GM vehicles that combine the advantages of both diesel and gasoline engines.
Two types of engines are mainly used in modern cars - gasoline and diesel. The former are distinguished by high power, the latter by good traction and economy.
Now many automakers are working on the creation of a motor that would combine both of these advantages. In principle, the design of conventional gasoline units has already become very similar to diesel: direct fuel injection made it possible to raise the compression ratio to 13-14 units (against 17-19 for diesel options).
On experimental models, the compression ratio is even higher - 15-16 units. However, this is not always sufficient for constant self-ignition of the mixture. Therefore, when starting the engine, as well as at high loads, the fuel is ignited by a conventional candle. With uniform movement, it turns off, and the engine switches to a “diesel” mode of operation, consuming a minimum of fuel. The entire system is controlled by electronics, which monitors the driving conditions and, when they change, gives the appropriate commands to the actuators. According to the developers, such engines are very economical and practically do not pollute the environment. However, it is already clear that the cost of cars with such engines will be quite high. Whether they will find their place in the market is still difficult to say.
