Magic Fires: the history of compressor technology IV

Magic Fires: the history of compressor technology IV

60s and 70s - the turbocharger seeks its place in the sun

It's time to go back in time and follow the development of the turbocharger - a technology that is an integral part of modern cars, but in the twenties and thirties of the last century is still in its infancy and does not play a significant role, despite its extremely rational nature. In fact, this amazing unit was born very soon after the birth of the car itself - on November 13, 1905, the Swiss engineer Alfred Buchi received a patent No. 1006907 of the US Federal Patent Office for his idea of ​​combining a gas turbine with a compressor and an internal combustion engine. burning.

Buchi, a graduate of the Swiss Technical University in Zurich, known for his extremely high level of education and for many years involved in turbine projects, is literally obsessed with the idea of ​​combining these devices with a piston internal combustion engine. Buchi's main idea is to pre-compress the "working fluid", meaning he wants to use not the mechanical energy generated by the engine itself, but the wasted energy of the exhaust gases. In the XNUMX-ies the Swiss received several patents for ingenious ideas, the content of which later became fundamental in this field. Among them is a turbine driven by an exhaust gas, which, in turn, drives a compressor impeller, which injects fresh mixture under pressure into the combustion chambers. In practice, Buchi's patent describes a schematic of a turbocharger known today.

Despite the obvious thermodynamic advantages, acc. To improve the efficiency of internal combustion engines, this unit goes through an extremely long stage of maturation - more than half a century passes from the moment of invention to the first attempts to introduce it into the automotive industry. In this case, it is interesting to mention that Buchi, as one of the most knowledgeable people in the field of thermodynamics of his time, came up with the idea of ​​increasing the efficiency of a turbocharger by cooling the compressed air with a heat exchanger. Thus, at the turn of the century, the inevitable companion of the turbocharger known as the intercooler or "intercooler" was born.

Buehi's idea did not find rapid mass adoption due to the very low level of metallurgical technology - it was just that at that time there was no company that could develop and manufacture a normally working compact turbocharger. For this reason, the first units of this type are rather large, do not withstand heavy loads, and therefore are used mainly in marine and stationary engines of significant displacement and dimensions.

Pioneer: General Motors

The first turbocharged diesel engines appeared in July 1925 on two German ships. This was followed by the equipment of several submarines, and in 1935 - diesel locomotives of the German railways with a capacity of 1400 hp. The pioneer in the design, development and testing of a compact turbocharger for a truck engine was the Swiss engineering plant Sauer, which in 1938 produced the first production vehicles of this type. In the 60s, the Swedish company Scania made a significant contribution to the development of turbo systems, followed by Saab and Volvo, who to this day remain one of the most serious defenders of turbotechnologists.

However, the base for the use of a turbocharger in the automotive industry is overseas. His career began in the USA, and the first steps were taken not by a small experimental adventurer, but by the giant conglomerate General Motors. The company simultaneously released two models from different divisions - the Oldsmobile Jetfire with a turbocharged V-XNUMX and Chevrolet Corvair Monza, powered by an upgraded version of the air-cooled six-cylinder boxer engine and turbocharger with bypass regulation.

But ... objectively, this is not the real premiere of a turbocharger in the automotive industry, because the Jetfire and Corvair Monza act as a kind of false start. The cause of the failures lies in the unbalanced operation of the turbocharger, an extremely uneven torque curve, significantly increased fuel consumption (although this did not play a decisive role in those days) and especially in the extremely low reliability of the engine and turbocharger. A significant problem with turbocharged engines is that if the compressor is located after the carburetor, it runs on a mixture of air and fuel, and the latter is separated by centrifugal forces. If the carburetor is behind the compressor, then it must be of a special type and operate above atmospheric pressure, and this creates problems.

The giant's two turbo models lasted only a few months in the US market and in 1964 were irrevocably removed from the price proposals.

However, just a few years later, in 1967, another Swiss engineer who graduated from the Zurich Polytechnic Institute revived turbotechnology ...

It's underway BMW

As soon as the frowning face of the new 2002 Turbo appears on the highway for the first time and begins to confuse other road users with a strange mirrored inscription on the front apron, reminiscent of an ambulance, the equally sullen Arab sheikhs sit down at the negotiating table. and under the influence of Western support for Israel in its war against Syria and Egypt, to impose a complete embargo on oil supplies. After only 1000 units were produced, the turbo was swept away by the whirlwind of the economic crisis. After only a few months, the embargo was lifted, but from 2002 Turbo remained only memories ...

Six years later, in 1979, BMW again made a tentative attempt at turbo technology. Contrary to conventional indications and model logic, the 745i (E23) luxury sedan doesn't actually have a 4,5-liter displacement. Behind the designation lies a new 3,2-liter turbocharged inline-six (M102, internally), but since the performance parameters equate it to much larger engines, BMW has resorted to this little marketing maneuver. By the way, it turned out to be quite successful and is still used today, when neither the 540d nor the 340i (etc.) D.) Displacement 4,0 liters (

Unfortunately, in the late 1979s, the Bavarians faced an obstacle - it was in 3,4 AD that the Islamic revolution broke out in Iran, which led to the second oil crisis. However, this time the BMW turbo adventure will last a little longer, but after increasing the displacement to 106 liters (M1980), the Munich company seems to have finally turned its back on turbocharging in gasoline engines (in fact, two turbo engines have been in production since 1986. to 324). In the 11s the company built its first diesel engine, and the turbocharged engine became an integral part of the diesel sector in the Bavarian fleet - all diesels except the six-cylinder 54d are equipped with turbochargers. Everything seems clear and well-established until ... 30 years ago, the line-up six-cylinder N12 gasoline engine with two turbochargers and modern direct injection suddenly appeared in the line in question. And if that doesn't sound like heresy. All this time, similar experiments were provided by the notorious Alpina. Back in the late 28s, he equipped the old classic M330 engine with a turbocharger for the fifth series E34, and then the E10, which reached 360 hp. depending on versions. The next five from the E1989 series with a twin turbocharged version of this engine (Alpina B1994 Biturbo) becomes one of the most iconic Alpina models, reaching XNUMX hp. and was released from XNUMX to XNUMX years.

It would seem, contrary to usual logic and completely in unison with the aforementioned series of unfavorable historical events, the new creation of the Munich engines appears just in the midst of another price paranoia. But only ostensibly, because in the meantime, electronic control systems for fuel injection, ignition and turbo technologies have reached a level where practice began to correspond to the theory that a positively charged gasoline engine should be significantly more economical than a dynamically equivalent atmospheric engine. motor. The new three-liter BMW masterpiece with two turbochargers smoothly expands its power like a naturally aspirated engine with a large displacement, and there can be no question of turbocharging. Another striking proof of the revival of gasoline turbo engines is the already mentioned engine Porsche The 911 Turbo, which for the first time in production history, uses a variable geometry turbocharger in a petrol engine. The system was developed by Borg Warner Turbo Systems in cooperation with Porsche, which has a solid tradition and is one of the pioneers in this field.

In parallel with the return of turbocharging to gasoline engines, the development of turbocharging in diesels did not slow down for an instant - just take as an example the Twin Turbo cascade system, which was previously used by BMW in the six-cylinder 535d and four-cylinder 123d, or the system with two small parallel turbochargers in the Peugeot 407 2,2 HDI, created by Borg Warner and Honeywell, respectively.

The road to Formula 1

Let's go back to history a few years after the cessation of production of the Oldsmobile Jetfire and Chevrolet Corvair - in the 1967 we mentioned, when another graduate of the Swiss Polytechnic Institute attempted to revive turbo technology. Mechanical engineer Michael May creates a special turbocharger designed to increase the power of V-XNUMX engines. Fordwhere he is brilliantly managed. Despite significantly improved dynamics and decent reliability of vehicles equipped with new equipment, redesigned Ford models remain a minor part of the company's production. However, there are advantages, albeit of a different nature - the development of Michael May plays the role of a spark that sparked the interest of the German automotive industry. The two companies are so impressed with the unfolding potential that they begin intensive research and development, laying the modern foundation in this area. You've probably already guessed that the names of these two companies are Porsche and BMW, but contrary to popular belief that the BMW 2002 Turbo is the pioneer of turbo technology in the modern automotive industry, this is not the case.

It is true that the 2002 Turbo was one of the first production cars to use a gas turbine compressor, but its real debut took place in 1972 when BMW created two “laboratories” on wheels, known as the BMW Turbo. The two sports prototypes will be remembered primarily for their styling, created by then chief BMW designer Paul Braque, but equally interesting are the advanced safety systems and state-of-the-art technical solutions used in them, including the two-liter four-cylinder engine. turbocharged engine. Six years later, the design of the BMW Turbo will be the basis for the emergence of the sports legend M1 and the genes of the 200 hp turbo engine. from. (280 hp is also possible with special settings) are transferred directly to the version used in the 2002 Turbo. Despite significantly less power than the prototype, the 2002 Turbo is 170 hp. which is 30% more compared to the standard naturally aspirated version with a two-liter engine. The torque, in turn, increases from 180 Nm at 4500 rpm to 245 Nm at 4000 rpm. Of course, in this case, it is important that these parameters are achieved by a four-cylinder two-liter unit, which makes the last skeptics reconsider their opinion about the capabilities of turbomachines.

Unfortunately, further history does not at all develop as a logical continuation of a promising beginning - as we said at the beginning, this powerful, but rather greedy unit appears just at the moment when the European highways are abandoned under the influence of the oil crisis. In addition, the pioneering BMW development, which by today's criteria can easily be called primitive, on the one hand, is not reliable enough, and on the other hand, suffers from the presence of the characteristic early deep "hole" with turbocharging in the deployment of power. At the beginning of the rev range, nothing happens - the BMW 2002 behaves meekly and timidly, like a normal naturally aspirated engine, until the turbine, which has time to pick up operating speed, explodes the atmosphere with a sharp thrust, and the car explodes like a catapult. The pressure is controlled by a simple safety valve on the suction lines that releases "steam". Thus, the turbine must develop a lot of power, which is practically unnecessary and creates unnecessary back pressure in the system. These uncontrolled engine spurts also led to extremely disharmonious road behavior of the 2002 Turbo, which soon entered the annals of history, failing to become a mass-produced car. BMW's second experience with the aforementioned 745i boasts slightly better results in this regard, albeit far from dizzying market success. However, the turbo developments of BMW, even in those years, did not follow the lead, but became the basis for a number of successes on the Formula 1 race tracks.

(to follow)

Text: Georgy Kolev



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