Little education
03-19-2006, 11:19 PM
#1
1.5 BAR
Thread Starter
Join Date: Aug 2003
Posts: 859
Little education
had to do a report foudna cool site about turbo history and theory.
The first exhaust-driven supercharger was developed by Dr. Alfred J. Buchi of Switzerland between 1909 and 1912, long before Garrett products entered the turbocharger picture. Dr. Buchi was Chief Engineer of Sulzer Brothers Research Department and in 1915 proposed the first prototype of a turbocharged diesel engine, but his ideas gained little or no acceptance at that time.General Electric began developing turbochargers during the late 1910's. In 1920, a LePere bi-plane that was equipped with a Liberty engine and a General Electric turbocharger set a new altitude record of 33,113 feet (10092m).
Turbochargers were used sparingly on aircraft in World War I, but their development occurred on a widening scale in the 1930's and 1940's - first in Europe and then in the United States. In the United States, General Electric developed turbochargers for military aircraft, and in World War II, thousands were used on fighter aircraft and bombers, such as the B-17. The Garrett Corporation, formed in 1936 by J. C. "Cliff" Garrett, supplied the charge air cooler (aftercooler) for the B-17, located between the General Electric turbocharger and the Pratt and Whitney engine.
In the late 1940's and early 1950's, Garrett was heavily committed to the design of small gas turbine engines from 20 - 90 horse power (15 - 67 kw). The engineers had developed a good background in the metallurgy of housings, high speed seals, radial inflow turbines, and centrifugal compressors.
On September 27, 1954, Cliff Garrett made the decision to separate the turbocharger group from the Gas Turbine department due to commercial diesel turbocharger opportunities. That was the beginning of the new AiResearch Industrial Division - for turbocharger design and manufacturing. AiResearch Industrial Division would later be named Garrett Automotive.
The Chevrolet Corvair Monza and the Oldsmobile Jetfire were the first turbo-powered passenger cars, and made their debut on the US market in 1962/63. Despite maximum technical outlay, however, their poor reliability caused them to disappear quickly from the market.
The internal combustion engine is an air consuming machine. This is because the fuel that is burned requires air with which it can mix to complete the combustion cycle. Once the air/fuel ratio reaches a certain point, the addition of more fuel will not produce more power, but only black smoke or unburned fuel into the atmosphere. The more dense the smoke, the more the engine is being over fueled. Therefore, increasing the fuel delivery beyond the air/fuel ratio limit results in excessive fuel consumption, pollution, high exhaust temperature (diesel) or low exhaust temperature (gasoline), and shortened engine life.
After the first oil crisis in 1973, turbocharging became more acceptable in commercial diesel applications. Until then, the high investment costs of turbocharging were offset only by fuel cost savings, which were minimal. Increasingly stringent emission regulations in the late 80's resulted in an increase in the number of turbocharged truck engines, so that today, virtually every truck engine is turbocharged.
In the 70's, with the turbocharger's entry into motor sports, especially into Formula I racing, the turbocharged passenger car engine became very popular. The word "turbo" became quite fashionable. At that time, almost every automobile manufacturer offered at least one top model equipped with a turbocharged petrol engine. However, this phenomenon disappeared after a few years because although the turbocharged petrol engine was more powerful, it was not economical. Furthermore, the "turbo-lag", the delayed response of the turbochargers, was at that time still relatively large and not accepted by most customers.
The real breakthrough in passenger car turbocharging was achieved in 1978 with the introduction of the first turbocharged diesel engine passenger car in the Mercedes-Benz 300 SD, followed by the VW Golf Turbodiesel in 1981. By means of the turbocharger, the diesel engine passenger car's efficiency could be increased, with almost petrol engine "driveability", and the emissions significantly reduced.
A turbo charger is basically an exhaust gas driven air compressor and can be best understood if it is divided into its two basic parts, the exhaust gas driven turbine and its housing, and the air compressor and its housing. I did say divided didn't I. Well I should have said like a set of Siamese twins because each of them perform different functions but, because they are joined together at the hip via a common shaft, the function of one impacts the function of the other. How? Take a perfectly set up compressor section and mate it with an incorrect turbine section, or visa versa, and you end up with with our Siamese twins trying to go in different directions. The result is that our Siamese twins end up wasting all of their energy fighting each other and go nowhere.
When considering a turbo charger most folks tend to look at the maximum CFM rating of the compressor and ignore everything else under the assumption that the compressor and the exhaust turbine are perfectly matched out of the box. I will grant you that in stock factory applications that is probably close to the truth but, in all out performance applications, nothing could be further from the truth because of the extremes of operation in a performance application.
The goal in a performance application is to get the exhaust turbine up to speed as quickly as possible however, it must be mated to a compressor wheel that will generate as much pressure as it can as soon as possible. This is a contradiction because the exhaust turbine generates the drive power and the compressor consumes that power. The larger the compressor and the higher the pressure (boost) we want, the quicker the power from the exhaust turbine is used up. Put in a larger exhaust turbine and it will take the engine longer to develop enough hot expanding exhaust gas to spin it, slowing down the compressor and causing turbo lag. At this point I am going to repeat something stated earlier, do not think of a turbo charger as a bolt on piece of equipment, think of it as a system.
The turbine is powered by hot expanding exhaust gas, a lot of hot expanding exhaust gas, the more and the hotter the expanding exhaust gas the better. I am sure many of you have seen pictures of turbo charged engines with cherry red hot exhaust systems and turbo housings. The captions under most of these types of pictures proclaim outstanding horse power numbers. What most of the articles related to these pictures do not tell you is that the engine was under an extreme load. A load so heavy that the engine was almost at its stall point for a prolonged period of time. A condition that most turbo charged engines will never see.
The real point I am trying to make is that the exhaust turbine will not generate enough power to turn the air compressor fast enough for it to work properly unless the engine is feeding the exhaust turbine a lot of hot expanding exhaust gas, a condition that can only be created when the engine is under a load. There is where the selection of transmission gear ratios and the ring and pinion ratio play a critical part. The fact that the engine must be under a load is the reason why, no matter how high you rev a turbo charged engine with no load on it, you will not see the boost gauge move.
This is also where the term 'turbo lag' came from. Turbo lag is basically the amount of time it takes from the time you place a load on the engine (stomp the gas peddle to the floor and dump the clutch or, get full converter lock up with your automatic trans) until the time the engine develops enough hot expanding exhaust gas to spin the turbine fast enough for the compressor to do its job.
Effectively, a turbo charged engine is a normally aspirated engine until the turbine and compressor spin up. To minimize turbo lag, it is imperative that the turbine and the compressor are properly matched to the engine as well as the engine being properly matched to the transmission gears, the ring and pinion gears, and the tires.
http://www.turbochargedpower.com/Tur...Simplified.htm
theres alot more ---- on the site but im ------ beat from written a report on turbo's, superchargers, nitrous, dual plain intake manifolds, and variable intake runner manifolds.
The first exhaust-driven supercharger was developed by Dr. Alfred J. Buchi of Switzerland between 1909 and 1912, long before Garrett products entered the turbocharger picture. Dr. Buchi was Chief Engineer of Sulzer Brothers Research Department and in 1915 proposed the first prototype of a turbocharged diesel engine, but his ideas gained little or no acceptance at that time.General Electric began developing turbochargers during the late 1910's. In 1920, a LePere bi-plane that was equipped with a Liberty engine and a General Electric turbocharger set a new altitude record of 33,113 feet (10092m).
Turbochargers were used sparingly on aircraft in World War I, but their development occurred on a widening scale in the 1930's and 1940's - first in Europe and then in the United States. In the United States, General Electric developed turbochargers for military aircraft, and in World War II, thousands were used on fighter aircraft and bombers, such as the B-17. The Garrett Corporation, formed in 1936 by J. C. "Cliff" Garrett, supplied the charge air cooler (aftercooler) for the B-17, located between the General Electric turbocharger and the Pratt and Whitney engine.
In the late 1940's and early 1950's, Garrett was heavily committed to the design of small gas turbine engines from 20 - 90 horse power (15 - 67 kw). The engineers had developed a good background in the metallurgy of housings, high speed seals, radial inflow turbines, and centrifugal compressors.
On September 27, 1954, Cliff Garrett made the decision to separate the turbocharger group from the Gas Turbine department due to commercial diesel turbocharger opportunities. That was the beginning of the new AiResearch Industrial Division - for turbocharger design and manufacturing. AiResearch Industrial Division would later be named Garrett Automotive.
The Chevrolet Corvair Monza and the Oldsmobile Jetfire were the first turbo-powered passenger cars, and made their debut on the US market in 1962/63. Despite maximum technical outlay, however, their poor reliability caused them to disappear quickly from the market.
The internal combustion engine is an air consuming machine. This is because the fuel that is burned requires air with which it can mix to complete the combustion cycle. Once the air/fuel ratio reaches a certain point, the addition of more fuel will not produce more power, but only black smoke or unburned fuel into the atmosphere. The more dense the smoke, the more the engine is being over fueled. Therefore, increasing the fuel delivery beyond the air/fuel ratio limit results in excessive fuel consumption, pollution, high exhaust temperature (diesel) or low exhaust temperature (gasoline), and shortened engine life.
After the first oil crisis in 1973, turbocharging became more acceptable in commercial diesel applications. Until then, the high investment costs of turbocharging were offset only by fuel cost savings, which were minimal. Increasingly stringent emission regulations in the late 80's resulted in an increase in the number of turbocharged truck engines, so that today, virtually every truck engine is turbocharged.
In the 70's, with the turbocharger's entry into motor sports, especially into Formula I racing, the turbocharged passenger car engine became very popular. The word "turbo" became quite fashionable. At that time, almost every automobile manufacturer offered at least one top model equipped with a turbocharged petrol engine. However, this phenomenon disappeared after a few years because although the turbocharged petrol engine was more powerful, it was not economical. Furthermore, the "turbo-lag", the delayed response of the turbochargers, was at that time still relatively large and not accepted by most customers.
The real breakthrough in passenger car turbocharging was achieved in 1978 with the introduction of the first turbocharged diesel engine passenger car in the Mercedes-Benz 300 SD, followed by the VW Golf Turbodiesel in 1981. By means of the turbocharger, the diesel engine passenger car's efficiency could be increased, with almost petrol engine "driveability", and the emissions significantly reduced.
A turbo charger is basically an exhaust gas driven air compressor and can be best understood if it is divided into its two basic parts, the exhaust gas driven turbine and its housing, and the air compressor and its housing. I did say divided didn't I. Well I should have said like a set of Siamese twins because each of them perform different functions but, because they are joined together at the hip via a common shaft, the function of one impacts the function of the other. How? Take a perfectly set up compressor section and mate it with an incorrect turbine section, or visa versa, and you end up with with our Siamese twins trying to go in different directions. The result is that our Siamese twins end up wasting all of their energy fighting each other and go nowhere.
When considering a turbo charger most folks tend to look at the maximum CFM rating of the compressor and ignore everything else under the assumption that the compressor and the exhaust turbine are perfectly matched out of the box. I will grant you that in stock factory applications that is probably close to the truth but, in all out performance applications, nothing could be further from the truth because of the extremes of operation in a performance application.
The goal in a performance application is to get the exhaust turbine up to speed as quickly as possible however, it must be mated to a compressor wheel that will generate as much pressure as it can as soon as possible. This is a contradiction because the exhaust turbine generates the drive power and the compressor consumes that power. The larger the compressor and the higher the pressure (boost) we want, the quicker the power from the exhaust turbine is used up. Put in a larger exhaust turbine and it will take the engine longer to develop enough hot expanding exhaust gas to spin it, slowing down the compressor and causing turbo lag. At this point I am going to repeat something stated earlier, do not think of a turbo charger as a bolt on piece of equipment, think of it as a system.
The turbine is powered by hot expanding exhaust gas, a lot of hot expanding exhaust gas, the more and the hotter the expanding exhaust gas the better. I am sure many of you have seen pictures of turbo charged engines with cherry red hot exhaust systems and turbo housings. The captions under most of these types of pictures proclaim outstanding horse power numbers. What most of the articles related to these pictures do not tell you is that the engine was under an extreme load. A load so heavy that the engine was almost at its stall point for a prolonged period of time. A condition that most turbo charged engines will never see.
The real point I am trying to make is that the exhaust turbine will not generate enough power to turn the air compressor fast enough for it to work properly unless the engine is feeding the exhaust turbine a lot of hot expanding exhaust gas, a condition that can only be created when the engine is under a load. There is where the selection of transmission gear ratios and the ring and pinion ratio play a critical part. The fact that the engine must be under a load is the reason why, no matter how high you rev a turbo charged engine with no load on it, you will not see the boost gauge move.
This is also where the term 'turbo lag' came from. Turbo lag is basically the amount of time it takes from the time you place a load on the engine (stomp the gas peddle to the floor and dump the clutch or, get full converter lock up with your automatic trans) until the time the engine develops enough hot expanding exhaust gas to spin the turbine fast enough for the compressor to do its job.
Effectively, a turbo charged engine is a normally aspirated engine until the turbine and compressor spin up. To minimize turbo lag, it is imperative that the turbine and the compressor are properly matched to the engine as well as the engine being properly matched to the transmission gears, the ring and pinion gears, and the tires.
http://www.turbochargedpower.com/Tur...Simplified.htm
theres alot more ---- on the site but im ------ beat from written a report on turbo's, superchargers, nitrous, dual plain intake manifolds, and variable intake runner manifolds.
03-20-2006, 12:18 AM
#2
0.0 BAR
Join Date: Feb 2003
Posts: 0
Re: Little education
Originally Posted by mattnteclipse
Dr. Buchi was Chief Engineer of Sulzer Brothers Research Department and in 1915 proposed the first prototype of a turbocharged diesel engine, but his ideas gained little or no acceptance at that time.
Fast forward to this mad, modern age... Tony Palo has a 2.0 GSR that is spooling a GT4088 at 4K, using the pressure-wave manifold design of Buchi's, fab'd by Full-Race. There are a lot of much smaller turbos that wouldn't spool until 4K on that particular engine, with a traditional constant pressure manifold design. Finally, 1910's technology! It's about time; we've been stuck in the 1900's from an engine theory standpoint, the only thing that has progressed in the automobile is materials selection and fabrication.
Now, for some ejectors stuffed into the bottom of the collector to convert it from a pressure-wave to a pulse-converter design, and see what we don't end up with... yup, nukka, launched right into the 1920's technology. You can not handle that ---- right there.
03-20-2006, 12:52 AM
#3
3.0 BAR
Join Date: Mar 2004
Posts: 1,729
Re: Little education
Originally Posted by Joseph Davis
Uhm, that's not quite it. Buchi had everything down to manifold theory licked, and he was ignored for decades. He was boosting diesels to 5 bar back in the late teens, because he was a hardcore ----------er.
Fast forward to this mad, modern age... Tony Palo has a 2.0 GSR that is spooling a GT4088 at 4K, using the pressure-wave manifold design of Buchi's, fab'd by Full-Race. There are a lot of much smaller turbos that wouldn't spool until 4K on that particular engine, with a traditional constant pressure manifold design. Finally, 1910's technology! It's about time; we've been stuck in the 1900's from an engine theory standpoint, the only thing that has progressed in the automobile is materials selection and fabrication.
Now, for some ejectors stuffed into the bottom of the collector to convert it from a pressure-wave to a pulse-converter design, and see what we don't end up with... yup, nukka, launched right into the 1920's technology. You can not handle that ---- right there.
Fast forward to this mad, modern age... Tony Palo has a 2.0 GSR that is spooling a GT4088 at 4K, using the pressure-wave manifold design of Buchi's, fab'd by Full-Race. There are a lot of much smaller turbos that wouldn't spool until 4K on that particular engine, with a traditional constant pressure manifold design. Finally, 1910's technology! It's about time; we've been stuck in the 1900's from an engine theory standpoint, the only thing that has progressed in the automobile is materials selection and fabrication.
Now, for some ejectors stuffed into the bottom of the collector to convert it from a pressure-wave to a pulse-converter design, and see what we don't end up with... yup, nukka, launched right into the 1920's technology. You can not handle that ---- right there.
03-20-2006, 02:25 AM
#8
0.0 BAR
Join Date: Feb 2003
Posts: 0
