Now, let’s see how the turbocharger went from an ace-in-the-hole for aircraft engines during World War II, to the go-to way to crank out horsepower in small engines.
Up until World War II, turbochargers were not a common sight in cars, and certainly not the most popular option for adding forced induction to an engine. Even following the war, some of the most notable post-war aircraft relied on piston engines as opposed to the modern turbojet engine, did not use turbochargers. Most R&D efforts for military aircraft propulsion was moving away from piston engines, and where piston engines were being used, they didn’t have turbos.
Take, for example, the Corvair B36. This behemoth of an airplane was adopted by the US Air Force for a short period of time after the war, but before the much more famous B52 Stratofortress was adopted. This gargantuan plane made use of a Pratt and Whitney radial engine similar to (although much larger than) the engines used in other US warplanes during World War II. Much like the other engines used by warplanes, these engines were typically not turbocharged, instead used geared superchargers to force more air into the 6(!) propeller engines.
From the get-go, this engine was quite dated, as the piston engines were maintenance heavy, and the unusual engine and propeller configuration gave the plane reliability issues. Additionally, the Peacemaker was retrofitted with 4 jet engines for use in takeoff as well as speed over a target to reduce the likelihood of being struck by enemy fire. It wasn’t long however, before the turbojet-powered B52 we all know and love was adopted. The B36 was more or less forgotten as a massive placeholder for the US Air Force for a short time following World War II. Read More
Hello! And welcome back for part 2 of our series on “A Brief History of the Turbocharger”. To read part 1, which compares superchargers and turbochargers, and explains the early history of turbochargers and forced induction from the turn of the century through to World War 1, click here. Having covered all of that, let’s pick up from where we left off!
Following World War 1, and the work of Dr. Sanford Alexander Moss, Alfred Büchi, who had created the first true turbocharger, had continued innovating following the failure of his first design. By 1925, he had a working turbocharger design that consistently and reliably worked (1).
Following this breakthrough, the turbocharger saw its first commercial application on ten-cylinder diesel engines. Since diesel engines are typically built to withstand the high-pressures required by their operating conditions, the pressures generated by using forced induction are easily accommodated. As a result of adding the turbochargers, the engines upped their horsepower ratings from 1750HP, all the way to a whopping 2,500HP. (1)
For Büchi, this was a great achievement, as it marked the first commercial application of a machine that he had first begun working with more than 20 years prior. For the turbocharger, however, this was just the beginning. Read More
Turbochargers are one of the more common turbomachines out there today! As everyone is making efforts to lower carbon dioxide emissions in automobiles, and the automotive OEMs engage in a “horsepower war”, the turbocharger will likely continue to grow in popularity for both civil and commercial uses.
But how did these machines get so popular? That’s what we’ll be exploring in this blog miniseries! Today’s blog will introduce the concept of the turbocharger, and the beginnings of its development around the turn of the 20th century.
Turbocharging engines and the idea of forced induction on internal combustion engines are as old as the engines themselves. Their intertwined history can be traced back to the 1880’s, when Gottlieb Daimler was tinkering with the idea of forced induction on a “grandfather clock” engine. Daimler was supposedly the first to apply the principles of supercharging an engine in 1900, when he mounted a roots-style supercharger to a 4-stroke engine.
The birth of the turbocharger, however, would come 5 years later, when Swiss engineer Alfred Büchi received a patent for an axial compressor driven by an axial turbine on a common shaft with the piston of the engine. Although this design wasn’t feasible at the time due to a lack of viable materials, the idea was there.
Turbochargers vs Superchargers
What idea was that, exactly? And how did it differ from supercharging?
I think it’s important to quickly go over the basic differences between turbocharging and supercharging. Both offer “forced induction” for piston engines. A naturally aspirated engine simply will draw in atmospheric air as the intake valve opens, and the piston travels down to bottom dead center. A forced induction engine, pushes more air into the cylinder than what the dropping of the piston would pull in, allowing more air to be combusted, and thus generating more power and efficiency. While turbochargers and superchargers are both forced induction , how superchargers and turbochargers go about compressing that air is different. Superchargers are driven by the engine themselves, typically via a belt or gear. This uses some of the engine’s available horsepower, but doing so provides more horsepower back to the engine. The compressors can be either positive displacement configurations (such as a Roots or Twin-Screw), or a centrifugal supercharger.
Turbochargers, as mentioned before, use the air from the exhaust of the engine to drive a turbine, and the work of the turbine is transmitted on a common shaft to a compressor. The most common configuration is a radial turbine driving a centrifugal compressor similar to the one above in the supercharger diagram. However, there are other configurations ,seen in larger examples, such as an axial turbine driving a centrifugal compressor. Read More
Welcome to this latest (and sadly, last) entry in the Micro Gas Turbines in Transportation series! Today, we’ll be having a quick look at micro gas turbines and their larger siblings, specifically the history of how they have been used in railroad locomotion and what the future holds for micro turbines and railroad technology. We’ll also consider the advantages and disadvantages of using them to drive trains.
Rail transportation has been around in one form or another for longer than you might think. There are examples of wheeled carts running on fixed roads and tracks that prevented any deviation being used since the 6th century BC in ancient Greece.
Up until the late 18th Century, however, railroads were rather limited in what they could be used for, since there was no way of mechanically propelling the vehicles used. Rather, these railroads relied on humans, animals, or gravity to move the carts along the tracks. This changed when in 1784, the great Scottish inventor James Watt created and patented the first steam engine locomotive which was an improvement of a steam engine designed by Thomas Newcomen. Following this invention, engineers in the UK working on different projects such as Richard Trevithick and his development of the first high-pressure steam engine would lead to the first uses of locomotive-hauled railway. His invention would be used in Wales on a short 9 mile run from an iron-works in Penydarren to the Merthyr-Cardiff canal.(2) On February 21st, 1804, the first trip took place on this railway using only steam propulsion.(2) However it wasn’t until George Stephenson’s creation paved the way for public use of steam engines like those created by James Watt on the rails, and in the coming years rail travel would play an important role not just in the United Kingdom but in the United States as well. This raises the question, where and when did turbines and turbomachinery come into play in rail travel?
Believe it or not, gas turbines in trains were being experimented with long before Frank Whittle and Hans von Ohain were designing them to take to the skies. As far back as 1861, the year that Abraham Lincoln became president of the United States, patents were being filed for a turbine that utilized ambient air mixed with combustion gasses to drive a turbine. As seen in patent 1633, Marc Antoine Francois Mennons created an engine that included all of the components needed in a modern gas turbine engine. It was called a “caloric engine” and it had a compressor (called a ventilator), combustion chamber (using ambient air and burned wood or coke), and a turbine to create work from the combustion gasses as well as a pre-heater (which he called a regenerating apparatus).(3)
Welcome to this special edition of the SoftInWay blog! While we at SoftInWay are known for helpful articles about designing various machines, retrofitting, and rotordynamics, we believe it is also important to examine the lives of some of the men and women behind these great machines.
The compound steam turbine is one of the greatest inventions, not just in turbomachinery but around the world. Once it was introduced to the marine industry, the steam turbine exploded in popularity as a means of allowing ships to travel faster and farther than ever before. It would go on to become a critical part in the naval arms race that preceded the First World War. The steam turbine not only revolutionized marine and naval propulsion, it became one of the best ways to generate electricity. After its inception, the steam turbine became one of the best ways to reliably generate power on a large scale, and make electricity the regular utility that it is today. But who invented the modern steam turbine?
Sir Charles Algernon Parsons, (1854 – 1931), is the inventor of the modern steam turbine. The work he undertook in his life had a massive impact on the world, continuing the legacy of James Watt by bringing steam technology into the modern era. Born on June 13th 1854 into an Anglo-Irish family, Sir Charles Parsons was born into a well-respected family with roots in County Offaly, Ireland. In fact the town now known as Birr was then known as Parsonstown, from the early 1600’s through to 1899. Parsons was the sixth son of the 3rd Earl of Rosse, and had a family lineage that had made great strides in the areas of military, political, and physical science. The family’s castle in Birr, which is still owned by the Parsons family and is the permanent residence of the 7th Earl of Rosse, was a rendezvous for men of science during the childhood of Sir Charles. Suffice it to say, there was no better place for a future-engineer to grow up. He alongside his brothers would receive private tutorship from Sir Robert Ball and Dr Johnstone Stoney, famous Irish astronomer and physicist, respectively. Read More
Hello! Or should I say, welcome aboard! In this edition of micro gas turbines in transportation, we’re going to be looking at micro gas turbines in the marine world. Marine transportation presents its own set of unique challenges not seen in other forms of transportation; although some of the common challenges and hurdles will be seen here too. If you haven’t read the other entries, or the introduction, I highly recommend you do so here.
Out of all the different vehicles and forms of transportation that will be covered in this series, the boat as we know it is one of the oldest ways of getting about. From rowing to sailing to paddle wheels and engines, the boat has a long history of carrying every kind of good and being imaginable. Much like the topic of turbines, marine transportation can take up oceans of information; in fact you might say that it’s a whale of a topic.
This blog will specifically cover a brief history of motorized marine transportation, where/how micro turbines can be used, and the inherent advantages and disadvantages. Let’s get started!
A Brief History of Engines in Marine Transportation
Steamboats became popular in the 19th Century when the Industrial Revolution was in its early stages. Steam engines like the ones designed by James Watt were used to propel everything from small riverboats like the ones that went up and down the Missouri river, to oceangoing steamships. The engines typically drove a propeller or “screw” or a large paddle wheel like what is commonly seen on a watermill. Different steam engines in different configurations dominated marine transportation throughout the 19th century, and by the turn of the 20th century, large expansion engines began to be utilized for oceangoing ships like the Olympic-class ocean liners as well as warships. Read More
Hello! Welcome to this edition of our series on micro turbines! Today we’ll be covering micro turbines and the roles they play in the automotive world.
“Big wheels keep on turnin’…”
Now here’s the real question, when you see that lyric which song do you think of first? Having gotten that stuck in everyone’s head, let’s get on with today’s topic: micro turbines in cars.
I mentioned in the intro to the series that when I think of micro turbines my mind immediately jumps to turbochargers like those used in reciprocating engines seen in cars, trucks, boats, and small airplanes.
They are, in essence, the same, but also different. For example, a turbocharger uses exhaust gas from a reciprocating engine to drive a compressor to pull more air into the engine, while a micro turbine drives a compressor to pull air into a combustor and then also drives a generator to create electric power.
The Achilles heel of turbochargers has always been the time between pressing your foot to the gas pedal and waiting for the engine to respond with the desired power. This lapse in engine response, commonly termed turbo lag, is what has hindered turbochargers from delivering optimal performance. The aim of a turbocharger is to provide more power, better efficiency and less lag in power delivery. Engine efficiency is becoming more important than ever before, leading to the development of smaller engines. However, the power requirements are not decreasing which means the loss in engine displacement from small designs must be picked up with alternative technologies, such as turbochargers, which can help improve power delivery and fuel economy.
Electric turbochargers (e-turbos) provide a solution to eliminating turbo lag while adding additional performance benefits. This allows for larger turbocharger designs which can provide larger power and efficiency gains, stay cooler over longer periods of use, and drastically improve engine responsiveness. Garrett Motion are developing e-turbos for mass market passenger vehicles set for launch in 2021, with a claimed fuel efficiency improvement of up to 10%. When used on diesel engines, this e-turbo could be up to a 20% reduction in NOx emissions. In most cases, fuel efficiency will be improved by about 2 – 4%. Other manufacturers such as Mitsubishi and BorgWarner are already developing their own electric turbos and are expected to have announcements in the near future matching the trend in e-turbo development.
If you’re familiar with turbomachinery, then you probably know the pivotal role they play in our lives. If you’re not, no biggie! Have a look at this blog where I discuss a world without turbomachinery. But where do microturbines fit in? I can’t speak for anyone else, but my mind immediately jumps to turbochargers in small-displacement car engines. There is, however, a whole slew of information, history, and applications for microturbines beyond being a component in your car.
The best place to start, is to establish just what a microturbine is and isn’t. Granted the prefix in the word is a dead giveaway, but just how small is a micro gas turbine? In terms of power output, a micro gas turbine puts out between 25 and 500 kW. The size of these machines varies; some systems can be the size of a refrigerator, while others can fit on your desk. For reference, some of these machines are smaller than your average corgi!
In terms of components, microturbines typically consist of a compressor, combustor, turbine, alternator, generator, and in most machines, a recuperator. While incorporating a recuperator into a microturbine system comes with its own set of challenges, the benefits are often well worth it as efficiency when recuperated hovers around 25-30% (with a waste heat recovery/cogeneration system, efficiency levels can reach up to 85% though).
When and how did the concept of micro gas turbines come about? After the advent of the jet engine in World War II and the prominence of turbochargers being used on piston-driven propeller planes during the war, companies started to see where else gas turbine technology could be utilized. Starting in the 1950’s automotive companies attempted to offer scaled down gas turbines for use in personal cars, and you can read our blog covering that more in-depth here. You can probably guess by the number of gas turbine-powered cars on the road today, that it wasn’t very successful.
Fast forward to the 1970s, companies started to take an interest in micro turbines for stationary power generation on a small, portable scale. Allison developed microturbine-powered generators for the military that showed substantially lower fuel consumption in initial testing. In the 80’s, GRI supported the AES program where they attempted to develop a 50kW turbine for aviation applications, using a heat recovery system to improve efficiency through a cogeneration system. More recently, companies like Capstone have worked with GRI on new projects to introduce microturbines to different industries where they could be useful, using the latest advancements in technology to ensure higher efficiencies and reliability of designs past. To discuss the current state of affairs for microturbines however, it might be good to list some of their present advantages and drawbacks, and then explore where in the world they could be most useful.
Advantages and Disadvantages of Microturbines
As with just about any other type of technology, microturbines have their own set of advantages and disadvantages as a result of their design that are seen in their different applications.
– Lower emissions
– Lower noise level than comparable reciprocating engines
– Fewer moving parts with results in less maintenance needs
– Lower vibration levels
– Ligherweight, compact systems
– Diverse fuel selection (jet fuel, kerosene, diesel, natural gas)
– Very low efficiency without recuperator/waste heat recovery system
– High work requires high speeds (30-120 krpm) for small diameters
– Poor throttle response
– Expensive materials required for manufacturing
– More sensitive to adverse operating conditions
Potential Transportation Industry Applications
There are a number of different industries which microturbines can be found both in and outside of the transportation. Throughout the upcoming months, we’ll be taking a closer look at:
– The Aviation Industry
– The Automotive Industry
– The Marine Industry
– The Rail Industry
Each of these industries has at least one application where micro gas turbine technology has the potential to conserve fuel and lower emissions without compromising power. In the next entry, we’ll look at the current state of the aerospace industry and where/how micro gas turbines can improve upon existing technology.
If you want to learn more about designing a micro gas turbine, or about the tools our engineers and thousands of others around the world rely on for their turbomachinery designs, reach out to us at firstname.lastname@example.org
There is a growing interest in electric and hybrid-electric vehicles propulsion system due to environmental concerns. Efforts are directed towards developing an improved propulsion system for electric and hybrid-electric vehicles (HEVs) for various applications in the automotive industry. The government authorities consider electric vehicles one of several current drive technologies that can be used to achieve the long-term sustainability goals of reducing emissions. Therefore, it is no longer a question of whether vehicles with electric technologies will prevail, but when will they become a part of everyday life on our streets. Electric vehicles (EVs) fall into two main categories: vehicles where an electric motor replaces an internal combustion engine (full-electric) and vehicles which feature an internal combustion engine (ICE) assisted by an electric motor (hybrid-electric or HEVs). All electric vehicles contain large, complex, rechargeable batteries, sometimes called traction batteries, to provide all or a portion of the vehicle’s propelling power.
EVs propulsion system offers several advantages compared to the conventional propulsion systems (petrol or diesel engines). EVs not only help reduce the environmental emissions but also help reduce the external noise, vibration, operating cost, fuel consumption while increasing safety levels, performance and efficiency of the overall propulsion system. However, there are many reasons why EVs and HEVs currently represent such a low share of today’s automotive market. For EVs, the most important factor is their shorter driving range, the lack of recharging infrastructure and recharging time, limited battery life, and a higher initial cost. Though HEVs feature a growing driving range, performance and comfort equivalent or better than internal combustion engine vehicles, their initial cost is higher and the lack of recharging infrastructure is a great barrier for their diffusion. Therefore, industry, government, and academia must strive to overcome the huge barriers that block EVs widespread use: battery energy and power density, battery weight and price, and battery recharging infrastructure. All major manufacturers in the automotive industry are working to overcome all these limitations in the near future.
Common Types of Electric Vehicles
A more universal EVs classifications is carried out based on either the energy converter types used to propel the vehicles or the vehicles power and function . When referring to the energy converter types, by far the most used EVs classification, two big classes are distinguished, as shown in Figure 1, namely: battery electric vehicles (BEVs), also named pure or full-electric vehicle, and hybrid-electric vehicles (HEVs). BEVs use batteries to store the energy that will be transformed into mechanical power by electric motors only, i.e., ICE is not present. In HEVs, propulsion is the result of the combined actions of electric motor and ICE. The different manners in which the hybridization can occur give rise to different architectures such as: series hybrid, parallel hybrid, and series-parallel hybrid. All these different EVs architectures are shown in Figure 2.