An opportunity to discuss turbocharger usage and design with Softinway engineer Ursula Shannon in a question and answer format:
What are some of the major current turbocharger design challenges?
When it comes to turbocharger design, there are two challenges that engineers generally face. “Turbo lag” and turbo boost power at varying engine RPMs. “Turbo lag” is the time that it takes for the engine to produce enough exhaust to start the turbocharger “working”. This can vary greatly depending on engine size, turbocharger geometry, exhaust output etc. Ideally, engineers want to reduce this “Turbo lag” by as much as possible in any given situation, as during that time, the exhaust is “wasted” in a sense. Finding the most efficient configuration with all of the parameters in mind can be a very challenging scenario from a design perspective.
The turbo boost design challenge is one of efficiency at variable exhaust outputs. A smaller charger for example will start to boost at lower engine speeds while a larger one will start to boost at engine speeds. The trade off however is that a smaller turbo will start to create what is known as back pressure at higher speeds, and this results in a loss of potential power. A larger turbocharger, will be able to create more overall boost at higher speeds, however the “Turbo Lag” is more pronounced as more engine exhaust is required. Minimizing these trade offs is another key challenge in turbocharger design.
Finally, the process of turbocharger design process itself is complex, and requires highly specialized software such as our own here in Softinway (AxSTREAM).
AxSTREAM Turbocharger Design Software ( Flowpath Design and Optimization )
AxSTREAM Turbocharger Design Software (Compressor 1D Design and Analysis)
What are some design changes do you see coming to turbochargers in the future?
As I mentioned some of the challenges engineers face in turbocharger design, currently many technologies and methods are being developed to alleviate some of the issues faced.
Two stage turbochargers are good example of trying to offer a solution to the boost powers at varying engine outputs, using a smaller turbocharger that operates at low RPMs and a larger turbocharger that operates at higher RPMs.
Electronic energy storage setups are currently being developed and used in European race cars which uses the output side of the turbocharger as a sort of generator which stores energy in a battery from turbocharger operations and acts as a boost during a turbocharger’s lag period.
Turbocharger usage in the United States
By model year 2025, the fuel efficiency standards of automobiles manufactured in the United States will have a target goal of 87.71 kilometers/hour as per government regulation. President Barack Obama, while enacting new automotive efficiency goals in 2012, stated “These fuel standards represent the single most important step we’ve ever taken to reduce our dependence on foreign oil. This historic agreement builds on the progress we’ve already made to save families money at the pump and cut our oil consumption. By the middle of the next decade our cars will get nearly 55 miles per gallon, almost double what they get today. It’ll strengthen our nation’s energy security, it’s good for middle class families and it will help create an economy built to last.”
At the forefront of fuel efficiency technology are turbochargers. By taking advantage of exhaust heat, that would otherwise be wasted, and converting it to mechanical energy that forces more air into the internal combustion engine reaction chamber, the turbocharger enhances the engine power per volume of fuel used. In other words, you can have a smaller engine produce the same power output as an engine without a turbocharger. This applies to any combustion engine, such as those used in boating and locomotive applications.
Do you see mass adaptation of turbochargers in the USA?
As we go forward people are starting to put more interest in more efficient and powerful internal combustion engine technology. Even though nowadays turbocharger demands comes mostly from the automotive industry, especially from Europe, it’s applicable for many other potential implementations which haven’t been much explored yet. Turbocharger increases an internal combustion engine’s power output for a given fuel volume, and implementation of such technology has been found to be very impactful.
The United States has always enjoyed lower fuel prices, especially gasoline, when compared to Europe. The higher gasoline prices in Europe have had a forceful effect on fuel economy standards there, and the automobile manufacturers realized very quickly that turbocharging an engine is one of the best and fastest solutions to fuel economy, as they were able to utilize much smaller changes than before.
Percentage of Vehicles sold with turbochargers
Though turbocharges themselves do not cause fires in automobiles, auxiliary systems which have incorrectly designed heat dissipation systems have been known to create hazards. Do you see this as a detriment to mass adaptation of turbochargers in thee USA?
No, there are always safety consequences to any new technology, though as the technology evolves and progresses, risk usually goes down. With that said, I believe as we further explore the potential of turbochargers, we will come up with more design ideas which could bring the failure rate down and improve the usage for turbochargers in general.
Are there any disadvantages to mass adaptation of turbochargers?
Turbochargers create an additional manufacturing and maintenance cost. I believe it is well worth the trade off however. A turbocharged engine runs of off the exhaust heat that would’ve been wasted otherwise. There is simply no reason to not turbo charge an internal combustion engine. Unlike a supercharger which requires energy from the engine power train, a turbo charger requires no additional energy input.
Which industries do you believe currently under utilizes turbochargers (Boating, Locomotive, Automotive etc.)?
The biggest industry that utilizes turbochargers would be automotive, though turbochargers could really be implemented in many other industries without necessarily any limitation. Many industries are starting to pick up the technology, and I believe that there are so many untapped potentials in this technology that have yet to be explored. So generally, the turbocharger has not been utilized to its maximum potential in most industries.
It is very clear that anything that any engine which uses combustible fuel to create exhaust heat can benefit from turbocharging its engine. This applies to many industries.
Do you think Governments should subsidize or incentivize turbocharger installation?
With higher efficiency and better fuel economy, installation of turbochargers helps with the human carbon footprint. I personally believe that government incentives would make sense to push people into implementing this technology in an effort to optimize energy utilization.
In a roundabout manner, without directly decreeing that all automobiles manufactured in the United States should have a turbo charger, but by insisting on a target fuel efficiency goals, manufacturers are realizing that turbocharger technology is the best option to achieve the required results.