# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Additive manufacturing

Additive manufacturing is better known as 3D printing, with thin layers of materials meticulously layered on top of each other, “printed” to form a final component that can be used to help create turbochargers and other components. Not only does additive manufacturing make it possible to create complex parts that may not be viable using more traditional manufacturing methods, such as casting, it also introduces the potential to dramatically cut development times for prototypes. Find out more about how Accelleron is using additive manufacturing here.


Ammonia is one of the fuels the maritime industry is looking towards to replace more traditional fossil fuels, building towards IMO 2030 and IMO 2050 targets. Ammonia is created from hydrogen and nitrogen. It also has a higher energy density than hydrogen, making it better suited for use as fuel in long-haul shipping.

Charge air cooler

With a forced induction engine, the compression of air also makes it hotter, which isn’t ideal for power or efficiency. That’s where a charge air cooler – also known as an intercooler – comes in. Sitting between the turbocharger and engine, a charge air cooler takes the compressed hot air from the turbo and cools it down before feeding it into the intake manifold, helping to increase efficiency and power.


A vessel’s CII (Carbon Intensity Indicator) is set by the IMO, and determines the annual reduction factor needed to ensure continuous improvement of a ship's operational carbon intensity within a specific rating level. The actual annual operational CII achieved must be documented and verified against the required annual operational CII.

Compressor housing and diffusor

This is the stator part of the compressor stage. The engine requires air pressure in the intake receiver rather than velocity. To convert the velocity into static pressure, the stator must slow down the air flow, by recompressing it. As this is the case for the turbine nozzle ring, a large turbocharger compressor typically comprises an additional blades ring, called the vane diffusor. This diffusor is inserted between the compressor wheel and the housing, in a way to better organize the air recompression process, with the optimal flow direction at the outlet of the wheel. The recompression is better achieved within the housing, whose divergent shape allows the gases to be further slowed down and compressed.

Compressor map

The compressor map is the fingerprint or the signature of the compressor. It represents its thermodynamic characteristics, linking air flow, pressure ratio, wheel rotational speed and efficiencies. This map also displays the operational limits of the compressor stage, like surge, choke and overspeed. This graphic representation allows linking the compressor and the engine operating points, and thus checking if both machines are correctly matched. This is the starting point for selecting the right turbocharger for a given engine and application.

Compressor wheel

This is the rotor part of the compressor stage. Driven into high rotational speed by the turbine through the shaft, the compressor wheel breaths the fresh air from the filter, starts compressing it, and brings it into rotation around its axle with high tangential velocity and kinetic energy.


Decarbonization is the reduction of carbon dioxide emissions through the adoption of low-carbon power sources, such as solar power, wind power and other sustainable alternatives. The aim is to reduce the number of greenhouse gases (GHG) that are released into the atmosphere, which is essential when it comes to meeting global temperature standards set by the Paris Agreement international treaty on climate change.


Derating is limiting the power output of a ship’s engines, helping owners and operators to reduce fuel consumption and cut emissions to meet decarbonization targets. Derating a marine engine opens the door for several turbo and engine upgrade solutions such as Engine Part Load Optimization, which can help ship owners and operators to meet increasingly rigorous sustainability regulations and targets.

Diesel Cycle

In 1893, Rudolf Diesel ran his first engine in Augsburg (Germany), with a compression self-ignition process. His idea was to get as close as possible to the ideal Carnot cycle, which allowed his new engine to outclass the already existing technologies: The Diesel engine was born. Rudolf Diesel’s vision was to create, mainly based on scientific considerations, a cheap and energy efficient engine for small business, as a means of improving social conditions.


E-fuels, also known as synthetic fuels, are alternative fuels manufactured from sustainable energy sources including wind, solar and nuclear power, and are likely to play a key role in creating a cleaner and more sustainable planet as we move away from more conventional fuels such as diesel. E-fuels include e-diesel and e-kerosene, which are produced using CO 2, along with other alternative fuels such as synthetic methanol, ammonia and hydrogen, which can all be produced using sustainable methods.


Energy Efficiency Existing Ship Index (EEXI) is a technical index created by the IMO to measure the efficiency of a ship’s design, calculating everything from the vehicle’s propulsion system to its transport capacity and speed. Created to measure the CO2 emissions per cargo ton and mile, EEXI is a valuable tool in the journey towards cutting greenhouse gas emissions for IMO 2030 and IMO 2050.


Engine part-load optimization (ELPO) is a tuning method that optimizes fuel-oil consumption during the part-load operation of four-stroke engine, helping to improve fuel efficiency and save costs for shipping owners and operators. There are multiple ways that owner/operators can approach EPLO, such as engine derating, turbocharger cut-out and turbocharger upgrades, and our story on engine efficiency will help you to find out more.


ESG stands for Environmental, Social and Governance, and refers to corporate performance evaluation criteria to assess an organization’s governance mechanisms and its ability to manage company impact on the environment and society.


The EU Emissions Trading System (EU ETS) is a key part of the EU’s policy to combat climate change, aiming to reduce greenhouse gas (GHG) emissions via a carbon market where polluters pay for GHG emissions. As part of the legislation, the cap for emissions is reduced each year, ensuring that the EU’s emission target by 2030 of 55% reduction, relative to 1990, can be met while becoming climate-neutral by 2050. Find out more about EU ETS here.


In 1876, the German Nikolaus Otto developed a gaseous fuel, compressed charge four-stroke cycle that would become known as the Otto-Cycle. This is the principle that still powers most car engines today. He based an engine on this cycle after 14 years of effort: it is a system characterized by four piston strokes (intake, compression, expansion-power and exhaust), under two engine revolutions.

Fuel cell

A fuel cell is an energy source that works much like a battery, but with a couple of key benefits: It doesn’t run down, and doesn’t need recharging. Instead, the cell converts fuel such as hydrogen, and an oxidising agent, such as oxygen, into electricity. As such, it can be used to power electric motors without worrying about downtime for recharging, or performance dropping, with plenty of potential as an alternative fuel source of the future.


Greenhouse Gas (GHG) emissions are gases that trap heat in the Earth's atmosphere, contributing to the greenhouse effect and thus global climate patterns. These gases effectively act like a blanket around the Earth, allowing sunlight to enter the atmosphere but preventing some of the heat from escaping back into space. The main greenhouse gases include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), fluorinated gases, and water vapor.

Green hydrogen

Green hydrogen is one of the possible solutions for future fuels. Unlike regular (blue) hydrogen, which is created using fossil fuels, green hydrogen is produced using renewable energy through electrolysis. Using an electrical currant to separate the hydrogen from oxygen in water, green hydrogen is created using renewable electricity sources such as solar or wind power.

High, medium and low-speed

Diesel engines can be split into three different types: High-speed, medium-speed and low-speed. High-speed engines run at around 1200rpm or more and can generally be found in smaller applications such as cars, trucks or construction vehicles, or powering generators. As the name suggests, medium-speed engines run at around 400rpm or more and are often found in larger applications including smaller boats and larger electrical generators. Low-speed engines run at less than 400rpm and are most typically found in larger ships.


The International Maritime Organization (IMO) is the global standard-setting authority for the safety, security and environmental performance of international shipping. Its main role is to create a regulatory framework for the shipping industry that is fair and effective, universally adopted and universally implemented, leading to targets such as IMO 2030 and IMO 2050.


An impeller is another name for a compressor wheel, which is the rotor part of a turbocharger’s compressor stage. Driven into high rotational speed by the turbine through the shaft, the compressor wheel breaths the fresh air from the filter, starts compressing it, and brings it into rotation around its axle with high tangential velocity and kinetic energy.


An injector is a component that atomizes and injects fuel into the combustion chamber on an internal combustion engine. Like turbochargers, a high-quality, well-maintained fuel injection system can have a large impact on fuel consumption and emissions. Find out more about fuel injection here.


LNG (liquified natural gas) is an  alternative fuel that is bridging the gap as the marine industry works towards a cleaner future. Although still a fossil fuel, LNG is actually 95% methane, and the combustion of natural gas generally results in emissions of water vapor and small amounts of carbon dioxide. Although the shipping industry is working towards decarbonization and targets such as IMO 2030 and IMO 2050, LNG is a reasonable interim solution, as associated CO 2 emissions are 30 to 50% lower than those produced by traditional combustible fuels.


Methanol is an alternative fuel generally produced by steam-reforming natural gas to create a synthesis gas. Lower production costs make it a more affordable option than other alternative fuel sources such as hydrogen and ammonia, and it has also been used in the past as an alternative for traditional fuels for domestic vehicles.


A microgrid is a self-sufficient energy source that’s generally designed to serve local power needs. Despite the name, there are no constraints on size, with the ability to connect clusters of microgrids to create larger, more powerful, systems. A microgrid could provide power to just a couple of homes, or it could also be used to provide electricity to thousands. What microgrids do generally have in common, however, is the fact that they tend to be decentralized and self-contained, making them the perfect power source for more remote locations.

Miller Cycle

Internal combustion engines may run on similar principles, but they don’t all feature the same operating cycles. While many engines feature a four-stroke cycle, comprising intake, compression, expansion-power and exhaust, the Miller Cycle, originally patented by the American Ralph Miller in 1957 and still used today, differs by having a longer expansion stroke than the compression stroke, which is synonym of better thermodynamic efficiency. This is generally done by closing the intake valves earlier than on a normal engine. Used alongside a turbocharger or supercharger, the part of the forced induction (cooled compression) into the global compression is larger, leading lower maximal cycle temperatures and better [NO x emissions and efficiency] trade-off, while improving combustion stability and keeping away the knocking in the case of spark-ignited engines. Miller Cycle engines can be more efficient as a result.

Off-highway vehicles

Off-highway vehicles are intended for use on uneven or steep ground, and include mining equipment, quarry trucks, and farming vehicles. These vehicles typically feature high-speed engines, and Accelleron provides turbocharges for a range of high-speed engines across multiple industries.

Otto Cycle

In 1876, the German Nikolaus Otto developed a spark-ignited gaseous fuel, compressed charge 4-stroke cycle that would become known as the Otto-Cycle. This is the principle that still powers most car engines today. He based an engine on this cycle after 14 years of effort; it is a system characterized by four piston strokes (intake, compression, expansion-power and exhaust), under two engine revolutions. Austrian watchmaker Christian Reithmann is also credited with having patented a 4-stroke engine during the early 1860s, and the Frenchman Alfonse Beau de Rochas described and patented the cycle exactly as N. Otto built it in 1862.

Peak shaving

The energy market faces major challenges in the face of energy transition and greater decentralization. Today, the entire system needs more flexibility to be able to efficiently guarantee the security of supply, and this is where peak shaving comes in. Peak shaving is the term used for flattening peaks in electricity use, addressing any imbalance and reducing stress on the electricity grid by providing power stability and flexibility to potentially avoid blackouts and maintain security of electrical supply.

Service agreement

Unexpected or unscheduled downtime in the maritime industry can cost businesses millions of dollars, which is why it’s so important to keep on top of maintenance and servicing. That’s where service agreements come in, helping companies to ensure the continued efficiency and reliability of parts. Not only does this help to keep engines running as efficiently as possible, it can also help to reduce total cost of ownership and the administrative workload of maintenance management. Check out how Vedanta Limited – Cairn Oil & Gas is benefitting from ABB Turbocharging’s service agreement here.

Slow steaming

Whatever your form of transport – from walking to riding a bike or driving a car – travelling as quickly as possible is never the most energy efficient way to get around. At a certain point, going faster will always take more effort and use more fuel. The same is true for shipping, where the costs of inefficiency can be huge. As such, the owners and operators of cargo ships engage in a practice known as slow steaming, where they deliberately reduce the speed of their vessels to reduce fuel consumption and cut carbon emissions.


Surging is a disruption of the airflow within the turbocharger, where increased backpressure can create turbulence that prevents efficient running, with the potential to cause unwanted oscillations, vibrations and increased wear on the parts. Surging can make a huge difference to the performance of a turbocharger, as optimal airflow is critical to any turbocharger, with the design perfectly tuned to direct exhaust gasses towards the turbine wheel and through the turbocharger in the most efficient way possible.

TPL upgrades

Accelleron’s TPL turbocharger component upgrades increase the performance of your engines as well as your turbochargers. It’s a plug-and-play solution that only replaces internal components. With no changes to external connections and interfaces, this upgrade can be delivered in just 12 hours. We upgrade the components that make the biggest difference - new compressor wheel and diffusor designs, an improved turbine and nozzle ring, and optimized low friction bearings. Right away, you benefit from fuel savings and reduce exhaust gas temperatures. Find out more about how our TPL upgrades can help your company here.

Turbine housing and nozzle ring

This is the stator part of the turbine stage. The turbine housing takes the exhaust gases from the engine and directs them onto the turbine wheel, by accelerating them through a pre-expansion process. In the case of large turbochargers, a nozzle ring is added between the housing and the wheel to improve the efficiency of this pre-acceleration by directing the gases toward the wheel blades with an optimal direction. The turbine efficiency itself is thereby strongly improved, and a larger part of the exhaust energy is then turned into mechanical power.

Turbine Wheel

This is the rotor part of the turbine stage. The turbine wheel features a number of finely designed blades, which turn the wheel when hit by the accelerated exhaust gases coming from the stator. This rotational power is further increased by the reaction of the gases continuing to expand themselves between the wheel blades. As the engine power increases, more exhaust gases are expelled, with increased internal energy, and directed into the turbine housing, turning the turbine wheel at faster speeds.

Turbo Insights

Accelleron’s Turbo Insights feature provides in-depth analytics, helping owners and operators to optimize their turbochargers. This opens up visibility into compressor maps to enable analysis of operational data from day one. Find out more about Turbo Insights here.


A turbocharger is an auxiliary component that helps to improve internal combustion engine power density and efficiency. To do so, the turbocharger turbine recovers a part of the exhaust energy which would have been otherwise lost, by expanding exhaust gases around a rotating wheel. This turbine wheel is driven into rotation and its mechanical power is transmitted to the compressor, which vacuums fresh air from ambient and compresses it toward the engine intake receiver. This gives the engine a higher air mass per cycle. This additional boost can multiply the output power of a given engine by up to six times in comparison to a naturally aspirated, non-turbocharged engine, and can also result in a substantial fuel consumption and CO 2 reduction of up to 70%.

Turbocharger cartridge

While there are plenty of different components within a turbocharger, including compressor and turbine wheels, shafts, bearings, nozzles and other parts, the turbocharger cartridge groups some of these components together, making maintenance, replacements and upgrades both easier and more affordable. Instead of having to put numerous parts together, or replace the turbocharger as a whole, it is possible to buy a turbocharger cartridge instead. This can simply be swapped out for the old cartridge, including both the compressor and turbine wheels, the shaft that connects them, and other parts that make up the heart of the turbocharger.

Turbocharger cleaning

If you want to see the biggest efficiency savings when it comes to fuel and emissions, it’s critical that you maintain your engine and turbocharger as per manufacturer guidelines. For the turbocharger, that includes cleaning internal components after a specified number of operational hours. Find out more about cleaning your turbocharger here.

Turbocharger cut-out

Turbocharger cut-out means that ship operators can use the number of turbochargers that best suits their expected load patterns and ‘cut-out’ the rest, switching back to all turbochargers as and when required. Find out more about turbocharger cut-out and how it can help the maritime industry to meet decarbonization targets here.

Turbocharger vanes

A vane is a specifically-shaped component that can help to direct airflow within the turbocharger. Accelleron’s VTG technology features a series of vanes arranged around the nozzle ring, and these vanes can be directed to help adjust the air-to-fuel ratio, controlling boost pressure and delivering optimum boost whatever the conditions.

Two-stage turbocharging

Turbochargers help to boost the efficiency of internal combustion engines by reusing exhaust gases energy, but that efficiency can be further increased through the use of two and even three stage turbocharging. Two-stage turbochargers feature two compressor and turbine stages, with the initial stage typically being low-pressure, which in turn feeds into a high-pressure stage. This enables engine builders to increase compression ratios far higher than those found on single-stage turbochargers. Also, thanks to the thermodynamic benefit of intercooling between both compressors, two-stage solutions such as ABB Turbocharging’s Power2 provide turbocharging efficiency above 75%, compared to 65% for conventional turbochargers. The engine efficiency is thereby positively impacted and thanks to thermal load reduction, its lifetime can also be improved as well.


While the majority of larger engines run on the four-stroke Otto-Cycle, there are still a number of engines that run a simple two-stroke cycle. In place of intake, compression, expansion-power and exhaust strokes, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, resulting in an engine cycle that only requires two revolutions of the crankshaft.

Variable turbine geometry (VTG)

ABB’s Variable turbine geometry (VTG) technology can continuously alter the geometry of a turbocharger’s turbine nozzle ring, helping to control the boost pressure that a turbocharger supplies to an engine. This provides more flexibility when it comes to adjusting the air-to-fuel ratio for varying ambient conditions. VTG can also broaden the engine operating range by increasing the boost pressure at low engine speed and/or load, without degrading the performance and efficiency at rated power. The benefits can be seen when it comes to both turbocharger efficiency and operating costs, with engines in long-haul locomotives saving as much as 4% on average on fuel, for example, across a wider range of temperatures and altitudes. In short, VTG provides more performance and additional flexibility in any situation.


Turbochargers make engines more efficient by recovering a part of the exhaust energy which would have been otherwise lost, expanding exhaust gases around a rotating wheel called a turbine wheel. A wastegate is used to control gasses, regulating boost pressure and diverting excess gasses away from the turbine wheel. The wastegate is generally a relatively simple valve, which is held shut by the wastegate actuator. When boost pressure increases, the actuator progressively opens the wastegate, enabling excess gasses to escape, regulating the speed of the turbine wheel.

Wastegate actuator

An actuator is a component that converts energy, such as electrical, air or hydraulic, into mechanical force. A turbocharger wastegate actuator generally includes an arm attached to the wastegate, with a spring inside the actuator helping to keep the wastegate valve shut. As boost pressure increases, the actuator allows the wastegate valve to gradually open, enabling excess gasses to escape and regulating the speed of the turbine wheel.