An engine without oil will not survive for very long. Pistons need plenty of lubricant in order to be able to move within the cylindrical sleeves in the engine block. Two things are known to raise the resultant level of friction. The first is attributed to distortion of the cylindrical bore hole when the cylinder head is attached, which is known as static distortion. The second occurs when the engine is running and temperatures warp the bore hole.
The honing tool adjusts its shape to match the piston bore holes. © Fraunhofer IWU
The extent of this thermal distortion depends on prevailing engine temperatures and the specific engine model. In reality, the piston does not follow a perfectly smooth up and down motion, but instead touches at points within the bore hole. This results in the engine requiring a great deal more oil as well as more gas. Automakers are already able to compensate static distortion.
During the final machining stage, honing, technicians mount a honing liner to the engine which simulates the cylinder head that will later be mounted. Only then the work on the bore hole is completed. Thermal distortion, on the other hand, presents difficulties since it has not been possible to compensate for this effect until now.
Saving two to three percent of fuel
This problem has now been solved by researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in collaboration with a car manufacturer and a machine tool producer. “Our technology makes it possible to compensate for both static and thermal distortion. This can lead to a fuel saving of two to three percent in combustion engines, and remove one step in their production,” says IWU head of department André Bucht.
This clever technology is based on a tool that can adapt its own shape. Researchers start by working out how an engine block is likely to become distorted: they determine the level of static distortion by unscrewing the cylinder head and measuring the extent to which the bore hole has been warped. They then simulate thermal distortion that occurs in each engine series, using an operating temperature of 90 degrees Celsius as their reference. The honing tool adjusts its shape based on these calculations, thereby altering the profile of the bore hole so that motions of the piston are perfectly smooth later on when the engine is running, preventing excessive friction.
Researchers have integrated small Piezo actuators into the tool which alter its shape and expand the diameter as required. “This is how we can incorporate any ‘imperfections’ in the otherwise perfectly round shape of the finished bore hole,” says Bucht.
A prototype of the tool already exists. The researchers have put it to use to prove that they can achieve the surface accuracy required without slowing down production – there being no more than 20 to 30 seconds for the assembly of each engine. Research is currently being performed on the test rig in collaboration with auto manufacturers. This is where an engine produced using the tool is put through its paces. Researchers are examining to what extent piston friction and fuel consumption are reduced, and how the lifespan of the engine might be affected in comparison with engines manufactured using conventional tools . The tests are scheduled to be completed by the end of the year. Researchers then plan to design the tool and the production process so that they can be adopted by manufacturers.
André Bucht | Fraunhofer Research News
Locating natural resources in the deep sea – easily and eco-friendly
25.04.2016 | Laser Zentrum Hannover e.V.
Aachen Center for Additive Manufacturing
05.04.2016 | Fraunhofer-Institut für Lasertechnik ILT
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
The trend-forward world of display technology relies on innovative materials and novel approaches to steadily advance the visual experience, for example through higher pixel densities, better contrast, larger formats or user-friendler design. Fraunhofer ISC’s newly developed materials for optics and electronics now broaden the application potential of next generation displays. Learn about lower cost-effective wet-chemical printing procedures and the new materials at the Fraunhofer ISC booth # 1021 in North Hall D during the SID International Symposium on Information Display held from 22 to 27 May 2016 at San Francisco’s Moscone Center.
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
25.05.2016 | Trade Fair News
25.05.2016 | Life Sciences
25.05.2016 | Power and Electrical Engineering