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Development of an Optical Investigation Method for Diesel and Oxymethylene Ether Spray in a Large-Bore Dual-Fuel Engine Using a Fisheye Optical System
- Stephan Bernhard Karmann - Technical University of Munich, Germany ,
- Stefan Weber - MAN Energy Solutions, Germany ,
- Wolfgang Stürzl - DLR Institute of Robotics and Mechatronics, Germany ,
- Maximilian Prager - Technical University of Munich, Germany ,
- Malte Jaensch - Technical University of Munich, Germany ,
- Georg Wachtmeister - Technical University of Munich, Germany
Journal Article
03-16-05-0036
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Topic:
Citation:
Karmann, S., Weber, S., Stürzl, W., Prager, M. et al., "Development of an Optical Investigation Method for Diesel and Oxymethylene Ether Spray in a Large-Bore Dual-Fuel Engine Using a Fisheye Optical System," SAE Int. J. Engines 16(5):605-622, 2023, https://doi.org/10.4271/03-16-05-0036.
Language:
English
Abstract:
Optical combustion phenomena investigation is a common tool for passenger car and
automotive engines. Large-bore engines for stationary and mobile applications,
on the other hand, have a lower optical examination density. This is mainly due
to the technically more complex design of the optical accesses that have to
provide a larger field of view and withstand high mechanical and thermal loads.
Nevertheless, an optical investigation of in-cylinder phenomena in large-bore
engines is essential to optimize efficient and environmentally friendly
combustion processes using new sustainable e-fuels. To realize a simple optical
access with maximum observability of the combustion chamber, a fisheye optic for
the direct integration into internal combustion engines was developed and used
for in-cylinder Mie-scattering investigations of diesel and Oxymethylene Ether
(OME3-5) pilot fuel spray of natural gas dual-fuel combustion
processes in a MAN 35/44DF single-cylinder research engine. As this special
application of a fisheye lens poses some technical challenges, a special image
processing procedure is necessary for result evaluation. This innovative
postprocessing of the fisheye images comprises a calibration of the fisheye
optic and a virtual three-dimensional (3D) re-projection method. Investigations
prove the accuracy of the method to be within 2.1 mm. To prove the advantage of
the method, optical spray investigations of two different fuels using
Mie-scattering in the skipped-fire optical accessible medium-speed large-bore
engine are carried out under realistic engine conditions. With the newly
developed post-processing procedure, it was possible to derive the mean liquid
penetration depth of the in situ investigations. Further, the postprocessing
includes a rectification of the fisheye images to improve the observability of
the pilot fuel spray in the fired combustion engine. The analysis reveals a more
compact and dense spray for OME3-5 compared to marine diesel fuel
(DMA) as well as about 39% reduced liquid penetration length.