Optical Studies in a Direct Injected Diesel Engine
2005 (English)Conference paper (Other academic)
A heavy-duty diesel engine with optical access through an extended piston has been used to study diesel spray combustion. Conventional photography using a solid-state camera was adopted to image the flames. The images were parameterized using image processing software. Due to extended crevices and reduced stiffness as compared to the original engine, the effective compression ratio was slightly lower in the optical cylinder. To compensate for the lowered compression ratio, the inlet pressure as well as the inlet temperature were increased. As top dead center conditions regarding gas density and temperature were desired to be maintained, this approach resulted in an increased overall air to fuel ratio. However, despite these drawbacks, the engine allows for spray combustion studies under realistic diesel engine conditions regarding pressure and temperature. The inlet pressure was kept at 400 kPa absolute and the temperature was 325 K. To predict the air mass in the cylinder as accurately as possible, the exhaust back pressure was always kept equal to the inlet pressure. To minimize the thermal load on the piston, fuel was injected only when an image was to be exposed. This was also beneficial when estimating the air mass in the cylinder, as the temperature of the rest gas was quite low. A nozzle with eight orifices fitted to a common-rail injector was used to generate the sprays. The rail pressures used were 160 MPa and 220 MPa, the injected amount of fuel was varied between 80 mg and 240 mg.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:kth:diva-180067OAI: oai:DiVA.org:kth-180067DiVA: diva2:891702
Fifth Symposium "Towards Clean Diesel Engines", Lund, 2-3 June 2005
QC 201601072016-01-072016-01-072016-01-07Bibliographically approved