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Investigation on the Effect of the Gas Exchange Process on the Diesel Engine Thermal Overload with Experimental Results

Lookup NU author(s): Sangram Nanda, Dr Boru Jia, Dr Andrew Smallbone, Professor Tony Roskilly



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


In this paper, the influence of the gas exchange process on the diesel engine thermal overload is provided. Main components involved in the gas exchange process are discussed. The ambient conditions, the turbocharger performance, and the valve timing that affect the gas exchange process have been investigated. Experiments were conducted to simulate ambient conditions at different geographical locations and demonstrated a decrease in oxygen concentration in the exhaust as the humidity level in the air increased. Additionally, the effect of an inefficient turbocharger on an engine operating at part-load was also investigated. It was observed that an overly lean air/fuel mixture caused inefficient scavenging and the corresponding level of residual gas trapped in the cylinder increased. This resulted in partial combustion which could be observed as white smoke from the engine exhaust stack, therefore indicating the presence of unburnt fuel. Exhaust valve timing measurements showed that the cylinder with the highest wear rate had its valve closure timing 10 crank angle degrees after the cylinder with least wear rate. The exhaust valves were closed earlier than the designed condition which impaired the scavenging process and increased the level of residual gas trapped in the cylinder. This resulted in a reduction of the actual air-to-fuel ratio and high exhaust gas temperatures.

Publication metadata

Author(s): Nanda SK, Jia B, Smallbone A, Roskilly AP

Publication type: Article

Publication status: Published

Journal: Energies

Year: 2017

Volume: 10

Issue: 6

Online publication date: 31/05/2017

Acceptance date: 26/05/2017

Date deposited: 31/05/2017

ISSN (electronic): 1996-1073

Publisher: MDPI AG


DOI: 10.3390/en10060766

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