Analysis of Transient Noise Behavior of a Truck Diesel Engine

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2012

In the current study, experimental tests were conducted on a turbocharged truck diesel engine in order to investigate the mechanism of combustion noise radiation during various accelerations and for various fuel blends. With this aim, a fully instrumented test bed was set up in order to capture the development of key engine and turbocharger parameters. Apart from the baseline diesel fuel, the engine was operated with a blend of diesel with either 30 vol % biodiesel or 25 vol % n-butanol. Analytical diagrams are provided to explain the behaviour of combustion noise radiation in conjunction with the cylinder pressure, the pressure rise rates, the frequency spectrum and the turbocharger and governor-fuel pump responses. The blend of diesel fuel with n-butanol exhibited the highest noise emissions throughout each of the transient tests examined, with differences up to 4 dBA from those with neat diesel operation. On the other hand, the biodiesel blend was found to behave marginally noisier than neat diesel oil but without a clear trend established throughout the transient events.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Combustion noise radiation during the acceleration of a turbocharged diesel engine operating with biodiesel or n-butanol diesel fuel blends

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2012

“…Moreover, the study was extended to another important, but often neglected, emission, namely combustion noise. Diesel engine noise radiation is attracting more and more attention in recent years [23,24], since it is associated with the discomfort of passengers and pedestrians. The primary sources of noise generation in a diesel engine are gas flow (exhaust system), mechanical processes (e.g.…”

Section: Introductionmentioning

confidence: 99%

Investigation of turbocharged diesel engine operation, exhaust emissions, and combustion noise radiation during starting under cold, warm, and hot conditions

Proceedings of the Institution of Mechanical Engineers, Part D:

2011

Control of performance and transient emissions from turbocharged diesel engines is an important objective for automotive manufacturers, since stringent criteria for exhaust emissions must be met. In particular, (cold) starting is of exceptional importance owing to its significant contribution to the overall emissions during a transient test cycle. In the present work, experimental tests were conducted on a turbocharged and after-cooled bus-truck diesel engine in order to investigate the engine operating behaviour and the formation mechanisms of nitric oxide, smoke, and combustion noise during cold, warm, and hot starting. With this as a target, a fully instrumented test bed was set up, using ultra-fast response analysers capable of capturing the instantaneous development of emissions and various key engine and turbocharger parameters. The experimental test pattern included a variety of starting conditions, defined by the thermal status of the engine (i.e. the coolant temperature) and its idling speed. As expected, turbocharger lag was found to be the major contributor for the pollutant emissions spikes in all cases, with the thermal status of the engine and its idling speed playing important roles in the combustion (in)stability, turbocharger response, and noise radiation.

“…Moreover, the analysis was extended to another important (but often neglected) emission, namely combustion noise. Diesel engine noise radiation gets more and more attention in recent years [31][32][33], since it is associated with the passengers' and pedestrians' discomfort. By including the measurement of noise in this investigation, it was made possible to derive some useful conclusions regarding potential common mechanisms of all three examined emissions.…”

Section: Introductionmentioning

confidence: 99%

Experimental Assessment of Turbocharged Diesel Engine Transient Emissions during Acceleration, Load Change and Starting

SAE Technical Paper Series

et al. 2010

The control of transient emissions from turbocharged diesel engines remains an important objective to manufacturers, since newly produced engines must meet the stringent criteria concerning exhaust emissions levels as dictated by the legislated Transient Cycles. In the present work, experimental tests are conducted on a medium-duty, turbocharged and after-cooled diesel engine in order to investigate the behavior and formation mechanism of nitric oxide (NO), smoke and combustion noise emissions under various transient operating schedules including acceleration, load change and starting. To this aim, a fully instrumented test bed was set up in order to record and research key engine and turbocharger variables during the transient events. The main parameters measured are nitric oxide concentration and smoke opacity (both using ultra-fast response analyzers) as well as combustion noise. Various other variables were monitored, such as in-cylinder pressure, engine speed, fuel pump rack position, boost pressure and turbocharger speed. The main focus of the experimental investigation was devoted to engine acceleration tests representative of automotive and truck applications, commencing from various engine speeds and loads. The experimental test pattern also included load increases and (cold and hot) startings. Analytical diagrams are provided to explain the behavior of exhaust emissions development in conjunction with turbocharger and governor/fuel pump response. Turbocharger lag was found to be the main cause for the emissions peak values observed during all transient events. During starting, the lack of air and its mismatch with fueling caused excessive black smoke, identified by the extremely high values of exhaust gas opacity.