Impact of military JP-8 fuel on heavy-duty diesel engine performance and emissions

Abstract

Investigating the impact of jet fuel on diesel engine performance and emissions is very important for military vehicles, due to the US Army Single Fuel Forward Policy mandating that deployed vehicles must refuel with aviation fuel JP-8. There is a known torque and fuel economy penalty associated with the operation of a diesel engine with JP-8 fuel, due to its lower density and viscosity. On the other hand, a few experimental studies have suggested that kerosene-based fuels have the potential for lowering exhaust emissions, especially particulate matter, compared to diesel fuel #2 (DF-2). However, studies so far have typically focused on quantifying the effects of simply replacing the regular DF-2 with JP-8, rather than fully investigating the reasons behind the observed differences. This research evaluates the effect of using JP-8 fuel in a heavy-duty diesel engine on fuel injection, combustion, performance, and emissions, and subsequently utilizes the obtained insight to propose changes to the engine calibration to mitigate the impact of the trade-offs. Experiments were carried out on a Detroit Diesel Corporation (DDC) S60 engine outfitted with exhaust gas recirculation (EGR). The results indicate that torque and fuel economy of diesel fuel can be matched, without smoke or NO x penalty, by increasing the duration of injection to compensate for the lower fuel density. The lower cetane number of JP-8 caused an increased ignition delay and increased premixed combustion, and their cumulative effect led to relatively unchanged combustion phasing. Under almost all conditions, JP-8 led to lower NO x and particulate matter (PM) emissions and shifted the NO x-PM trade-off favourably.

Combustion, Performance and Exhaust Emissions of the Diesel Engine Operating on Jet Fuel

“…Analysis of the needle-valve lifts and in-cylinder heat release characteristics shows that the replacement of the diesel fuel by commercial aviation fuel F-34 leads to the autoignition delay longer over all loads and speeds than that of the normal diesel. Such autoignition delay behaviour matches pretty well with the test results of commercial JP-8 aviation fuel, which is comparable with military F-34 fuel, on various types of DI diesel engines obtained by other researchers [3,5,6].…”

“…The lower cetane number of JP-8 cause an increased ignition delay and increased premixed combustion, and their cumulative effect led to relatively unchanged combustion phasing. Under almost all conditions, JP-8 led to lower NO x and PM emissions and shifted the NO x -PM trade-off favourably [6].…”

Combustion phenomenon, performance and emissions of a diesel engine with aviation turbine JP-8 fuel and rapeseed biodiesel blends

“…and a wider spray angle improved atomisation and the air and jet fuel vapours mixing rate [14,15]. The tests conducted on a Detroit Diesel Corporation (DDC) military, heavy-duty S60 engine outfitted with EGR showed that under almost all conditions, the NO x emissions and particle matters decrease and the NO x -PM trade-off shifts favourably when running with JP-8 fuel [16]. This happened because of a higher mixing rate of the air and jet fuel vapours and smoother temperature variation in the combustion chamber.…”

Innovative approach to air management strategy for turbocharged diesel aircraft engines

“…According to the results presented in reference [8], it is possible to match the performance of the engine with a D2 fuel to that of a JP-8 fuel by engine calibration. Moreover, according to reference [8], brake-specific fuel consumption (BSFC) values of both fuels are very close when the performance is matched. It can therefore be concluded that results for diesel fuel D2 is representative for kerosene-based fuels and other heavy fuels.…”