Tornatore, C., Marchitto, L., Valentino, G., Iannuzzi, S. et al., "Spectroscopic Investigation of Post-Injection Strategy Impact on Fuel Vapor within the Exhaust Line of a Light Duty Diesel Engine Supplied with Diesel/Butanol and Gasoline Blends," SAE Technical Paper 2013-24-0066, 2013, doi:10.4271/2013-24-0066.
In this paper, a high temporal resolution optical technique, based on the multi-wavelength UV-visible-near IR extinction spectroscopy, was applied at the exhaust of an automotive diesel engine to investigate the post-injection strategy impact on the fuel vapor.Experimental investigations were carried out using three fuels: commercial diesel (B5), a blend of 80% diesel with 20% by vol. of gasoline (G20) and a blend of 80% diesel with 20% by vol. of n-butanol (BU20). Experiments were performed at the engine speed of 2500rpm and 0.8MPa of brake mean effective pressure exploring two post-injection timings and two EGR rates.The optical diagnostic allowed evaluating, during the post-injection activation, the evolution of the fuel vapor in the engine exhaust line. The investigation was focused on the impact of post-injection strategy and fuel properties on the aptitude to produce hydrocarbon rich gaseous exhaust for the regeneration of diesel particulate trap (DPF).The main results showed that advanced start of post-injection produced UV optical signal with a slightly lower intensity due to a tiny energy thermal activity that reduced the fuel vapor amount in the exhaust. BU20 and G20 blends induced a higher concentration of fuel vapor within the exhaust manifold and consequently a lower tendency to lubrication oil dilution.