In the present paper, results of an experimental investigation carried out in a modern Diesel engine running at different operating conditions and fuelled with commercial diesel and n-butanol-diesel blend are reported. The investigation was focused on the management of injection strategy and combustion timing (CA50) exploring the effect of intake oxygen concentration and boost pressure on engine out emissions.
The aim of the paper was to compare, with respect to commercial diesel, the effects of a fuel blend with a lower cetane number and higher volatility on performance and engine out emissions. Engine tests, with baseline diesel and a blend made by the baseline low sulphur diesel with 20% in volume of n-butanol (B20), were performed comparing engine out gaseous, smoke emissions and combustion efficiency. The investigation was performed on a turbocharged, water cooled, DI diesel engine, equipped with a common rail injection system. The engine equipment included an exhaust gas recirculation system, a piezo-quartz pressure transducer to detect the in-cylinder pressure signal and a current probe to acquire the energizing current to the injector. A parametric analysis was carried out exploring the effect of combustion phasing (CA50), O2 concentration at intake and injection strategy on combustion behavior and engine out emissions (NOx, HC, CO, Smoke) at medium load and engine speed (2500rpm@0.8MPa of BMEP).