An assessment of the biodiesel low-temperature combustion engine under transient cycles using single-cylinder engine experiment and cycle simulation

An operational strategy was developed to implement LTC (low-temperature combustion) with 50% biodiesel blended fuel (B50), named B-LTC, and evaluated under a combination of a single-cylinder engine experiment and a cycle simulation. The fuel consumption, regulated emissions, and exhaust gas temperature maps were constructed from experiments in a single-cylinder diesel engine at the speed range between 1000 and 1600 rev/min. A dataset of pumping and friction of a 6-cylinder diesel engine was employed to construct a 6000-cm3 B-LTC engine from the SCRE (single-cylinder research engine) experimental results. The engine maps of the virtual 6-cylinder B-LTC engine were then input into a zero-dimensional (0-D) model for the transient-cycle simulation. The cycle simulation was performed under the two representative transient cycles, namely the WHTC (worldwide harmonized transient cycle) and the NRTC (non-road transient cycle). The WHTC simulation estimated the engine-out CSNOx (cycle-specific NOx) of 0.94 g/kWh, which was lowered to 0.30 g/kWh by the SCR (selective catalytic reduction), while CSFC (cycle-specific fuel consumption) and cycle-specific soot (CSsoot) were 310 g/kWh and 0.01 g/kWh, respectively. The NRTC simulation results also showed that the engine-out CSsoot emission was 0.01 g/kWh. The urea-dosing SCR model reduced CSNOx from 0.99 g/kWh to 0.25 g/kWh. The CSFC was 274 g/kWh in the NRTC simulation.