Effect of premixing ratio, injection timing and compression ratio on nano particle emissions from dual fuel non-road compression ignition engine fueled with gasoline/methanol (port injection) and diesel (direct injection)

•Effect of premixing ratio, injection timing & compression ratio on soot particles is investigated.•Study conducted using gasoline and methanol premixing in a stationary diesel engine.•Total particle number concentration increases with increase in fuel premixing ratio.•Increase in premixing ratio increases the nucleation mode particle numbers.•Methanol-diesel dual fuel operation has a higher particle number as compared to gasoline. In present study, the effect of fuel premixing ratio, direct fuel injection timings and engine compression ratio on the soot particle emissions in nano-size range from a non-road compression ignition engine is investigated. Experiments are conducted on modified dual fuel single cylinder engine at 1500rpm. To run the engine in dual fuel mode, port fuel injection (PFI) system is installed by modifying intake manifold of the engine and developing a PFI controller. Experiments are conducted for various fuel premixing ratio of gasoline/methanol-diesel at different engine load, diesel fuel injection timing and compression ratios. Differential mobility spectrometer based particle sizer is used for investigation of the soot particle number-size distribution, surface area-size distribution, particle mass-size distribution and total particle number concentration from the engine exhaust at various test conditions. Results revealed that total particle number concentration is higher at full engine load and increases with fuel premixing ratio (especially in case of methanol-diesel dual fuel operation). Additionally, the peak particle number and mass concentration reduces with an increase in compression ratio of the engine.