Comparative study of engine control strategies for particulate emissions from direct injection light-duty vehicle fueled with gasoline and liquid phase liquefied petroleum gas (LPG)

► Nano-particle emission was investigated in the LPG-DI vehicle. ► Engine parameters were optimized to improve mixture preparation for cold start stage. ► Bi-modal particles were generated in the LPG-DI engine including sub-23 nm PM. ► PN concentrations were 1.6 × 1010 N/km for the FTP-75 and 3.4 × 109 N/km for the HWFET.