The laminar combustion characteristics of the liquefied petroleum gas-hydrogen-air mixture were studied in a constant volume combustion chamber under the excess air ratios from 0.6 to 1.4

the hydrogen volume fractions from 0 to 60% and the initial pressures from 0.081 to 0.124 MPa. Influences of the excess air ratio

the hydrogen fraction and the initial pressure on the combustion characteristics such as the normalized mass burning rate and the combustion duration were discussed. The results show that the mass burning rate and the peak value of the rate of pressure rise reach their maximum values at a specific excess air ratio from 0.8 to 1.0. With the decrease of the initial pressure

the normalized mass burning rate increases while the combustion duration decreases

especially for the rich and/or the lean mixtures. The rate of pressure rise and the normalized mass burning rate increase while the combustion duration decreases remarkably with the increase of hydrogen fraction. The short combustion duration over a wide range of the excess air ratio occurs with the increase the hydrogen fraction.