The effect of different fuel injection strategies on the combustion and emissions of a free-piston linear engine was researched

and diesel fuel injection patterns suitable for the engine were explored. A three dimensional moving mesh model was established based on the AVL FIRE platform

and the accuracy of the simulation model was validated by the experimental in-cylinder pressure under a rectangle-shaped injection strategy. The engine combustion and emissions under four different injection strategies(normal triangle-shaped

isosceles triangle-shaped

rectangle-shaped and trapezoid-shaped) were simulated. The results indicated that the mixing rate in cylinder was the greatest when adopting the rectangle-shaped injection strategy before the top dead center(TDC)

and the mixture homogeneity was better when employing the isosceles triangle-shaped injection strategy after TDC. The peak pressure in cylinder was the greatest and nearest to TDC when adopting the isosceles triangle-shaped injection strategy

with which the indicated thermal efficiency was the highest

reaching 0.371. Besides

the NO mass fraction under the isosceles triangle-shaped injection strategy was the largest while the soot emission was the least among the four injection strategies.