Abstract: A two-stroke internal combustion engine 7 is provided. The engine 7 has a first piston 12 with a head 16 and a second piston 28 with a head 30 which faces the first piston 12. First and second pistons 12, 28 have valved exhaust lines 20 intersecting with the piston heads 16, 30. A sleeve 32 encircles the first piston 12. The sleeve 32 has a closed end 36 forming a first intake space 40. A second sleeve 44 encircles the second piston 28 and has a closed end 50 forming a second intake space 54. Check valves 56 are provided for allowing flow of air into the intake spaces 40, 54. A cylinder 60 is slidably mounted on the pistons 12, 28 for reciprocal movement thereon. The cylinder 60 is H-shaped having an internal pressure boundary 64 forming separate combustion chambers 70, 72 with the pistons 12, 28. The cylinder 60 has ends 76, 86 sealed with the pistons 12, 28 and the sleeves 32, 44 forming a variable volume induction/compression area in the intake spaces 40, 54.