<p>The internal-combustion engine has an exhaust-driven turbocharger and also a propellant gas generator (17) in the form of a small gas turbine with compressor (18), combustion chamber (19), compressor-driving turbine (20) and governor (21). The gas produced by the generator is delivered to the turbine portion of the turbocharger (17) in addition to the exhaust from the engine (11). The gas turbine governor can be regulated by the operating parameters of the engine e.g. speed, charge air pressure and/or governor rack setting. There can be an ejector-type mixing chamber (22) in the engine exhaust (14).</p>
