Abstract: An apparatus to produce a low oxygen containing gas in which exhaust gases from an engine are cooled by passing them through a manifold cooler. Harmful gases are removed by passing the exhaust gases through a catalytic converter for removal of NOX. Air in injected and the exhaust gas passed through a further catalytic converter for removal of CO. The exhaust gases are then cooled by passing them through an air to gas heat exchanger, and a series of water-cooled heat exchangers which are water-cooled and the resulting condensate removed by condensate drain. The water coolant is supplied by a closed circuit radiator system. The exhaust gases are then passed through a condensate screen and two filter beds for removal of moisture which may be regenerated by passing warm air derived from the air to gas heat exchanger through them when not in use. The operation of the system may be regulated by a fuel management system which includes an oxygen sensor.