Motorization system including a Diesel engine and a catalyst

The system has an air circuit for driving the air to a diesel type engine (1), and a catalyst (3) receiving the exhaust gas coming from the engine through an exhaust manifold (16). A valve (22) is provided in the circuit for throttling the passage of air. A control unit (24) acts on the valve according to the temperature of the catalyst for increasing the temperature of the exhaust gas arriving at the catalyst. An independent claim is also included for a process of control of a motorization system.