Engine operating method and engine system for improved load step acceptance

An engine system comprising:

• an engine having a plurality of combustion cylinders formed therein;
• a turbocharger including a turbine and a compressor;
• an intake system including an intake conduit extending between an air inlet and the compressor, and between the compressor and the plurality of combustion cylinders;
• an exhaust system having an exhaust conduit extending between the plurality of combustion cylinders and the turbine;
• a fuel system having a first fuel admission valve coupled with the intake conduit at an upstream delivery location, and a second fuel admission valve coupled with the intake conduit at a downstream delivery location;
• an insulator forming a heat exchange cavity in heat transference contact with the exhaust conduit between the plurality of combustion cylinders and the turbine;
• and
• a pump structured to feed a heat exchange fluid into the heat exchange cavity to displace an insulating fluid, for varying heat dissipation of a flow of exhaust from the engine to the turbine.

A method of accepting a load step in an engine comprising:

• receiving a load step request;
• increasing a fueling rate of the engine based on the load step request;
• boosting a pressure of intake air supplied to the engine with a compressor in a turbocharger based on the increasing of the fueling rate;
• operating the engine in a load step acceptance mode at least in part by limiting dissipation of heat energy of a flow of exhaust to a turbine of the turbocharger during the boosting of the pressure of intake air;
• and
• transitioning the engine to a steady state mode after satisfaction of the load step request at least in part by increasing dissipation of heat energy from the flow of exhaust to prevent overheating of the turbine.