A system and method for improving the functioning of a turbocharged diesel engine equipped with a cylinder deactivation system includes detecting when the turbocharged diesel engine is at risk of compressor surge, and then delaying the implementation of the cylinder deactivation. The delay may be a set period of time, or it may be determined by performing a set of instructions effective for estimating changes in intake manifold pressures over time if cylinders are deactivated, and then comparing the intake manifold pressure estimates to acceptable intake manifold pressure information. A formula for performing the required estimates is provided.

An engine cooling system may include a main intake line for supplying external air to an intake manifold attached to an engine including a cylinder block and a cylinder head, a supplementary intake line branched from one side of the main intake line and joined to the other side of the main intake line, an intake route control valve in the main intake line, a main exhaust line for flowing exhaust gas from an exhaust manifold, an exhaust route control valve in the main exhaust line, a turbocharger, an intercooler mounted to the supplementary intake line on a downstream side of the turbocharger, an EGR cooler branched from the exhaust manifold for recirculating the exhaust gas and provided in an EGR line connected to the main intake line; and a cooling line for flowing a coolant supplied from a water pump to cool the EGR cooler, the exhaust route control valve and/or the turbine housing of the turbocharger.

Starting an internal combustion engine may be difficult as a consequence of the operating conditions of the engine. Even after the engine has started, it may take a long period of time for the engine to reach operating temperatures. In the present disclosure, when engine start difficulty is expected, before starting the engine a forced induction compressor arranged with the engine may be turned on to increase the engine intake air pressure before the engine is started.

Methods and systems are provided for increasing engine power via partial engine enrichment and exhaust gas recirculation. In one example, a method may include enriching a first set of engine cylinders and enleaning a second, remaining set of the engine cylinders, exhaust gas from the first set and the second set producing a stoichiometric mixture at a downstream emission control device, and providing exhaust gas recirculation (EGR) to an intake passage of the engine from the first set of cylinders and not from the second set. In this way, cooling effects from the partial enrichment and the EGR enable engine air flow, and thus engine power, to be increased while an efficiency of the emission control device is maintained, thereby decreasing vehicle emissions.

Methods and systems are provided for increasing engine power via partial engine enrichment and exhaust gas recirculation. In one example, a method may include enriching a first set of engine cylinders and enleaning a second, remaining set of the engine cylinders, exhaust gas from the first set and the second set producing a stoichiometric mixture at a downstream emission control device, and providing exhaust gas recirculation (EGR) to an intake passage of the engine from the first set of cylinders and not from the second set. In this way, cooling effects from the partial enrichment and the EGR enable engine air flow, and thus engine power, to be increased while an efficiency of the emission control device is maintained, thereby decreasing vehicle emissions.

Embodiments for operating an engine having parallel turbochargers and two fluidically coupleable, separated intake manifolds is provided. In one example, a method includes responsive to a first condition, operating a first cylinder group of an engine, deactivating a second cylinder group of the engine, and blocking fluidic communication between a first intake manifold coupled to the first cylinder group and a second intake manifold coupled to the second cylinder group, and responsive to a second condition, activating the second cylinder group and establishing fluidic communication between the first and second intake manifolds.

An internal combustion engine (20) has two exhaust valves (24, 25) for each combustion chamber, to permit separation of blow-down and expulsion phases of an exhaust stroke. The separate exhaust streams are directed to different geometries of an exhaust turbocharger (30), so as to make best use thereof. Variable exhaust valve timing, and bypass passage for the exhaust streams are disclosed.

An internal combustion engine (20) has two exhaust valves (24, 25) for each combustion chamber, to permit separation of blow-down and expulsion phases of an exhaust stroke. The separate exhaust streams are directed to different geometries of an exhaust turbocharger (30), so as to make best use thereof. Variable exhaust valve timing, and bypass passage for the exhaust streams are disclosed.

Methods and systems of controlling a dual fuel engine with at least two banks of cylinders are provided. The method may include sensing at least one of temperatures of exhaust from the at least two banks and a pressure of an intake manifold of the at least two banks, and adjusting at least one of a gas flow, a charge flow, or an air flow to one of the at least two banks to balance one of exhaust temperatures of the at least two banks and intake manifold pressures of the at least two banks.

Methods and systems of controlling a dual fuel engine with at least two banks of cylinders are provided. The method may include sensing at least one of temperatures of exhaust from the at least two banks and a pressure of an intake manifold of the at least two banks, and adjusting at least one of a gas flow, a charge flow, or an air flow to one of the at least two banks to balance one of exhaust temperatures of the at least two banks and intake manifold pressures of the at least two banks.