An apparatus for adjusting power and noise characteristics of an internal combustion engine comprises a wall configured to define an engine cylinder that includes a bore and a compression relief passage. A compression relief valve is configured to selectively adjust fluid flow capacity of the compression relief passage. A manifold is configured to be in fluid communication with the exhaust passage and includes an exhaust bypass valve to permit exhaust to at least partially bypass a noise suppressor. Operational characteristics of the engine can be adjusted along a range that extends from a first set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully open position to a second set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully closed position.

Additional approaches for the reduction of particulate emissions in gasoline engines using optimized port+direct injection are described. These embodiments include control of the amount of directly injected fuel so as to avoid a threshold increase in particulates due to piston wetting and reduction of cold start emissions by use of air preheating using variable valve timing.

Additional approaches for the reduction of particulate emissions in gasoline engines using optimized port+direct injection are described. These embodiments include control of the amount of directly injected fuel so as to avoid a threshold increase in particulates due to piston wetting and reduction of cold start emissions by use of air preheating using variable valve timing.

The control device 80 for an internal combustion engine comprises a control unit 81 configured to perform control processing comprising, during warming-up of the internal combustion engine 10, advancing valve opening timing and valve closing timing of an exhaust valve 18 of the internal combustion engine 10 with respect to respective preset reference values thereof, and retarding fuel injection timing of the internal combustion engine 10 with respect to a preset reference value thereof. According to this control device 80 for the internal combustion engine, warming-up of the internal combustion engine 10 can be effectively facilitated, and the warming-up time of the internal combustion engine 10 can thus be shortened.

An engine control device controls a cylinder direct fuel injection type spark ignition engine provided with a fuel injection valve configured to directly inject fuel into a cylinder and an ignition plug configured to perform spark ignition for a gas mixture inside the cylinder. The engine control device executes a catalyst warm-up operation for retarding an ignition timing, during a compression stroke of the fuel injection timing, in a case where it is necessary to warm up an exhaust gas purifying catalyst inserted into an exhaust passage. In addition, the engine control device increases a valve overlap period as a piston crown surface temperature increases during execution of the catalyst warm-up operation.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, one or more valves of a set of first exhaust valves coupled to the second exhaust manifold may be deactivated in response to select engine operating conditions, while maintaining active all valves of a set of second exhaust valves coupled to the first exhaust manifold. The select engine operating conditions may include one or more of a deceleration fuel shut-off condition, a part throttle condition, and a cold start condition.

An exhaust heat recovery system. The system includes a heat exchanger configured to transfer heat from engine exhaust to a heat transfer fluid. A reservoir is in fluid communication with the heat exchanger. A pump is configured to pump the heat transfer fluid out of the heat exchanger and into the reservoir, and in doing so displace air out of the reservoir to the heat exchanger, when temperature of the heat transfer fluid exceeds a predetermined temperature.

A method for operating a combustion engine after a cold start, the combustion engine including a supercharger device, a plurality of combustion chambers, a fuel-injection device injecting into each of the combustion chambers, and a gas-exchange valve control device that controls gas-exchange valves in a variable manner. A rich fuel-air mixture is generated in the combustion chambers, and the combustion-chamber charges are ignited in a retarded manner. Following the cold start, the combustion engine is operated with first valve overlaps that are greater than in a warm combustion engine. A first exhaust valve of a first combustion chamber is initially closed at such a late point that its opening duration overlaps with the opening duration of a second exhaust valve of a second combustion chamber that directly follows the first combustion chamber in the ignition sequence and that discharges into the same exhaust manifold as the first combustion chamber.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, one or more valves of a set of first exhaust valves coupled to the second exhaust manifold may be deactivated in response to select engine operating conditions, while maintaining active all valves of a set of second exhaust valves coupled to the first exhaust manifold. The select engine operating conditions may include one or more of a deceleration fuel shut-off condition, a part throttle condition, and a cold start condition.

The control apparatus of the engine according to the invention controls an opening timing of each of intake valves to a predetermined opening timing after an intake top dead center when the engine operation starts. The apparatus prohibits the opening timing from advancing from the predetermined opening timing until a total intake air amount correlation value reaches a threshold after the engine operation starts. The apparatus permits the opening timing to advance from the predetermined opening timing after the total intake air amount correlation value reaches the threshold after the engine operation starts.