The disclosure concerns an internal combustion engine comprising an exhaust camshaft, an intake camshaft, a turbocharger, and a control system. The turbocharger comprises a compressor. A timing of the exhaust camshaft and a timing of the intake camshaft are controllable by the control system, which is configured to: store a compressor map related to the compressor, store a reference area within the compressor map, and determine at least two parameters. In response to the at least two parameters indicating that a current operational point of the compressor is outside the reference area, the control system changes the timing of the exhaust camshaft to advance closing of the exhaust valve, and the timing of the intake camshaft to delay opening of the intake valve.

A combustion system is applied to an engine. The combustion system includes an injection device that injects a fuel into a combustion chamber, a spark plug that ignites fuel in the combustion chamber, and a control device that controls the injection device and the spark plug. The control device includes a first control unit that executes predetermined first control. In the first control, control is performed such that, a total injection amount corresponding to all the fuel injected by the injection device in one combustion cycle of the engine is injected within a first period corresponding to a period from valve close timing which brings an intake valve into a closed state until a first half of a compression stroke of the engine ends.

Methods and systems for heating an emission control device are provided. In one example, a method for a vehicle comprises during an engine cold start, heating an emission control device of the engine using a dual heat exchanger to heat secondary air and cool exhaust gas, and further heat secondary air with an electric heater. The method further comprises directing the heated secondary air to each exhaust runner of the engine via individual air injectors to mix with exhaust gas. In this way, an improved mixture of air and exhaust reduces catalyst light-off time and increases conversion efficiency, thereby reducing hydrocarbon emissions during engine cold start.

Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

An overhead cam engine system comprises a rotating overhead exhaust cam rail comprising a plurality of exhaust lobes. A first switching roller finger follower actuates a first exhaust valve, and is configured to switch between a first lift profile and a second lift profile. A second switching roller finger follower is coupled to actuate a second exhaust valve, and is configured to switch between a third lift profile and a fourth lift profile. The third and fourth lift profile are different than the first and second lift profile. An actuation assembly is connected to switch the first switching roller finger follower and the second switching roller finger follower to select between at least three exhaust lift modes to open and close the first exhaust valve and the second exhaust valve using combinations of the first, second, third and fourth lift profiles.

A variety of methods and arrangements for reducing noise, vibration and harshness (NVH) in a skip fire engine control system are described. In one aspect, a firing sequence is used to operate the engine in a skip fire manner. A smoothing torque is determined that is applied to a powertrain by an energy storage/release device. The smoothing torque is arranged to at least partially cancel out variation in torque generated by the skip fire firing sequence. Various methods, powertrain controllers, arrangements and computer software related to the above operations are also described.

A method for diagnosing a part of a powertrain system is provided. The powertrain system comprising an internal combustion engine system having an internal combustion engine provided with a plurality of cylinders, each cylinder being provided with an air inlet valve and an exhaust gas valve, the method comprising the steps of operating any one of the inlet valve and the exhaust valve for any one of the cylinders to adjust the frequency and/or duration of air pulses during different load conditions of the internal combustion engine; determining an operational behaviour of the part of the powertrain system in response to the adjusted frequency and/or duration of the air pulses; and comparing the determined operational behaviour of the part of the powertrain system with an expected behaviour of the part of the powertrain system.

Methods and systems are described for enhanced engine friction generation. The enhanced engine friction generation improves the effectiveness of vehicle braking in deceleration fuel cut-off driving conditions by using engine vacuum and backpressure to temporarily increase engine pumping losses, thereby increasing powertrain drag and increasing deceleration torque to the wheels. The engine vacuum and backpressure may be created by changing the duration of the intake and/or exhaust valves. The system includes a processor and a non-transitory computer-readable storage medium storing instructions that, when executed by the processor, cause the processor to perform operations comprising adjusting an intake valve time duration or an exhaust valve time duration to increase engine friction to enhance mechanical friction on a drivetrain of a vehicle.

If an engine coolant temperature is equal to or lower than a first low-temperature determination value and a battery temperature is equal to or lower than a second low-temperature determination value when a request to start up an engine is made, the advancement driving of a variable valve operating mechanism is first started. Then, when an advancement amount of the variable valve operating mechanism later becomes equal to or larger than a prescribed startup start determination value, is started.

A continuously variable valve duration (CVVD) system includes an electronic control unit (ECU) configured to output a command for adjusting an actuator and a controller configured to determine a operation range of a control shaft of the actuator and adjust the control shaft in the determined operation range based on the command of the ECU. The controller positions the control shaft at a predetermined target phase and determines a control state of each target phase based on a target phase value transmitted from the actuator when the control shaft is positioned at the target phase.