Various methods and arrangements for improving fuel economy and noise, vibration, and harshness (NVH) in a skip fire controlled engine are described. An engine controller dynamically selects a gas spring type for a skipped firing opportunity. Determination of the skip/fire pattern and gas spring type may be made on a firing opportunity by firing opportunity basis.

Methods and systems are provided for reducing air flow to an emission control device during a fuel shut-off event. In one example, a method may include adjusting a timing of an exhaust valve and a timing of an intake valve of a cylinder during the fuel shut-off event using a common actuator. The actuator may include a planetary gear system configured to rotate a first portion of a camshaft in a first direction and a second portion of the camshaft in a second, opposite direction.

A controller may identify an indication to initiate an engine braking procedure associated with an engine of a machine. The controller may obtain, based on identifying the indication to initiate the engine braking procedure, information relating to a requested amount of engine braking power of the engine. The controller may cause one or more components of a variable geometry turbocharger (VGT) of the engine to adjust, and a throttle valve of the engine to adjust, based on the information relating to the requested amount of engine braking power of the engine.

Methods and systems are provided for estimating a PCV flow to an engine based on the output of an exhaust gas oxygen sensor. During DFSO conditions, a reference voltage of the sensor is modulated initially with an intake throttle open and then with the intake throttle closed. PCV flow leaking past the piston valves in an aging engine, as well as an ambient humidity estimate, are inferred based on the outputs of the sensor during the modulating with the intake throttle open and closed.

An internal combustion engine has a control device, an EGR valve that adjusts an EGR rate, a PCV valve that adjusts an opening degree of a first PCV passage that communicates an inside of a crankcase and a downstream side of a throttle valve. The control device operates the throttle valve in a closing direction in response to a deceleration request. The control device adjusts an opening degree of the PCV valve based on an immediately preceding EGR rate immediately before reception of the deceleration request.

Aspects of the present invention relate to a controller for controlling operation of an internal combustion engine, a control system, an internal combustion engine, a vehicle, a method and a non-transitory computer readable medium. The controller is configured to, during fuel cut, cause opening of an intake valve of a cylinder of the internal combustion engine to enable air having a mass to enter the cylinder. The mass is below a first range of masses which enable the internal combustion engine to provide combustion torque.

Set a lower limit for an engine revolution speed when an accelerator is off while a temperature of the gasoline particulate filter is equal to or lower than a predetermined first temperature or equal to or higher than a predetermined second temperature, the predetermined second temperature being higher than the predetermined first temperature, and continue the lower limit setting for the engine revolution speed until the accelerator becomes on when the temperature of the gasoline particulate filter increases over the predetermined first temperature from the predetermined first temperature or lower or decreases below the predetermined second temperature from the predetermined second temperature or higher after the lower limit for the engine revolution speed is set.

A variable valve operating system assembled in an engine includes a first rocker arm contacting with a valve, a second rocker arm no contacting with any valve, a lost motion spring bringing the second rocker arm into contact with a cam, and switching device for switching the first/second rocker arms to a coupled or uncoupled state. An operation control apparatus for the engine includes element for determining whether or not an engine speed is higher than a first speed at which supply of fuel is allowed to be temporarily stopped, and element for setting a requested quantity of increase/decrease in internal resistance of the engine. When the engine speed is higher than the first speed and an accelerator opening degree is 0%, the switching device switches the first/second rocker arms to the coupled or uncoupled state based on the requested quantity.

A controller and a method for a hybrid drive, which includes an internal combustion engine and an electrical machine are provided. The internal combustion engine includes adjustment devices that deactivate the intake and exhaust valve opening actuation. The controller is designed in such a way that, in the case of at least one specified condition (such as regeneration during unfired overrun or in the case of electric travel, in particular in the case of operation with high activation frequency of the internal combustion engine, e.g., in charge sustaining or HEV operation), the intake and exhaust valves are kept at least approximately (preferably completely) closed at least approximately simultaneously while the internal combustion engine is unfired. The internal combustion engine must be connected to the electrical machine. If there is a disconnect clutch, the disconnect clutch is brought into the closed state or remains closed.

Methods are provided for engines. In one example, method, at higher engine load, cool compressed air is drawn into an engine via an air intake passage, and at lower engine load, ambient air is drawn into the engine via a duct while retaining cooled compressed air in the air intake passage. The compressed air may be released from the air intake passage based on heat transferred to the compressed air during the lower engine load, in at least one example.