Cross-port air flow that improves engine fuel economy and reduces pumping losses during part-throttle operation can be implemented in various types of internal combustion engine systems using ports that interconnect the intake ports of different cylinders, thus allowing different cylinders to share combustion air. Cross-port air flow is commenced during part-throttle engine operation to disrupt the primary combustion air flow from each throttle to its associated cylinder, which reduces charge density and engine power. The engine compensates for the reduced power by incrementally opening the throttles, thus increasing the primary combustion air flow, reducing pumping losses and improving fuel economy.

A control system for a fuel cutoff system of a motor vehicle includes a fuel cutoff module that generates a fuel cutoff signal for disabling a supply of fuel to an engine, in response to the fuel cutoff module detecting a deceleration fuel cutoff (DFCO) event. The control system further includes an oxygen storage module determining an amount of oxygen accumulated in a catalyst and comparing this amount to an oxygen storage capacity (OSC) of the catalyst, in response to the fuel cutoff module determining the DFCO event. The control system further includes an intake valve timing module generating a phasing signal to actuate a plurality of cam phasers to reduce a flow rate of oxygen to the catalyst, in response to the fuel cutoff module determining the DFCO event and the oxygen storage module determining that the amount of oxygen stored in the catalyst is less than the OSC.

Methods and systems are provided for an engine. A condition of the engine may be diagnosed based on information provided by signals from a generator operationally connected to the engine and/or other signals associated with the engine. Different types of degradation may be distinguished based on discerning characteristics within the information. Thus, a degraded engine component may be identified in a manner that reduces service induced delay.

A control arithmetic unit uses a control storage area to compute a target control amount for combustion of an internal combustion engine according to a user required torque. A monitoring arithmetic unit uses a monitoring storage area to perform computation and to monitor presence or absence of a torque anomaly state in which an estimated torque is deviated from an engine required torque by a predetermined amount or more. The monitoring arithmetic unit computes the estimated torque by using a blow through state amount. The blow through state amount is a quantity of intake air blowing through out of an exhaust port in an intake stroke of the internal combustion engine, a degree to which intake air blows through out of the exhaust port, or an in-cylinder air quantity which is a quantity of air filled into a combustion chamber of the internal combustion engine.

Various methods and systems are provided for correcting relative error between a gaseous fuel torque estimate and a liquid fuel torque estimate in a multi-fuel engine. A system (e.g., a system for an engine) may include a controller with computer readable instructions stored on non-transitory memory that when executed during operation of the engine cause the controller to: operate the engine at a first substitution ratio of gaseous fuel and liquid fuel; correct for relative error between a gaseous fuel to torque conversion factor and a liquid fuel to torque conversion factor; and upon correcting for the relative error, operate the engine at a second substitution ratio, higher than the first substitution ratio.

An intercooler for cooling air exiting a turbocharger for delivery to an internal combustion engine can include an inlet, an outlet, a condensate collection space and a filter. The inlet can be configured to be in fluid communication with the turbocharger. The outlet can be configured to be in fluid communication with the internal combustion engine. The condensate collection space can be located between the inlet and the outlet. The filter can be located between the condensate collection space and the outlet such that water vapor in the air that condenses in the intercooler flows through the filter and into the condensate collection space in a first direction and condensed water flowing from the condensate collection space toward the outlet passes through the filter in a second direction before exiting through the outlet, and the second direction is different from the first direction.

An intercooler for cooling air exiting a turbocharger for delivery to an internal combustion engine can include an inlet, an outlet, a condensate collection space and a filter. The inlet can be configured to be in fluid communication with the turbocharger. The outlet can be configured to be in fluid communication with the internal combustion engine. The condensate collection space can be located between the inlet and the outlet. The filter can be located between the condensate collection space and the outlet such that water vapor in the air that condenses in the intercooler flows through the filter and into the condensate collection space in a first direction and condensed water flowing from the condensate collection space toward the outlet passes through the filter in a second direction before exiting through the outlet, and the second direction is different from the first direction.

A system and method for monitoring the negative impact of a filtration system on the fuel economy of an internal combustion engine. A filter monitoring controller receives engine operating parameters of the internal combustion engine. The filter monitoring controller determines an amount of power generated by the internal combustion engine based at least in part on the engine operating parameters. The filter monitoring controller determines a filter hydraulic power consumption of a filtration system providing a fluid to the internal combustion engine. The filter monitoring controller determines a fuel economy impact of the filtration system on the internal combustion engine based at least in part on the filter hydraulic power consumption of the filtration system. The filter monitoring controller compares the fuel economy impact of the filtration system to a threshold fuel economy impact to determine whether a filter element of the filtration system requires servicing.

An engine friction monitor uses commanded torque and measured torque to provide a prognostic feature to identify failure modes of an engine that causes the engine from delivering the commanded torque.

Cross-port air flow that improves engine fuel economy and reduces pumping losses during part-throttle operation can be implemented in various types of internal combustion engine systems using ports that interconnect the intake ports of different cylinders, thus allowing different cylinders to share combustion air. Cross-port air flow is commenced during part-throttle engine operation to disrupt the primary combustion air flow from each throttle to its associated cylinder, which reduces charge density and engine power. The engine compensates for the reduced power by incrementally opening the throttles, thus increasing the primary combustion air flow, reducing pumping losses and improving fuel economy.