Methods and systems are provided for reducing engine stall incidence during canister purging. A fuel vapor canister is purged at a higher purge ramp rate to an engine with one or more cylinders selectively deactivated. In response to an indication of potential or partial engine stall, the deactivated cylinders are reactivated and the canister purge ramp rate is lowered.

The disclosed embodiments relate to a device for operating a tank ventilation system of an internal combustion engine. This device has a fuel tank, an activated carbon filter for collecting and buffering fuel vapors escaping from the fuel tank, a purge air pump and a control unit. The outlet of the purge air pump is connected to the intake tract of the internal combustion engine via a first tank venting valve and connected to the exhaust tract of the internal combustion engine via a second tank venting valve.

This exhaust purification system includes: a pump disposed in an exhaust-side purge passage to supply air or purge gas purged from a canister to a catalyst; a three-way valve disposed upstream of the pump in the exhaust-side purge passage and configured to switch the exhaust-side purge passage between a communicating state allowing the pump to communicate with the canister and an atmosphere open state allowing the pump to communicate with the atmosphere; a flow control valve disposed downstream of the pump and configured to control a flow rate of air to be supplied to the catalyst; and a controller configured to, when a request to regenerate the catalyst occurs, control a purge valve, the pump, the three-way valve, and the flow control valve to supply, to the catalyst, purge gas purged from the canister and air by a necessary amount to burn particulates trapped in the catalyst.

Methods and systems are provided for reducing or avoiding engine hesitation and/or stall during engine idle conditions. In one example, a method may include inferring an engine idle condition, and in response, controlling a speed of an engine to a compensated engine idle speed that is a function of an extent to which a canister purge valve that regulates an amount of fluid flow to the engine from a fuel system and/or an evaporative emissions system, is degraded. In this way, an amount of fuel utilized to compensate for the degraded canister purge valve may be proportionate to the extent to which the canister purge valve is degraded.

Methods and systems are provided for reducing or avoiding engine hesitation and/or stall during engine idle conditions. In one example, a method may include inferring an engine idle condition, and in response, controlling a speed of an engine to a compensated engine idle speed that is a function of an extent to which a canister purge valve that regulates an amount of fluid flow to the engine from a fuel system and/or an evaporative emissions system, is degraded. In this way, an amount of fuel utilized to compensate for the degraded canister purge valve may be proportionate to the extent to which the canister purge valve is degraded.

An intake and exhaust system for preventing generation of condensed water may include: an exhaust gas recirculation (EGR) system circulating some of combustion gas from an exhaust pipe to an intake pipe; an active purging system compressing and supplying evaporation gas generated from a fuel tank to the intake pipe; and a controller to control the EGR system and the active purging system. In particular, the controller calculates a saturated water vapor pressure based on temperature at a position between the EGR system and the intake pipe, and calculates a saturated water vapor pressure based on temperature of the intake pipe and then compares one of the two saturated water vapor pressures with a water vapor pressure of intake air so as to reduce an EGR rate of the EGR system or a purging rate of the active purging system based on the comparison result.

The disclosed embodiments relate to a device for operating a tank ventilation system of an internal combustion engine. This device has a fuel tank, an activated carbon filter for collecting and buffering fuel vapors escaping from the fuel tank, a purge air pump and a control unit. The outlet of the purge air pump is connected to the intake tract of the internal combustion engine via a first tank venting valve and connected to the exhaust tract of the internal combustion engine via a second tank venting valve.

Systems and methods for detecting a clogged intake air filter in a turbocharged engine system are provided. In one example a method for an engine coupled to an air filter and to a fuel tank includes indicating air filter clogging responsive to a measured fuel tank pressure during boosted engine operation. In this way, clogging of the air filter may be determined using existing engine system components.

An internal combustion engine includes combustion chambers, each having a controllable intake valve controlling an intake port, a controllable exhaust valve controlling an exhaust port, a piston, and a fuel injector. An intake manifold is connected to the intake port of each chamber. In catalytic converter warm-up mode, each chamber is driven in four-stroke operation including a 720 crank angle degrees cycle, and opens the intake port, starting to open in 90-180 CAD, and fully closes the intake port in 180-270 CAD, opens the exhaust port during the power stroke, starting in 405-495 CAD, opens the intake port during the exhaust stroke, starting in 610-690 CAD, and fully closes the exhaust port during the exhaust stroke in 630-710 CAD. Exhaust gas is forced into the intake manifold by the piston, mixing fuel and exhaust in the intake manifold, and fully closes the intake port in 700 to 720+20 CAD.

A controller for an internal combustion engine includes processing circuitry that performs a dither control process on condition that a temperature increase request of a catalyst is made. The processing circuitry operates fuel injection valves so that during the dither control process, one or more cylinders are lean combustion cylinders in a first period and another one or more cylinders are rich combustion cylinders and so that the average value of an exhaust gas-fuel ratio is a target air-fuel ratio in a second period including the first period. The dither control process is restricted in a manner that, on condition that the rich process is performed, the degree of richening of the richest exhaust gas-fuel ratio of exhaust gas-fuel ratios in the cylinders is reduced.