A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

Methods and systems are provided for increasing EGR delivered to an engine. In one example, a method may include determining an EVO timing set point and an external EGR setpoint in parallel, based on an inverse model. The EVO timing may be adjusted based on a combination of the EVO timing setpoint and an EGR cylinder balancing feedback loop, thereby varying internal EGR to the engine to supplement external EGR.

Methods and systems are provided for catalyst control. In one example, a method may modulate a downstream catalyst by applying a square waveform to an outer feedback control loop. A fuel adjustment is performed in accordance with the square waveform to create an air-fuel ratio oscillation at an upstream catalyst brick and at a downstream catalyst brick.

Methods and systems are provided for an oxygen sensor heater. In one example, a method may include applying a less than maximum duty cycle of voltage to the oxygen sensor heater during an engine cold start (e.g., when a temperature of the oxygen sensor is less than its light-off temperature) and adjusting the applied duty cycle of voltage to maintain a constant amount of power. In this way, the oxygen sensor may be heated at a constant rate even as a resistance of the oxygen sensor heater increases, decreasing an amount of time before the oxygen sensor reaches its light-off temperature.

Methods and systems are provided for catalyst control. In one example, a method may modulate a downstream catalyst by applying a square waveform to an outer feedback control loop. A fuel adjustment is performed in accordance with the square waveform to create an air-fuel ratio oscillation at an upstream catalyst brick and at a downstream catalyst brick.

Systems and methods for determining fuel delay in a fuel injected engine with cylinders that may be deactivated are presented. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

Systems and methods for injecting fuel to an engine in response to a fuel injection delay are presented. The method includes determining fuel delay in a fuel injected engine with cylinders that may be deactivated. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via a weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

A canister purge control method for a vehicle can reduce the number of components of an active purge system provided in the vehicle. An active purge operation is performed using a pressure value measured by an intake pressure sensor, instead of a pressure value measured by a rear-end pressure sensor, after a purge control solenoid valve is fully opened.

A controller for an internal combustion engine includes processing circuitry. The processing circuitry performs a dither control process and a multi-injection process. Multiple injections in the multi-injection process includes a first injection and a second injection performed at a timing retarded from the first injection. The dither control process includes at least one of a process performed on a cylinder changed to a lean combustion cylinder so that a reduction amount of fuel injected through the first injection is greater than a reduction amount of fuel injected through the second injection and a process performed on a cylinder changed to a rich combustion cylinder so that an increase amount of fuel injected through the first injection is greater than an increase amount of fuel injected through the second injection.

In the disclosure, an F/B correction coefficient correcting a fuel injection amount so that a detected equivalence ratio detected by an LAF sensor becomes a target equivalence ratio is calculated by using a feedback control containing a predetermined gain, and a reference F/B correction coefficient is further set. By changing a valve overlap characteristic between an intake valve and an exhaust valve in a supercharging state, a scavenging control that scavenges a combustion chamber by blow-by of intake air is executed. During the scavenging control, when the F/B correction coefficient is changing relative to the reference F/B correction coefficient in a direction of further correcting the fuel injection amount to a rich side, the gain of the feedback control is reduced.