Methods and systems are provided for diagnosing whether active engine mounts configured to isolate engine vibration from a cabin and chassis of a vehicle are functioning as desired. In one example, a method includes indicating degradation of an active engine mount by inducing degraded combustion events in a preselected engine cylinder, and operating the active engine mount in multiple modes, the indication responsive to an amount of vehicle chassis vibration during each of the modes. By monitoring chassis vibrations as a function of induced degraded combustion events, and further responsive to the active engine mounts being controlled to the multiple modes, it may be indicated as to whether the active engine mounts are functioning as desired.

An abnormality diagnosis system of an internal combustion engine that is installed on a vehicle and includes an actuator includes an electronic control unit. The electronic control unit receives vehicle outside information concerning a period of time for which the vehicle speed is less than a predetermined value, and determines whether the period for which the vehicle speed is less than the predetermined value is expected to be equal to or longer than a length of time required for an abnormality diagnosis of an abnormality diagnosis target device. The electronic control unit activates the actuator and starts the abnormality diagnosis as the vehicle speed becomes lower than the predetermined value, when it determines that the period for which the vehicle speed is lower than the predetermined value is expected to be equal to or longer than the time required for the abnormality diagnosis of the target device.

An abnormality detector of a turbocharged engine includes: a compressor including a plurality of blades that are detected portions; and a detecting portion configured to electrically detect the plurality of blades. Each time the blades are detected a predetermined number of times, one pulse having a pulse width corresponding to a measurement time required to detect the blades is output, and a turbo revolution is calculated from the pulse width of the output pulse. When it is judged that a rotation change of the rotating body which change is calculated based on a pulse width of a first pulse and a pulse width of a second pulse output after the first pulse exceeds a predetermined rate in a region where the rotating body exceeds a predetermined revolution, it is determined that an abnormality of the blade or an electromagnetic noise abnormality of the detecting portion occurs.

Systems and methods for operating an engine in response to a condition of an engine air intake throttle being degraded are presented. In one example, the engine air intake throttle is held closed while a position of a fuel vapor storage canister vent valve is adjusted to control air flow into the engine based on a position of an accelerator pedal. In this way, the engine air amount may be adjusted to provide additional torque from an engine while a throttle is degraded.

Methods and systems for an engine are provided for monitoring cylinder valve deactivation of an engine. One example method includes, responsive to a request to diagnose a cylinder valve actuator of an engine during a non-fueling condition of the engine, commanding an EGR valve open and determining a first exhaust gas flow, and deactivating one or more cylinder valves and indicating cylinder valve actuator degradation when a second exhaust gas flow is not less than a threshold relative to the first exhaust gas flow.

On-board diagnostic monitoring of a two-stroke cycle, opposed-piston engine includes diagnostic monitoring of an air handling system equipped with a supercharger to determine whether the supercharger is functioning properly.

Systems and methods are provided for providing redundant pulse-width modulation (PWM) throttle control. The system includes a manual throttle controller configured to generate a manual PWM throttle control signal, and an automated throttle control system. The automated throttle control system includes a plurality of automated throttle controllers, each of which being configured to independently control a throttle of a vehicle, and each including a processor configured to generate and output an automated PWM throttle control signal, a first double pole double throw (DPDT) relay that, when engaged, is configured to receive and output the manual PWM throttle control signal, and a second DPDT relay, configured to receive and output the automated PWM throttle control signal to an engine, when the second DPDT relay is engaged; and receive and output the manual PWM throttle control signal to the engine, when the DPDT relay is disengaged.

An EGR apparatus includes an EGR passage to allow part of exhaust gas discharged from an engine to an exhaust passage to flow as EGR gas into an intake passage; an EGR valve to regulate an EGR flow rate in the EGR passage; various sensors for detecting an engine running state; and an ECU to control the EGR valve based on the detected running state to diagnose abnormality in the EGR valve. The ECU calculates a reference intake pressure according the detected engine rotation speed and load by reference to a reference intake pressure map showing a relationship of the reference intake pressure to engine rotation speed, and engine load, and determine whether or not the EGR valve has abnormality in opening/closing by comparing the reference intake pressure with the detected intake pressure.

A throttle control system includes a throttle device and a controller that controls the throttle device. The controller executes a driving process of driving the electric motor such that a target angular position of the specific gear continues to increase beyond or decrease below the initial position. The controller executes a determination process of determining that wear has occurred in the gear mechanism based on that a non-rotation time in which the angular position detected by the rotation sensor does not change during execution of the drive process being greater than or equal to a predetermined specified time.

Systems and methods for diagnosing and operating an engine with a fuel pump that supplies fuel to a fuel injector that may be temporarily deactivated are described. In one example, injection of fuel may commence in response to a level of lubrication of a fuel pump. The system and methods may extend fuel pump life in systems where fuel injection may be deactivated.