This engine system is provided with a throttle device, an EGR valve, and an ECU. The ECU diagnoses an abnormality of the EGR valve on the basis of an operating state during an engine deceleration, and diagnoses combustion deterioration of an engine on the basis of a crank angle speed change during the engine deceleration (not during a fuel cut-off). The ECU executes an engine stall avoidance control with the throttle device when it is determined there is an abnormality in the EGR valve, makes a final determination that the EGR valve has an abnormality and continues the engine stall avoidance control when it is determined thereafter that there is combustion deterioration, and makes a final determination that the EGR valve is normal and cancels the engine stall avoidance control when it is determined that there is no combustion deterioration.

A control apparatus for an internal combustion engine includes an electronic control unit configured to i) perform a fuel introduction process, ii) calculate a total injection amount in the fuel introduction process, and control each of fuel injection valves based on a required injection amount per cylinder when the fuel introduction process is performed, and iii) perform a cylinder deactivation process for stopping fuel from being injected for one or some of cylinders, and controlling each of the fuel injection valves such that an amount of the fuel obtained by dividing the total injection amount is injected for a cylinder or cylinders other than the one or some of the cylinders for which the fuel is stopped from being injected, when the fuel introduction process is performed.

Systems and methods for reducing noise and vibration that may be associated with engine braking are presented. In one example, intake and exhaust valve timings are adjusted to reduce engine noise and vibration at lower engine braking request levels. The engine intake and exhaust valve timings increase compression engine braking and decrease engine expansion braking for higher engine braking request levels.

Methods and systems are provided for protecting an exhaust catalyst from degradation during a DFSO event. Exit from DFSO due to pedal input received from an operator with a jittery foot is averted by filtering the pedal input differently when operating in a DFSO mode as compared to when operating out of the DFSO mode. Exit from DFSO is confirmed after receiving a higher than threshold pedal position input for a sustained period of time, or when an integrated fuel injection amount exceeds a threshold amount.

An internal combustion engine includes a cylinder and a valve assembly configured to activate and deactivate the at least one cylinder. The valve assembly includes an intake valve configured to control air flow into the at least one cylinder. A controller outputs a first control signal to the valve assembly to deactivate the at least one cylinder in response to detecting a deceleration event. The controller also outputs a second control signal to command the valve assembly to delay opening the intake valve from a closed position after re-activating the cylinder so that the torque output produced in response to re-activating the cylinder is reduced.

A vehicle control apparatus includes input-side and output-side rotating elements, a fuel injection controller, and an ignition timing controller. The ignition timing controller controls ignition timing of an engine to first timing on the condition that the engine is controlled from a fuel cut state to a fuel injection state, and afterwards, changes the ignition timing to second timing on advance side of the first timing. The ignition timing controller changes the ignition timing toward the second timing at a first change rate until a rotational acceleration rate of the output-side rotating element reaches a threshold. After the rotational acceleration rate of the output-side rotating element reaches the threshold, the ignition timing controller changes the ignition timing toward the second timing at a second change rate greater than the first change rate.

Methods and apparatus for conducting engine related diagnostics during cylinder cutoff (DCCO) operation of an engine are described. In one aspect, changes in the amount of oxygen in the exhaust system are monitored while the engine is operating in the DCCO mode. Changes in the oxygen level are then analyzed to determine various faults. Some of the faults that can be detected using this approach include cylinder deactivation faults and exhaust system leak faults. In another aspect, the rate of change of manifold pressure within the air intake manifold is monitored while operating the engine in a DCCO mode with the throttle closed. A fault indicative of potential air leakage into the air intake manifold is indicated when it is determined that the rate of change of the manifold pressure exceeds a designated threshold.

A straddled vehicle has a plurality of modes for engine brake controlling. The straddle vehicle includes a mode setter that selectively sets one of at least a normal mode and a first reduced mode that are included in the plurality of modes. An engine controller controls an electronic throttle valve and a fuel injector so that a torque of an internal combustion engine is equal to a target torque. When the torque of the internal combustion engine is less than zero while in the first reduced mode, an engine brake controller corrects the target torque by adding a first additive torque to the target torque. The first additive torque is set so as to be smaller as an amount of operation of an accelerator grip becomes larger so that an opening of the electronic throttle valve increases as the amount of operation of the accelerator grip increases.

This engine system is provided with: an engine; an intake passage; an exhaust passage; an electronic throttle device; an EGR device including an EGR valve; a fresh-air flow device including a fresh-air inflow valve; and an ECU. The ECU, in order to throttle intake air to the engine during deceleration of the engine, causes the electronic throttle device to be closed from an open valve state to a predetermined deceleration opening while causing the EGR valve to become closed to shut off introduction of EGR gas into the intake passage, and, in order to introduce fresh air into the intake passage (intake manifold) downstream of the electronic throttle device, causes the fresh-air inflow valve to become opened from the closed valve state at a timing delayed by a predetermined period from the timing of closing the electronic throttle device.

A vehicle includes an engine including an injector of cylinder injection type and a forced induction device, a second motor generator that generates electric power with an output torque of the engine, and an ECU that controls the engine and the second motor generator. When an amount of intake air and a fuel pressure of the engine decrease in boosting of suctioned air by the forced induction device, the ECU reduces a decrease in the amount of intake air during a period in which an injection amount is equal to a minimum injection amount, and when an excessive torque is generated in the output torque of the engine along with reducing a decrease in the amount of intake air, the ECU absorbs the excessive torque by a power generation operation of the second motor generator.