The invention relates to a maintenance system for a fuel injection system provided in an internal combustion engine, the fuel injection system defining a hydraulic circuit having a high-pressure pump, a solenoid valve, a pressure sensor, a metering solenoid valve, a common rail and injectors. The maintenance system includes a manual control unit connected to a hydraulic unit, the hydraulic unit being capable of being inserted into the hydraulic circuit of the fuel injection system and including a test solenoid valve and a test pressure sensor mounted in a body provided with an inlet mouth, an outlet mouth and a leakage mouth.

Methods and systems are provided for diagnostics of a cylinder valve actuation mechanism in a variable displacement engine (VDE). In one example, during an engine-off condition, the engine may be rotated unfueled, via a starter motor, and a reference exhaust air flow may be estimated. One or more deactivatable engine cylinders may then be deactivated and degradation of the cylinder valve actuation mechanism may be indicated based on a difference between the exhaust air flow following the cylinder deactivation and the reference exhaust air flow.

An EGR device is provided with: an EGR passage for allowing a portion of exhaust gas from an engine to flow to an intake passage; an EGR valve for adjusting an EGR flow rate through the EGR passage; a throttle valve provided in the intake passage; and an electronic control device which calculates a fully closed reference intake pressure based on an operating state of the engine during EGR valve fully-closing, and which diagnoses an abnormality due to valve-opening locking of the EGR valve based on the calculated fully closed reference intake pressure. The ECU determines a foreign matter biting abnormality of the EGR valve based on the intake pressure, and based on the result of adding the fully closed reference intake pressure, calculated according to the rotational speed and the load of the engine, to an intake-pressure increase allowance calculated according to the rotational speed.

A control device may be configured to control an aperture of a throttle valve. The control device may include a pressure detector configured to detect a pressure in an intake pipe of a throttle; a flow rate detector configured to detect an amount of air flowing in the intake pipe; a current value detector configured to detect a current value of a throttle motor operating the throttle valve; a torque estimator configured to estimate torque of an engine based on the detected current value; a first aperture estimator configured to estimate the aperture of the throttle valve based on the detected pressure; a second aperture estimator configured to estimate the aperture of the throttle valve based on the detected amount of air; and a third aperture estimator configured to estimate the aperture of the throttle valve based on the estimated torque and a revolution speed of the engine.

A controller for a hybrid vehicle controls an electric motor such that a motor torque is input to a crankshaft in order to compensate for a decrease in an engine torque when a cylinder deactivation control is executed, the decrease resulting from suspension of combustion in one or some of cylinders. The controller calculates an engine torque calculated value using an engine rotation speed, a motor rotation speed, and the motor torque. The controller diagnoses that the cylinder deactivation control is functioning normally when the engine torque calculated value is less than a torque determination value and diagnose that the cylinder deactivation control is not functioning normally when the engine torque calculated value is not less than the torque determination value during the execution of the cylinder deactivation control.

The present disclosure relates to a method and a system capable of determining the cause of misfire if the misfire occurs due to the mechanical failure of an injector. The present disclosure senses whether the misfire of an engine occurs, determines whether the mechanical failure occurs in an injector of a cylinder in which the misfire occurs, if the misfire of the engine is sensed, and determines that the misfire of the engine occurs due to the injector, and stores the failure content of the injector in a maintenance code, if it is determined that the mechanical failure occurs in the injector.

Methods and systems for unsticking a stuck gaspath actuator are disclosed. In one embodiment, an engine operating method includes adjusting exhaust valve timing of one or more cylinders of an engine in response to an indication that a gaspath actuator is stuck in position. In this way, pressure waves in an exhaust manifold and/or an intake manifold may be generated, which may act to unstick the gaspath actuator.

An EGR device for a vehicle includes a valve driver, a pressure comparison unit, a freeze determination unit, and an EGR controller. The valve driver drives an EGR valve to open, when fuel cut has been continued for a predetermined time in a state where an engine speed of a vehicle's engine is equal to or higher than a predetermined rotational speed. The pressure comparison unit compares a pre-driving pressure of an engine's intake pipe with a post-driving pressure of the intake pipe. The freeze determination unit sets a flag indicating that the EGR valve is frozen when a difference between the pre-driving pressure and the post-driving pressure is less than a predetermined value and an external temperature is less than a threshold. When the flag has been set, the EGR controller sets a control state of the EGR valve to a closed state and stops EGR control.

Methods and systems are provided for monitoring corking of a canister vent valve (CVS) in a fuel vapor line during diagnostics of an evaporative emissions control (EVAP) system of a vehicle. In one example, a method includes, after isolating the EVAP system from atmosphere, opening each bypass valve of one or more bypass valves of one or more fuel vapor canisters to couple the EVAP system to a fuel system of the vehicle, and opening a canister vent valve (CVS) responsive to an EVAP system pressure decreasing to a threshold EVAP system pressure.

An energization control unit is configured to perform a constant current control by repeatedly switching between an on-state and an off-state of at least one upstream switch provided in an energization path of a coil of a fuel injection valve to control opening of the fuel injection valve in a drive period in which the coil is energized to drive the fuel injection valve. A current detection unit is configured to detect a coil current flowing through the coil. A valve-opening detection unit is configured to detect valve-opening timing of the fuel injection valve based on a change in at least one frequency spectrum of the coil current in a constant current control period in which the constant current control is performed. A valve-opening correction unit is configured to correct valve opening of the fuel injection valve based on a detection result of the valve-opening detection unit.