A variable valve timing apparatus for an internal combustion engine, including: an actuator that activates a variable valve timing mechanism; a detection unit that detects a driving position of the actuator; a control unit that drive-controls the actuator, and when a predetermined execution condition is established, executes one of a first initialization process and a second initialization process that match the driving position of the actuator detected by the detection unit with an actual driving position of the actuator; and an abnormality determination unit that determines whether or not an abnormality is present in the driving position detected by the detection unit and stores an abnormality history after determining that an abnormality is present. The control unit executes the first initialization process when the abnormality history is stored and the second initialization process when the abnormality history is not stored.

Disclosed herein is a method for diagnosing and controlling a two-step exhaust variable valve lift (VVL) system, including: a controlling device acquiring an operation state signal of a vehicle; when the vehicle is in the over-run state, the controlling device outputting a mode conversion signal of the two-step exhaust VVL system; an air mass sensor measuring an air mass entering an engine, and the controlling device comparing a predetermined prediction value of the air mass with the measured air mass; when a difference of the compared air mass corresponds to a predetermined mode conversion comparing amount, the controlling device determining that a mode conversion of the two-step exhaust VVL system is completed; and when the difference of the compared air mass does not correspond to the mode conversion comparing amount, the controlling device determining that the two-step exhaust VVL system is faulty and outputting a result thereof.

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.

Methods and systems are provided for conducting a canister purging operation and for rationalizing components of a vehicle evaporative emission system. In one example, after completion of a refueling event, a first fuel vapor canister purge operation is conducted to desorb hydrocarbon light ends from the fuel vapor canister, and subsequently the canister is heated to desorb hydrocarbon heavy ends from the canister, which are routed to a hydrocarbon sensor to rationalize the hydrocarbon sensor, before being purged to engine intake in a second purging operation. In this way, a fuel vapor storage canister may be thoroughly cleaned of hydrocarbon light ends and hydrocarbon heavy ends, while additionally indicating whether a canister heating element, and a hydrocarbon sensor positioned between the canister and atmosphere, 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.

A control device for an internal combustion engine includes a fuel tank, a high pressure fuel passage, a pressure increasing device, a switching device, a low pressure fuel passage, a temperature sensor, a fuel injector, and an electronic control unit. The electronic control unit is configured to determine that there is an abnormality in the switching device when a temperature measured by the temperature sensor when the pressure increase signal is output is not higher than a temperature measured by the temperature sensor when the pressure increase signal is not output. The electronic control unit is configured to stop fuel pressure increase by the pressure increasing device by stopping an output of the pressure increase signal regardless of the engine operation state when the electronic control unit determines that there is the abnormality in the switching device.

Methods and systems for diagnosing operation of a compression ratio adjusting mechanism are described. In one example, an output of a pressure sensor is sampled and an assessment of the engine's present compression ratio is made after adjusting sampling of the output. Engine operation may be adjusted responsive to whether or not degradation of the compression ratio adjusting mechanism is indicated.

Provided is a method for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation. Pressurized fuel is intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion. An oxidation catalyst is arranged downstream said cylinders. The method comprises: determining the pressure in the fuel accumulator tank and whether said pressure is decreasing; and determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel. The method further comprises the steps of: determining whether the temperature associated with the oxidation catalyst is above a certain level and/or determining whether the air/fuel ratio is below a certain level and/or determining whether an amount of particulate matter is above a certain level; and confirming an unintended fuelling based on the determined conditions.

The present invention relates to a fuel system for a combustion engine, the fuel system comprising a low-pressure circuit comprising at least one fuel tank, at least one low-pressure fuel pump, a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump, and a high-pressure circuit comprising a high-pressure fuel pump. The high-pressure fuel pump comprises means to suck fuel from the low-pressure circuit and in case of failure in the at least one low-pressure fuel pump, to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump and optionally, at least one of the first or second fuel filters, via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank.

Some examples described herein may involve determining an advance timing window between the valve opening or closing and a designated time that the valve is scheduled to open or close; determining a closing velocity of the valve; monitoring an engine speed of the engine; determining valve lash information based on the advance timing window, the closing velocity, and the engine speed, wherein the valve lash information identifies a magnitude of the valve lash or whether the magnitude of the valve lash associated with the valve satisfies a threshold; and performing an action based on the valve lash information.