When imbalance diagnosis is not executed, target fuel pressure is set based on a rotation speed and volumetric efficiency of an engine, and when the imbalance diagnosis is executed, fuel pressure smaller than the target fuel pressure settable when the imbalance diagnosis is not executed is set as the target fuel pressure, and a high-pressure fuel pump that supplies fuel to a delivery pipe connected to the in-cylinder injection valve, is driven and controlled such that detected fuel pressure becomes the target fuel pressure. With this, it is possible to execute the imbalance diagnosis with higher accuracy.

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.

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.

Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

A method for the injector-specific diagnosis of a fuel injection device of an internal combustion engine, including the following steps: detecting a pressure progression in an individual accumulator of an injector in a time-resolved manner; evaluating the detected pressure progression; determining if there is a fault state of the injection device in the region of the injector on the basis of the detected and evaluated pressure progression; and identifying the fault state on the basis of the detected and evaluated pressure progression.

A system and method for measuring fuel pressure decreases in a fuel accumulator caused by a fuel injector of an internal combustion engine is provided. The system includes the ability to stop a fuel flow to a fuel accumulator of the engine. Pressure signals are transmitted to a control system of the engine until the fuel pressure in the fuel accumulator drops by a predetermined amount, at which time fuel flow is re-enabled. The pressure signals are then analyzed to determine the amount or quantity of fuel delivered by each fuel injector. The system and method maintain engine and emissions performance by limiting the amount of fuel pressure decrease in the fuel accumulator.

An MBT ignition time and a knock ignition time are acquired from an engine rotation speed and engine load, and an ignition time on a delay angle side, out of these ignition times, is set as the most advance angle ignition time. An ignition time on the delay angle side only by the KCS learning value with respect to the most advance angle ignition time is set as a required ignition time, and when an actual ignition time set by a knock control system exceeds a predetermined amount and is positioned on the delay angle side with respect to the required ignition time, it is determined that abnormality occurs in an oil jet. Fail-safe processing to the effect that the opening degrees of a throttle valve are corrected to a closed side is executed in response to the abnormality determination.

The present invention relates to a control device (26) for a turbocharger (17) for supplying compressed intake air to an internal combustion engine (1). The control device includes: a storage part (27) configured to pre-store a map (33); a detection part (28) configured to a characteristic parameter; a calculation part (29) configured to obtain an efficiency of the turbocharger on the basis of the detected characteristic parameter; a determination part (30) configured to determine presence of deterioration of the turbocharger by comparing the detected characteristic parameter and the obtained efficiency with the map (33); and an informing part (31) configured to inform a user of a maintenance request.

Systems and methods for determining the presence or absence of deposits that may accumulate within a compressor recirculation valve positioned in parallel with a turbocharger compressor are presented. The systems and methods adjust actuators to maintain engine operation such that it may be more difficult for a driver to become aware that a compressor recirculation valve diagnostic is being executed.

A method of calculating a nitrogen oxide (NOx) mass reduced from a lean NOx trap (LNT) during regeneration includes calculating a C3H6 mass flow used to reduce the NOx among a C3H6 mass flow flowing into the LNT of an exhaust purification device, calculating a NH3 mass flow used to reduce the NOx among a NH3 mass flow flowing into the LNT, calculating a reduced NOx mass flow based on the C3H6 mass flow used to reduce the NOx and the NH3 mass flow used to reduce the NOx, and calculating the reduced NOx mass by integrating the reduced NOx mass flow over a regeneration period.