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.

Methods and systems are provided for conducting vehicle fuel system and/or evaporative emissions system diagnostics, where the diagnostics rely on a positive pressure with respect to atmospheric pressure. In one example, a method comprises activating an electric compressor positioned in an intake of an engine configured to receive purge gasses from the evaporative emissions system under boosted engine operation and natural engine operation, to direct a positive pressure with respect to atmospheric pressure to the fuel system and/or evaporative emission system to conduct said diagnostic. In this way, diagnostics that rely on positive pressure with respect to atmospheric pressure may be conducted in vehicles with a dual-path purge system, without introduction of a pump in the evaporative emissions system.

A diagnostic device incorporates a processor and a memory and diagnoses a failure related to a fuel injection system for an engine whose air-fuel ratio of is feedback-controlled. The diagnostic device includes a calculation unit which calculates a corrected value of a fuel injection amount according to a difference between a target value and a measured value of the air-fuel ratio. The diagnostic device includes a setting unit which sets a mask period in which a failure diagnosis is suspended, according to the corrected value upon switchover of a fuel injection mode. The diagnostic device includes a diagnostic unit which does not carry out the diagnosis in the mask period and carries out the diagnosis outside the mask period.

Methods and systems are provided for indicating a presence or absence of degradation in a vehicle evaporative emissions system, where degradation includes a restriction in the evaporative emissions system and/or a source of undesired evaporative emissions. In one example, a method includes, under conditions where an engine is not combusting air and fuel, applying a pressure from the evaporative emissions system to an intake of the engine, and indicating an absence of degradation in the evaporative emissions system based on a test flow in the intake of the engine being within a predetermined threshold of a baseline flow obtained at an earlier time via applying the pressure. In this way, a presence or absence of degradation may be indicated without relying on engine operation.

A powertrain arrangement for use with additized Dimethyl Ether (DME) fuel, the additized DME comprising DME and a lubricity additive, is provided. The powertrain arrangement includes a powertrain comprising an engine adapted for use with the additized DME fuel, a fuel tank, a conductivity sensor in the fuel tank; the conductivity sensor being arranged to transmit a signal, corresponding to a conductivity of fuel in the fuel tank, a temperature sensor in the fuel tank, the temperature sensor being arranged to transmit a signal corresponding to a temperature of the fuel in the fuel tank, and a controller configured to receive and process the conductivity signal and the temperature signal and to send a control signal to control functioning of the powertrain in response to the conductivity signal and the temperature signal. A measuring apparatus and method are also provided.

When the vehicle is stopped and removal of deposits is not required, and forced charging of a power storage device is not being performed, the controller controls the fuel supply device so that a supply fuel pressure is at the first fuel pressure. When the vehicle is stopped and the removal of deposits is required, and the forced charging of the power storage device is being performed, the controller controls the fuel supply device so that the supply fuel pressure is at a second fuel pressure higher than the first fuel pressure. When the vehicle is stopped and the removal of deposits is required, and the forced charging of the power storage device is not being performed, the controller controls the fuel supply device so that the supply fuel pressure is at a third fuel pressure higher than the first fuel pressure and lower than the second fuel pressure.

Methods and systems are provided for indicating a presence or absence of degradation in a vehicle evaporative emissions system, where degradation includes a restriction in the evaporative emissions system and/or a source of undesired evaporative emissions. In one example, a method includes, under conditions where an engine is not combusting air and fuel, applying a pressure from the evaporative emissions system to an intake of the engine, and indicating an absence of degradation in the evaporative emissions system based on a test flow in the intake of the engine being within a predetermined threshold of a baseline flow obtained at an earlier time via applying the pressure. In this way, a presence or absence of degradation may be indicated without relying on engine operation.

An electrically driven solenoid coupled to a spring-operated valve, regulates pressure in an accumulator by opening when a predefined threshold pressure in a pressure accumulator is exceeded. The solenoid provides an assistive force to a spring-closed valve, reducing the amount of pressure required to open the valve responsive to the amount of current provided to the solenoid. The threshold pressure at which the valve opens is thus determined by the amount of current provided to the solenoid. Increasing the current decreases the threshold pressure; decreasing the current increases the threshold pressure.

A method and a device detect and characterize fuel leakage in an injection system of an internal combustion. The injection system has an injection device for injecting fuel into a combustion chamber of the internal combustion engine, a closable high-pressure branch for supplying the injection device with fuel placed under a first fuel pressure, and a closable low-pressure branch for feeding fuel placed under a second, lower fuel pressure from a fuel supply to the high-pressure branch. The high-pressure branch and the low-pressure branch are each closed, wherein in the high-branch branch and in the low-pressure branch an associated curve of fuel pressure over time is sensed at the same time during a measurement time period. On the basis of the sensed curve of fuel pressure of the high-pressure branch, it is checked whether fuel loss occurred in the closed-off high-pressure branch during the measurement time period. By way of the sensed curve of fuel pressure of the low-pressure branch, it is checked whether a flow of fuel into the closed-off low-pressure branch occurred during the measurement time period. If the existence of fuel loss was determined in the first checking step and additionally it was determined in the second checking step that no flow of fuel into the low-pressure branch occurred, a signal is output, which indicates fuel leakage from the high-pressure branch into the combustion chamber.

An example system includes a controller configured to: receive pressure information indicative of a pressure level of the pressurized fuel between an electro-mechanical valve and an engine; based on the pressure level being below a first threshold pressure, send a first signal to open the electro-mechanical valve; determine, based on the pressure information, that the pressure level is increasing upon sending the first signal; in response to the pressure level increasing, send a second signal to activate a pump; determine that the pressure level has increased to a second threshold pressure; and provide information indicating that the engine is ready for operation.