Method and system for diagnosing unintended fuelling from fuel injectors of an engine

A system for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation, where a pump unit is arranged to provide pressurized fuel to a fuel accumulator tank based on a fuel demand, pressurized fuel being intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion, and an oxidation catalyst is arranged downstream said cylinders, the system comprising:

• means for determining the pressure in the fuel accumulator tank and whether said pressure is decreasing;
• means for determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel;
• means for determining whether the temperature associated with the oxidation catalyst is above a certain level and/or means for determining whether the air/fuel ratio is below a certain level, and/or means for determining whether an amount of particulate matter is above a certain level;
• and
• means for confirming an unintended fuelling if the pressure in the accumulator tank is decreasing and/or the amount of fuel provided by the pump unit exceeds the demanded amount of fuel by a certain amount, and said temperature is above said certain level and/or said air/fuel ratio is below said certain level and/or said particulate matter is above said certain level.

A vehicle comprising a system for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation, where a pump unit is arranged to provide pressurized fuel to a fuel accumulator tank based on a fuel demand, pressurized fuel being intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion, and an oxidation catalyst is arranged downstream said cylinders, the system comprising:

• means for determining the pressure in the fuel accumulator tank and whether said pressure is decreasing;
• means for determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel;
• means for determining whether the temperature associated with the oxidation catalyst is above a certain level and/or means for determining whether the air/fuel ratio is below a certain level, and/or means for determining whether an amount of particulate matter is above a certain level;
• and
• means for confirming an unintended fuelling if the pressure in the accumulator tank is decreasing and/or the amount of fuel provided by the pump unit exceeds the demanded amount of fuel by a certain amount, and said temperature is above said certain level and/or said air/fuel ratio is below said certain level and/or said particulate matter is above said certain level.

A computer program product stored on a non-transitory computer-readable medium, said computer program product for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation, where a pump unit is arranged to provide pressurized fuel to a fuel accumulator tank based on a fuel demand, pressurized fuel being intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion, and an oxidation catalyst is arranged downstream said cylinders, said computer program product comprising computer instructions to cause one or more electronic control units or computers to perform the following operations:

• determining a pressure in the fuel accumulator tank and whether said pressure is decreasing;
• determining whether an actual amount of fuel provided by the pump unit exceeds a demanded amount of fuel;
• determining whether a temperature associated with the oxidation catalyst is above a certain level and/or determining whether a 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, if the pressure in the accumulator tank is decreasing and/or the amount of fuel provided by the pump unit exceeds the demanded amount of fuel by a certain amount, and said temperature is above said certain level and/or said air/fuel ratio is below said certain level and/or said particulate matter is above said certain level.