Compression-ignition internal combustion engine

A compression-ignition internal combustion engine, comprising a fuel injection valve for injecting fuel into a combustion chamber in a cylinder, the quantity and timing of the fuel injected through the fuel injection valve being controlled based on the engine operating conditions;

• wherein the compression-ignition internal combustion engine comprises as fuel injection control modes:
• a first injection mode in which pilot injection is carried out through the fuel injection valve with a fuel injection quantity and fuel injection timing such that the maximum rate of heat release induced by the pilot injection is 60 kJ/s or less, and main injection is then carried out through the fuel injection valve at a timing beyond the top dead center of compression;
• and
• a second injection mode in which pilot injection and main injection are carried out through the fuel injection valve on the basis of conditions that do not fulfill the conditions of the first injection mode;
• and
• the fuel injection control modes are switched such that fuel injection control is implemented in the second injection mode in the low-load areas of the engine operating conditions, and fuel injection control is implemented in the first injection mode in the high-load areas of the engine operating conditions.

A common-rail diesel engine, comprising a fuel injection valve for injecting fuel into a combustion chamber in a cylinder, a common rail for constantly supplying high-pressure fuel to the fuel injection valve, and control means for controlling the injector such that the quantity and timing of the fuel actually injected through the fuel injection valve are equivalent to the target fuel injection quantity and target fuel injection timing determined in advance based on the operating conditions of the engine;

• wherein the control means comprises, as fuel injection control modes:
• a first injection mode in which pilot injection is carried out through the fuel injection valve with a fuel injection quantity and fuel injection timing such that the maximum rate of heat release induced by the pilot injection is 60 kJ/s or less, and main injection is then carried out through the fuel injection valve at a timing beyond the top dead center of compression;
• and
• a second injection mode in which pilot injection and main injection are carried out through the fuel injection valve on the basis of conditions that do not fulfill the conditions of the first injection mode;
• and
• the fuel injection control modes are switched such that fuel injection control is implemented in the second injection mode in the low-load areas of the engine, and fuel injection control is implemented in the first injection mode in the high-load areas of the engine.

A method for controlling a compression-ignition internal combustion engine such that the quantity and timing of the fuel injected through the fuel injection valve into the combustion chamber in the cylinder is controlled based on the operating conditions of the engine;

• wherein, as fuel injection control modes, are set:
• a first injection mode in which pilot injection is carried out through the fuel injection valve with a fuel injection quantity and fuel injection timing such that the maximum rate of heat release induced by the pilot injection is 60 kJ/s or less, and main injection is then carried out through the fuel injection valve at a timing beyond the top dead center of compression;
• and
• a second injection mode in which pilot injection and main injection are carried out through the fuel injection valve on the basis of conditions that do not fulfill the conditions of the first injection mode;
• and
• the fuel injection control modes are switched such that fuel injection control is implemented in the second injection mode in the low-load areas of the engine, and fuel injection control is implemented in the first injection mode in the high-load areas of the engine.