Direct-injection spark-ignition engine with a turbo charging device

A direct-injection spark-ignition engine with a turbo-charging device, comprising:

• a fuel injector for directly injecting fuel into a combustion chamber;
• a piston for compressing the injected fuel;
• an ignition device for igniting the injected fuel;
• an exhaust-gas purification catalyst disposed downstream of a turbine of the turbo charging device in an exhaust-gas passage;
• a fuel injection controller for controlling the amount and the timing of the fuel injection by the fuel injector;
• an ignition controller for controlling the ignition timing by the ignition device;
• an intake-air controller disposed in an intake-air passage leading to an inlet of the combustion chamber for controlling the amount of intake-air introduced into the combustion chamber;
• and
• a required engine-output monitoring device for monitoring the required engine output, wherein said fuel injection controller causes the fuel injector to divide fuel injection into a leading fuel injection during a leading period of an intake stroke of the piston prior to the ignition timing, and a trailing fuel injection during a trailing period of an expansion stroke of the piston after the ignition timing, during a predetermined operating condition where the exhaust-gas purification catalyst is to be activated at low engine rotational speed and low engine load, and said fuel injection controller controls the fuel injector based on the required engine-output and said intake-air controller controls the amount of intake-air so that the excess air ratio λ in the combustion chamber is within the range from 2 to 3 when the fuel delivered by the leading fuel injection combusts, and the excess air ratio λ in the combustion chamber is within the range of about 1 to 2 when the fuel delivered by the trailing fuel injection combusts.

A direct-injection spark-ignition engine with a turbo-charging device, comprising:

• a fuel injector for directly injecting fuel into a combustion chamber;
• a piston for compressing the injected fuel;
• an ignition device for igniting the injected fuel;
• an exhaust-gas purification catalyst disposed downstream of a turbine of the turbo charging device in an exhaust-gas passage of the engine;
• a fuel injection controller for controlling the amount and the timing of fuel injection by said fuel injector;
• an ignition controller for controlling the ignition timing by said ignition device;
• and
• an intake-air controller for controlling the amount of intake-air introduced in the combustion chamber, wherein during an early stage, wherein said exhaust-gas purification catalyst is in an inactivated state, said ignition controller causes the ignition device to ignite at a timing after MBT by a predetermined period and said fuel injection controller causes the fuel injector to inject fuel during a latter half of the compression stroke and in a period prior to the period before the ignition timing so that an exhaust-gas air-fuel ratio is equal to or rich of the stoichiometric air-fuel ratio, and wherein during a late stage, where the exhaust-gas purification catalyst is in an inactivated state, said fuel injection controller causes the fuel injector to divide fuel injection into a leading fuel injection during a leading period of an intake stroke of the piston, prior to the ignition timing, and a trailing fuel injection during a trailing period of an expansion stroke of the piston, after the ignition timing, and said fuel injection controller controls the fuel injector and said intake-air controller controls the amount of intake-air, so that the exhaust-gas air-fuel ratio after the combustion of the fuel by the trailing fuel injection is lean of the stoichiometric air-fuel ratio.

A direct-injection spark-ignition engine with a turbo-charging device, comprising:

• a fuel injector for directly injecting fuel into a combustion chamber;
• a piston for compressing the injected fuel;
• an ignition device for igniting the injected fuel;
• an exhaust-gas purification catalyst disposed downstream of a turbine of the turbo charging device in an exhaust-gas passage of the engine;
• a fuel injection controller for controlling the amount and the timing of fuel injection by the fuel injector;
• an ignition controller for controlling the ignition timing of said ignition device;
• an intake-air controller disposed in an intake-air passage leading to an inlet of the combustion chamber for controlling the amount of intake-air introduced in the combustion chamber;
• and
• an engine-output monitoring device for monitoring the required engine output, wherein during an early stage of a condition where the exhaust-gas purification catalyst is in an inactivated state, said ignition controller causes the ignition device to ignite after MBT by a predetermined period and said fuel injection controller causes said fuel injector to inject fuel during a latter half of a compression stroke of the piston and in a period prior to the period before the ignition timing, so that the excess air ratio λ in the combustion chamber is equal to or smaller than 1, and during a late stage of a condition where the exhaust-gas purification catalyst is in an inactivated state, said fuel injection controller causes said fuel injector to divide fuel injection into a leading fuel injection during a leading period of an intake stroke of the piston, prior to the ignition timing, and a trailing fuel injection during a trailing period of an expansion stroke of the piston, after the ignition timing, and said fuel injection controller controls the fuel injector based on the required engine-output and said intake-air controller controls the amount of intake-air so that an excess air ratio λ in the combustion chamber is within the range of about 2 to 3 when the fuel injected during said leading fuel injection combusts, and the excess air ratio λ in the combustion chamber is within the range of about 1 to 2, when the fuel injected during said trailing fuel injection combusts.

direct-injection spark-ignition engine with a turbo-charging device, comprising:

• a fuel injector which directly injects fuel into a combustion chamber;
• a piston for compressing the injected fuel;
• an ignition device which ignites the injected fuel;
• an exhaust-gas purification catalyst disposed downstream of a turbine of said turbo charging device in an exhaust-gas passage of the engine;
• an ignition controller which controls the ignition timing by said ignition device;
• an intake-air controller which controls the amount of intake-air introduced into the combustion chamber;
• and
• a fuel injection controller which controls said fuel injector to perform divided injection of a leading fuel injection into a leading period prior to the ignition timing during an intake stroke of the piston, the amount of which causes an excess air ratio λ in the combustion chamber to be within the range of about 2 to 3 with the amount of intake-air controlled by said intake-air controller when the fuel by the leading fuel injection combusts, and a trailing fuel injection during a trailing period of an expansion stroke of the piston after the ignition timing, the amount of which causes the excess air ratio λ in the combustion chamber to be within the range of about 1 to 2, with the amount of intake-air controlled by said intake-air controller when the fuel injected during said trailing fuel injection combusts, during a predetermined operating condition where said exhaust-gas purification catalyst is to be activated at low engine rotational speed and low engine load.

A direct-injection spark-ignition engine with a turbo-charging device, comprising:

• a fuel injector which directly injects fuel into a combustion chamber;
• a piston for compressing the injected fuel;
• an ignition device which ignites the injected fuel;
• an exhaust-gas purification catalyst disposed downstream of a turbine of the turbo charging device in an exhaust-gas passage of the engine;
• an intake-air controller which controls the amount of intake-air introduced in the combustion chamber;
• an ignition controller which controls said ignition device to ignite at a timing after MBT by a predetermined period during an early stage of a condition where the exhaust-gas purification catalyst is in an inactivated state, and ignite at a timing prior to MBT during a late stage of a condition where said exhaust-gas purification catalyst is in an inactivated state;
• and
• a fuel injection controller which controls said fuel injector to perform fuel injection, the amount of which causes an exhaust air-fuel ratio to be rich of the stoichiometric air-fuel ratio with the amount of intake-air controlled by said intake-air controller in the early stage of the condition where said exhaust-gas purification catalyst is in an inactivated state, and to divide fuel injection into a leading fuel injection during a leading period of an intake stroke of the piston prior to the ignition timing, and a trailing fuel injection during a trailing period of an expansion stroke of the piston after the ignition timing, the amount of which causes an exhaust-gas air-fuel ratio after the combustion of the fuel by the trailing fuel injection to be lean of the stoichiometric air-fuel ratio with the amount of intake-air controlled by said intake-air controller during the late stage of the condition, where said exhaust-gas purification catalyst is in an inactivated state.