Methods and systems are provided for improving the performance of a variable displacement engine. Split injection and spark retard may be used in active cylinders during a VDE mode to heat an exhaust catalyst and extend the duration of VDE mode operation. Split injection and spark retard may also be used in reactivated cylinders at a time of cylinder reactivation to improve restart combustion stability.

A variety of methods and arrangements are described for operating an engine in a skip fire manner so that engine requirements, such as exhaust temperature, exhaust flow, torque and NVH, are met.

Provided is a forced-regeneration treatment method for an exhaust-gas aftertreatment device (DPF) and an associated engine-driven compressor. When the amount of particulate matter (PM) deposited in a filter element of a DPF reaches a predetermined amount and a forced-regeneration start command is input, a capacity controlling means of the engine-driven compressor is disabled to close an intake valve and to open the discharge side of a compressor main unit to atmosphere, thereby causing the compressor main unit to achieve a low-load state. The operation mode of the engine is switched to a predetermined forced-regeneration mode to operate the engine at a predetermined speed and to increase the temperature of the gas. The temperature inside the DPF is increased to reach a temperature at which an oxidative catalyst is activated and to a temperature lower than the self-combustion temperature of the PM, thereby forcibly burning the PM.

Methods and systems are provided for fuel post injection for diesel particulate filter (DPF) regeneration. In one example, a method may include, responsive to a request for generating exotherms in an exhaust system of an engine while combustion is discontinued in at least one cylinder of the engine, injecting fuel into a cylinder within a threshold crank angle range around top dead center (TDC) of a compression stroke of the cylinder and also within the threshold crank angle range around top dead center of an exhaust stroke of the cylinder, the threshold crank angle range extending from no more than 40 crank angle degrees before TDC to no more than 40 crank angle degrees after TDC. In this way, fuel post injections may be injected +/−40 crank angle degrees after TDC of the compression and exhaust strokes to increase exhaust temperature while avoiding wall wetting and oil-in-fuel dilution.

An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust system; and a regeneration treatment unit, which recovers an NOx purification capacity of the NOx reduction type catalyst, wherein the regeneration treatment unit includes: a target setting unit, which sets a target injection amount of at least one of a post injection and an exhaust pipe injection that is required for setting an excess-air-ratio of the exhaust gas to the target excess-air-ratio, based on a suction air amount of the internal combustion engine, the target excess-air-ratio, and a fuel injection amount of the internal combustion engine; and an injection controller, which controls an injection amount of at least one of the post injection and the exhaust pipe injection, based on the target injection amount input from the target setting unit.

A fuel injection control device of an engine is disclosed, that is provided with a fuel injection valve configured to inject a fuel according to a target pulse width into an intake passage, an intake flow rate detection unit arranged to detect a flow rate of an intake air supplied to the engine, an intake pressure detection unit arranged to detect an intake pressure in the intake passage, a fuel pressure detection unit arranged to detect a pressure of a fuel supplied to the fuel injection valve, and a pressure control unit configured to control the fuel pressure according to an engine operation state. The device is further provided with a request pulse width calculation unit configured to calculate a request pulse width on the basis of an intake flow rate detected by the intake flow rate detection unit, a fuel pressure detected by the fuel pressure detection unit, and a differential pressure between the fuel pressure and an intake pressure detected by the intake pressure detection unit, a post-correction request pulse width calculation unit configured to calculate a post-correction request pulse width through correcting the request pulse width according to the differential pressure, when injecting a fuel of which flow rate is lower than a predetermined flow rate; and a target pulse width setting unit configured to set the target pulse width on the basis of the post-correction request pulse width.

An object is to provide a DPF regeneration control device whereby it is possible to prevent clogging of a DOC more efficiently than conventional techniques, and to recover the DOC securely from a clogging condition even if the DOC is actually clogged. A DPF regeneration control device (10) includes: a DPF temperature-increase unit (10A) including a first temperature-increase unit (12) configured to heat a DPF (37) to a predetermined temperature, and a second temperature-increase unit (14) configured to heat the DPF to a temperature higher than the predetermined temperature in cooperation with the first temperature-increase unit; a DOC clogging detection unit (10D) configured to detect that a DOC (35) is clogged if a clogging parameter detected during execution of the automatic regeneration exceeds a clogging threshold value determined in advance for a predetermined period, the clogging parameter being related to clogging of the DOC, and a DOC clogging countermeasure unit (10C) configured to stop the automatic regeneration and issue an alert to prompt execution of the manual regeneration, if the clogging of the DOC is detected.

There is provided a regeneration device for an exhaust-gas purifying device 40 which is provided in an exhaust system of an internal combustion engine, the regeneration device including: an injector for injecting fuel into a cylinder; a glow plug which is energized to be heated to thereby increase a temperature inside the cylinder; and a regeneration control unit for executing a regenerating operation for restoring a purification capacity of the exhaust-gas purifying device by controlling the injection of fuel of the injector and the energization of the glow plug , wherein during the regenerating operation, the regeneration control unit controls the injection of fuel of the injector by a multi-stage injection including at least a post injection and energizes the glow plug at a predetermined duty ratio to burn, within the cylinder, fuel supplied by the post injection.

An exhaust gas purification system comprises an exhaust gas purification device which is arranged in an exhaust gas route of an engine, renewing devices for burning and removing a particulate matter within the exhaust gas purification device, renewal advance notifying means which is actuated in the case that a clogged state of the exhaust gas purification device becomes equal to or more than a prescribed level, and renewal informing means which informs of a fact that the renewing devices are under operation. The renewal advance notifying means is actuated before actuating the renewing devices.

An exhaust gas purification control device includes an engine, an actuator using the engine as a driving source, an operation unit used by an operator to operate the actuator or the engine, an operation detector detecting whether or not the operation unit is being operated, a purification device for capturing soot in exhaust gas of the engine, an accumulation amount detector detecting an accumulation amount of the soot captured by the purification device, a regeneration unit for performing an regenerating operation of regenerating the purification device by burning the soot captured by the purification device, and a controller controlling the regenerating operation. The controller switches a control from a control of prioritizing an operation by the operation unit to a control of prioritizing the regenerating operation in a stepwise manner as the accumulation amount of the soot detected by the accumulation amount detector increases.