Abstract:
An object of the present invention is to provide a technology that enables better reduction of NOx stored in an NOx catalyst in an exhaust gas purification system for an internal combustion engine. According to the present invention, when NOx stored in an NOx catalyst is to be reduced, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to a target air-fuel ratio by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine. In doing so, if the temperature of the NOx catalyst is not lower than a specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to the target air-fuel ratio while bringing the combustion state into low temperature combustion (S104, S105). On the other hand, if the temperature of the NOx catalyst is lower than the specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to the target air-fuel ratio while decreasing the quantity of EGR gas in a cylinder so that the amount of generated smoke is kept within an allowable range (S107, S105).
Abstract:
A control device for a compression-ignited internal combustion engine includes a nozzle that includes plural injection holes arranged at intervals in the circumferential direction and that directly injects fuel to a combustion chamber, a piston that includes a cavity with an inner circumferential side surface to which a distance from the nozzle varies in the circumferential direction, a first injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the largest out of the plural injection holes, a second injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the smallest out of the plural injection holes, a detection unit that detects a heat release rate in the combustion chamber, and a control unit that determines which of the first and second injection holes is abnormal.
Abstract:
In an exhaust gas recirculation apparatus for an internal combustion engine (1), a technique is provided which suppresses a temperature fall of combustion chambers and hence resultant troubles even if an idle operation continuation time continues for a long period of time. The apparatus includes a turbocharger (15) having a turbine (5b) and a compressor (5a), a low pressure EGR passage (31), a high pressure EGR passage (41), a low pressure EGR valve (32) that is arranged on the low pressure EGR passage (31) for controlling an amount of low pressure EGR gas, a high pressure EGR valve (42) that is arranged on the high pressure EGR passage (41) for controlling an amount of high pressure EGR gas, an idle operation continuation time counting unit for counting an idle operation continuation time of the internal combustion engine (1), and a control unit that controls the low pressure EGR valve (32) to its closing side and the high pressure EGR valve (42) to its opening side when the idle operation continuation time calculated by the idle operation continuation time counting unit continues for a predetermined period of time T1 or more.
Abstract:
A control apparatus for an internal combustion engine (10) includes intake valve control means (50). The internal combustion engine (10) includes a variable intake valve operating mechanism (66) that changes a valve opening characteristic of an intake valve (64), and rich combustion is performed in the internal combustion engine (10) to control an exhaust gas purification catalyst (24) disposed in an exhaust passage (18). The intake valve control means (50) controls the valve opening characteristic of the intake valve (64) to increase a flow rate of intake air in an early stage of an intake stroke when the rich combustion is performed, as compared to when non-rich combustion is performed.
Abstract:
A compression ignition internal combustion engine includes: a cylinder block and a cylinder head; a piston including a cavity that defines a combustion chamber in cooperation with the cylinder block and the cylinder head; and a nozzle for injecting fuel into the combustion chamber, wherein the cavity includes: a raised portion raised toward the nozzle; a bottom surface formed around the raised portion; and a first surface and a second surface that are continuous to the bottom surface, a depth of the first surface becomes shallower toward a radially outer side of the piston, the first surface and the second surface are provided at different positions in a circumferential direction about a central axis of the piston, a distance from the nozzle to the first surface is greater than a distance from the nozzle to the second surface, and the nozzle respectively injects first and second fuel sprays toward the first surface and the second surface, and injects a third fuel spray between the first and second fuel sprays.
Abstract:
An exhaust gas recirculation system includes a high-pressure EGR unit (40); a low-pressure EGR unit (30); a high-pressure EGR valve (42); a low-pressure EGR valve (32); and an EGR control unit (20) that adjusts the opening amount of the high-pressure EGR valve (42) to a required value for achieving the target EGR rate based on the characteristics of the exhaust gas in the low-pressure EGR passage (31) before the operation mode is changed, and that maintains the required value during a period from when the operation mode is changed until when the low-pressure EGR gas is changed to the exhaust gas discharged from the internal combustion engine in the post-change operation mode.