Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.

Kazutoshi Nomura

Satoshi Yamada

Akihiro Yuuki

Daisuke Takemoto

Shunya Sasaki

Tomohide Yamada

Kazuki Nishizawa

Mizuki Kanai

Daisuke Sato

Kenji Hiraoka

Ryuji Kita

A regeneration control apparatus for controlling, in an exhaust gas treatment apparatus of a diesel engine including a diesel oxidation catalyst (DOC) disposed in an exhaust passage of an internal combustion engine and a diesel particulate filter (DPF) disposed downstream of the DOC, execution of forced regeneration to remove an exhaust particulate matter (PM) which accumulates on the DPF through a temperature increase of the DPF, includes: a late-post injection amount determination part which determines a late-post injection amount. The late-post injection amount determination part is configured to determine an upper limit value of the late-post injection amount on the basis of an air excess ratio of exhaust gas flowing into the DOC obtained on the basis of a temperature index of the DOC.

Regeneration control apparatus

A precombustion chamber gas engine includes a main-chamber forming portion forming a main combustion chamber, a precombustion-chamber forming portion forming a precombustion chamber communicating with the main combustion chamber via a plurality of nozzle holes, and an ignition device disposed in the precombustion chamber and having an ignition portion spaced from a main chamber central axis of the main combustion chamber at a predetermined distance. In a plan view, the precombustion chamber has a near-ignition region including the ignition portion and a far-ignition region opposite to the near-ignition region separated by a borderline passing through a precombustion chamber central axis of the precombustion chamber and perpendicular to a straight line passing through the precombustion chamber central axis and the ignition portion. The distance between the precombustion chamber central axis and a precombustion-chamber-side opening end, connected to the precombustion chamber, of a specific far nozzle hole which is at least one nozzle hole in the far-ignition region is shorter or longer than the distance between the precombustion chamber central axis and a precombustion-chamber-side opening end of a specific near nozzle hole which is at least one nozzle hole in the near-ignition region.

Precombustion chamber gas engine

A control device is configured to direct an opening degree of a throttle valve disposed in an intake passage or an exhaust passage of an engine including a DOC disposed in the exhaust passage and a DPF disposed downstream of the DOC in the exhaust passage. The control device includes: a hysteresis occurring condition determination unit configured to determine whether a hysteresis occurring condition (predetermined time elapses after instructed opening degree of throttle valve becomes equal to or smaller than predetermined opening degree and/or predetermined time elapses after engine output becomes equal to or smaller than predetermined output) is met; and a hysteresis elimination execution unit configured to cause, if it is determined that the hysteresis occurring condition is met, the throttle valve to execute hysteresis elimination that involves temporarily increasing the opening degree of the throttle valve from the instructed opening degree and then returning it to the instructed opening degree.

Control device, exhaust gas purification system, and control method

A precombustion chamber gas engine includes a main-chamber forming portion forming a main combustion chamber, a precombustion-chamber forming portion forming a precombustion chamber communicating with the main combustion chamber via nozzle holes, and an ignition device disposed in the precombustion chamber and having an ignition portion spaced from the main chamber central axis at a predetermined distance. In a plan view, the precombustion chamber has a near-ignition region including the ignition portion and a far-ignition region opposite to the near-ignition region separated by a borderline passing through the precombustion chamber central axis and perpendicular to a straight line passing through the precombustion chamber central axis and the ignition portion. The cross-sectional area of a specific near nozzle hole which is at least one nozzle hole in the near-ignition region is smaller than the cross-sectional area of a specific far nozzle hole which is at least one nozzle hole in the far-ignition region.

Particular embodiments may provide a piston for a prechamber-type gas engine and a prechamber-type gas engine taking into consideration the shape of the piston top surface portion so that the region where flame propagation due to torch jet is delayed, a piston for a prechamber-type gas engine where torch jet formed by combustion a prechamber fuel in a precombustion chamber is injected to a main combustion chamber through a plurality of injection holes, may include a piston top surface portion comprising a land portion formed in a first region extending between axis line directions of adjacent injection holes, and the first region is positioned at a higher position than a second region extending across the axis line direction. The land portion may be formed on a cavity formed in the piston top surface portion. A plurality of land portions are provided corresponding to the plurality of injection holes, and the plurality of land portions are provided so as to be offset toward a same direction from a middle position between axis line directions of adjacent injection holes.

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Tokyo, Japan

Kazutoshi Nomura