Abstract: Provided is an engine system including: a bypass pipe (bypass flow passage) connecting an upstream side and a downstream side of the turbine on an exhaust flow passage; a bypass valve configured to open and close the bypass flow passage; and a catalytic activation controller configured to control the bypass valve and a compression ratio of a combustion chamber.

Abstract: Provided is an engine, including: a cylinder including a cylinder liner; a piston provided inside the cylinder liner; a piston ring provided on the piston; a contact detector configured to detect a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring; and a compression ratio controller configured to control a top dead center position of the piston so that the piston ring at the top dead center position is located on a combustion chamber side with respect to the step when the contact is detected.

Abstract: Provided is an engine, including: a cylinder; a piston accommodated in the cylinder; a combustion chamber facing the piston; a sliding portion (large-diameter portion) configured to perform a stroke motion together with the piston; a hydraulic surface of the sliding portion facing a side opposite to the combustion chamber; a hydraulic chamber, which the hydraulic surface faces; and an auxiliary hydraulic chamber, which communicates with the hydraulic chamber, and has a volume changeable in accordance with a hydraulic pressure in the hydraulic chamber.

Abstract: A variable compression device includes a piston rod, a first fluid chamber configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto, a regulation member configured to regulate movement of the piston rod in a direction in which a compression ratio is increased, a second fluid chamber provided between the piston rod and the regulation member and configured to store the working fluid, a supply flow path configured to guide the working fluid supplied to the second fluid chamber, a discharge flow path configured to guide the working fluid discharged from the second fluid chamber, and a flow rate regulation unit provided in the discharge flow path and configured to regulate a flow of the working fluid when the piston rod approaches the regulation member.

Abstract: Provided is a marine engine, including: a piston; and a compression ratio controller configured to execute lowering processing of moving a top dead center position of the piston toward a bottom dead center side when an engine rotation speed falls within a resonance occurrence range set in advance. A geometrical compression ratio is reduced, and a resonance stress caused by a torsional vibration in a rotary system can thus be suppressed while suppressing a decrease in thermal efficiency compared with a case in which retarding control is applied to a fuel injection timing or a closing timing of an exhaust valve.

Abstract: Provided is a marine engine, including: an air controller configured to supply compressed air to a combustion chamber in an upstroke of a piston after a crash astern signal is output; a fuel controller configured to stop supply of fuel to the combustion chamber when the crash astern signal is output, and to resume the supply of the fuel after a backward rotation of a crankshaft; and a compression ratio controller configured to move a top dead center position of the piston toward an opposite side of a bottom dead center position of the piston when the crash astern signal is output, and the top dead center position of the piston is on the bottom dead center position side with respect to a predetermined position set in advance.

Abstract: A compression ratio control device includes a compression ratio controller configured to control a compression ratio of a combustion chamber so that the maximum combustion pressure approaches a combustion pressure upper limit value (cylinder-internal-pressure upper limit value) based on a detection signal of a detector at least when an engine load is equal to or less than a predetermined load (engine full load).

Abstract: Provided is an engine system including: a bypass pipe (bypass flow passage) connecting an upstream side and a downstream side of the turbine on an exhaust flow passage; a bypass valve configured to open and close the bypass flow passage; and a catalytic activation controller configured to control the bypass valve and a compression ratio of a combustion chamber.

Abstract: A compression ratio control device includes a compression ratio controller configured to control a compression ratio of a combustion chamber so that the maximum combustion pressure approaches a combustion pressure upper limit value (cylinder-internal-pressure upper limit value) based on a detection signal of a detector at least when an engine load is equal to or less than a predetermined load (engine full load).

Abstract: Provided is a marine engine, including: an air controller configured to supply compressed air to a combustion chamber in an upstroke of a piston after a crash astern signal is output; a fuel controller configured to stop supply of fuel to the combustion chamber when the crash astern signal is output, and to resume the supply of the fuel after a backward rotation of a crankshaft; and a compression ratio controller configured to move a top dead center position of the piston toward an opposite side of a bottom dead center position of the piston when the crash astern signal is output, and the top dead center position of the piston is on the bottom dead center position side with respect to a predetermined position set in advance.

Abstract: Provided is an engine, including: a cylinder; a piston accommodated in the cylinder; a combustion chamber facing the piston; a sliding portion (large-diameter portion) configured to perform a stroke motion together with the piston; a hydraulic surface of the sliding portion facing a side opposite to the combustion chamber; a hydraulic chamber, which the hydraulic surface faces; and an auxiliary hydraulic chamber, which communicates with the hydraulic chamber, and has a volume changeable in accordance with a hydraulic pressure in the hydraulic chamber.

Abstract: Provided is a marine engine, including: a piston; and a compression ratio controller configured to execute lowering processing of moving a top dead center position of the piston toward a bottom dead center side when an engine rotation speed falls within a resonance occurrence range set in advance. A geometrical compression ratio is reduced, and a resonance stress caused by a torsional vibration in a rotary system can thus be suppressed while suppressing a decrease in thermal efficiency compared with a case in which retarding control is applied to a fuel injection timing or a closing timing of an exhaust valve.

Abstract: Provided is an engine, including: a cylinder including a cylinder liner; a piston provided inside the cylinder liner; a piston ring provided on the piston; a contact detector configured to detect a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring; and a compression ratio controller configured to control a top dead center position of the piston so that the piston ring at the top dead center position is located on a combustion chamber side with respect to the step when the contact is detected.

Abstract: A piston ring is provided with a thermal spray coating that contains tungsten carbide and chrome carbide as a hard phase, and contains nickel as a metallic binder phase, and is characterized in that the thermal spray coating is formed by the spraying of a thermal spray powder that has been produced by means of a granulation sintering method, and that contains hard particles in which the mean particle diameter of the tungsten carbide has been adjusted by means of a BET method to fall within a range of not less than 0.15 ?m and not more than 0.45 ?m.

Abstract: A uniflow-scavenged two-cycle engine includes: a cylinder which has a combustion chamber; a piston; a scavenging chamber that surrounds one end side of the cylinder in the stroke direction of the piston and to which compressed active gas is guided; a scavenging port that is provided in a portion of the cylinder which is positioned in the scavenging chamber and suctions active gas from the scavenging chamber to the combustion chamber in response to a sliding motion of the piston; a fuel injection opening that injects fuel gas into the active gas which is suctioned into the scavenging port; and a fuel injecting valve that opens and closes a fuel supply path through which a fuel tank, communicates with the fuel injection opening, and is disposed in an space isolated from the scavenging chamber.

Abstract: Provided is an engine that includes a first member, a second member, a first hydraulic pressure chamber formed between facing parts of the first and second members, and a hydraulic pressure adjustment mechanism. The hydraulic pressure adjustment mechanism has a plunger pump having a pump cylinder and a plunger and configured to supply hydraulic oil in the pump cylinder to the first hydraulic pressure chamber by pushing the plunger into the pump cylinder. The plunger pump moves in a stroke direction along with a piston and a power transmission section, and the plunger is pushed into the pump cylinder by receiving a reaction force opposite to reciprocating forces of the piston and the power transmission section.

Abstract: A uniflow-scavenged two-cycle engine includes: a cylinder which has a combustion chamber; a piston; a scavenging chamber that surrounds one end side of the cylinder in the stroke direction of the piston and to which compressed active gas is guided; a scavenging port that is provided in a portion of the cylinder which is positioned in the scavenging chamber and suctions active gas from the scavenging chamber to the combustion chamber in response to a sliding motion of the piston; a fuel injection opening that injects fuel gas into the active gas which is suctioned into the scavenging port; and a fuel injecting valve that opens and closes a fuel supply path through which a fuel tank, communicates with the fuel injection opening, and is disposed in an space isolated from the scavenging chamber.

Abstract: Provided is a crosshead engine that includes: a cylinder; a piston; a piston rod; a crosshead; a connecting rod; a crankshaft; and a variable mechanism varies positions of top and bottom dead centers of the piston by changing a relative position between the piston rod and the crosshead in a stroke direction of the piston. The variable mechanism includes: a hydraulic pressure chamber which is provided in the crosshead and into which an end of the piston rod is inserted; and a hydraulic pressure adjustment mechanism which supplies hydraulic oil to the hydraulic pressure chamber or discharges the hydraulic oil from the hydraulic pressure chamber and which adjusts an entering position at which the end of the piston rod is inserted into the hydraulic pressure chamber in the stroke direction.

Abstract: Provided is an engine that includes a first member, a second member, a first hydraulic pressure chamber formed between facing parts of the first and second members, and a hydraulic pressure adjustment mechanism. The hydraulic pressure adjustment mechanism has a plunger pump having a pump cylinder and a plunger and configured to supply hydraulic oil in the pump cylinder to the first hydraulic pressure chamber by pushing the plunger into the pump cylinder. The plunger pump moves in a stroke direction along with a piston and a power transmission section, and the plunger is pushed into the pump cylinder by receiving a reaction force opposite to reciprocating forces of the piston and the power transmission section.

Abstract: Provided is a crosshead engine that includes: a cylinder; a piston; a piston rod; a crosshead; a connecting rod; a crankshaft; and a variable mechanism varies positions of top and bottom dead centers of the piston by changing a relative position between the piston rod and the crosshead in a stroke direction of the piston. The variable mechanism includes: a hydraulic pressure chamber which is provided in the crosshead and into which an end of the piston rod is inserted; and a hydraulic pressure adjustment mechanism which supplies hydraulic oil to the hydraulic pressure chamber or discharges the hydraulic oil from the hydraulic pressure chamber and which adjusts an entering position at which the end of the piston rod is inserted into the hydraulic pressure chamber in the stroke direction.