Abstract: A combustion chamber structure for an engine is provided. The combustion chamber structure includes a piston formed with a downward dented cavity at a central part of an upper surface thereof, and a fuel injector provided above the piston and on an extended line of a central axis of the piston, the fuel injector changing an injection timing of fuel on a compression stroke according to an operating state of the engine. A fuel injection angle of the fuel injector is designed to satisfy conditions in which the fuel is injected into the cavity and in which a fuel spray collision distance defined from a fuel injection position of the fuel injector to a collision position of the fuel with the cavity is longer than a breakup length defined from the fuel injection position of the fuel injector to a position where an initial breakup of the fuel occurs.

Abstract: An engine body includes a cylinder with a geometrical compression ratio of 15 or higher, and is supplied with fuel containing at least gasoline. When an operating mode of the engine body is in a high load range, a controller (i.e., a PCM 10) drives a fuel injection valve (i.e., an injector) 67 to inject the fuel at a time within a retarded period between a terminal stage of a compression stroke and an initial stage of an expansion stroke in a low speed range. The controller drives the fuel injection valve to inject the fuel in an intake stroke until an intake valve 21 is closed in a high-load high-speed range.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller controls a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection valve to perform a fuel injection at least at a timing that is more retarded than an injection timing of a fuel within the low engine load range and is within a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing within the retard period and further after the fuel injection.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller controls a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection valve to perform a fuel injection at least at a timing that is more retarded than an injection timing of a fuel within the low engine load range and is within a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing within the retard period and further after the fuel injection.

Abstract: A multi-hole injector directly injects fuel into a combustion chamber. Intake air is introduced into the combustion chamber through intake ports to provide tumble flow in the combustion chamber. A cavity is formed in a part of the top surface of a piston which is eccentric to the exhaust side. In the intake stroke, fuel injection ends in a downstroke of a piston. When the crank angle is 100 degrees after the top dead center in the intake stroke at which the fuel injection ends, a most downward lower spray collides with a part of the top surface of the piston which ranges on the intake side from the edge on the exhaust side of the cavity. A most upward upper spray does not come into contact with a spark plug. Thus, the fuel injection can enhance the tumble flow to promote homogeneous dispersion of fuel-air mixture in the combustion chamber.

Abstract: Disclosed is an internal combustion engine (A), which has a valve overlap period (T) during which an intake valve (1) and an exhaust valve (2) are opened, and a geometric compression ratio of 13.0 or greater. The engine (A) is designed to satisfy, at a center timing (Tc) of the valve overlap period (T), a conditional expression: S1?S2, where S1 is a cross-sectional area of a combustion chamber (4) taken along any selected one of a plurality of mutually parallel hypothetical cutting-planes (IP) each of which extends parallel to a linear reciprocating direction (d1 or d2) of at least one of the intake and exhaust valves (1, 2) and passes through a valve head (1a or 2a) of the at least one of the valves (1, 2), and S2 is an effective opening area defined between the valve head (1a or 2a) and a corresponding valve seat (11a or 12a) in a region on an outward side of the combustion chamber (4) relative to the selected hypothetical cutting-plane (IP).

Abstract: Disclosed is a direct-injection spark-ignition engine designed to promote catalyst activation during cold engine operation. A fuel injection timing for a fuel injection period in an compression stroke (second fuel injection period F2) is set to allow a first fuel spray Ga injected from a first spray hole 40a to enter a cavity 34 in a piston crown surface 30, and allow a second fuel spray Gb to impinge against a region of the piston crown surface 30 located closer to an injector than the cavity 34, so as to cause the second fuel spray Gb having a lowered penetration force due to the impingement to be pulled toward the cavity 34 by a negative pressure generated in the cavity 34 as a result of passing of the first fuel spray Ga therethrough.

Abstract: A duct structure, includes: a vessel forming therein a chamber, the vessel including: an inlet port, an outlet port, wherein the vessel is configured such that a fluid flows into the chamber through the inlet port and flows out of the chamber through the outlet port, and a swirling flow suppressing member disposed in a position inside the chamber adjacent to the outlet port, wherein the swirling flow suppressing member is configured to suppress a swirling flow from occurring to or adjacent to the outlet port.

Abstract: Disclosed is a direct-injection spark-ignition engine designed to promote catalyst activation during cold engine operation. A fuel injection timing for a fuel injection period in an compression stroke (second fuel injection period F2) is set to allow a first fuel spray Ga injected from a first spray hole 40a to enter a cavity 34 in a piston crown surface 30, and allow a second fuel spray Gb to impinge against a region of the piston crown surface 30 located closer to an injector than the cavity 34, so as to cause the second fuel spray Gb having a lowered penetration force due to the impingement to be pulled toward the cavity 34 by a negative pressure generated in the cavity 34 as a result of passing of the first fuel spray Ga therethrough.

Abstract: There is provided a method of controlling a spark ignited internal combustion engine having a fuel injector which injects fuel directly into its combustion chamber. The method comprises injecting a total amount of fuel into a combustion chamber by early in a compression stroke during a cylinder cycle at a first engine speed. The method further comprises injecting a first stage of fuel into the combustion chamber during a cylinder cycle by an early in a compression stroke of the cylinder cycle, and injecting a second stage of fuel by late in the compression stroke during the cylinder cycle at a second engine speed less than the first engine speed, after injecting the first stage of fuel. The amount of the second stage fuel is greater than an amount of said first stage fuel. Accordingly, the first and second stage fuels may not be pre-ignited before the spark ignition.

Abstract: Disclosed is an internal combustion engine, which has a geometric compression ratio of 13.0 or greater, and a combustion chamber (4) configured to satisfy a condition of S/V2?0.12 (mm?1) when a radius r of a hypothetical sphere (IS) with its center at an ignition point (CP) of a spark plug (3) is set to satisfy a condition of V2=0.15×V1, where: S (mm2) is an area of an interference surface between the hypothetical sphere (IS) and an inner wall of the combustion chamber (4) in a state when a piston (30) is at its top dead center position; V1 (mm3) is a volume of the combustion chamber 4 in the state when the piston (30) is at the top dead center position; and V2 (mm3) is a volume of a non-interference part of the hypothetical sphere (IS) which is free of interference with the inner wall of the combustion chamber (4) when the piston (30) is at the top dead center position. The internal combustion engine of the present invention can more reliably improve fuel economy.

Abstract: An internal combustion engine is described herein. The engine may include a combustion chamber having a pair of intake ports arranged at one side, and an exhaust port arranged at the other side. The engine may also include a fuel injector configured to inject fuel into said combustion chamber from a side of said intake ports toward a side of said exhaust port, a variable flow restrictor capable of making flow resistance of said second intake port greater than flow resistance of said first intake port, a first spark plug arranged on a ceiling of the chamber and having its spark gap in the proximity of a center portion of said ceiling, and a second spark plug arranged on said ceiling and having its spark gap which is positioned closer to said first intake port in the axial direction of said crankshaft than said first spark plug.

Abstract: A multi-hole injector directly injects fuel into a combustion chamber. Intake air is introduced into the combustion chamber through intake ports to provide tumble flow in the combustion chamber. A cavity is formed in a part of the top surface of a piston which is eccentric to the exhaust side. In the intake stroke, fuel injection ends in a downstroke of a piston. When the crank angle is 100 degrees after the top dead center in the intake stroke at which the fuel injection ends, a most downward lower spray collides with a part of the top surface of the piston which ranges on the intake side from the edge on the exhaust side of the cavity. A most upward upper spray does not come into contact with a spark plug. Thus, the fuel injection can enhance the tumble flow to promote homogeneous dispersion of fuel-air mixture in the combustion chamber.

Abstract: Disclosed is an internal combustion engine, which has a geometric compression ratio of 13.0 or greater, and a combustion chamber (4) configured to satisfy a condition of S/V2?0.12 (mm?1) when a radius r of a hypothetical sphere (IS) with its center at an ignition point (CP) of a spark plug (3) is set to satisfy a condition of V2=0.15×V1, where: S (mm2) is an area of an interference surface between the hypothetical sphere (IS) and an inner wall of the combustion chamber (4) in a state when a piston (30) is at its top dead center position; V1 (mm3) is a volume of the combustion chamber 4 in the state when the piston (30) is at the top dead center position; and V2 (mm3) is a volume of a non-interference part of the hypothetical sphere (IS) which is free of interference with the inner wall of the combustion chamber (4) when the piston (30) is at the top dead center position. The internal combustion engine of the present invention can more reliably improve fuel economy.

Abstract: Disclosed is an internal combustion engine (A), which has a valve overlap period (T) during which an intake valve (1) and an exhaust valve (2) are opened, and a geometric compression ratio of 13.0 or greater. The engine (A) is designed to satisfy, at a center timing (Tc) of the valve overlap period (T), a conditional expression: S1?S2, where S1 is a cross-sectional area of a combustion chamber (4) taken along any selected one of a plurality of mutually parallel hypothetical cutting-planes (IP) each of which extends parallel to a linear reciprocating direction (d1 or d2) of at least one of the intake and exhaust valves (1, 2) and passes through a valve head (1a or 2a) of the at least one of the valves (1, 2), and S2 is an effective opening area defined between the valve head (1a or 2a) and a corresponding valve seat (11a or 12a) in a region on an outward side of the combustion chamber (4) relative to the selected hypothetical cutting-plane (IP).

Abstract: A duct structure, includes: a vessel forming therein a chamber, the vessel including: an inlet port, an outlet port, wherein the vessel is configured such that a fluid flows into the chamber through the inlet port and flows out of the chamber through the outlet port, and a swirling flow suppressing member disposed in a position inside the chamber adjacent to the outlet port, wherein the swirling flow suppressing member is configured to suppress a swirling flow from occurring to or adjacent to the outlet port.

Abstract: A throttle device is arranged in the midstream of an individual passage consisting of a low-speed individual intake passage and a high-speed individual intake passage on the downstream of a surge tank. A valve body is rotatably provided in the throttle valve device. The inside of the valve body is formed with an in-valve low-speed passage and an in-valve high-speed passage that are adjacently placed with respect to the rotational axis of the valve body. The intake air supply is performed through only the low-speed individual passage when the opening of the valve body is equal to or less than a predetermined value, and through both the low-speed individual intake passage and high-speed individual intake passage when the opening of the body is larger than the predetermined value.

Abstract: A throttle valve device is arranged in the midstream of an individual passage consisting of a low-speed individual intake passage and a high-speed individual intake passage on the downstream of a surge tank. A valve body is rotatably provided in the throttle valve device. The inside of the valve body is formed with an in-valve low-speed passage and an in-valve high-speed passage that are adjacently placed with respect to the rotational axis of the valve body. The intake air supply is performed through only the low-speed individual passage when the opening of the valve body is equal to or less than a predetermined value, and through both the low-speed individual intake passage and high-speed individual intake passage when the opening of the valve body is larger than the predetermined value.