Abstract: An engine system includes a combustion chamber including a cylinder, a fuel supply that supplies fuel including gasoline into the combustion chamber, circuitry configured to predict a knock will occur in the combustion chamber, and a fluid injector that injects a fluid into the combustion chamber. Further, there is circuitry configured to suppress a knock by instructing the fluid injector, when the knock is predicted to occur by the circuitry configured to predict, to inject the fluid into the combustion chamber within a period before a burned mass fraction reaches 50% after a start of combustion.

Abstract: A method and system for predicting the occurrence of a knock which will have a predetermined intensity or higher (intense knock) in an engine that burns an air-fuel mixture of gasoline fuel. The pressure in a combustion chamber is detected during an initial stage of combustion. This pressure is compared with a preset reference value to determine whether or not the cylinder inner pressure exceeds the reference value during the combustion. When the cylinder inner pressure exceeds the reference value, it is predicted that the intense knock will occur before an end of the combustion. If the intense knock is predicted, additional fuel or other material can be injected into the combustion chamber to prevent the occurrence of the intense knock.

Abstract: A control device for an engine is provided, which includes a knock intensity sensor configured to detect a knock intensity, an output adjustment mechanism configured to adjust an engine output torque, and a controller configured to control the output adjustment mechanism based on the knock intensity. The controller executes a first control in which the output adjustment mechanism is controlled to reduce the knock intensity when the number of strong knocks that is the number of times the knock intensity becomes a second determination intensity or greater is a given determination number or less and when the knock intensity is greater than a first determination intensity, and executes a second control in which the output adjustment mechanism is controlled to reduce the maximum torque more than when the number of strong knocks is the determination number or less, when the number of strong knocks is greater than the determination number.

Abstract: A control device for an engine is provided, which includes a knock intensity sensor configured to detect a knock intensity, an output adjustment mechanism configured to adjust an engine output torque, and a controller configured to control the output adjustment mechanism based on the knock intensity. The controller executes a first control in which the output adjustment mechanism is controlled to reduce the knock intensity when the number of strong knocks that is the number of times the knock intensity becomes a second determination intensity or greater is a given determination number or less and when the knock intensity is greater than a first determination intensity, and executes a second control in which the output adjustment mechanism is controlled to reduce the maximum torque more than when the number of strong knocks is the determination number or less, when the number of strong knocks is greater than the determination number.

Abstract: An engine system includes a combustion chamber including a cylinder, a fuel supply that supplies fuel including gasoline into the combustion chamber, circuitry configured to predict a knock will occur in the combustion chamber, and a fluid injector that injects a fluid into the combustion chamber. Further, there is circuitry configured to suppress a knock by instructing the fluid injector, when the knock is predicted to occur by the circuitry configured to predict, to inject the fluid into the combustion chamber within a period before a burned mass fraction reaches 50% after a start of combustion.

Abstract: A method and system for predicting the occurrence of a knock which will have a predetermined intensity or higher (intense knock) in an engine that burns an air-fuel mixture of gasoline fuel. The pressure in a combustion chamber is detected during an initial stage of combustion. This pressure is compared with a preset reference value to determine whether or not the cylinder inner pressure exceeds the reference value during the combustion. When the cylinder inner pressure exceeds the reference value, it is predicted that the intense knock will occur before an end of the combustion. If the intense knock is predicted, additional fuel or other material can be injected into the combustion chamber to prevent the occurrence of the intense knock.

Abstract: A method of controlling a spark-ignition engine including an ignition plug for spark-igniting mixture gas inside a cylinder in an engine body, and an effective compression ratio changing module for changing an effective compression ratio of the engine body is provided. The method includes estimating, based on engine speed, engine load, and environmental conditions, a limit effective compression ratio serving as a maximum effective compression ratio where pre-ignition does not occur, calculating a current effective compression ratio, calculating a value obtained by subtracting the effective compression ratio from the limit effective compression ratio, as a margin before pre-ignition occurs, and decreasing, when the margin is below a predetermined minimum margin, the effective compression ratio of the engine body by using the effective compression ratio changing module so that the margin is increased to be above the minimum margin, which is set constant regardless of at least environmental conditions.

Abstract: A starting device of a spark-ignition multi-cylinder engine is provided. The device includes a multi-cylinder engine body having cylinders, fuel injection valves, ignition plugs, an intake valve drive mechanism for opening and closing intake valves, a hydraulic variable valve phase mechanism for changing a close timing of each intake valve, an engine-driven hydraulic pressure supply source for supplying a hydraulic pressure, and a start controller for controlling the fuel injection valves, the ignition plugs, and the variable valve phase mechanism. When the supplied hydraulic pressure is below a predetermined pressure, the variable valve phase mechanism locks the close timing. When an engine temperature in an engine-start is high, the start controller retards a fuel injection timing of the cylinder on intake stroke at an engine stopped timing and retards an ignition timing thereof. The start controller does not retard the close timing of the intake valve until the engine-start completes.

Abstract: A method for controlling an engine includes, when the engine is operating within a particular range with comparatively low engine speed and high load, setting an effective compression ratio of 10:1 or above, retarding ignition timing by a predetermined amount and retarding the ignition timing within a first, relatively low engine speed range more than within a second, higher engine speed range, setting an injection mode of an injection valve to divided injections performed at least twice in a period from an intake stroke to an earlier-half stage of a compression stroke, performing, within the first engine speed range, a final injection in the earlier-half stage of the compression stroke, and performing, within the second engine speed range, the final injection in a late stage of the intake stroke and at least one injection other than the final injection in a middle stage of the intake stroke.

Abstract: An exhaust manifold has a plurality of branched exhaust passages connected to respective exhaust ports of individual cylinders; a plurality of first collector segments each of which joins the branched exhaust passages for the cylinders which are not adjacent in the exhaust order sequence; a plurality of middle exhaust passages connected to the downstream of the first collector segments, respectively; and a second collector segment that joins the middle exhaust passages. In at least low and middle speed ranges in a high load region of the engine, a valve opening time of an exhaust valve is changed according to the engine speed so that a predetermined amount of a valve overlap period is ensured and that negative pressure waves from exhaust pressure pulses reach an exhaust port during the valve overlap period in a plurality of engine speed ranges.

Abstract: When preignition is detected, and an engine speed is less than a predetermined value (Nex), an air/fuel ratio is enriched (S22), and then, when the preignition is detected even after enriching the air/fuel ratio, an effective compression ratio of an engine is reduced (S23), whereafter, when the preignition is detected even after reducing the effective compression ratio, a part of injection fuel is injected in a compression stroke (S24). On the other hand, when preignition is detected, and an engine speed is equal to or greater than the predetermined value (Nex), the air/fuel ratio is enriched (S31), and then, when the preignition is detected even after enriching the air/fuel ratio, a part of the fuel is injected in the compression stroke (S32). This makes it possible to effectively suppress the occurrence of preignition while maximally avoiding deterioration in emission performance and lowering in engine power output.

Abstract: A starting device of a spark-ignition multi-cylinder engine is provided. The device includes a multi-cylinder engine body having cylinders, fuel injection valves, ignition plugs, an intake valve drive mechanism for opening and closing intake valves, a hydraulic variable valve phase mechanism for changing a close timing of each intake valve, an engine-driven hydraulic pressure supply source for supplying a hydraulic pressure, and a start controller for controlling the fuel injection valves, the ignition plugs, and the variable valve phase mechanism. When the supplied hydraulic pressure is below a predetermined pressure, the variable valve phase mechanism locks the close timing. When an engine temperature in an engine-start is high, the start controller retards a fuel injection timing of the cylinder on intake stroke at an engine stopped timing and retards an ignition timing thereof. The start controller does not retard the close timing of the intake valve until the engine-start completes.

Abstract: When a maximum value of vibration intensity (maximum vibration intensity)(Vmax) acquired from a vibration sensor (33) in a low engine speed/high engine load (operating region (R)) is equal to or greater than a given threshold value (X), a spark timing of a spark plug (16) is shifted from a point set in a normal state on a retard side with respect to a compression top dead center, farther toward the retard side. Then, when a maximum vibration intensity (Vmax2) acquired after the spark timing retard is greater than a maximum vibration intensity (Vmax1) acquired before the spark timing retard, it is determined that preignition occurs. This technique makes it possible to reliably detect preignition using the vibration sensor, while distinguishing the preignition from knocking. An in-cylinder pressure sensor for detecting an in-cylinder pressure of an engine may be used to determine the presence or absence of the preignition, in the same manner.

Abstract: An engine has a geometric compression ratio of higher than 12, and includes an exhaust manifold, a variable exhaust valve timing mechanism, an ignition timing controller, and an effective compression ratio adjuster. The exhaust manifold has a plurality of branched exhaust passages connected to the respective exhaust ports of the individual cylinders; a plurality of first collector segments each of which joins the branched exhaust passages for the cylinders which are not adjacent in the exhaust order sequence; a plurality of middle exhaust passages connected to the downstream of the first collector segments, respectively; and a second collector segment that joins the middle exhaust passages.

Abstract: A method of controlling a spark-ignition engine including an ignition plug for spark-igniting mixture gas inside a cylinder in an engine body, and an effective compression ratio changing module for changing an effective compression ratio of the engine body is provided. The method includes estimating, based on engine speed, engine load, and environmental conditions, a limit effective compression ratio serving as a maximum effective compression ratio where pre-ignition does not occur, calculating a current effective compression ratio, calculating a value obtained by subtracting the effective compression ratio from the limit effective compression ratio, as a margin before pre-ignition occurs, and decreasing, when the margin is below a predetermined minimum margin, the effective compression ratio of the engine body by using the effective compression ratio changing module so that the margin is increased to be above the minimum margin, which is set constant regardless of at least environmental conditions.

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: A method for controlling an engine includes, when the engine is operating within a particular range with comparatively low engine speed and high load, setting an effective compression ratio of 10:1 or above, retarding ignition timing by a predetermined amount and retarding the ignition timing within a first, relatively low engine speed range more than within a second, higher engine speed range, setting an injection mode of an injection valve to divided injections performed at least twice in a period from an intake stroke to an earlier-half stage of a compression stroke, performing, within the first engine speed range, a final injection in the earlier-half stage of the compression stroke, and performing, within the second engine speed range, the final injection in a late stage of the intake stroke and at least one injection other than the final injection in a middle stage of the intake stroke.

Abstract: A system and method of controlling an internal combustion engine are provided. The method may include closing said intake valve at a timing in a first range, which is before a maximum charge closing timing with which an amount of air inducted into said cylinder from said air intake passage would be maximized at a given engine speed, during a cylinder cycle when a desired amount of air to be inducted into said cylinder is less than or equal to a predetermined air amount at the given engine speed. The method may further include closing said intake valve at a timing in a second range, which is after said maximum charge closing timing and separated from said first range during a cylinder cycle, when a desired amount of air to be inducted into said cylinder is greater than said predetermined air amount at the given engine speed.

Abstract: Methods and systems for controlling an internal combustion engine are provided. One example method may include closing an intake valve later during a cylinder cycle than a timing with which an amount of air inducted into a cylinder from an air intake passage would be maximized, and earlier during the cylinder cycle as a desired amount of air to be inducted into the cylinder increases, while an engine is operating at a given engine speed. The method may further include closing the intake valve earlier during a cylinder cycle as the engine speed increases when the desired amount of air to be inducted into the cylinder is at a maximum.

Abstract: When preignition is detected, and an engine speed is less than a predetermined value (Nex), an air/fuel ratio is enriched (S22), and then, when the preignition is detected even after enriching the air/fuel ratio, an effective compression ratio of an engine is reduced (S23), whereafter, when the preignition is detected even after reducing the effective compression ratio, a part of injection fuel is injected in a compression stroke (S24). On the other hand, when preignition is detected, and an engine speed is equal to or greater than the predetermined value (Nex), the air/fuel ratio is enriched (S31), and then, when the preignition is detected even after enriching the air/fuel ratio, a part of the fuel is injected in the compression stroke (S32). This makes it possible to effectively suppress the occurrence of preignition while maximally avoiding deterioration in emission performance and lowering in engine power output.