Abstract: Provided is a spark-ignition internal combustion engine capable of ensuring engine output power while setting a geometric compression ratio of an engine body to a high value. In the spark-ignition internal combustion engine, each of a clearance between a top surface (3a) of a piston (3) located at a top dead center position and a lower surface (8a) of each of two intake valves (8) in a full-closed state, and a clearance between the top surface (3a) of the piston (3) located at the top dead center position and a lower surface (9a) of each of two exhaust valves (9) in a full-closed state, is set to 5 mm or more, and a stroke length S of the piston (3) is set to satisfy the following relation: S?0.977×B+18.2, where B is a bore diameter of a cylinder.

Abstract: The variable compression engine may include a cylinder formed in a cylinder block, a piston moving upward and downward in the cylinder, a combustion chamber formed by the cylinder and the piston for combusting a fuel-air mixture, a fuel injector configured to inject a fuel into the combustion chamber, an exhaust valve selectively opened to discharge a combustion gas from the combustion chamber, an intake valve selectively opened to supply an intake air into the combustion chamber, an intake manifold that guides the intake air into the cylinder, an air injector configured to suck a gas from the combustion chamber and transfer the gas into the intake manifold, an air passage configured to connect the air injector and the intake manifold so that the gas sucked by the air injector passes therethrough, and a control unit configured to control an operation of the air injector.

Abstract: An engine having improved combustion characteristics is provided. The engine includes a fuel injection system that is variable between two operational states. In the first operating state, the fuel injectors provide a fuel spray having first spray pattern characteristics. When the system detects that an operation characteristic exceeds a threshold, the fuel injectors are displaced into a second operating state. In the second operating state, the fuel injectors provide a spray pattern having first spray pattern characteristics. The combustion cycle may be characterized by timing the fuel injection so that the fuel is sprayed into the cylinder early in the compression stroke. Further still, the combustion cycle may be characterized by controlling the fuel pressure so that the fuel pressure is inversely related to the load on the engine.

Abstract: Methods and systems are provided for a direct injection fuel pump. The methods and system control pressure within a compression chamber so as to improve fuel pump lubrication.

Abstract: A direct-injection engine combustion chamber structure including, at a top surface of a piston, an inclined surface and an orthogonal surface. The inclined surface, continuous with an inner peripheral wall surface of a cavity, extends outward in a radial direction of the piston and becomes shallower toward an outer side in a radial direction of the piston. The orthogonal surface, continuous with an outer periphery of the inclined surface, without a gap, extends to an outer peripheral surface of the piston and is orthogonal to a central axis of the piston.

Abstract: In a hybrid vehicle, when using an ignition start to start a direct injection engine while any one of the cylinders has stopped near top dead center, engine revolutions are raised by producing a first explosion in a first cylinder, which is situated before a second cylinder in an ignition sequence and is in an expansion stroke and in which an exhaust value is not open, by directly injecting fuel into the first cylinder and igniting the fuel. Furthermore, assistance in increasing the engine revolutions is started by transmitting assist torque output from a motor-generator to the direct injection engine via a clutch, in a peak section immediately after the start of increase in the engine revolutions.

Abstract: A method for improving combustion in a combustion chamber of an internal combustion engine, a heat retaining element, and an internal combustion engine are provided. The internal combustion engine includes a main combustion chamber arranged between a head and a reciprocating piston, and a heat retaining element provided between the head and the main combustion chamber. The heat retaining element is a self-supporting structure coupled to the head that is configured to reduce heat transfer from the main combustion chamber into the engine head. The heat retaining element includes a head-facing portion substantially corresponding in shape to a portion of the head facing the main combustion chamber. The heat retaining element is provided such that a gap is provided between the head-facing portion of the heat retaining element and the portion of the head facing the main combustion chamber.

Abstract: An improved multi-stroke DIG or diesel engine and method includes a cylinder formed within an engine cylinder block, a piston is movably disposed within the cylinder, and a combustion chamber is formed in a space between the piston and a cylinder head. An injector is disposed within the engine cylinder head for supplying fuel into the cylinder. An intake valve is disposed within an intake opening formed in the engine and an exhaust valve is disposed within an exhaust opening formed in the engine. An actuator is connected to the piston, wherein movement of the piston causes the actuator to open the exhaust valve a first predetermined amount at a beginning of the compression stroke of the piston to vent air through an exhaust channel formed in the engine and to close the exhaust valve after a predetermined period of time within the compression stroke of the piston.

Abstract: A fuel supply system for a gasoline direct injection (GDI) engine may reduce noise caused by a high pulsation pressure generated in a high-pressure pump due to fuel pressure control. The fuel supply system may include: a high-pressure pump; a high-pressure rail; an injector that is installed at the high-pressure rail and injects a fuel into a combustion chamber of the GDI engine; and a high-pressure pipe that is connected between the high-pressure pump and the high-pressure rail so as to supply the fuel to the high-pressure rail, wherein a porous member for reducing a pulsation pressure through which a plurality of through holes through which the fuel to be supplied to the high-pressure rail passes, is formed, is installed on a flow passage of the high-pressure pipe.

Abstract: A fuel injection device includes at least one fuel injector, one mounting hole in a cylinder head for the fuel injector, and a decoupling element between a valve housing of the fuel injector and the wall of the mounting hole. As a lenticular spring element, the decoupling element has a nonlinear, progressive spring characteristic curve, such that a low rigidity of the decoupling element prevails during idle operation and a high rigidity of the decoupling element prevails during nominal system pressure.

Abstract: When alcohol-blended fuel is supplied to an internal-combustion engine, the magnitude of alcohol concentration (more particularly, ethanol concentration Cetha) is judged (Step 1005) and, based on this judgment, the magnitude of operational status temperature (more particularly, cooling water temperature THW) is judged (Step 1015). Then, when the alcohol concentration is large and the operational status temperature is low, generation of an intermediate product which is an oxide of alcohol contained in the alcohol-blended fuel in an unburnt state after main injection and alcohol contained in the alcohol-blended fuel in an unburnt state after post injection (more particularly, aldehyde) is promoted, and the generated intermediate product is trapped in an intake passage by making an intake valve into an opened state in an exhaust stroke of the internal-combustion engine (Step 1055).

Abstract: An internal combustion engine operates on a six-stroke combustion cycle including a first compression stroke, a first power stroke, a second compression stroke, and a second power stroke. A first preliminary fuel charge is introduced to a combustion chamber of the engine during the first compression stroke. Subsequently, a first main fuel charge is introduced and the first preliminary and first main fuel charges are combusted to power the first power stroke. During the second compression stroke, a second preliminary fuel charge is introduced to the combustion chamber. Subsequently, a second main fuel charge is introduced during one of the second compression stroke and second power stroke. The second preliminary and second main fuel charges are combusted to power the second power stroke.

Abstract: A method for starting an internal combustion engine having direct fuel injection, comprising of adjusting a number of direct injections per combustion cycle based on a cylinder event number from a first cylinder event.

Abstract: It is possible to improve fuel efficiency with improved combustion performance of an engine by increase volatility of fuel supplied to a combustion chamber as much as possible and can reduce toxic exhaust substances, by appropriately controlling injection of two injectors in an engine with a dual injector.

Abstract: In a support structure of a direct fuel injection valve capable of supporting a fuel injection valve stably for a long period of time, a valve housing is made of a metal and is provided with a first load bearing portion which is to be supported by an engine in an axial direction of the valve housing, a rear end portion of the fixed core is provided with a second load bearing portion which is to be supported by a resilient holding member in the axial direction, and the first and second load bearing portions are held between the engine and the resilient holding members with a forward set load applied to the resilient holding member by a fuel distribution pipe fitted to a fuel inlet tube and fixed to the engine.

Abstract: A method for controlling controlled-auto-ignition operation in an eternal combustion engine is described. The method includes the injection of air into a combustion cylinder at an appropriate time in the combustion cycle in response to measured conditions. The injection of air acts to alter the CAI-phasing, thus providing the ability to extend the CAI operation further into a vehicle speed/load range.

Abstract: A combustion system is presented. The combustion system includes a hollow combustion chamber having a chamber head, chamber sidewalls, and a chamber bottom. Further, the combustion system includes a fuel injector coupled to the combustion chamber and configured to introduce a plurality of fuel droplets in the combustion chamber. Moreover, the combustion system includes a first electrode and a second electrode disposed on or about the combustion chamber such that an electromagnetic field is generated between the first electrode and the second electrode in response to an applied electric signal, and where the electromagnetic field is configured to control a trajectory of the plurality of fuel droplets within the combustion chamber.

Abstract: A direct-injection engine having a cylinder in which a combustion chamber is jointly formed by a piston crown of a piston, which is movable along the longitudinal axis of the cylinder, and a cylinder head, and an injection nozzle, which is arranged in the cylinder head on the opposite side of the piston crown eccentrically, spaced apart from the longitudinal axis of the cylinder, for the direct injection of fuel, which injection nozzle has a nozzle needle movable in a nozzle body, wherein the needle in the open position of the nozzle is moved into the combustion chamber, opening up an annular gap arranged between the nozzle body and needle.

Abstract: A method and apparatus for producing laminar flow through a fuel injection nozzle are provided. The method may comprise the steps of: providing a housing defining a cavity; providing a nozzle assembly having a first portion and a second portion extending from the first portion, the nozzle assembly being disposed within the cavity; placing the nozzle assembly in a closed position wherein the nozzle assembly is engaged with a valve seat defined by the housing; displacing the nozzle assembly and moving the nozzle assembly in an open position; expelling fuel through a gap defined between the second portion of the nozzle assembly and the housing, wherein the gap is sized to restrict fuel flow and create a laminar flow output stream having a Reynolds Number of equal to or less than 2000. The method may further include the step of returning the nozzle assembly to the closed position.

Abstract: A ‘Blackburn Cycle’ internal combustion engine has maximised ‘air only’ induction and ‘air only’ exhaust strokes between usual 4 stroke cycles. One or more inlet valves open fully via lever 7 for the alternate ‘air only’ inductions. The travel for the next fuel/air induction through the same inlet valve 13 is varied by variable fulcrum 10 acting on rocker 8 via push rod 11. This gives controllable fuel/air inductions without the need for a throttle. An inlet valve opens twice with one cam form and one cam revolution. Fuel is injected directly into the cylinder as required for the usual 4 stroke cycles between the ‘air only’ cycles.

Abstract: An injection valve for injecting fuel into a combustion chamber of an internal combustion engine comprises a valve seat, a valve element, at least one injection opening formed in the valve seat and leading to the combustion chamber, the at least one injection opening opened or closed by a stroke motion of the valve element, a catalytic coating provided in a region of the injection valve which faces the combustion chamber, and at least one protuberance which is elongated in a direction of the combustion chamber and projects into the combustion chamber.

Abstract: An internal combustion engine (1), preferably for a motor vehicle, having at least one cylinder (2) which encloses a combustion chamber (3) and in which a piston (4) is situated in such a way that it may perform a stroke movement, and having at least one injector (5) per cylinder for injecting fuel into the combustion chamber (3). The respective injector (5) has multiple injection openings (9, 10) through which the fuel exits from the injector (5) and enters into the combustion chamber (3). To be able to react more fuel, first injection openings (9) and second injection openings (10) are situated relative to one another in such a way that first injection jets (15) from the first injection openings (9) reach the piston (4) essentially without contacting second injection jets (18) from the second injection openings (10).

Abstract: The present invention relates to a diesel engine control system and methods for substantially operating a diesel engine at stoichiometric fuel to air ratios. The system may include a fuel processor which receives instructions for a desired engine output and current operating conditions. The fuel processor may also generate fueling instructions for the cylinders, including: substantially regulating fuel delivery into to a first group of cylinders at or near stoichiometric fuel levels, and substantially disabling fuel injection into to a second grouping of cylinders. The number of cylinders being fueled, and therefore undergoing a combustion event corresponds to the desired engine output. This may be calculated by dividing the desired output by the power provided by one cylinder operating at substantially stoichiometric fuel levels. The number of cylinders receiving fuel may be varied over a succession of engine revolutions such that the actual average engine power output conforms to the desired output.

Abstract: A system in an internal combustion engine is provided. The system a combustion chamber, a first exhaust port in fluidic communication with the combustion chamber, a second exhaust port in fluidic communication with the combustion chamber, and a direct fuel injector positioned between the first and second exhaust port and fluidly communicating directly with the combustion chamber.

Abstract: A system and methods are provided to deactivate a cam driven fuel pump. The system comprises a direct fuel injection system; a port fuel injection system; a pump for the direct injection system driven by a cam, wherein the pump can be activated and deactivated as a function of the activation of the direct injection system. Deactivating a pump when no fuel is pumped through it minimizes wear on pump components and increases efficiency.

Abstract: An engine includes an engine casing and a first piston configured to reciprocate relative to the engine casing. The first piston has a wall that defines a substantially cylindrical chamber. One or more second pistons are configured to reciprocate inside the substantially cylindrical chamber. A combustion chamber intake port and a combustion chamber exhaust port extend through the wall. A shutter is outside the wall and is movable between a first position substantially blocking fluid flow through the combustion chamber exhaust port but not blocking fluid flow through the combustion chamber intake port and a second position substantially blocking fluid flow through the combustion chamber intake port but not blocking flow through the combustion chamber exhaust port. An actuator causes the shutter to move between the first position and the second position in response to the first piston reciprocating relative to the engine casing.

Abstract: An object of the present invention is to provide a direct-injection internal combustion engine capable of suppressing the occurrence of knocking and providing increased combustion stability. The internal combustion includes a supercharger for supercharging intake air that flows into the internal combustion engine, and a fuel injection valve for directly injecting fuel into a combustion chamber in the internal combustion engine. After an exhaust valve and an intake valve are opened during an exhaust stroke, the intake valve and the exhaust valve close at a timing advanced from an intake top dead center, and then the intake valve opens at a timing retarded from the intake top dead center during an intake stroke. The fuel injection valve injects the fuel during an interval between the intake top dead center and the retarded timing.

Abstract: A fuel injector according to the present invention includes a needle valve mechanism including a needle valve provided near a nozzle portion, and a fuel chamber; a needle valve actuator mounted with a piston, wherein a spring is disposed into the piston; a booster formed with first through third chambers in an upper portion, a middle portion, and a lower portion, respectively, based on a piston, and having only the spring-free piston; a pilot valve operating by a pressure difference between pressure for injection of the fuel chamber and working pressure of a solenoid, having a spool and a spacer mounted above the spool and formed with a second orifice on one side thereof; and a solenoid valve controlling working pressure of fuel to operate the needle valve actuator or the pilot valve.

Abstract: A nozzle for a fuel injector is disclosed. The nozzle may have a body having a base end, a tip end, and a central bore extending from the base end to the tip end. The nozzle may also have a sac located within the central bore at the tip end. Further, the nozzle may have an orifice located within the tip end and in communication with the sac. The orifice may be skewed at an azimuthal angle relative to a radial direction of the central bore.

Abstract: Various systems and methods are disclosed for controlling an internal combustion engine system having an internal combustion engine, and a fuel injector which directly injects fuel into a combustion chamber of the internal combustion engine. One example method comprises, when a desired torque for the internal combustion engine system is in a first range, injecting a first stage fuel into the combustion chamber so that it ends during a middle stage of a compression stroke at the latest in a cylinder cycle; determining combustion of the first stage fuel initiated by its compression self-ignition; and injecting a second stage fuel into the combustion chamber in a period when the determined combustion of the first stage fuel continues at a timing determined so as to cause combustion of the second stage fuel with its compression self-ignition.

Abstract: A piston for a compression ignition internal combustion engine includes a piston body having a combustion face defining a combustion bowl, and the combustion face including a compound bowl surface and a compound rim surface. The combustion face is profiled to balance a combustion efficiency property of the piston with emissions properties of the piston. A ratio of a diameter of the combustion bowl to a diameter of the cylinder bowl bore is from 0.68 to 0.74. Other dimensional and proportional features of the piston support low smoke and NOx production during operation.

Abstract: An energy transducer comprising: a body; a crankshaft; a rotor mounted to the crankshaft and housed within the body such that the rotor may rotate within the body along an axis defined by the crankshaft; one or more chambers located circumferentially around the rotor and angled inward toward the direction of travel of the rotor; an injector connected to the body such that the injector injects fuel into the one or more chambers; and an igniter connected to the body such that the igniter ignites the fuel in the one or more chambers, which causes the rotor to rotate. The fuel may be hydrogen or a mixture of hydrogen and oxygen.

Abstract: A fuel injector (10) for liquid phase injection of liquefied gaseous fuels for combustion chambers of an internal combustion engine. The fuel injector (10) comprises a nozzle portion (15) having an end (30) from which gaseous fuel can be delivered through an outlet (21), the end (30) being configured to prevent or at least inhibit formation of ice thereon upon delivery of gaseous fuel through the outlet.

Abstract: A gaseous fuelled two-engine system comprises a high pressure direct injection engine as the main power source and an auxiliary fumigated engine that can be fuelled with vapor removed from a storage tank that stores the gaseous fuel in liquefied form at cryogenic temperatures. The fuel supply system comprises a cryogenic pump for raising the pressure of the fuel to the injection pressure needed for the high pressure direct injection engine, and the cryogenic pump is powered by the auxiliary fumigated engine.

Abstract: A device for injecting fuel into the combustion chamber of an internal combustion engine with at least one injector includes an injector body equipped with a high-pressure accumulator, a nozzle needle axially displaceably guided in the injector and surrounded by a nozzle chamber, a high-pressure line connecting the high-pressure accumulator to the nozzle chamber, and a resonator line arranged in parallel with the high-pressure line and communicating with the nozzle chamber and opening into the high-pressure accumulator via a resonator throttle. The resonator line and the high-pressure line, at least in their sections adjacent the high-pressure accumulator, are formed in a retaining body which, on its end face, is screwed into the accumulator pipe forming the high-pressure accumulator.

Abstract: An engine and a method of operating an engine. One method includes: routing air to both a donor and a non-donor cylinder of an engine; combusting an air fuel mixture in the cylinders; routing exhaust gas from the non-donor cylinder through an exhaust manifold; and recirculating exhaust gas from the donor cylinder through an aftertreatment system and a cooler back to the intake manifold. Another method includes: recirculating exhaust gas from a first cylinder of an engine to an intake stream or air-fuel mixture of the engine, whereby: the recirculated exhaust gas from the first cylinder flows through an after treatment system; and the recirculated exhaust gas is cooled to a lower temperature after the after treatment system; and routing exhaust gas from the second cylinder through an exhaust manifold.

Abstract: The invention provides a gas fuel supply kit for the existing vehicle (vehicle mounting a gasoline engine, or a diesel engine), in order to use a gas fuel such as hydrogen after wards. A post-installable type gas fuel supply kit to be installed in the existing vehicle such as a gasoline vehicle, comprising a gas fuel injector for supplying the gas fuel such as hydrogen to an intake path; an injector installing means for installing said gas fuel injector to a location which is a different location where a gasoline injector is installed; and a control unit for controlling at least an injection amount, and an injection timing of the gas fuel at the hydrogen fuel injector.

Abstract: An energy transducer comprising: a cylinder; a piston within the cylinder connected to a connecting rod extending out of the cylinder and connected to a crankshaft; a chamber within the cylinder defined by the first end of the cylinder and the piston; a direct injector in fluid communication with the chamber and in fluid communication with a fuel tank such that the direct injector is capable of injecting fuel from the fuel tank into the chamber, where the fuel is hydrogen or a mix of hydrogen and oxygen; and an igniter located such that the igniter is capable of igniting the fuel within the chamber; such that ignition of the fuel within the chamber causes an explosion that forces the piston toward the crankshaft, causing the crankshaft to rotate 180°, followed by an implosion that forces the piston away from the crankshaft, causing the crankshaft to complete one full rotation.

Abstract: Systems and methods for reducing NOx emissions are provided, comprising: adjusting an amount of water injected into an intake manifold responsive to an oxygen concentration, temperature and pressure in the intake manifold; and heating the injected water if humidity is higher than a threshold. Water injected into the intake manifold decreases the temperature of, and dilutes the oxygen content of intake gases thereby decreasing NOx emissions.

Abstract: An improved internal combustion engine of the four-stroke variable volume type operates by refraining from introducing substantial fuel into the working medium during the compression stroke until substantially maximum pressure of the working medium has been reached and utilizing at least one of the following processes: (a) causing combustion of fuel under substantially constant volume conditions; and (b) causing the power stroke to provide a larger volume to combustion products than the compression stroke provides to the working medium. Related methods are also provided.

Abstract: A piston is arranged for reciprocal movement in a combustion engine cylinder. Protrusions are or a ridge is arranged half way between flame plume impingement areas in a plane perpendicular to the reciprocal movement and protrude to the combustion chamber having a smooth form adapted for preserving kinetic energy in a flame plume. The protrusion or ridge includes a left side flank, a top section and a right side flank, and a transition section between each of the side flanks and the top section, the transition section including a deflection edge in order to minimize flow losses.

Abstract: A fuel shroud assembly (100) into which fuel (118) is injected for mixing with an air stream (120) in a fuel manifold. The shroud assembly (100) comprises a plurality of parallel fuel scoops (102) each receiving the injected fuel (118). The fuel stream (118) flows through each scoop (102), exiting at an open scoop end (114A). The air stream (120) flows between scoops, creating a shear region proximate each scoop end (114A) where the fuel exits. The shear causes mixing of the air (120) and the fuel (118) streams, wherein the degree of mixing is not dependent on the momentum ratio of the air (120) or fuel (118) streams.

Abstract: An aircraft monitoring system uses aircraft engine and system transducers to monitor critical engine and aircraft system parameters. Simple controls and graphical user interfaces facilitate the display of different kinds of critical information to the pilot. Such data may also be recorded for later downloading and analysis.

Abstract: A toroidal combustion chamber shape with side injectors is being developed for an opposed-piston engine. Favorable combustion characteristics of such configuration are transferred to a conventional engine, i.e., one with a combustion chamber delimited by a piston, a cylinder wall, and a cylinder head. At least one injector is disposed in the cylinder head at the periphery. The fuel is injected substantially along the plane of interface between the cylinder head and the cylinder block. The intake system is configured to provide a swirling flow in the combustion chamber. The fuel is injected in an angle that is displaced from the central axis of the cylinder and directed along the swirl. In some embodiments, a substantially torus-shaped volume is formed between the piston and the cylinder head when the piston is at top center. The injector or injectors spray fuel into the toroidally-shaped volume substantially tangent to the torus.

Abstract: An internal combustion engine includes in one aspect a source of a pressurized working medium and an expander. The expander has a housing and a piston, movably mounted within and with respect to the housing, to perform one of rotation and reciprocation, each complete rotation or reciprocation defining at least a part of a cycle of the engine. The expander also includes a septum, mounted within the housing and movable with respect to the housing and the piston so as to define in conjunction therewith, over first and second angular ranges of the cycle, a working chamber that is isolated from an intake port and an exhaust port. Combustion occurs at least over the first angular range of the cycle to provide heat to the working medium and so as to increase its pressure.

Abstract: According to various embodiments, a system includes a gasification fuel injector. The gasification fuel injector includes a tip portion, an annular coolant chamber disposed in the tip portion, and a first structural support extending through the annular coolant chamber. The first structural support divides the annular coolant chamber into a first passage and a second passage.

Abstract: In an internal combustion engine, a valve actuating mechanism actuates an intake valve member to open an intake port, and actuates an exhaust valve member to return a first part of exhaust gas with a high-temperature from a gas exhaust passage into a combustion chamber via an exhaust port. A cooling and recirculation system recirculates a second part of the exhaust gas from the gas exhaust passage into the gas intake passage via a recirculation passage while cooling the second part of the exhaust gas. This results in a stratified temperature distribution of a high-temperature mixture of first fresh air and the first part of the exhaust gas with the high temperature and a low-temperature mixture of second fresh air and the second part of the exhaust gas with a low temperature in the combustion chamber.

Abstract: Embodiments of the invention are directed toward a fuel injection system for a variable temperature and pressure direct injection engine, comprising: a high-pressure fuel pump capable of providing fuel at a pressure between 100 bar and 800 bar; a fuel heater for heating the fuel from 50° C. to 500° C.; and a common fuel rail operatively connected to at least one direct injector for injecting heated fuel into a cylinder of the engine.

Abstract: In a method relating to an engine with n cylinders, fuel is injected in a predetermined order into the cylinders in a manner which is synchronized with the position of the pistons of the engine. The method includes the following steps after start-up: injection into m cylinders in a predetermined order of injection; measurement of engine speed and/or acceleration; continuation of injection in a predetermined order of injection if engine speed and/or acceleration exceed(s) a predetermined threshold; continuation of injection with a delay in the event of the contrary. The method can be used with respect to the start-up of a direct injection engine.

Abstract: A combustion chamber for an internal combustion engine is disclosed in which the piston has a large squish region at a peripheral location on the piston top and a depression in the center of the piston top. A side injector sprays fuel into the depression in the piston top through a channel defined in the squish region. In some embodiments, two injectors are provided that are diametrically opposed to each other. In some embodiments, the engine is an opposed-piston engine in which each piston has the squish regions and depressions in the piston top.