Showing papers on "Four-stroke engine published in 1993"

Skip-cycle strategies for four cycle engine

Abstract: Strategies for operating a four cycle engine in skip-cycle manner include providing the engine with a valve control so that each intake and exhaust valve for each cylinder can be individually activated or deactivated essentially instantaneously to provide a skip-cycle pattern that varies as a function of the load. Individual of the valves permits changing the purpose of the stroke off each piston of each deactivated cylinder from compression to exhaust or intake to expansion, as the case may be, to assure firing of all of the engine cylinders within as short a period as one skip cycle to prevent cylinder cooldown, which promotes emissions. Unthrottled operation also is provided by closing the intake and exhaust valves in a particular sequence during skip cycle operation, and controlling the intake valve closure timing during load periods between skip cycle periods to continue unthrottled operation for all load levels. Further individual activation or deactivation of the fuel injectors and spark plugs enhances the skip cycle, unthrottled operation.

System and method for synchronously activating cylinders within a variable displacement engine

Abstract: A system for synchronously activating cylinders of a multicylinder, fuel injected, four stroke cycle internal combustion engine, includes a valve operator for deactivating intake and exhaust valves associated with the cylinders and a controller for selecting a cylinder to be deactivated, as well as a timing mechanism for determining when the selected cylinder is operating during intake events. The controllers directs the valve operator to begin deactivating the valves of a selected cylinder during a predetermined intake event, with the valve operator completing the deactivation by a time not later than the beginning of the next exhaust event.

Apparatus and method for analyzing events for an internal combustion engine

Abstract: In one aspect of the present invention, an apparatus for analyzing a plurality of events of an internal combustion engine is provided. A crankshaft sensor monitors the rotational position of the crankshaft and responsively produces a crankshaft pulsetrain. A cylinder pressure sensor senses the pressure produced in the engine cylinder and responsively produces a cylinder pressure signal. A memory device stores previously calculated values representing engine cylinder volumes at predetermined crankshaft positions. A microprocessor determines the start of combustion for an occurring engine cycle in response to a cylinder pressure signal magnitude, P 2 , at a current crankshaft position being equal or greater than the relationship: P.sub.1 (V.sub.1 /V.sub.2).sup.n where, P 1 equals the cylinder pressure corresponding to a previous crankshaft position, V 1 equals cylinder volume corresponding to the previous crankshaft position, V 2 equals the cylinder volume corresponding to the current crankshaft position, and n equals a predetermined polytropic value. Advantageously, the start of combustion is determined prior to the next occurring engine cycle.

Four-cycle engine

Abstract: A motorcycle engine having an exhaust passage air introduction system. Each cylinder includes two exhaust passages which are joined at a point displaced from the engine. Air is introduced into one of the exhaust passages of the two so as to more fully combust the unburned gasses within the exhaust passage and then to more fully combust the unburned exhaust in the joined passage. The timing of the valves associated with each exhaust passage is such that the valve associated with the passage having the air inlet has advance timing. A chain tensioner for the timing chain includes a tensioner cylinder hydraulically actuated by the engine oil. A gasket having an orifice therein is positioned between components in the oil passageway extending to the tensioner cylinder. The oil cooling system of the engine includes an oil filter and an oil cooler which are displaced from one another and mounted to a common base which is in turn mounted to the engine. The base includes passageways to direct oil into and out of each of these components.

Performance improvement design for two-stroke engines

Abstract: A two stroke engine having a variable inlet port timing device in conjunction with a piston port controlled timing apparatus for filling the top of transfer passages, that connect the crankcase chamber to the combustion chamber of the engine, with buffer gas such as exhaust gas or secondary air for the reduction of pollutants, improvement of performance, and delivery ratio of an internal combustion two-stroke engine and the like. Piston port controlled timing is provided by buffer air passages having a movable portion with inlet and outlet ports disposed through the piston. In another embodiment piston controlled selective exhaust gas recirculation is provided and a rotary valve in the exhaust gas recirculation passage is fitted to improve the performance of the engine. The pressure in the crankcase may be controlled by a rotary valve comprises a pair of rotary disc plates.

Method and controller for supplying fuel to cylinders of multicylinder internal combustion engine

Abstract: A method and a controller for supplying a fuel to a plurality of cylinders of an internal combustion engine, in which engine operation conditions including the operating temperature of the engine are detected by various sensors attached to the engine and by using a microcomputer, and the fuel is successively supplied by being injected to the engine cylinders based on the detected engine operation conditions. The timing of fuel injection into each of the plurality of cylinders is . .shifted from an exhaust stroke period to a suction stroke period according to the operating temperature of the engine among the detected engine operation conditions.!. .Iadd.set in a suction stroke period at the time of the engine starting in a low temperature condition, and is shifted to an exhaust stroke period as the level of the engine temperature rises.Iaddend..

Compression release engine braking systems

Abstract: In a compression release engine braking system for a turbocharged internal combustion engine, excessive stress associated with opening the exhaust valves of the engine near top dead center of engine compression strokes when the engine is turning at high speed is prevented by reducing the intake manifold pressure from what it otherwise would be at that high speed. This is done by retarding the turbocharger so that its speed is less than it otherwise would be at high engine speed. Turbocharger retarding can be accomplished in any of several ways such as by restricting the flow of engine exhaust gas to or from the turbocharger, or by allowing a portion of the exhaust gas to bypass the turbocharger.

Compression release engine brake with selectively reduced engine exhaust noise

Abstract: In order to make the use of compression release engine brakes on the internal combustion engines of vehicles more acceptable in areas (e.g., urban areas) where high levels of engine exhaust noise are undesirable, the operator of the vehicle can adjust the "lash" of the engine brake to reduce engine exhaust noise whenever desired. The "lash" of the engine brake is the "at rest" clearance between engine brake slave piston and the engine exhaust valve mechanism operated on by the slave piston to produce engine braking. Engine exhaust noise associated with engine braking is reduced by reducing this lash or clearance so the engine brake opens exhaust valves in the engine at lower engine cylinder pressures, thereby reducing the associated exhaust noise. Despite the reduced exhaust noise, the engine brake still provides a substantial amount of engine braking horsepower.

Differential stroke internal combustion engine

Abstract: An internal reciprocating engine (10) effective to operate at one engine cycle per revolution is provided with a differential stroke piston (14) having an inner piston part (14a), for sealing the cylinder (12), operating at a cycle different from its corresponding outer piston part (14b), and a differential stroke actuating means (62) for operating the inner and outer piston parts (14a, 14b) in the same and the opposite directions within the cylinder (12) and to provide differential stroke periods and/or stroke lengths for the inner piston part (14a) cycle.

Method for recognizing the power stroke of a four-stroke engine

Abstract: A method for recognizing a power stroke of each cylinder in a four-stroke engine calls for sensing a parameter of a cylinder in the engine for producing a signal of the parameter, the parameter being selected from the group consisting of pressure and knocking, and comparing the signal with a threshold value for determining whether the signal exceeds the threshold value and thereby is indicative of the cylinder being in a corresponding combustion stroke. In addition to sensing the pressure and knocking of the cylinder, sensing of sound signals from the cylinder is also employed in order to determine power and intake strokes of the cylinders.

Internal combustion engine having high performance combustion chamber

Abstract: An internal combustion engine has a cylinder head with a combustion chamber defined by a depression in the head. The raised face surface of a piston extends into the combustion chamber in the cylinder head as the piston approaches top dead center, and creates turbulent squish currents within the chamber as closely matching surfaces on the piston face and on the walls of the combustion chamber in the head force gases out from between these surfaces. The turbulence helps to prevent autoignition and allows higher compression ratios than would otherwise be possible.

Control system and method for governing turbocharged internal combustion engines

Abstract: A control system and method for governing turbocharged internal combustion engines is disclosed including an electronic control unit, a fuel flow control valve, an engine speed sensor, and a bypass valve to control exhaust gas flow through an exhaust bypass conduit. When engine speed is above a first predetermined engine speed, the electronic control unit controls the bypass valve to regulate exhaust gas flow through the bypass conduit, thereby limiting exhaust gas flow through the turbocharger. When the engine speed reaches a second, predetermined engine speed value that is higher than the first predetermined engine speed value, the electronic control unit completely opens the bypass valve allowing virtually total bypass of the turbocharger, and limits fuel flow to the engine by controlling the fuel flow control valve.

4-cycle engine

Abstract: A V-type multi-cylinder 4-cycle engine E accommodated in an engine room in an outboard motor includes a pair of left and right banks. A surge tank is disposed in a space defined between both the banks and connected to two left and right combustion chambers through intake ports. A throttle body is connected to a lower portion of the surge tank and also to an intake silencer mounted in a left space of the engine room through an elbow. A subsidiary tank for supplying a fuel to an injector is disposed symmetrically with the intake silencer in a right space of the engine room. The employment of the above-described layout makes it possible to reduce the size of the intake device of the 4-cycle engine.

Pulsed piston-compressor jet engine

Abstract: An air-breathing pulsed jet engine for aircraft propulsion which employs a piston compressor rather than much more expensive axial or centrifugal compressors and turbines employed by conventional turbojet engines. The engine is similar to the common two-cycle gasoline engine, except its cylinder head comprises a jet nozzle with an internal pressure-activated nozzle-blocking valve. A spring keeps this valve closed during the engine's compression stroke when the piston, connected to a crankshaft and flywheels by a connecting rod, is forced by the moment-of-inertia of the flywheels toward the cylinder head. When ignition and combustion of the compressed air and fuel occurs slightly before the piston reaches the top of its stroke, the much greater pressures within the engine's combustion chamber force the valve to pivot open. This allows a jet of combustion gases to be released through the jet nozzle into the atmosphere. The reactive forces of the gas jet work against the piston to produce linear thrust (due to the moment-of-inertia of the flywheels) and to store up energy in the flywheels to motivate the piston through the next compression stroke. The jet pulse continues until the pressure inside the combustion chamber drops to a predetermined level, when the spring is able to close the valve. Since the pressures inside the combustion chamber of a gasoline engine are on the order of those inside many rocket motors, the thrusts imparted to the engine during each jet pulse is substantial.

Monoblock internal combustion engine with air compressor components

Abstract: Monoblock engine/air compressor combinations, particularly those providing high pressure gas, experience problems in lubricating the piston pins connecting the compressor piston assemblies to the engine connecting rods. To alleviate this problem, additional weight is added to the compressor piston assemblies to force a load reversal at a determinable point in the piston cycle just after top dead center, thereby facilitating lubrication of the piston pins. An equation is disclosed for calculating the weight of the compressor piston as a function of the compressor gas pressure, geometry of the rotating components and engine speed. In another aspect of the invention, weight is added to the engine flywheel to balance an unbalanced compressor piston after the additional weight has been added. In another feature of the invention, a fluid system is provided in a natural gas powered engine in the monoblock combination, which system is designed to purge a volatile residual natural gas/air mixture collecting in the engine crankshaft through piston blow-by. A final feature concerns a supercharger system for providing supercharged air to the engine air intake manifold, which incorporates a plenum surrounding the fan and heat exchanger element of the engine cooling system.

Rotary piston machine and method of manufacturing piston

Abstract: The rotary piston (6) with rotation axis C performs a relative rotation in an annular cylinder (1) with rotation axis O which is displaced with respect to said piston axis (C) by an eccentricity e. The cylinder (1) comprises three chambers (2) having cylindrical surfaces (3) which engage the piston (6). The piston (6) has two semi-cylindrical surfaces connected by connecting surfaces (8). Each connecting surface (8) has a shape generated by replacing one of the three rollers with a machine tool (5') and displacing the piston with the other two rollers (5). The surface of said piston (6) is continually supported on three rollers (5) of said cylinder (1). The relative position, i.e. the relative movement of said piston (6) and said cylinder (1), is rigidly determined by the support of the piston on rollers (5) and by the eccentricity (e) between the piston and the cylinder axes. The machine can be used as a combustion engine, a volumetric pump, or as a hydraulic motor. The rotational movements of the piston and of the cylinder are well equilibrated without any unbalance, and the machine can turn at high speeds without vibrations and without noise. As a combustion engine, it allows a high efficiency, a minimum pollution and a high specific power.

Internal combustion (IC) engine

Abstract: An internal combustion (IC) engine with at least one pair of aligned and opposed cylinders has a reciprocating double-headed piston in each cylinder pair. The axis of the double-headed piston is perpendicular to a driveshaft. The reciprocating motion of the double-headed piston is transmitted to the driveshaft by a rotating crankdisk. The crankdisk is rigidly mounted to the driveshaft, which is rotably mounted to a crankcase. The resulting IC engine has a low engine profile, as well as simpler engine construction with fewer moving parts and fewer bearing surfaces compared to conventional IC engines and yoke-type engines.

Apparatus and process for determining top dead center of a piston and crank shaft in an internal combustion engine

Abstract: An apparatus and process which can be used to determine the top dead center position of a piston. The apparatus includes an actuator plunger which engages the rocker lever of an engine cylinder, and a gauge indicator to measure movement in the rocker lever when it is engaged by the piston. The process includes measuring the position of the piston on the upswing of the power cycle and in a corresponding position on the downswing of the piston during the exhaust cycle. The center point between these two measurements is the top dead center point of the piston.

Large two-stroke internal combustion engine

Abstract: An internal combustion engine (1) has hydraulically driven exhaust valves (13) and fuel pumps (18). The hydraulic drives are controlled by means of a computer (16) and electrically activated positioning means (64) setting a spool in a spool valve. If the electronic control of the engine fails, the spool movement may be controlled by a first piston (41) on which the pressure in a hydraulic hose or conduit (48) acts, said conduit extending to a second piston (44) which may follow a cam (26) on a rotating camshaft. The hydraulically driven cylinder members (13, 14, 18) associated with each of the engine cylinders are mounted at the pertaining cylinder, whereas the camshaft (23) independently of the positioning of the cylinder members is disposed at an appropriate shaft drive, such as the crankshaft (11). The cam shaft has a very short length and small mass and may for instance be disposed at one end of the engine.

Variable cycle three-stroke engine

Abstract: A virtual three-stroke engine (1) with intake and compression strokes approximately one half of the power stroke of approximately 12 to one expansion ratio and with total firing cycle stroke lengths equal to approximately three expansion strokes to minimize engine throttling and frictional losses over the real world drive cycle and provide high torque from a one-to-one drive shaft RPM to engine firing cycle RPM provided by a cam type driver for controlling the piston motions and extracting the power from the piston.

Cam drive arrangement for driving the pump piston of an injector pump of a four-stroke internal combustion engine

Abstract: A special control cam arrangement for controlling the pump pistons of an injection pump of a 4-stroke internal combustion engine, especially a diesel engine, is created, which is characterised in that the control cam(s) (17) and the associated base circle(s) (20) are provided on the crankshaft (4) of the internal combustion engine and that a pump is used as injection pump (11), the delivery of which is controlled by solenoid valves (18 and 22, 23 and 24, 25, 26). This produces a series of advantages such as reduced engine manufacturing costs, higher rates of delivery, excitation of less torsional vibration and noise, and lower Hertzian stresses.

Engine brake for diesel IC engine - has operating device with hydraulic piston for decompression in area of TDC with hydraulic piston control line in chamber enclosed by cylinder head and cylinder head hood

Abstract: Near the exhaust valve is arranged a separated decompression valve (3) and the path control (9) connected to it is integrated in the housing interior of the IC engine. The control line (10) is located in the chamber enclosed by the cylinder head (1) and the cylinder head hood (2) or in the cylinder head itself. The path control (9) is formed by a slider valve, the control slide of which is longitudinally displaceable and is transferable from an injection position connecting the injection pump with the injection nozzle (6) to an engine brake position connecting the injection pump with the decompression valve (3). USE/ADVANTAGE - Engine brake system for goods vehicle diesel engine which takes up little space and provides durable trouble-free braking.

Two-state internal combustion engine

Abstract: The invention is directed to a two-stroke internal combustion engine for handheld portable tools such as a motor-driven chain saw with the engine having a piston guided in a cylinder. The base of the piston is rotationally symmetrical and delimits a combustion chamber. An injection valve is mounted in the cylinder wall opposite an exhaust opening for exhaust gases. The injection valve injects fuel toward the piston base at an angle of less than 90°. At least one overflow opening is arranged in the cylinder wall between the exhaust opening and the injection valve. Combustion air flows in through the overflow opening with the downward movement of the piston. The injection jet is directed opposite to the flow direction of the entering combustion air. The injection jet is directed for the most part to the half of the piston base which is disposed away from the exhaust opening and the injection opening is the last opening to be closed by the piston travelling toward top dead center. The duration of injection is continued beyond the closure of the overflow opening and of the exhaust outlet. In this way, an optimal air/fuel mixture is assured even at high rotational speeds.

Engine brake for heavy goods vehicle 4 stroke engine

Abstract: The invention relates to an engine brake in a 4-stroke internal combustion engine of a commercial vehicle, in which, during braking, the engine's own injection pump acts as hydraulic sensing device for hydromechanical actuating devices, by means of which the exhaust valves of the internal combustion engine are for a limited period during the compression cycles kept open by a smaller amount than normal. For this purpose an injection pump (1), specially designed for injection and braking operation, with special control grooves and edges (2, 3, 4, 5, 6, 11, 13) for each delivery element (K1 - Kn) and at least one fuel admission bore (7) and two associated outlet bores (8, 9) are provided. At the same time an injection pressure line (L1 - Ln) with built-in pressure valve (DV) and leading to an injection valve (E1 - En) of an engine cylinder (Z1 - Zn) is connected to each first outlet bore (8), whereas the control pressure line (S1 - Sn), which is staggered by at least one angular ignition interval within the given firing order, leading to the actuating device (10) of the exhaust valve (A1 - An) of each engine cylinder (Z1 - Zn) is connected to each second outlet bore (9). The delivery elements (K1 - Kn) of the injection pump (1) can be set with their control grooves and edges to such a position that during braking the injection pump-side delivery stroke can be utilised for opening and keeping the exhaust valve open, at least over the entire compression cycle. The engine brake can thereby be achieved cost-effectively using relatively simple means.

Four-cycle engine

Abstract: PURPOSE:To provide such an engine as capable of freeing a driving attitude with a four cycle which is advantagous from the viewpoint of heat efficient emission CONSTITUTION:This engine is featured that it is provided with a fuel feeder, supplying a mixture of air, fuel and lubricating oil, an air charging passage 26 installed in a cylinder head 3, each valve gear installed in an exhaust passage 25 and the cylinder head 3, an air charging chamber 27 installed in the air charging passage 26, a check valve connecting this chamber 27 to a crankcase 2, a cylinder 1 fitted with a cylinder exhaust port 21 in a side wall nearby the bottom dead center of a piston 4, and one muffler being interconnected each to the exhaust passage 26 and the cylinder exhaust port 21

Power plant for automobile

Abstract: An automobile power plant includes an engine with a crankshaft mounted transversely in an engine compartment, a differential disposed behind the engine, and a transmission which is transversely mounted between and below the engine and differential so as to place its input, primary output and counter output shafts in parallel with the crankshaft

Starter for multicylinder direct-injection four-stroke engine - employs crankshaft angle detector and computer to open magnetic injector valve immediately on passage through TDC.

Abstract: A suction pump (9) draws fuel and air from respective supply lines (10,11) and forces the mixt. through individually controlled magnetic valves (12-17) into the cylinders (2) just as each piston passes its TDC point. The angular position of the crankshaft (19) is detected by a static sensor (21) on the toothed flywheel (20), causing a computer (18) with memorised crankshaft angle recordings to open the valves and trigger the ignition in the respective cylinders according to its program. ADVANTAGE - Engine is started as soon as it is switched-on by device taking up less space and consuming less current.