Showing papers on "Four-stroke engine published in 1982"

Method of improving the efficiency of a supercharged diesel engine

Abstract: The invention relates to a method and a device for improving the efficiency of a four-stroke-cycle internal combustion engine. The main purpose of the invention is to obtain an effective compression ratio that is capable of automatic variation without introducing additional elements whatever the load, but only by adapting the engine cycle timing diagram. Said timing diagram includes an overlap stage between the lifts of at least one exhaust valve and at least one intake valve, said intake valve being closed near or before the bottom dead center of the piston, and said exhaust valve being closed beyond the instant of fixed closing of the intake valve.

Method and apparatus for improved engine braking and operation

Abstract: A method and apparatus for providing improved engine braking and improved engine operation following a braking operation is disclosed. The invention relates to a turbocharged internal combustion engine fitted with a compression relief type of engine brake wherein the turbocharger comprises a double entry turbine. In addition, a diverter valve is provided which is adapted to divert all the flow of exhaust gases into one portion of the turbine. The combination of the present invention increases the retarding horsepower developed by the engine by increasing the mass flow of the air through the engine and increasing the exhaust manifold temperature and pressure. Improved performance following braking results from the higher turbocharger speeds and increased engine temperature produced in the engine during the braking operation.

Free-piston engine with operatively independent cam

Abstract: A free-piston engine formed by one or more units, each comprising a pair of opposed pistons connected to a common piston rod and movable within two opposed cylinders, with a load, such as the inductor of a linear alternator, connected to an intermediate point of the piston rod, and in which there is provided at least a cam controlled by an operatively independent motor and engaging at least a tappet connected to the piston rod of a unit of pistons. This cam is profiled and controlled in such a way as to substantially follow the movement of the tappets which is produced by the free-piston engine during normal operation, but to limit the travel of the piston units and provide the energy for the compression stroke, in case of anomalous operation. The cam serves also to start the engine, as well as to mutually synchronize the various units of pairs of pistons in engines having a plurality of units. The engine may also be in the form of an adiabatic engine fed by coal dust or other solid fuel.

Engine retarder slave piston return mechanism

Abstract: An hydraulic slave piston return mechanism is provided for an engine retarder of the compression relief type. The mechanism senses the position of the slave piston at the time when the engine exhaust valve has been opened. At this point, the hydraulic pressure on the slave piston is equalized by opening a passageway through the slave piston to an accumulator whereupon the engine exhaust valve spring immediately closes the exhaust valve. Thereafter, the accumulator returns the hydraulic fluid to the hydraulic circuit. The mechanism assures that the exhaust valve opened near the end of the compression stroke to produce the desired engine retarding effect is closed prior to the end of the expansion stroke without affecting the retarding horsepower produced by the engine retarder or the normal functioning of the exhaust valve during the exhaust stroke of the engine.

Four stroke thermal engine capable of temporary boost

Abstract: The invention relates to a thermal engine provided with inlet and exhaust valves and with a system for controlling said engine comprising a computer which regulates opening and closure of said valves and which imposes on said engine an operation close to the one corresponding to minimum specific fuel consumption. According to the invention, this assembly is characterized in that said engine is essentially of the four-stroke cycle type, in that said system comprises means adapted to detect overloads of the engine and means adapted to cause the engine to operate exceptionally in two-stroke mode, these latter means being actuated by said detection means when the detected overload exceeds a predetermined threshold so that in that case the engine passes to two-stroke operation, four-stroke operation being resumed as soon as the overload has disappeared. The invention leads to obtaining a low consumption of fuel for increased power.

Control device for the turbine bypass valve of a turbocharged internal combustion engine

Abstract: A control method and device for the waste gate of a turbocharged internal combustion engine. This exhaust discharge control device entails a waste gate held closed by at least one spring which pushes it back into the closed position against the engine air feed pressure prevailing immediately downstream from the compressor and acting on a control piston for the gate in order to bring about the opening of the gate and to bypass the turbine. The control chamber (20) delimited by at least a part of the surface of the control piston (22) is connected by a conduit (25) and a control valve (27) to a source of fluid under pressure (29, 28a). The control valve (27) is activated by the accelerator pedal (35) of the engine in the area (36) of low engine loads. The invention is applicable to the automatic bypassing of a supercharging turbocompressor's turbine at low engine loads.

Measurements in a Motored Four-Stroke Reciprocating Model Engine

Abstract: Measurements of ensemble-averaged axial and swirl velocities and the rms of the corresponding fluctuations obtained by laser-Doppler anemometry, are reported for the axisymmetric swirling flow in a four-stroke model engine motored at 200 rpm with a compression ratio of 3.5. A centrally located valve, incorporating a 60 degree seat angle and 30 degree swirl vanes resulting in a swirl number of 1.2, was used to draw in and exhaust seeded air. The piston-head configurations included a flat surface and a cylindrical bowl with and without a lip. Comparison of the results with those obtained previously, with a flat piston in the absence of compression, shows that the mean and rms profiles during the intake stroke are similar. In the axial plane a system of vortices is created which has almost disappeared by the time the inlet valve closes with a small vortex existing near the cylinder head at the early part of compression; later on this vortex breaks up and the mean velocities tend to become uniform. The intake generated turbulence decays gradually until the inlet valve closes; it then becomes uniform and remains constant in magnitude for the rest of the compression stroke. The mean swirl flow has a spiralling nature during intake but tends towards solid body rotation during compression with associated turbulence levels of similar magnitude to the axial ones. During the expansion stroke the rms velocities decrease further until the exhaust valve opens and new turbulence is generated. The influence of the piston bowl is generally small but the addition of a lip results, during the compression stroke, in inward movement of the air towards the bowl as the piston approaches TDC. The reverse squish effect, observed during the expansion stroke and due to the outgoing motion of the entrapped air inside the bowl, results in significant reversed velocities near the axis and increase in the turbulence levels close to the piston.

Hydraulic valve timing control device for an internal combustion engine

Abstract: A device for controlling the intake and exhaust valves (6 and 7 respectively) of an internal combustion engine. Separate valve actuators (10a, 10b) are provided for opening and closing the intake and exhaust valves (6 and 7 respectively) of each cylinder (2) of an engine. Each such actuator (10a, 10b) is connected to a pair of cam actuated pumps (14) for providing timed pulses of pressurized fluid to the valve actuators (10a, 10b). The cams (19, 24) which actuate the pumps (14) are turned by a planetary gear mechanism (22, 23, 29) which permits the incidence of pump actuation in relation to the rotation of a shaft (5) turned by the engine to be varied. The device permits close, precise and variable control of the valve timing of the engine to thereby achieve enhanced engine performance.

Fuel system for compression ignition engine

Abstract: A fuel system for a compression ignition engine includes a body defining a mounting for a fuel injection nozzle. The body also accommodates a reciprocable piston fuel pump having a piston which is actuable by an engine driven cam. The body also defines a surface which in use locates against a surface on the engine cylinder head. The surface is well removed from the bore in the cylinder head of the engine which contains the injection nozzle. In this manner forces applied to the body during operation of the system are applied to the cylinder head of the engine in an area which is sufficient strong to withstand the forces.

Cylinder Cutoff of 4-Stroke Cycle Engines at Part-Load and Idle

Abstract: In order to improve fuel consumption, the effects of cylinder cutoff on engine performance were investigated on a 4-stroke cycle in-line 6-cylinder gasoline engine. It was found that the cylinder cutoff obtained by deactivating both the inlet and exhaust valves was very effective for reducing the fuel consumption at part-load and idle, as both the pumping power for the inlet and the power for activating the inlet and exhaust valves were noticeably decreased. 10 refs.

Centrifugal governor for internal combustion engine

Abstract: A centrifugal governor ensures a positive engine starting operation as well as a smoke control in the low engine speed range and a usual fuel injection control responsive to an increase in engine speed. A control rod with a rack is operatively connected with a floating lever through a spring biased piston and cylinder assembly, so that the control rod can be freely moved to its maximum fuel injection position during engine starting without being effected by a smoke limiter, which may be associated with the governor for a smoke control purpose. A unique lever mechanism is operable to move the control rod to the maximum fuel injection position during engine starting but, after a predetermined engine speed is reached, yields to a movement of the control rod in a fuel decreasing direction caused by the floating lever through the piston and cylinder assembly.

Time Dependent Analytical and Optical Studies of Heat Balanced Internal Combustion Engine Flow Fields.

Abstract: : Comparison is made of the nonsteady combustion and flow processes predicted by the method of characteristics for time dependent compressible flow in a heat balanced engine with photographic records of combustion flow fields observed by high speed Fastex Schlieren and holographic interferometry. Pressure exchange and the accompanying mass transport are demonstrated analytically and observed optically. Qualitative agreement between the initial top dead center calculation and photographic evidence is seen. Schlieren and interferometer records give typical combustion flow field interactions through all strokes of an operating four stroke glass walled two dimensional engine. At least four models of time dependent combustion are identified over the entire power stroke and the influence of geometry on the control of combustion chamber pressure and temperature is discussed. (Author)

Crankcase supercharged four cycle engine with jet pump assist

Abstract: A crankcase supercharged four cycle engine (10) includes an outside air inlet port (22) positioned so that upon each expansion stroke of the piston (11) a charge of pressurized air is fed to the crankcase (15), and hence through a one-way valve (25) and nozzle (26) into an enclosed surge tank (28). A tuning pipe (30) disposed within the surge tank has an inlet (31) at the nozzle outlet and provides a tuned passage which connects for discharge through a valved port (20, 21) into the engine cylinder (12). On one downward stroke of the piston, air from the outside air inlet port is compressed into the crankcase and is forced through the one-way valve and nozzle to provide a charge of compressed air which is trapped within the surge tank and tuning pipe. On the next downward stroke of the piston, another charge of compressed air is forced through the nozzle and into the tuning pipe inlet. A venturi effect is created which draws the previous charge of air trapped in the surge tank into the tuning pipe, which increases the pressure within the tuning pipe for discharge through the valved port into the engine cylinder.

Four-cycle engine

Abstract: Several embodiments of induction systems for internal combustion engines which provide stratification with an open chamber thus eliminating the need for auxiliary chambers and obviating the need for employing fuel injection In all embodiments, first and second intake passages communicate with the chamber and one of these intake passages delivers a substantially weaker mixture than the other This weaker mixture is admitted during the initial intake stroke and a richer fuel/air mixture is admitted at the end of the intake stroke so as to insure the existence of a stoichiometric mixture at the spark plug at the time of firing

Method of regulating the charge of combustion gas delivered to an internal combustion engine

Abstract: In a method of regulating the delivery of the combustion fluid (i.e. air or mixture of air and fuel) to an internal combustion engine (1), the combustion fluid is conducted through a gas engine or positive displacement device capable of operating as a fluid motor or a fluid compressor (2) which is drivingly coupled with the internal combustion engine, and the flow rate through the device (2) is varied in the sense of the desired load change by means of a control device (3, 23) on the device. The positive displacement device (2) may be operated as a fluid motor and/or as a supercharger. As a fluid motor the work done by the expansion of the combustion gas is used to assist the engine (1), whereas the engine (1) drives the gas engine (2) when operating as a supercharger. In a preferred embodiment the device (2) is of the rotary vane type (FIG. 3) and the rotational speed ratio between the internal combustion engine (1) and the device (2) is fixed, the fluid flow rate being varied by a control device which has a displaceable control edge (22) in the gas inlet region (5) of the device for varying the intake volume and which is moved by an actuating lever (15) linked to the load regulator of the internal combustion engine (1). In the embodiment of FIG. 3, the control device comprises a segment (23) of the casing (19) bounding the working space (20) of the gas engine, the segment being rotatable about the vane axis (11). The control edge (22) is formed by one end of the segment (23), and a further control edge (24) may be formed at its opposite end for operating in the gas outlet region (21) if the engine (2) is required to operate as a supercharger in an upper load range.

Device for controlling the compression ratio of a 4-stroke reciprocating piston internal combustion engine as a function of the load

Abstract: The invention relates to a device for controlling the compression ratio of a 4-stroke reciprocating piston internal combustion engine as a function of the load with a secondary piston, assigned to each cylinder and adjusting the volume of a secondary combustion chamber connected to the cylinder working chamber, to which secondary piston an adjustable piston, which can be acted upon by a pressure medium supplied at essentially constant pressure and which slides in a hydraulic cylinder, is connected. In order to achieve as compact and simple a construction as possible and a rapid response of the control device, it is proposed that a control sleeve, adjustable in an axial direction of the hydraulic cylinder, be provided which has a control edge interacting with the pressurised face of the adjusting piston in order to control the outflow of pressure medium. At the same time the control sleeve may be adjustable as a function of the load of the internal combustion engine in that, for example, it is connected to the load control element.

Valveless internal combustion engine

Abstract: In an internal combustion engine operating on the two-stroke principle holes (7, 8, 9) in the cylinder wall are fully or partially closed or opened by a slide valve (10). A quantity of combustion air matched to the respective fuel injection quantity is thereby retained in the cylinder (1), whilst the excess air for the stoichiometric air-gas ratio escapes through the exhaust port (6) before compression by the piston (3).

Air-compressing, direct-injection internal combustion engine

Abstract: An air-compressing, direct-injection internal combustion engine formed with a combustion chamber in the shape of a solid of revolution in the piston crown into which fuel is injected via only one jet through an injection nozzle arranged obliquely in the cylinder head, in the direction of the rotating air for combustion. The working of the internal combustion engine is proposed to be improved in such a way that fuel deflection liable to occur in all operating ranges, mainly at the start and at the end of injection due to the rotating air flow and, respectively, when the gas is flowing out of the combustion chamber after the top dead center position, is prevented from affecting the working of the engine and from producing erosion on the piston crown and/or cylinder head. According to the new disclosure, this is essentially achieved by having the fuel jet discharge point of the injection nozzle at top dead center of the piston lying below the piston crown level and projecting into the combustion chamber, and by having the injection nozzle surrounded, with a clearance, by a longitudinally slotted sleeve which is open at the end and projects beyond the discharge orifice (fuel emission point).

Device for the releasable fixing of the pistons to the piston rods of an internal combustion engine

Abstract: Device for the releasable fixing of the pistons to the piston rods of an internal combustion engine with two mutually opposite cylinders and a central slider crank to which the piston rods are coupled in order to convert the reciprocating movements of the pistons into a rotary movement, the device being a necked-down bolt which passes centrally through the piston bottom and the piston rod along their lines of symmetry.

Conical piston and cylinder head in internal combustion engine

Abstract: In an internal combustion engine a piston and a cylinder head defining a cylinder with a blind end thereatop are formed in a conical configuration. The piston compresses charges of an air/fuel mixture in the blind end of the cylinder, whereupon ignition of the fuel is initiated. Combustion of the fuel proceeds first from the region of ignition in the blind end of the cylinder and then along the interstitial space between the diverging conical walls of the cylinder head and piston. The expanding products of combustion squeeze the piston from the top and the sides, thereby transferring power smoothly and directly to the piston. The progress of combustion spreads equally both downwardly and radially outwardly from the axis of the piston, thereby providing an efficient transfer of power with a high fuel economy.

Inlet tuning of crankcase supercharged four cycle engine

Abstract: A crankcase supercharged four cycle engine (10) includes an outside air inlet port (22) positioned so that upon each expansion stroke of the piston (11) a discrete pulsed charge of pressurized air is fed to the crankcase (15), and hence from the crankcase through a one-way valve (26) into surge tank (28). The surge tank chamber (29) is connected through a tuning pipe (31) to a manifold volume chamber (34) leading to the air intake (20) of the engine cylinder (12). The tuning pipe is designed with the correct length and volume to provide a resonant frequency which increases engine torque at low speed. The construction provides a closed loop connection (24) between the crankcase and engine cylinder which is subjected to air pressure pulses which are directly responsive to the frequency of reciprocation of the piston. A pressure multiplier effect is obtained within the loop to substantially increase the pressure of air ultimately fed to the cylinder.

Internal combustion engine piston

Abstract: A piston for medium-speed internal combustion engines having a ring groove for receiving a compression piston ring. The upper and lower flanks of the ring groove when the engine is cold deviate from a plane-parallel position in relation to the adjoining upper and lower flanks respectively of the ring to such an extent that under the mechanical and thermal loading of the combustion gases in operation of the engine under rated load they are deformed into a position plane-parallel with the flanks of the ring.

Non-compression internal-combustion engine

Abstract: A method of operating a three-stroke internal combustion engine having a cylinder (1) and a piston (2) reciprocable in said cylinder, said piston having a crank rod (3) pivoted to the piston, the opposite end of the crank rod being rotatably mounted to a crank shaft (4) to be rotated under the influence of the reciprocating movement of the piston. The operating cycle of the engine comprises a suction stroke, an expansion stroke and an exhaust stroke. According to the invention, the suction stroke extends over a fraction only of the total stroke of the piston, an instant ignition of the fuel mixture sucked into the cylinder then being effected. The following expansion is effective during the remaining portion of the movement of the piston towards the lower end position in the cylinder.

Method and apparatus for utilizing ethanol of any purity as a fuel in 4-stroke internal combustion engines

Abstract: A method and apparatus for thoroughly mixing ethanol and air in the right proportion for efficient combustion in the engine consisting the active steps of aspirating the air by means of the vacuum pressure developed by the piston displacement of the engine in the intake stroke; bubbling said air into the liquid ethanol thereby evaporating said ethanol; mixing them in a homogeneous air-fuel flammable mixture; and introducing the mixture into the engine's intake manifold.

Internal combustion engine having a rotating piston assembly

Abstract: An internal combustion engine having a rotating piston assembly is proposed in which the rotating piston assembly includes a cylinder which rotates about its longitudinal axis, at least one piston element pivotably mounted at one end within the cylinder for pivotal movement in the radial direction of the cylinder, at least one work chamber disposed adjacent to at least one piston element, and at least one valve slide which is displaceable with the piston element for controlling flow into and out of the work chamber.

An internal combustion engine

Abstract: An internal combustion engine of the piston and cylinder type is provided. The conventional cylinder head is replaced by a detachable head assembled from two hollowed out cylinder head components one of which (3a) is shown. The components when assembled provide a cavity (4) which is contoured so as to accommodate in gas-tight sealing with the walls thereof a rotor (5) having a pair of drums (7, 8) thereon, each drum (7,8) has a rotor passage (7a, 8a) thereon so that when the rotor (5) is rotated (in a conventional manner), the rotor passages (7a, 8a) provide an uninterrupted conduit between the carburettor and the cylinder or the cylinder and the exhaust manifold during the induction stroke and the exhaust stroke respectively of the piston of one cylinder of the engine. Four pairs of drums are provided on the same rotor for use in a four cylinder, four stroke engine. Each drum (7,8) has a spherical section (130) defined by two parallel planes (131,132) of a sphere the planes being disposed symmetrically about the centre of the sphere, and the intersection between the planes and the spherical section being rounded off.

Multi-cylinder piston engine with controlled valves.

Abstract: 1. Multi-cylinder piston engine with controlled valves, with a V-arrangement of its cylinders, in addition with an even number of cylinders and a cam shaft for each row of cylinders to control gas exchange valves and other engine units, like fuel pumps, which cam shafts can be driven by the crankshaft by means of a control drive, characterised by the following features, - the cam arrangement on the cam shaft (10) of one row of cylinders is identical to the cam arrangement on the cam shaft (9) associated with the other row of cylinders, - the cam shaft (10) of one row of cylinders is arranged on the internal-combustion engine turned by 180 degrees lengthways with respect to that (9) of the other row of cylinders, - the crankshaft (12) - dependent on the firing order predetermined on the cam shafts (9, 10) - is arranged in the internal-combustion engine for running in one direction of rotation (28) in a first fitting position and for running in the opposite direction of rotation (29) in a second fitting position rotated by 180 degrees lengthways with respect to the first fitting position, - the control drive (13) is constituted by gears through which the two cam shafts (9, 10) can be driven with opposite direction of rotation (11, 15), - the control drive (13) further has an intermediate gear (14) which is variable in such a way that the directions of rotation (11, 15) of both cam shafts (9, 10), predetermined on the part of the cam arrangement and on the part of the firing order, are preserved with each crankshaft rotation direction - right hand run or left hand run (28, 29), with which in the case of a reversible internal-combustion engine it is the crankshaft main direction of rotation.

Stratified charge variable compression ratio engine

Abstract: An engine includes an engine block (10) provided with cylinders (12,14) having two pistons (16,18) and a cylinder head (19) having a piston (20) biased by means of torsion bars (24). The biased piston (20) is held in position by an arm (22) which is restrained by torsion bars (24). During the compression stroke of the engine the biased piston (20) is seated with faces (30,32), in contact and on ignition of the compressed mixture the biased piston (20) is lifted off the seat (32) creating a common combustion chamber in which separate charges are mixed. The biased piston (20) limits the combustion space and thereby controls the compression ratio to suit the desired performance.