Showing papers on "Four-stroke engine published in 1990"

A method and a device for engine braking a four stroke internal combustion engine

Abstract: The invention relates to a method and an arrangement for engine braking a four-stroke internal combustion engine. The engine has for each cylinder (2) at least one inlet valve (7) and at least one exhaust valve (9) for controlling communication between a combustion chamber (5) in the cylinder (2) and an inlet system (8) and an exhaust system (10) respectively. In accordance with the invention, the arrangement also includes means for establishing communication between the combustion chamber (5) and the exhaust system (10) in conjunction with the exhaust stroke and also when the piston (3) is located in the proximity of its bottom-dead-centre position after the inlet stroke and during the latter part of the compression stroke and during at least a part of the expansion stroke. Communication of the combustion chamber (5) with the exhaust system (10) is effected upstream of a throttling device (13) provided in the exhaust system, this throttling device being operative to throttle at least a part of the flow through the exhaust system (10) during an engine braking operation, therewith to increase the pressure upstream of the throttling device (13).

Exhaust back pressure control system

Abstract: An exhaust back pressure control system includes a valve in the exhaust outlet of a turbocharger of an internal combustion engine which is controlled by an engine control microcomputer. When the valve is moved toward a closed position, it restricts the exhaust flow, thereby increasing back pressure and friction within the engine by producing an artificial load thereon, and thus speeds up the warming process taking place within the engine upon starting thereof. The valve is moved by an actuating piston within a hydraulic cylinder using engine oil pressure controlled by an electrically operated valve receiving a pulse width modulated operating signal from the engine microcomputer, the operating signal being generated to provide a desired back pressure as a function of engine coolant temperature, engine speed, engine fuel comsumption, and actual back pressure. Operation of the system is enabled if the ambient air temperature is below 2° C. and also for the period that the elapsed time since start of engine is less than thirty seconds, the latter enablement being provided to exercise the system during extended periods of warm weather operation when the system would otherwise be inactive.

Engine cycle control system

Abstract: An engine cycle control system controls an engine so that it operates in a two-cycle mode when the rotational speed of the engine is lower than a predetermined speed and in a four-cycle mode when the rotational speed of the engine is higher than the predetermined speed. The engine con­trolled by the engine cycle control system (5) has intake ports (13) defined in a lower circumferential surface of a cylinder (1), an exhaust port defined in an upper portion of the cylinder and openable and closable at variable timing, and a fuel injec­tion valve (22) for injecting fuel into the cylinder at variable timing and in a variable quantity. Depending on the rota­tional speed of the engine, the timing of operation of an exhaust valve is varied to select the two-cycle mode or the four-cycle mode. The engine is associated with a turbocha­rger (4) combined with an electric motor (43). In a large-load range in the two-cycle mode, the electric motor is energized to assist in turbocharging operation for thereby increasing the torque produced by the engine.

Two plus two stroke opposed piston heat engine

Abstract: Combustion engines have opposed pistons in one or more cylinders, with the piston motion determined by cams. Ports, for intake and exhaust, are at one end of the cylinder, opened or closed by one piston, with the combustion chamber at the other end, and the engine being well suited to the optional use of a combustion chamber separate from the cylinder and with the communicating passages controlled by the other piston. That arrangement makes the engine particularly suitable for using heavy or unconventional fuels. The cam profile provides for a four-stroke cycle; one piston moves during the intake and exhaust strokes, while the second piston moves for compression and power strokes. Thus the advantages of a four-stroke engine are obtained while retaining the simplicity of a two-stroke engine. The cam profile may be tailored to the burning characteristics of the fuel, as by providing a period of dwell between the end of the compression stroke and the beginning of the power stroke. The engine is well suited to the use of compression ignition, but spark ignition is feasible. The isolated combustion chamber may also be replaced by a heat exchanger, to use an external heat source.

Reciprocating piston engine with pumping and power cylinders

Abstract: An internal combustion engine power unit comprises two power cylinders (3, 4) spaced equidistant about a pumping cylinder (5). All cylinders operate on two-stroke cycles, the power cylinders (3, 4) having a phase difference of 180°. Power piston asssemblies (13, 14) in the power cylinders (3, 4) drive crankshaft (1). Pumping piston (16) and separate crankshaft (2) are driven at twice the cyclic speed of the power pistons (13, 14) and crankshaft (1) through gear train (6, 7) between the respective crankshafts (1, 2). Air inducted into pumping cylinder (5) via intake ports (20) is compressed and passed alternately to power cylinders (3, 4) via valve controlled transfer passages (21, 24). All valves, ports and gas passages are found in a cylinder head (19). Timed fuel injection and ignition are provided. An engine may comprise one or more power units. There is also disclosed a turbo-charged diesel engine comprising two power units in ''V'' configuration.

OHC vertical crankshaft engine

Abstract: An OHC vertical crankshaft engine, comprising: a vertically disposed crankshaft having a first timing pulley at its lower end; a cooling fan attached to an upper end of the crankshaft; a camshaft extending in parallel with the crankshaft at a cylinder head end of the engine and having a second timing pulley at its lower end; and a timing belt passed around the timing pulleys. Thus, the need for lubrication for the transmission mechanism between the crankshaft and the camshaft is substantially eliminated, and the noise generation is reduced. Additionally, since the upper part of the cylinder head is directly exposed to the cooling air produced by a fan provided at an upper end of the crankshaft, a high engine cooling efficiency can be achieved. This effect is even more enhanced if the exhaust port of the engine is disposed above the intake port and extends horizontally and linearly away from the engine.

Delayed drop power stroke internal combustion engine

Abstract: This invention is designed to increase the net engine efficiency of four body linkage mechanisms used to generate power or do useful work. This is accomplished by decreasing the piston velocity in the first half of the power stroke of a typical engine cycle. The piston velocity is altered by the addition of three components at the crankarm pin location on the crankshaft. The new components convert a normal engine from a four body to a five body linkage mechanism. One component is an eccentric pin and the other two are an internal ring and pinion gear assembly that indexes and rotates the eccentric pin in a fixed relationship with the crankshaft rotation. The pinion gear and eccentric pin are integral and rotate together as a single part in a direction opposite to the crankshaft rotation. The outer eccentric diameter moves up as the crankarm moves down during the first part of the power stroke. This action decreases the piston velocity and allows more time for the cylinder pressure to increase while the cylinder chamber is still small. This results in higher cylinder pressures that act over a larger crankarm arc.

Continuous Identification of a Four-Stroke SI Engine

Abstract: Compact engine models often consist of a set of nonlinear differential equations which predict the time development of the mean value of the engine state variables (and perhaps some internal variables): such models are sometimes called mean value engine models. Currently a great deal of attention is focused on constructing such continuous time models and on finding their parameters. This paper shows, that it is possible to identify an engine model from a linearized version of a mean value model for a CFI four-cycle spark ignition (SI) engine. Such an approach is useful because it preserves a physical understanding of the engine throughout the identification stage. Afterwards the identification results are available for general dynamic engine studies. The identfication techniques discussed in this paper include classical methods (step response) as well as modern statistical methods (Kalman filtering and Maximum Likelihood estimation). These techniques have been applied to a four cylinder SI engine. The results include an identification of the most important parameters and time constants of the engine. These are of interest for the construction of engine simulation models, for control studies and condition monitoring applications.

Spark ignited internal combustion engine and a control system therefor

Abstract: A spark ignited internal combustion engine is disclosed in which at least one of the inlet tracts of the engine has an optical knock sensor in the form of an infra-red temperature sensor located in it. The infra-red temperature sensor is positioned to sense by viewing past an inlet valve means associated with the respective inlet tract at least during part of the induction stroke of the respective cylinder of the engine the temperature of the upper surface of the respective piston. A control system for such an engine is also disclosed in which the output from the infra-red temperature sensor is supplied to an electronic control unit. The electronic control unit operates so as to adjust the ingition timing of the engine in response to the signal received from the infra-red temperature sensor.

Control system for a supercharged internal combustion engine

Abstract: A control system for an internal combustion engine having an air pump provided in an intake passage for supplying air into a cylinder of the engine. A continuously variable belt-drive automatic transmitting device is provided between a crankshaft of the engine and a drive shaft of the air pump. The transmitting device control unit is controlled by a control unit in accordance with operating conditions of the engine. A throttle valve is provided upstream of the air pump.

Four stroke concentric oscillating rotary vane internal combustion engine

Abstract: The four stroke concentric oscillating rotary vane internal combustion engine performs the four stroke Otto cycle inside four arcuate combustion chambers formed between the shell, rotor cylinder and two transverse end plates analogous to the engine cylinder; two fixed diametrically opposed vanes inwardly projecting from the shell serving as cylinder heads; and two fixed diametrically opposed vanes projecting outwardly from the rotor cylinder functioning as pistons. An output shaft mechanism orchestrates the synchronized operations of the fuel injection and spark ignition systems, pair of cranking mechanisms controlling the rotary strokes of the rotor, and pair of forced porting mechanisms forcing the complete removal of combustion byproducts from and sufficient supply of air into the combustion chambers.

Internal combustion engine having opposed pistons

Abstract: An opposed piston engine includes at least one pair of pistons synchronously reciprocatingly mounted in a hollow cylinder. At least one projection is formed on the face of one piston, while a corresponding recess is formed on the face of the other piston, the recess being dimensioned to at least partly and preferably substantially receive the projection in the recess, upon reciprocation of the pistons. The piston construction is particularly advantageous in opposed cylinder diesel engines, and can eliminate the need for a glow plug to initiate combustion in even a cold engine.

Hypergolic combustion model for four-stroke heat-barrier piston engines

Abstract: A numerical model for hyperbolic combustion within a four-stroke heat-barrier piston engine has been developed. An idealized fuel injector simulates the type of injector used in current experimental hypergolic combustion research. Significant to the modeling of this injector is the need to overcome the problems posed by a unit Mach number boundary condition at the injector orifice opening. Overall, the model is used to simulate a compression stroke and fuel injection portion of a power stroke. An implicit finite-difference solution of the governing flow field equations is used. The engine is modeled with the fuel injector being colocated with a single valve, making possible an axisymmetric solution. Because of its physics, hypergolic combustion dictates an eddy dissipation combustion approach. In the final run a 20 × 26 mesh is used for the greater region, which is made up of the flow field and a thin portion of the adjacent cylinder linings and piston.

Internal combustion engine with two-stage exhaust

Abstract: An internal combustion engine is provided having pairs of separately designated combustion and exhaust cylinders for implementing a two-stage exhaust system which derives work from the combustion gases of the combustion cylinders. The piston within each exhaust cylinder is timed by the engine's crankshaft to lead its corresponding combustion cylinder's piston by roughly a 30 to 90 degree crankshaft angle. Ignition of a combustible fuel mixture within the combustion cylinder produces combustion gases. The expansion of the combustion gases drives the combustion piston during a power stroke, and are expelled from the combustion cylinder during an exhaust stroke. The combustion gases exit the combustion cylinder via a fluidic passage to the exhaust cylinder. The combustion gases are received by the exhaust cylinder at the start of its piston's intake stroke. The timing between the combustion and exhaust piston is such that the combustion gases exert a force upon the exhaust piston during its intake stroke. From there, the combustion gases are expelled from the exhaust cylinder during its piston's exhaust stroke.

Fuel controller for an internal combustion engine

Abstract: A fuel controller for an internal combustion engine has an air temperature sensor in an air intake pipe and a cylinder pressure sensor which measures the pressure within a cylinder of the engine during a compression stroke. A control unit calculates the air quantity in each cylinder based on the measured intake air pressure and cylinder pressure and controls the fuel injectors of the engine so as to obtain a desired air-fuel ratio.

Engine with variable combustion chamber

Abstract: An engine with a variable combustion chamber has a a first combustion chamber defined in a piston slidably disposed in a cylinder, a second combustion chamber defined in a cylinder head and communicating with the cylinder through a communication port, and a valve for opening and closing the communication port. When the engine is under low load, the valve is closed and fuel is injected into the first combustion chamber, so that the engine operates as a direct-injection-type engine. When the engine is under high load, the valve is opened and fuel is injected into the second combustion chamber, so that the engine operates as a prechamber-type engine.

Four cycle diesel engine with pressurized air cooling system

Abstract: An internal combustion engine apparatus includes a cylinder having a head, an intake valve cooperating with the head for selectively allowing passage of fluids into the cylinder and an exhaust valve for selectively allowing passage of fluids out of the cylinder. The exhaust and inlet valves are open during both the intake and exhaust phases of operation of the engine. A piston is mounted for reciprocal movement in the cylinder between a top dead center position and a bottom dead center position. The cylinder has at least one opening therein, the opening is disposed in a side wall thereof intermediate the top dead center position and the bottom dead center position. The opening communicates between the interior of the cylinder and space outside of the cylinder and the opening is fully covered by the piston in at least one position of the piston. The engine also includes apparatus for pressurizing air and apparatus for fluid coupling the apparatus for pressurizing air to the opening and to the intake valve simultaneously during both intake and exhaust phases of the engine.

Cooling system for piston of IC engine - by nozzle which directs jet of oil upwards onto undersurface of piston crown

Abstract: The piston of an internal combustion engine is cooled by a jet of oil from a nozzle mounted below the piston in its lowest position. This nozzle directs the oil upwards onto the undersurface of the piston crown. The nozzle (2) is fitted with a spring-loaded valve. The force exerted by the spring is such that when the engine is idling and the oil pressure is low the valve remains closed so that the piston is not cooled at low engine speed. USE - Cooling thea piston of an internal combustion engine.

A digital simulation of the exhaust nitric oxide and soot formation histories in the combustion chambers of a swirl chamber diesel engine

Abstract: This work presents a computer simulation of the exhaust nitric oxide and soot emission histories from a four stroke, naturally aspirated, Diesel engine with a swirl prechamber (divided chamber). The simulation is based on a thermodynamic analysis, which was validated successfully concerning the performance of the engine (load, fuel consumption, maximum pressures, etc). The analysis includes the calculation of the heat exchange between gas and walls in both the main chamber and (swirl) prechamber, after computing the relevant characteristic velocities and lengths, while combustion in both the main chamber and the swirl prechamber is attacked by proposing a two-zone combustion model. The concentration of the constituents in the exhaust gases is calculated by incorporating a complete chemical equilibrium scheme for the C−H−O system of the eleven species considered, together with chemical rate equations for the calculation of nitric oxide (NO). A model for the evaluation of soot formation and oxidation rates is also included, in order to compute the net soot concentration. The contribution of each chamber to the formation of NO and soot is given by presenting time (crank angle) diagrams of the net NO and soot formation inside each chamber (histories of formation).

Radial internal combustion engine

Abstract: A radial internal combustion engine comprises an engine housing and a plurality of piston-cylinder pairs arranged on the periphery of the housing. The piston-cylinder pairs are arranged in two rows, three cylinders in each row. A connecting rod connects each piston to the crankshaft axially disposed within the engine housing. The connecting rods terminate in an arcuate flange. The connecting rods in each row of cylinders lie in a common plane equally sharing the crankshaft journal bearing surface. Lubrication about the crankshaft journal is provided through an oil flow passage which extends through the crankshaft for lubricating the crankshaft journal an the valve train of the engine.

Cylinder blanking system for internal combustion engine

Abstract: A combustion engine is provided having a cylinder blanking system. The cylinders are deactived according to turbo-pressure and engine RPM. Specifically, when low load conditions exist for a predetermined period of time, fuel is cut off from some of the cylinders. The system may be manually overriden.

Powertrain assembly with a cross-axis disposition of the engine crankshaft and the transmission torque input shaft

Abstract: A T-drive powertrain for an automobile having an internal combustion engine mounted in a vehicle engine compartment with its crankshaft axis disposed transversely with respect to the vehicle geometric center plane and a power transmission mechanism having its principal gearing axis disposed in a fore-and-aft direction generally on the vehicle geometric center plane; the driving connection between the engine and the transmission gearing including a direct-drive, cross-axis gear assembly with a driving gear carried by the engine crankshaft at a location on the crankshaft near a midpoint between the crankshaft ends

Detonation control device for an internal combustion engine

Abstract: The invention is directed towards adjusting the combustion ratio of an internal combustion engine The apparatus has a compensator piston which is selectively hydraulically positioned The piston is linked to a shock adsorber so as to keep the combustion chamber charge from reaching the pressure detonation limit

4-stroke, stratified gas engine

Abstract: A 4-stroke, internal combustion engine having two intake valves for each cylinder wherein a single rocker-arm assembly actuates both of the intake valves in a timed sequence to provide a stratified charge to the cylinder.

Cylinder sleeve for two-cycle engine

Abstract: A two-cycle, crankcase compression, internal combuston engine and a piston liner therefore having an exahust port opening that is chamfered along its top edges so as to reduce the likelihood of piston ring sticking without affecting the port timing Different forms of chamfering tools are depicted

Heat-insulated four-cycle engine with prechamber

Abstract: A heat-insulated four-cycle engine includes a heat-insulated main combustion chamber, a prechamber having an ejection port communicating with the main combustion chamber and associated with an exhaust valve, a projection mounted on the piston head surface of a piston and movable into the ejection port in the vicinity of the top dead center, a recess defined in the piston head surface around the projection, and intake ports defined in the cylindrical wall of a cylinder which defines the main combustion chamber. Combustion gases produced as a result of combustion of fuel in the prechamber are held in the prechamber by the projection in a high-temperature condition for a certain period of time. Thereafter, as the piston is lowered from the top dead center, the combustion gases are discharged from the prechamber into the main combustion chamber, thus lowering the pressure in the prechamber. Therefore, the temperature in the prechamber is lowered, and the amount of NOx, HC, CO, and black smoke which are emitted is also reduced. Since the intake and exhaust ports are isolated from each other, the amount of heat transferred from the exhaust port to the intake port is small. As a result, the temperature of the region around the intake ports is not increased, and the intake efficiency is not lowered. Inasmuch as the engine has an adiabatic expansion stroke between exhaust and intake strokes, the temperature of the wall of the combustion chamber is lowered when the fuel is ignited, resulting in less knocking possibility.

Variable volume internal combustion engine

Abstract: The invention relates to an engine, the compression ratio of which varies in operation due to movement of the crankshaft in relation to the cylinder head. It comprises an independent cylinder block 1 and crankshaft block 3, the first receiving the cylinder head and the second the crankshaft 2, the connecting rods and the pistons; the two blocks are moved one in relation to the other by means of a displacement device 6, 7, 8 and are held connected together by support and guide elements. The relative displacement of the two blocks modifies the volume of the combustion chambers and allows the maximum admissible pressure to be maintained there so that the engine functions with maximum efficiency. The present engine gives fuel economy at low load and excess power at high speed. It is intended particularly for touring and racing cars.

Generating unit for current supply pref. for vehicle - has RPM regulated IC engine designed as air or liquid cooled radial engine with fan impeller fitted at rotor of current generator

Abstract: A generating unit consisting of a piston engine and a ring generator, whereby the swept vols of the piston engine are arranged adjacent to the rotational axis of the ring generator. The piston engine (BKM) is arranged with its axis of rotation essentially vertical to the plane of the ring generator (STG). The cylinders (5) of the piston engine are arranged distributed around the axis of rotation of the rotor (2). The axes of rotation of the piston engine and the rotor (2) are in alignment and at least two cylinders (5) of the piston engine (BKM) are arranged inside the circular space parallel to the plane of the ring generator (STG). USE/ADVANTAGE - Generating set pref. for current supply of motor vehicles. Improvement of generator sets for mains independent current supply bearing in mind increased in electrical load. Suitable for vehicles of all types.

Conjugate conduction-convection heat transfer model for the valve flow-field region of four-stroke piston engines

Abstract: A multidimensional method has been devised to solve the conjugate conduction-convection heat transfer process at the surface of a moving valve of finite thickness within the flow field of an operating four-stroke internal combustion (IC) engine. Heat exchange processes between the valve and the gases adjacent to these boundaries were also computed during the portions of the engine cycle when the valve was closed. Boundaries of the solution scheme were extended fixed distances into the piston and cylinder liner. The valve was simulated as having a small but measurable thickness for the purpose of heat transfer calculations and as being immeasurably thin for the purpose of other flow-field calculations. The effects of fluid entrainment caused by valve motion were also considered and modeled. The implicit finite-difference solution of the governing equations for the primitive variables in the flow field was conducted in three regions: one fixed in space and time, one using a stretching and compressing computational mesh, and one that moved with time without stretching or compressing. This paper reports use of the model to simulate a portion of an exhaust stroke for an axisymmetric four-stroke engine piston.