Showing papers on "Four-stroke engine published in 1984"

Method of controlling reciprocating four-stroke internal combustion engines

Abstract: The present invention relates to a method for unthrottled load control of an internal combustion engine by means of exhaust gas. The method requires entirely freely adjustable opening and closing times for the inlet and exhaust valves. Starting at full load with the minimum of exhaust gas in the cylinder the amount of exhaust gas in the cylinder is increased thereby reducing the available combustion chamber volume for receiving fresh mixture mass thereby reducing the load. The fresh mixture mass and the exhaust gas mass are controlled exclusively by coordinating the opening and closing times of the intake and exhaust valves.

Influence of Induction Swirl and Piston Configuration on Air Flow in a Four-Stroke Model Engine:

Abstract: Measurements of ensemble-averaged mean, rms and cycle resolved instantaneous swirl velocities, obtained by laser—Doppler anemometry, are reported for the in-cylinder flow in a four-stroke model engine motored at 200 r/min Variable induction swirl was created by 30° and 60° vanes located in axisymmetric and off-centre intake ports with flat and re-entrant bowl piston configurationsThe results showed that the main features of the initial swirl velocity distribution, which are determined by the intake port/valve geometry, persist through the compression stroke The swirl centre performed in all cases a helical motion whose development was a function of the clearance volume at top dead centre; the weakness of this motion made it susceptible to cyclic variations which were significantly reduced with the re-entrant piston bowl High induction swirl resulted in lower turbulence intensity at top dead centre of compression, in the flat piston case, and more complex vortex pattern inside the re-entrant piston

Water-cooled, four-cycle internal combustion engine for outboard motors

Abstract: A compact improved four-cycle internal combustion engine of the water-cooled type for use with an outboard motor. The engine includes an exhaust arrangement wherein the exhaust gases are returned from the cylinder head to the cylinder block in proximity to a cooling jacket for cooling the exhaust gases before delivery into the lower unit. In addition, the cooling jacket and method of casting the cylinder head provides an opening in which a sacrificial anode may be placed to protect the engine from corrosion, particularly when operated in salt water. The engine is given a compact arrangement, in part, by positioning the thermostat of the cooling system in the area between the driving and slack sides of the belt that drives the overhead camshaft. The lubricating system also includes a baffled cover plate for the camshaft that receives oil flung from the camshaft and redistributes it to the valve train for lubrication.

Engine valve timing control system

Abstract: © An engine valve timing control system using electrohydraulic valve lifters or adjusters (51, 52, 53, 54, 55, 56, 57, 58) operatively connected to a microprocessor based electronic control unit (32) will provide real time charges in engine valve timing. As a result, engine performance will be improved over the mechanically controlled engine valves which at best are compromises between engine operating extremes. Each lifter is "homed" to the base circle of the cam through the use of check valves (67, 69, 69a) and high pressure pulses generated in the oil lines (60) supplying the lifters.

Variable stroke, electronically controlled fuel injection control system

Abstract: A fuel injection control system for an internal combustion engine utilizes a fuel injection pump in which the pump cylinder is in fluid communication with the fuel injection nozzle and a piezoelectric actuated spill valve. A cam drive actuates the pump piston to achieve a constant velocity during the pumping cycle (constant velocity relative to degrees of rotation of the engine crankshaft). An index wheel connected to either the engine crankshaft or the pump camshaft is used in conjunction with an initial position detector, angular position detector and a pump control unit to close and open the spill valve at predetermine positions of the pump piston during the pumping cycle. The pump control unit includes a computer connected to various engine parameter transducers to adjust the closing and opening of the spill valve to achieve a desired fuel injection volume.

Four-stroke internal combustion engine for outboard motors

Abstract: Two embodiments of lubricating systems for the four cycle engine of an outboard motor, each of which embodies a lubricant sump that is disposed beneath the engine and to which lubricant is returned by gravity. In each embodiment, a buffer volume is provided that receives lubricant when the engine is oriented in other than a desired position so that the oil will flow into this buffer volume rather than being discharged from the sump. The lubricant is returned to the engine from the buffer volume when the engine is again placed in its normal orientation. In one embodiment of the invention, the buffer volume is provided by the camshaft chamber of the engine.

Hydraulic pulse engine retarder

Abstract: A compression release engine retarder for a multicylinder four-stroke cycle engine is disclosed. The retarder incorporates an hydraulic pulse generator including a multichamber positive displacement pump of the piston and cylinder or gear pump type which is positively driven at engine speed or at half engine speed in synchronism with the engine crank shaft. Means are provided to adjust the timing of the hydraulic pulses so as to control precisely the opening of the engine exhaust valves and to maximize the compression release retarding power developed by the engine. Additional means are provided to control the timing of the hydraulic pulses in response to the boost pressure in the engine inlet manifold produced by the engine turbocharger.

Temperature control arrangement for combustion engine

Abstract: An arrangement is provided for controlling the coolant temperature in a coolant circulating system of an internal-combustion engine, such as in a motor vehicle, containing a thermostatic valve that controls the coolant flow from the internal-combustion engine through a direct return flow means and/or through a heat exchanger back to the internal-combustion engine, and containing a thermostatic working element having a housing carrying a valve disk of a valve controlling coolant flow to the heat exchanger, and having a working piston extendable under heat and being supported at a counterbearing. The working piston and the counterbearing form an adjusting mechanism, and a control element is connected to the working piston or the counterbearing which forces the working piston into an adjusted position.

Method for the control of four-stroke piston internal combustion engines

Abstract: In a method for the control of four-stroke piston internal combustion engines with load control by means of the amount of fresh mixture in the working chamber and with variable exhaust fraction in the cylinder charge, the amount of fresh mixture is controlled by way of mutually independent inlet and exhaust devices, with a constant flow cross section in the intake and exhaust gas systems outside the inlet and exhaust devices, exclusively by opening and closing times of the inlet and exhaust devices which are matched to one another, in such a way that a certain amount of exhaust gas is present in the cylinder on conclusion of the charge cycle and the remaining cylinder volume for receiving fresh mixture is thereby reduced for the purpose of load control, the exhaust gas and fresh mixture fractions being mixed in the cylinder during the filling and compression process.

Automatic decompression device for internal combustion engine

Abstract: A decompression device for facilitating startup of an internal combustion engine including a member formed with an auxiliary cam operative to decompress a cylinder in a compression stroke when the engine is in a low engine speed range. The member is supported by a stopper pin secured to the member in a position substantially symmetrical with the auxiliary cam with respect to the axis of camshaft. The auxiliary cam is of a cylindrical pillar shape.

Fuel intake system for a supercharged engine

Abstract: For a supercharged internal combustion engine having at least one engine cylinder, a fuel intake system comprises a primary intake passage for supplying a combustible air-fuel mixture to the engine cylinder, and an auxiliary intake passage including a supercharger for supplying at least supercharged air to the engine cylinder, said supercharger being constituted by a displacement air pump and adapted to be driven by the engine such as to produce and supply the supercharged air into the engine cylinder at least during the period in which the engine cylinder is held under the compression stroke.

Engine valve timing

Abstract: A method of optimizing valve timing events for a modern high speed internal combustion engine for the purpose of improving fuel economy during idle, high speed performance and allowing for a leaner fuel/air ratio during idle. The method is based on an analytical treatment of the instantaneous relationship between valve flow area and the changes in cylinder volume occurring because of piston motion.

A consideration on piston second land pressure and oil consumption of internal combustion engine

Abstract: Piston second land pressure, combustion pressure, and oil consumption (OC) of a four-stroke gasoline engine have been measured to investigate the relationship between 2nd land pressure and OC. Test results have revealed that OC increases when, past midway in the expansion stroke, 2nd land pressure exceeds combustion pressure and, inversely OC decreases when the 2nd land pressure is below combustion pressure. Based on both theoretical analyses and experiments, this paper describes the reason for the above observation and proposes a method for reducing OC.

Four-cycle engine for marine propulsion device

Abstract: Several embodiments of outboard motors incorporating improved arrangements for lubricating the cam lobes and associated components of the camshaft that is relatively independent of the pressure lubricating system of the engine. In each embodiment, a porous member is saturated with lubricant and engages the cam lobe surface so as to lubricate it even immediately upon starting.

Piston crankshaft interface

Abstract: An internal combustion engine with extended power stroke and shortened compression stroke has an improved efficiency over internal combustion engines having strokes of equal length.

Four-stroke internal combustion engine

Abstract: A four-stroke internal combustion engine with crankcase scavenging comprises a cylinder provided with inlet and exhaust valves, a reciprocating piston, which by way of a connecting rod drives a crankshaft supported in the crankshaft housing, an ignition device, a mixture preparation device and an intake port for an air-fuel-lubricating oil mixture. At the same time the intake port is connected by way of a non-return valve to the crankshaft housing. In addition a line connecting the crankshaft housing to a precompression chamber is provided, the controls and drives for the inlet and exhaust valves being arranged in the precompression chamber. In order to be able to accelerate the four-stroke internal combustion engine essentially without any transition from the lower speed range into the top speed range with optimum torque output, the precompression chamber (11) is constantly connected by a connecting line (15) to the intake port (7), which leads from the mixture preparation device (8) to the inlet aperture of the cylinder (figure 1).

Diesel internal combustion engine

Abstract: In a turbocharged diesel internal combustion engine (10) with low compression ratio, at least one cylinder (11) operating as an engine cylinder is charged during starting and at partial load operation by several cylinders (18, 21, 28) operating as compressors. The pistons of the compressor cylinders (18, 21, 28) lead the piston of the engine cylinder (11). As a result thereof, the engine cylinder can be charged during its compression stroke. The compressor cylinder (28) which by reason of its large angular ignition spacing to the engine cylinder cannot feed directly into the engine cylinder, delivers its supplied air at first to another compressor cylinder (18) which is located more favorably. Only thereafter, the air of the two compressor cylinders (18 and 28) is fed in common and in parallel with a further, possibly also favorably located compressor cylinder (21), to the engine cylinder (11).

Torque Boosting of 4-Stroke Cycle Spark-lgnition Engine in Low and Middle Engine Speed Ranges by Crankcase-Supercharging

Abstract: As a mechanical supercharging system for 4-stroke cycle engines, crankcase-supercharging seems attractive because of its low production cost and simple construction. Therefore, a crankcase-supercharged 4-stroke cycle spark-ignition engine was developed and tested in both motoring and firing modes. It was found that the motoring volumetric efficiency could be increased over the entire engine speed range, but the increase was more noticeable at lower engine speeds. In the firing mode it was proved that a favorable throttle response and a 20 to 30% torque rise could be obtained by crankcase-supercharging without sacrificing the brake specific fuel consumption of the naturally aspirated baseline condition.

Piston with adjustable compression height for combustion engines

Abstract: In a piston, the compression height of which can be adjusted during operation of the engine by control chambers (8, 9), to which oil is admitted, provided in the piston, it is proposed that the oil be introducible at constant pressure into the control chamber system (8, 9) irrespective of the engine speed. To this end a pressure control valve (15) is provided upstream of the inlet valve (12) of the control chamber system (8, 9). This pressure control valve may be incorporated, for example, into the piston pin (5).

Lubrication of an ancillary pump fitted to an engine

Abstract: In combination with an internal combustion engine having a crankcase in which an air/oil mist mixture exists during normal operation of the engine, a pump having a crankshaft journalled in a crankcase, a cylinder, a piston coupled to said crankshaft to reciprocate in the cylinder, an intake and a return passage each communicating the pump crankcase with said engine compartment, and one-way valves in each of said passages arranged so that reciprocation of the pump piston will circulate the air/oil mist mixture from the engine compartment through the pump crankcase to provide lubrication to the compressor crankshaft and piston.

Internal combustion engine with a positive displacement supercharger mechanically driven from the engine crankshaft

Abstract: A piston-type internal combustion engine is fitted with a mechanically driven displacement supercharger such that the displacement volume of a supercharging chamber for compression of the combustion air is made equal to the maximum requirement of an engine cylinder to be filled. The stroke rate of the supercharger is equal to the ignition rate of the engine and the piston motion of the supercharger bears a given phase relation to the piston motion of the engine in line with the desired supercharging effect, such phase relation preferably being adjustable.

Internal combustion engine with direct fuel injection

Abstract: An internal combustion engine with direct fuel injection includes at least one cylinder in which is slidable a piston the crown of which has a cavity constituting at least part of the combustion chamber of the cylinder, and a fuel injector with a nozzle having several holes facing the cavity in the piston and oriented so that its axis is at an angle of between 15° and 30° to the axis of the cylinder. The cavity in the crown of the piston has an inclined flat base wall which is oriented perpendicularly to the axis of the injector, and a mouth which is centered on the axis of the cylinder.

A Thermodynamic Simulation Model for a Four Stroke Medium Speed Diesel Engine

Abstract: In this paper, a thermodynamic simulation model for a four-stroke medium speed, diesel engine is described The model deals with the fuel injection system, combustion and gas exchange processes Special emphasis is laid on the latter two processes In the first phase, a single zone combustion model is discussed Subsequently, an improved two zone combustion model, which needs lesser computational time is presented Both these models have satisfactorily predicted the performance of a single cylinder and locomotive engines and a comparison has been made between the results obtained from them The Leap-Frog scheme has been applied to solve the unsteady equations during the gas exchange process and the computed data from this scheme are found to agree well with the measured data

Compound engine with plural stage intercooled exhaust pump

Abstract: A compound internal combustion engine includes a piston type internal combustion engine drive coupled with a gas turbine, the piston engine exhaust gases driving the turbine whose exhaust preheats the piston engine air intake and then enters the suction input of a multistage turbocompressor driven by the gas turbine and having interstage cooling the output of the compressor discharging to exhaust.

Four-cycle engine

Abstract: PURPOSE:To improve output by communicating a crank chamber through an air feed pipe to a suction port at a cylinder head. CONSTITUTION:During a compression stroke where a piston 1 rises, a suction reed valve 14 is opened to supply an air-fuel mixture into a crank chamber 3. During an explosion stroke where the piston 1 lowers, a feed reed valve 13 is opened to feed the air-fuel mixture in the crank chamber 3 through an air feed pipe 8 to a chamber 17. During an exhaustion stroke where the piston 1 rises, the suction reed valve 14 is opened to supply an air-fuel mixture into the crank chamber 3. During a suction stroke where the piston 1 lowers, the air-fuel mixture previously stored in the chamber 17 is fed to a cylinder 2. Until the piston 1 is lowered to reach a bottom dead center, the air-fuel mixture in the crank shaft 3 is fed to the cylinder 2.

Fuel control system and apparatus for gas turbine engine

Abstract: The disclosure embraces a fuel control system and apparatus for delivering or supplying liquid fuel to a gas turbine engine comprising a body construction (12) in which is contained a first diaphragm-actuated fuel control valve arrangement (40) for regulating fuel flow to the turbine engine for normal engine operation, a second diaphragm-actuated fuel control valve arrangement (42) for regulating fuel flow to the turbine engine for engine idling operation, the diaphragm-atuated valve arrangements (40) and (42) being responsive to the difference between the engine burner pressure and the compressor discharge pressure. A third diaphragm-actuated fuel control valve arrangement (44) is provided for supplying fuel to the turbine engine for engine starting purposes. The system and arrangement includes an operator-controlled member (80) for varying resilient biasing pressure on a relief valve (86) for varying the compressor discharge pressure effective on the first diaphragm-actuated valve arrangement for regulating the speed of the turbine engine.

Four-stroke planetary piston internal combustion engine

Abstract: The invention discloses a rotary piston engine in the form of a four-stroke planetary piston internal combustion engine which has at least one chamber, circular in plan view, in its housing. Accommodated in each chamber is a circular piston which revolves eccentrically about a shaft in continuous contact with the wall of the chamber and against the outer surface of which three slides displaceable approximately radially to the axis of the shaft are placed, dividing the crescent-shaped space between the piston and the chamber wall into subchambers. Situated between two slides in the housing is an ignition space open towards the chamber, and channels for feeding in the fuel mixture and letting out the exhaust gases are provided on both sides of the third slide. The piston is arranged on a crankshaft and the slides are in continuous contact with a piston contact surface extending, for example, tangentially to the cylindrical piston surface. Two slides contain transfer channels open or closed depending on the position of piston.