Showing papers on "Four-stroke engine published in 1999"

Design and Simulation of Four-Stroke Engines

Abstract: This book provides design assistance with the actual mechanical design of an engine in which the gas dynamics, fluid mechanics, thermodynamics, and combustion have been optimized so as to provide the required performance characteristics such as power, torque, fuel consumption, or noise emission.

Compression Ratio Effect on Methane HCCI Combustion

Abstract: The authors have used the HCT (hydrodynamics, chemistry, and transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, burn duration, NO{sub X}production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. intake pressure) with 14:1, 16:1 and 18:1 compression ratios at 1200 rpm. HCT has been modified to incorporate the effect of heat transfer and to calculate the temperature that results from mixing the recycled exhaust with the fresh mixture. This study uses a single reaction zone that varies as a function of crank angle. The ignition process is controlled by adjusting the intake equivalence ratio and the residual gas trapping (RGT). RGT is internal exhaust gas recirculation, which recycles both thermal energy and combustion product species. Adjustment of equivalence ratio and RGT is accomplished by varying the timing of the exhaust valve closure in either two-stroke or four-stroke engines. Inlet manifold temperature is held constant at 300 K. Results show that, for each compression ratio, there is a range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated efficiency above 50 percent andmore » NO{sub X}levels below 100 ppm. HCT results are also compared with a set of recent experimental data for natural gas.« less

System and method for controlling internal combustion engine

Abstract: When a failure of a variable valve timing mechanism of an internal combustion engine is detected, both a cylinder which is associated with the mechanism in failure and another cylinder which has a symmetrical phase in operation to the above-mentioned cylinder with respect to the stroke cycle are brought into inoperative condition. At the same time, the amount of air/fuel mixture fed to the remaining cylinders is increased. With this measure, engine vibration and power drop are suppressed or at least minimized.

Four-cycle internal combustion engine and valve timing control method thereof

Abstract: In a disclosed four-cycle internal combustion engine and a method of controlling valve timing according to the present invention, a load put on the four-cycle internal combustion engine is detected, and a judgment is made as to whether or not the load of the four-cycle internal combustion engine is low, and when the judgment is made that the load of the four-cycle internal combustion engine is low, valve timing of an exhaust valve of the four-cycle internal combustion engine is set so that valve closing time of the exhaust valve advances before a top dead center of a piston of the four-cycle internal combustion engine.

Multiple-position, operator-carried, four-stroke engine

Abstract: A portable, operator-carrier power tool having an implement supported on an operator-carrier frame, and a lightweight, four-stroke, internal combustion engine (16) drivably connected to the implement and supported by the frame (12). The engine (16) has a crankshaft (28) situated in a crankshaft housing (24) and a cylinder block (74) secured to the crankshaft housing (24), the crankshaft (28) being provided with a crankcase ventilation passage extending between the crankcase and an outlet end in communication with an air/fuel induction passage. A passage establishes communication between the interior of the crankcase and the valve chamber through a cam (118) and cam gear region of the cylinder block (74). An oil mist generator (141) is connected drivably to the crankshaft (28) for agitating liquid oil in the crankcase to establish a lubricating oil mist. The crankcase, the cam region and the valve chamber form a closed oil mist containment whereby lubricating oil mist is distributed throughout the engine (16) during operation regardless of angular orientation of the engine. The crankshaft ventilation passage establishes lean crankcase gas distribution to the engine air/fuel intake. The crankcase is designed to avoid flow of liquid oil through the crankshaft passage when the engine is not running.

Dual-cylinder expander engine and combustion method with two expansion strokes per cycle

Abstract: An internal combustion engine is provided with an expansion cylinder (10) and at least one combustion cylinder (20), preferably two or four combustion cylinders per expansion cylinder. An air-fuel mixture is ignited within the combustion cylinders to drive a combustion piston (13) which, in turn, drives an engine crankshaft (38). The gaseous products of combustion are exhausted at a pressure substantially above atmospheric to an expansion cylinder wherein they are allowed to further expand against an expander piston (28) to drive an expander crankshaft (40). Torque produced at the engine crankshaft and torque produced at the expander crankshaft are combined to drive vehicle wheels.

Multi-fuel engine

Abstract: An engine capable of use with multiple different types of fuels including gasoline and alcohol based flues and heavy fuels such as diesel fuel, JP5, JP8, Jet A and kerosene based fuels. The engine includes a main cylinder having a compression chamber at one end and a piston that is movable along the length of the cylinder and which connects to a crankshaft for the engine. A fuel delivery system delivers a combustible mixture of fuel and air through a fuel delivery valve into the combustion chamber at a sonic velocity of flow such that the fuel is substantially atomized into the air of the combustible mixture delivered to the combustion chamber. The combustible mixture is ignited by an igniter within the combustion chamber to urge the piston along the cylinder for driving the crankshaft of the engine.

Two stroke engine conversion

Abstract: A method is provided for converting a conventional four stroke internal combustion engine having four cylinders into a two stroke engine. The camshaft assembly including the camshaft having cams thereon and the drive assembly which couples the camshaft to the crankshaft are replaced with a modified camshaft assembly such that the inlet and exhaust valves are each opened once per revolution of the camshaft. The resulting two stroke engine includes two pairs of pistons, each pair of pistons having a first and second piston which are fired synchronously. The pairs of pistons being spaced 180 degrees apart such that two pistons are fired synchronously for every half rotation of the crankshaft.

Method and arrangement for operating an internal combustion engine

Abstract: A method for operating an internal combustion engine of a motor vehicle with the engine developing a torque during the operation thereof includes deriving a desired value of the torque of the engine from operating variables. The desired value of the torque is made available by at least adjusting the air supply and the ignition angle of the engine. The efficiency of the engine is deteriorated in at least one operating state of the engine compared to the efficiency in operating states outside of the one operating state by retarding the ignition angle and increasing the air supply whereby the torque developed by the engine remains essentially constant. The presence of the one operating state is detected when a startup intent of the driver of the vehicle is recognized.

Controlled self-ignition combustion process and associated four-stroke engine with residual gas storage volume and dedicated valve

Abstract: The present invention relates to a self-ignition combustion process in a four-stroke internal-combustion engine comprising at least one cylinder ( 1 ) having at least a first intake ( 2 ) and at least a first exhaust. The process according to the invention, at partial load, fills an external volume ( 10 ) independent of cylinder ( 1 ) with burned gases, the volume ( 10 ) being connected to cylinder ( 1 ) by a specific port and a specific line ( 9 ), and in controlling the flow and/or the pressure of the burned gases in the volume ( 10 ) through a throttle 15 ( 11; 14 ) associated with a seal allowing selective sealing of the specific port such as a valve (S or S 1 and S 2 ). The present invention further relates to a four-stroke engine implementing the above-described process.

A low cost new internal combustion engine with increased mechanical efficiency, fuel saver and pollution controlled

Abstract: A low cost new internal combustion engine with increased mechanical efficiency, fuel saver and pollution control and in particular a new internal combustion engine having improved lubricating mechanism for getting extra time to burn the fuel without knock and combustion noise for achieving increased fuel economy wherein the lubricating system consists of at least one first cross head oil groove formed at the interface cylindrical bearing surfaces of the moving contacting parts on the inner and outer surface of internal combustion engine components. At least one axial oil groove intersecting with first or second oil groove (50, 51) on outer surface of piston skirt (52), at least one deep 'v' furrow (124) and one slot on the outer surface of rocker arm (130, 140) and the spark ignition or fuel injection device having spring governed centrifugal advance fly weights for self regulation in proportion with engine speed from idle to maximum engine speed.

Reduced volume scavenging system for two cycle engines

Abstract: A reduced volume scavenging system for a two cycle engine embodying a duplex cylinder having an upper cylinder bore and a reduced-diameter lower cylinder bore. The lower bore communicates with a crankcase that houses a crankshaft, connecting rod(s) and engine lubricating oil. A fixed sleeve lines the upper cylinder bore and extends up into the cylinder head. A piston disposed for reciprocating motion within the fixed sleeve has an attached cylindrical, reciprocating sleeve that extends down into the lower cylinder bore and moves with the piston. The reciprocating sleeve has compression rings that seal the lower bore and the crankcase against blowyby gases that might contaminate the oil. The fixed sleeve has an intake opening in registry with an inlet port in the upper cylinder bore for admission of fresh air-fuel mixture. The fixed sleeve also has an exhaust opening diametrically opposite the intake opening and in registry with an exhaust port in the upper cylinder bore, as well as upper and lower pairs of scavenging openings in registry with transfer passageways recessed into the upper cylinder bore, such that each out stroke of the piston forces fresh air-fuel mixture through the passageways and into the combustion chamber to flush out burnt gases. This arrangement permits use of four cycle engine lubricating methods and apparatus in two cycle engines, without unduly adding to their weight and complexity, thereby reducing the emission of air pollutants and increasing engine life.

Cylinder-injection type internal combustion engine, method of controlling the engine, and fuel injection nozzle

Abstract: A cylinder-injection type internal combustion engine capable of performing a stratified operation in running at a speed of 120 km/h and/or at an engine speed of 3200 rpm so as to improve a fuel efficiency and/or clear off an emission control, wherein an air and/or air flow layer is formed between an atomized fuel sprayed from an injection nozzle and the upper surface of a piston and/or an inside wall surface of a combustion chamber, and an improved surface form to guide the air flow is formed on the upper surface of the piston, whereby the stratified operation is enabled even at a cold start or cranking.

Four-cycle internal combustion engine

Abstract: A four-cycle internal combustion engine having a piston reciprocably movable within a cylinder, a crankshaft, a rod connecting the piston to the crankshaft and means arranged between the rod and the crankshaft to vary the stroke of the piston, said means for varying the stroke comprising an internal gear, an external gear and an eccentric member, characterized in that the eccentric distance of the crankpin, the radius of the pitch circle of the external gear and the radius of the pitch circle of the internal gear are in the ratio of one to two to three.

Four-Stroke Performance Tuning

Abstract: Fully revised and updated with much new information added. New information covering the adoption in recent years of roller-finger cam-follower arrangements on OHC and DOHC engines. The tuning implications of recent developments in fuel and oil technology. Significantly expanded chapters with new material. Explains and analyses all areas of engine operation, from air and fuel, through carburation, fuel injection, ignition, engine management, cylinders, camshafts and valves, bottom end, exhaust systems, to cooling and lubrication. Fully illustrated throughout with many new photographs and line diagrams.

Internal combustion engine for a portable handheld work apparatus

Abstract: The invention is directed to an internal combustion engine for a portable handheld work apparatus. The engine includes a cylinder having a combustion chamber and a piston rotates a crankshaft via a connecting rod. The crankshaft is mounted in a crankcase and is connected to a cam drive. The cam drive drives a valve control for an inlet valve and an outlet valve. The inlet valve controls an overflow channel which leads from the crankcase to the combustion chamber, and the outlet valve controls an outlet channel branching away from the combustion chamber. Furthermore, an intake channel, which opens into the crankcase, and a housing, which is separate from the crankcase, are provided for the cam drive. In order to provide a lubrication for the cam drive which is independent of position, the cam drive is configured as a gear wheel drive and an oil sump is provided in the housing of the cam drive. At least one gear wheel of the cam drive is so arranged that it dips at least partially into the oil sump and pumps oil for lubricating the movable parts of the engine.

Piston engine with adjustable compression ratio

Abstract: The piston engine has cylinders in line in an engine block and pistons (6) in the cylinders, connected by connecting rods (5) to a crankshaft (1), the bearings of which are in eccentric rings (3). The rings are in bearing housings (4) in the engine block. At least some of them are fitted with a rotation device (7). A coupling element (8) is connected to the rotation device and also to an actuator (10). One ring may have a groove connected to an inward boring leading to the bearings.

Portable handheld work apparatus having a four-stroke engine

Abstract: The invention relates to a motor-driven chain saw having an internal combustion engine for driving the saw chain of the chain saw. The engine is mounted in the housing of the chain saw and includes a cylinder and a combustion chamber formed in the cylinder. The combustion chamber is delimited by a piston and the piston drives a crankshaft via a connecting rod. The crankshaft is rotatably journalled in a crankcase. An inlet and an outlet are provided for gas exchange in the combustion chamber and the inlet is connected via an intake channel to a mixture preparation device. A stroke/bore ratio of less than 0.8 is used in order to provide an engine of reduced structural elevation which is useable in all positions. The inlet and outlet are controlled via valves having a valve drive charged with the air/fuel lubricating oil mixture supplied via the mixture preparation device.

Internal combustion engine piston assembly and method

Abstract: A piston assembly for an internal combustion engine comprising an upper piston member, a piston skirt, and an insert which is fastened together. The insert is tapered and urges the piston skirt towards the upper piston member. The principle use is for light weight pistons having a skirt made of a lighter weight material, however any two piece piston assembly will benefit from this invention.

Two-cycle internal combustion engine with enhanced lubrication

Abstract: A gasoline internal combustion engine, including an engine block having a cylinder, fuel intake port and exhaust port therein. A piston is mounted in the cylinder for two-cycle, reciprocating movement therein, and includes an annular piston head and a cylindrical piston skirt, a connecting rod rotatably-mounted by a top end thereof to a piston roller bearing carried on a piston pin of the piston, and by a bottom end of the connecting rod to a crankshaft for outputting power from the reciprocating piston, the crankshaft mounted on a pair of spaced-apart crankshaft roller bearing assemblies, and an array of holes extending through the piston skirt for drawing gasoline from an opposing fuel intake side of the piston to the exhaust side of the piston on the downstroke of the piston to lubricate the exhaust side of the piston and cylinder without the mixture of engine oil with the gasoline.

Method of operating a free piston internal combustion engine with a short bore/stroke ratio

Abstract: A method of operating a free piston internal combustion engine includes the steps of: providing a housing with a combustion cylinder and a second cylinder, the combustion cylinder having a bore with an inside diameter; providing a piston including a piston head reciprocally disposed within the combustion cylinder, a second head reciprocally disposed within the second cylinder, and a plunger rod interconnecting the piston head with the second head; and moving the piston between a top dead center position and a bottom dead center position during a return stroke, the return stroke having a stroke length between the top dead center position and the bottom dead center position, the moving step being carried out with a bore/stroke ratio represented by a quotient of the inside diameter divided by the stroke length which is between 12 and 15 An air scavenging port is in fluid communication with the bore during between 50 and 70 percent of a cycle time period

Piston for internal combustion engine

Abstract: The piston for an internal combustion engine has a groove (3) for a piston ring (4). At least one edge area of the groove upper face (7) is faced with a hardened material and has an inner chromed area (8).

Internal combustion engine; has knocking sensor connected to evaluation electronics, which receive signals during movement of gas exchange or injection valve

Abstract: The engine has a crankshaft casing (1) for a rotating crankshaft (2), which is connected to at least one connecting rod for a piston (9) that acts in a cylinder having gas exchange valves and channels in the cylinder head. A knocking sensor (13) connected to evaluation electronics is provided. The evaluation electronics receive signals from the knocking sensor during movement of a gas exchange valve or an injection valve (6) of the engine. An Independent claim is included for a method for operating the engine.

Crankcase breather oil collector for motorcycles

Abstract: A crankcase breather oil collector serves to capture oil vapor mixed with crankcase blowby gases, and contain the oil vapor to preclude its exiting to the atmosphere and/or collecting on external machinery components. The device basically comprises a canister which communicates with the crankcase of a four stroke reciprocating internal combustion engine by a tube or line. blowby gases and oil vapor mixed therewith are routed to the canister by the tube or line, with the oil vapor cooling and falling out of suspension with the blowby gases to condense and collect as a liquid in the bottom of the canister. The blowby gases then exit the canister through a filtered vent or outlet. The outlet filter serves to preclude significant particulate matter from being expelled to the ambient atmosphere, and also serves to protect the engine by precluding the entrance of airborne contaminants to the engine when the engine is shut down and cools to provide a relatively low pressure within the crankcase. The oil collected within the canister may be drained by a petcock or drain valve for periodic proper disposal as required. While the present oil collector may be adapted to virtually any type of four stroke reciprocating internal combustion engine not having a positive crankcase ventilation system, it is particularly well suited for use with motorcycles, which are not required to have any form of emissions controls thereon.

Controlled self-ignition combustion process and associated 4 stroke combustion engine with residual gas storage volume and valve for it

Abstract: The procedure consists of filling a separate external chamber (10) with exhaust gases from the cylinder (1) through a special valve (8) and duct (9) on the expansion stroke and returning some of the gases to the cylinder on the next inlet stroke, when the pressure in the cylinder is lower than in the chamber, so that the fresh charge is ignited by the hot exhaust gases. The chamber (10) is insulated to maintain the temperature of the exhaust gases.

Low emission two-cycle internal combustion engine for powering a portable tool

Abstract: A low emission two-cycle internal combustion engine for powering a portable tool is provided. The two-cycle engine comprising a cylinder block containing two parallel cylinders adjacent to each other receiving two reciprocating pistons. One cylinder in cooperation with the power piston, operates as the power source. The second cylinder in cooperation with the slave piston, operates as a volumetric fuel pumping system. Both cylinders centerlines lying in a plane perpendicular to a crankshaft. The cylinder block is disposed over an engine block containing the crankshaft and a crankcase. The two pistons are connected by a connecting rod to a common crankpin. The kinematics of this engine leads to a considerable advance of the slave piston in relation to the power piston, resulting in a significant higher pressure within the pump cylinder than into the power cylinder during the compression period. The combustion gasses are evacuated by pure air compressed into the crankcase through the scavenging ports. After the exhaust port closes, a rich fuel/air mixture is progressively introduced into the power piston by the pumping action of the slave piston. This fuel/air mixture is introduced into the combustion chamber of the power cylinder through a fuel transfer port communicating the upper portion of both cylinders and through a unidirectional valve located at the end of such transfer port. Because the injection occurs after the piston has closed off the exhaust port, virtually no unburned fuel escapes, therefore, HC emissions are greatly reduced and fuel economy is enhanced.

Four-stroke internal combustion engine with direct injection

Abstract: The invention relates to a four-stroke internal combustion engine with applied ignition, wherein fuel is directly injected into a combustion chamber (28) by means of an injector (22). Said engine comprises at least one admission channel (14) with an admission valve (15) and at least one exhaust channel (16) with an exhaust valve (17), the admission valve (15) and the exhaust valve (17) being placed on opposite sides of the combustion chamber (28), and the injector (22) being placed on the admission valve side. Said engine also comprises a cavity (32; 36, 38) formed in a piston top (12). A piston (10) exhibits a central longitudinal axis (30) extending in the direction of displacement of said piston. The cavity (32; 36, 38) is placed on the admission valve side and exhibits, relatively to said admission valve (15) and the injector (22), a marginal area forming the highest point of the piston top (12), so that an air flow (26) originating in the appropriately designed admission channel (14) and penetrating into the combustion chamber (15) through the admission valve (15) and an injection jet (24) originating in the injector (22) and penetrating into the combustion chamber (28) enter the cavity (32; 36, 38) at opposite points.

Engine cylinder head

Abstract: A push rod operated multi-valve V-type engine particularly adapted for use in motorcycles or like vehicles and which engine is air cooled. The engine employs a very simplified construction and overhead valve actuating mechanism utilizing push rods. The push rods are contained within push rod tubes formed at one side of the engine that provide a neat appearance and ease of servicing without adversely affecting the air cooling. A composite cylinder head construction is employed, as well as an improved and simplified lubricating system for the pair of driven camshafts.

Cam shaft for 4-stroke IC engine has cams opening intake valves/ejection valves during ejection/intake strokes, for adjustment of valve opening timing/period during stroke

Abstract: The camshaft (2) is for an engine with variable valve drive. The cams (4) opening the intake valve during the ejection stroke are formed so that opening timing and/or the opening period of the valve can be adjusted during the ejection stroke. The cams opening the outlet valves during the intake stroke are formed, so that the opening timing and/or period of the valve can be adjusted during the intake stroke. The cams are additional cams, turnable about the longitudinal axis (3) of the camshaft relative to the main cam (1).