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Showing papers on "Four-stroke engine published in 1976"


Patent
13 Oct 1976
TL;DR: In this paper, a gas turbine engine is provided with a long nacelle which forms both the inlet and exhaust of the engine, and a non-redundant system of mounts are provided to secure the engine to the pylon of an aircraft in such a manner as to reduce engine thrust induced bending loads and insure symmetry of these thrust loads.
Abstract: A gas turbine engine is provided with a long nacelle which forms both the inlet and exhaust of the engine. The nacelle is spaced apart from a core engine to define an annular bypass duct therebetween. The incoming air stream is pressurized by a front fan disposed in the inlet and then divided between the core engine and bypass duct. A lobed mixer device is provided downstream of the core engine to intermix the core engine and bypass duct exhaust streams. The mixed streams are discharged from a common nozzle formed at the downstream end of the nacelle. A non-redundant system of mounts are provided to secure the engine to the pylon of an aircraft in such a manner as to reduce engine thrust induced bending loads and insure symmetry of these thrust loads. The total reaction of the thrust loads at the mounting points is reduced by a unique interlocking system by which all of the major engine assemblies are joined. The engine is configured such that it may be easily removed from an aircraft and replaced with a spare engine in minimum time. This quick change capability is achieved by mounting the engine such that it may be removed from the aircraft by disconnecting the forward and rear mounts and an engine bleed duct. The mid portion of the engine nacelle and all accessories mounted thereon remain with the aircraft.

66 citations


Patent
10 Aug 1976
TL;DR: In this article, a two-stroke engine with a piston mounted in a cylinder having a full diameter bore throughout its major length and a reduced diameter upper bore portion is described, where air and finely-divided water droplets are admitted into an annular space formed between the piston reduced diameter and the cylinder's full diameter.
Abstract: The two-stroke engine has a piston mounted in a cylinder having a full diameter bore throughout its major length and a reduced diameter upper bore portion. The piston has the same configuration and in its upward compression stroke, air and finely-divided water droplets are admitted into an annular space formed between the piston's reduced diameter and the cylinder's full diameter. Flow of the air water mixture through an exhaust valve cools the motor. At TDC (top dead center) the upper surfaces of the piston and the cylinder mutually form a relatively small spheroidal combustion chamber. Differing compression ratios in the annular and the spheroidal chamber cause the air-water mixture to rush into the spheroid in a swirling motion to intimately mix with injected fuel. Ignition produces a complete burning. End gases or the like are burnt in the cooler annular space to avoid detonation. The fuel injection is in measured increments determined by the temperature and pressure of the water mixture. The water supply also is metered responsively both to the engine temperature and the fuel demands. To increase engine output, an operator varies the amount and pressure of the air supply by varying the eccentricity of an eccentric vane blower. A special high pressure injection system is provided for improving both safety and performance.

32 citations



Patent
15 Apr 1976
TL;DR: In this article, a gasoline engine torque regulator is proposed to reduce the quantities of harmful oxides of nitrogen emitted via the exhaust of a four-stroke cycle gasoline engine and to increase the efficiency of the engine at part load, with an engine torque characteristic either approximately constant with engine speed or alternatively controllably decreasing with increasing engine speed.
Abstract: The gasoline engine torque regulator described herein provides means of reducing the quantities of harmful oxides of nitrogen emitted via the exhaust of a four stroke cycle gasoline engine and also of increasing the efficiency of the engine at part load, with an engine torque characteristic either approximately constant with engine speed or alternatively controllably decreasing with increasing engine speed These beneficial objects are achieved by adjustably delaying the closing of the engine intake valve as a means of controlling the engine torque, the opening of the intake valve remaining fixed This manner of intake valve opening and closing can be achieved by adding to the conventional intake valve operating mechanism a dashpot device with a check valve and a positive displacement flow regulator The check valve allows ready flow of the dashpot fluid between dashpot chambers when the intake valve is being opened but closes and forces fluid to flow oppositely, during intake valve closing, at least partially via the positive displacement flow regulator which proportions the flow and hence the rate of valve closure to the speed of the engine With intake valve closing thereby delayed, a portion of the air-fuel mixture, drawn into the engine cylinder during the intake stroke, is pushed back into the intake manifold during the compression stroke As a result less air-fuel mixture remains in the engine cylinder and the engine torque is reduced, the extent of such torque reduction increasing as the intake valve closing is longer delayed The engine compression ratio is reduced at reduced torque and, in consequence, gas temperatures during compression, combustion and expansion are reduced, producing a beneficial decrease in the quantities of oxides of nitrogen formed and subsequently emitted Part load efficiency of the engine is increased because pumping work is essentially eliminated

19 citations


Patent
27 Feb 1976
TL;DR: In this paper, the Stirling engine is provided with a sealing ring resiliently mounted to one of two sliding-able members of the engine with a limited freedom of movement relative to that member and sealingly slidable along the other member.
Abstract: A free piston, Stirling engine is provided with seals which permit a limited range of friction-free displacer piston movement for allowing a starting perturbation of displacer piston position. The seal is a sealing ring resiliently mounted to one of two slidably engaged members of the Stirling engine with a limited freedom of movement relative to that member and sealingly slidable along the other member.

18 citations


Patent
19 Apr 1976
TL;DR: In this article, the authors converted a conventional four-cycle internal combustion engine into a single acting reversible steam, or fluid pressure operated engine by changing the timing cycle of the valves relative to the crankshaft and connecting the valve ports to a reversing valve for admitting live steam to the intake ports while connecting the exhaust ports to the atmosphere, and for reversing the connection selectively.
Abstract: The method converts a conventional four cycle internal combustion engine into a single acting reversible steam, or fluid pressure, operated engine by changing the timing cycle of the valves relative to the crankshaft and connecting the valve ports to a reversing valve for admitting live steam to the intake ports while connecting the exhaust ports to the atmosphere, and for reversing the connection, selectively.

17 citations


Patent
09 Aug 1976
TL;DR: An internal combustion, reciprocating-piston engine which includes a sealed crankcase for inducting and compressing air or an air-fuel mixture into the engine is described in this article.
Abstract: An internal combustion, reciprocating-piston engine which includes a sealed crankcase for inducting and compressing air or an air-fuel mixture into the engine. The compressed gas is then forced into a holding tank for subsequent induction into the cylinder combustion chamber. This pre-compresses or "supercharges" the fuel mixture before compression by the piston. An enclosed lift tube within the connecting rod is provided for conveying lubricating oil through the crankcase to the cylinder walls.

14 citations


Patent
27 Feb 1976
TL;DR: In this paper, an internal combustion four cycle engine is provided with a plurality of stationarily mounted cylinders radially arranged in equal spaced apart relationship within the inner circumference of a rotatably mounted drive drum and in parallel relationship with the axis of rotation thereof, a movable track anchorably supported by a pair of oppositely disposed raised lobes fixed to the interior webbed surface of the drum and comprised of two pairs of declining slope track quadrants serving to receive the driving thrust of each piston during its power stroke and to activate each piston in its intake, compression and exhaust strokes,
Abstract: An internal combustion four cycle engine is provided with a plurality of stationarily mounted cylinders radially arranged in equal spaced apart relationship within the inner circumference of a rotatably mounted drive drum and in parallel relationship with the axis of rotation thereof, a movable track anchorably supported by a pair of oppositely disposed raised lobes fixed to the interior webbed surface of the drum and comprised of two pairs of declining slope track quadrants serving to receive the driving thrust of each piston during its power stroke and to activate each piston during its intake, compression and exhaust strokes, and a cam ring fixed to the inner circumference of the drive drum serving to activate an intake-exhaust slide of each cylinder commensurate with the requirements of its intake, compression, power and exhaust strokes. Means resiliently coupled to a hollow exterior hub of the drum and extending internally thereof into rotatable relationship with the webbed surface serves as output means for the engine and to variably elevate the declining slope track quadrants according to the torque load that is applied to the output means, whereby the pistons of the cylinders are provided with a constant power stroke and a variable intake stroke and whereby the intake stroke attains a predetermined maximum length in the presence of a torque load applied to the output means and a predetermined minimum length in the absence of a torque load.

11 citations



Patent
13 Feb 1976
TL;DR: In this article, an exhaust gas re-circulation system for an internal combustion engine is provided with a single flow-control valve for regulating the flow of the recirculating exhaust gas which is re-introduced from an exhaust system of the engine into an intake system.
Abstract: An exhaust gas re-circulation system for an internal combustion engine is provided with a single flow-control valve for regulating the flow of the re-circulating exhaust gas which is re-introduced from an exhaust system of the engine into an intake system of the engine in a two step-like manner, depending upon change in the state of operation of the internal combustion engine and/or change in the operating condition of said internal combustion engine.

8 citations


Patent
02 Feb 1976
TL;DR: In this article, the authors proposed an approach to adjustably delaying the closing of the engine intake valve as a means of controlling the engine torque, the opening of the intake valve remaining fixed.
Abstract: The gasoline engine torque regulator described herein provides means of reducing the quantities of harmful oxides of nitrogen emitted via the exhaust of a four stroke cycle gasoline engine and also of increasing the efficiency of the engine at part load, with an engine torque characteristic either approximately constant with engine speed or alternatively controllably decreasing with increasing engine speed. These beneficial objects are achieved by adjustably delaying the closing of the engine intake valve as a means of controlling the engine torque, the opening of the intake valve remaining fixed. This manner of intake valve opening and closing can be achieved by adding to the conventional intake valve operating mechanism a dashpot device with a check valve and a positive displacement flow regulator. The check valve allows ready flow of the dashpot fluid between dashpot chambers when the intake valve is being opened but closes and forces fluid to flow oppositely, during intake valve closing, at least partially via the positive displacement flow regulator which proportions the flow and hence the rate of valve closure to the speed of the engine. With intake valve closing thereby delayed, a portion of the air-fuel mixture, drawn into the engine cylinder during the intake stroke, is pushed back into the intake manifold during the compression stroke. As a result less air-fuel mixture remains in the engine cylinder and the engine torque is reduced, the extent of such torque reduction increasing as the intake valve closing is longer delayed The engine compression ratio is reduced at reduced torque and, in consequence, gas temperatures during compression, combustion and expansion are reduced, producing a beneficial decrease in the quantities of oxides of nitrogen formed and subsequently emitted. Part load efficiency of the engine is increased because pumping work is essentially estimated.

Patent
05 Feb 1976
TL;DR: In this article, a four-stroke engine comprises a turbocharger with a turbine (4) and compressor (6), and an auxiliary electric fan (13) for conveying secondary air under running conditions in which the air conveyed by the turbo-charger compressor is insufficient.
Abstract: Four-stroke engine comprises a turbocharger with a turbine (4) and compressor (6), and an auxiliary electric fan (13) for conveying secondary air under running conditions in which the air conveyed by the turbocharger compressor is insufficient. Between the output side (9) of the compressor and the input side (10) of the turbine is a bypass pipe (11, 43, 12) in which is mounted the auxiliary fan leading to the turbine. The auxiliary fan pref. draws in air directly from the atmosphere in the lower performance range, and is directly connected to the turbo charger compressor in the middle and upper performance ranges.

Patent
15 Oct 1976
TL;DR: An engine de-compression mechanism in which the valves to one or more of the cylinders are locked in open position to prevent fuel from being drawn into the engine cylinder during the normal intake stroke and to prevent compression back pressure on the piston during the compression stroke is described in this paper.
Abstract: An engine de-compression mechanism in which the valves to one or more of the cylinders are locked in open position to prevent fuel from being drawn into the engine cylinder during the normal intake stroke and to prevent compression back pressure on the piston during the compression stroke. The function of the de-compression mechanism is to put one or more of the cylinders of the engine out of operation to conserve fuel when driving at high speeds.

Patent
28 Dec 1976
TL;DR: In this article, a method of operating a four-stroke internal combustion engine of the carburator or fuel injection type, with one or several reciprocating or rotary pistons, where during the intake movement of the one or the several pistons an additional gaseous or liquid or gas-liquid mixture fluid is introduced into the cylinder working space through a cylinder side wall aperture in the vicinity of the piston to establish a layer charge overlying the piston.
Abstract: A method of operating a four-stroke internal combustion engine of the carburator or fuel injection type, with one or several reciprocating pistons or one or several rotary pistons wherein during the intake movement of the one or the several pistons an additional gaseous or liquid or gas-liquid mixture fluid is introduced into the cylinder working space through a cylinder side wall aperture in the vicinity of the piston to establish a layer charge overlying the piston. The introduction of this fluid may be effected by suction effects caused by the piston movement. The amount of fluid supplied may be controlled in dependence upon combustion pressure and/or exhaust gas composition. The internal combustion engine includes an aperture in a cylinder wall in communication with a fluid source whereby this aperture is adapted to be obstructed or exposed by the moving piston to control the admission of the additional fluid. Between the aperture and the fluid source may be provided control valve means.


Patent
03 Aug 1976
TL;DR: In this article, a two piston hydraulic fluid separated internal combustion cylinder system utilizing a cylinder having fuel inlet ports, ignition means, a viewing window, a filling plug; a first piston, hydraulic fluid cushion and a smaller piston which may be connected to a crankshaft.
Abstract: A two piston hydraulic fluid separated internal combustion cylinder system utilizing a cylinder having fuel inlet ports, ignition means, a viewing window, a filling plug; a first piston, hydraulic fluid cushion and a smaller piston which may be connected to a crankshaft.

Patent
20 Apr 1976
TL;DR: In this article, the exhaust gas cleaning system for a four stroke combustion engine is described, where the cylinders (2) are combined as cylinder groups, each of which comprises two cylinders, and the opening times of the outlet valves (6,A) in each cylinder group do not overlap.
Abstract: The exhaust gas cleaning system is for a four stroke combustion engine where the cylinders (2) are combined as cylinder groups, each of which comprises two cylinders. The opening times of the outlet valves (6,A) in each cylinder group do not overlap. An air channel (14,17,18,19) connects the exhaust channels (12,7) of the cylinders of one group with atmosphere. A valve (13,13') in the air channel automatically opens when the pressure in the cylinder exhaust channels of one group falls below a given value. Consequently air is passed into the exhaust gas channels of the cylinders of this group.

Patent
21 Oct 1976
TL;DR: In this article, a two or four stroke design with direct or indirect fuel injection is provided with a piston and cylinder unit off-set to the main engine so that the duplicate engine inlet valve admits the exhaust gas from the exhaust valve, compresses it and with an injection charge of water or a similar inexpensive liquid able to vapourise causes it to expand again and perform a second working stroke before being allowed to escape to atmosphere.
Abstract: The engine which may be of any conventional two or four stroke design with direct or indirect fuel injection is provided with a piston and cylinder unit off-set to the main engine so that the duplicate engine inlet valve admits the exhaust gas from the main engine exhaust valve, compresses it and with an injection charge of water or a similar inexpensive liquid able to vapourise causes it to expand again and perform a second working stroke before being allowed to escape to atmosphere. A non-toxic liquid gaseous or dust liek substance could also be injected at the highest point of compression to bring about a combustion instead of an expansion so that the exhaust gases would be almost completely eliminated.

Patent
22 Mar 1976
TL;DR: In this article, an external auto-ignited four-stroke cycle gas engine with a combustion chamber arranged in the piston rotation symmetrically with regard to the cylinder axis and which in the upper dead center point of the piston absorbs nearly the total gas-air mixture was presented.
Abstract: An external auto-ignited four stroke cycle gas engine with a combustion chamber which is arranged in the piston rotation symmetrically with regard to the cylinder axis and which in the upper dead center point of the piston absorbs nearly the total gas-air mixture. The engine, furthermore, includes means for imparting turbulence upon the gas-air mixture about the longitudinal cylinder axis, and also has a trough which is arranged in the cylinder head, and into which a spark plug extends. The combustion chamber in the form of a truncated cone open and widening toward the cylinder head has a substantially plane bottom while the greatest diameter of this truncated cone-shaped combustion chamber equals from 55 to 70% of the piston diameter and the depth of this combustion chamber is in a range from 15 to 20% of the piston diameter. The mantle surface of the combustion chamber is at an angle of from 10° to 30° inclined relative to the longitudinal axis of the cylinder. The trough into which the spark plug extends is truncated cone shaped and located entirely above the opening of the combustion chamber. The greatest diameter of the trough amounts to about twice the diameter of the thread of the spark plug while the depth of the trough amounts to from 20 to 25% of the trough diameter. Adjacent to and communicating with the trough is an ignition passage which ends in a tip at the longitudinal cylinder axis. The present invention relates to an external auto-ignited four-stroke cycle gas engine with a combustion chamber which is arranged in the piston rotation-symmetrically with regard to the cylinder axis and which in the upper piston dead center point absorbs approximately the entire gas-air mixture, the gas engine being provided with means for generating turbulence of the gas-air mixture about the cylinder axis and furthermore being provided with a depression provided in the cylinder head while an ignition plug extends into this depression. It is an object of the present invention to provide an engine of this type which in spite of the fact that its exhaust gases are substantially free from harmful components has a low fuel consumption and a high output.

Patent
20 Sep 1976
TL;DR: In this paper, the gudgeon pin bearing of a connecting rod was used to provide a guiding surface for a coolant and/or lubricant spraying from a crankcase chamber of the internal combustion engine against the piston.
Abstract: A piston for internal combustion engines, especially Diesel engines, which is equipped with a mantle connecting the piston head with the piston foot and which by means of this foot is pivotally connected to a gudgeon pin bearing of a connecting rod. Within the region of the gudgeon pin bearing there is provided at least one guiding surface for a coolant and/or lubricant sprayed from a crankcase chamber of the internal combustion engine against the piston. The coolant and/or lubricant are directed relative to the gudgeon pin bearing in such a way that the coolant and/or the lubricant carry out a flow around the gudgeon pin bearing while simultaneously flowing against the foot of the piston as well as against the gudgeon pin bearing.

Patent
21 May 1976
TL;DR: In this article, a vane-type internal combustion engine with a spring-compressed spring is described, in which, during a power stroke, a spring is compressed which delivers back power to the engine during a non-powered stroke.
Abstract: A vane-type internal combustion engine in which, during a power stroke, a spring is compressed which delivers back power to the engine during a non-powered stroke and provides relatively even torque.

Patent
26 Feb 1976
TL;DR: In this article, a combustion engine of 4-stroke type with variable combustion space is constructed such that the radially disposed and pref opposed combustion spaces always have the same valume during rotation around the drive axle in each angular disposition if the volume of the combustion spaces is simultaneously radially varied.
Abstract: A combustion engine of 4-stroke type with variable combustion space but without valve control is constructed such that the radially disposed and pref opposed combustion spaces always have the same valume during rotation around the drive axle in each angular disposition if the volume of the combustion spaces is simultaneously radially varied The housing containing the combustion spaces can rotate about the mid point of the drive shaft The transmission of power to the crankshaft may be direct or indirect The pistons of the device undergo simultaneous rotation about the drive axis and radial stroke motion

Patent
15 Jul 1976
TL;DR: Cam-driven four-stroke reciprocating-piston engines as discussed by the authors are a type of engines that use a single-cylinder engine with a single cam on a central variable-length main shaft, which transmits axial forces to the piston via the piston rod.
Abstract: Cam-driven four-stroke reciprocating-piston engine comprises a cam (3) which is mounted on a central variable-length main shaft (2) and which transmits only axial forces to the piston (4) via the piston rod which is provided with low-friction means (15, 16): engine speed, piston travel, piston speed, piston acceleration and the lengths of the four strokes can be varied in any manner by the shape of the cam The valves (11, 12) or ports are controlled by a cam (7) which is also mounted centrally on the main shaft or by push rods The first cam pref consists of two concentric identically shaped annular segments

Patent
19 Feb 1976
TL;DR: In this paper, each cylinder is provided with two separate air fuel mixture induction pipes (3, 4) controlled by separate inlet valves (7, 8) actuated by cams having approximately the same contours.
Abstract: Each cylinder is provided with two separate air fuel mixture induction pipes (3, 4) controlled by separate inlet valves (7, 8) actuated by cams having approximately the same contours The one induction pipe (3) feeds a comparatively rich mixture from a carburettor to the inlet valves (7) close to the spark plug electrodes (14) The second induction pipes feeds a comparatively weak air fuel mixture to the second inlet valve (8) from a second carburettor which produces a greater air mixture ratio at part load and a less air mixture ratio at full load than the usual accepted ratio The resulting toxic exhaust emmission content is reduced thereby to an acceptable level

Patent
30 Sep 1976
TL;DR: In this article, the piston is a disc fixed to a tubular piston rod connected to a fork-shaped crankshaft provided with bearing surfaces and a gear profile to engage with planet wheels running inside a sun wheel.
Abstract: The piston (8) takes the form of a disc fixed to a tubular piston rod (7) connected to a fork shaped crankshaft provided with bearing surfaces and a gear profile to engage with planet wheels running inside a sun wheel. The air intake flows via a transfer channels cast in the transfer housing below the cylinder when the piston uncovers the upper slots formed in the cylinder wall when the piston reaches bottom dead centre. A labrynth oil seal (12) is provided in the crank case to permit the piston connecting rod to pass with a minimum oil loss and to permit an alternating depression and compression in the crank case.

Patent
16 Jun 1976
TL;DR: In this paper, a self charging double working piston working on a two stroke diesel engine principal with the cylinder (2) reciprocating in phase opposition is presented. But this engine is not suitable for application as motor vehicle propulsion without the necessity of gearing.
Abstract: The engine has a self charging double working piston working on two stroke diesel engine principal with the cylinder (2) reciprocating in phase opposition. the cylinder pivot axis is provided with diametrically opposite coils (5) which in conjunction with the piston (4) form the starter motor and alternator generator. An exhaust gas turbo charger (3) is provided. A simple compact economical construction is claimed suitable for application as motor vehicle propulsion without the necessity of gearing having great durability with considerably less harmful exhaust emission then contemporary engines.

Patent
28 Apr 1976
TL;DR: In this paper, the authors proposed to improve the combustion efficiency by varying a closing and opening timing of an intake valve to facilitate the fuel atomization and generation of swirls, but they did not specify the timing of the intake valve itself.
Abstract: PURPOSE:To improve the combustion efficiency by varying a closing and opening timing of an intake valve to facilitate the fuel atomization and generation of swirl.

Patent
29 Apr 1976
TL;DR: In this article, a four-stroke internal combustion engine inlet and exhaust valves are operated by small hydraulic motors connected to the respective valves and fed with pressure fluid supplied through a distributor valve connected to hydraulic pumps and operating to connect the pumps and motors in cyclic order for the feed and return of the fluid to and from the motors.
Abstract: In a four-stroke internal combustion engine inlet and exhaust valves are operated by small hydraulic motors connected to the respective valves and fed with pressure fluid supplied through a distributor valve connected to hydraulic pumps and operating to connect the pumps and motors in cyclic order for the feed and return of the fluid to and from the motors. Preferably, the distributor valve has a valve member executing a combined rotory and axial motion and is provided with ports extending obliquely to the axis of the member for the control of the flow to and from the motors.

Patent
19 Oct 1976
TL;DR: In this paper, a closed cylinder with a piston dividing the cylinder into two compartments, with the piston rod extending beyond one end of the cylinder to power both the air conditioner compressor pump and a liquid pump that supplies the engine with pressurized liquid.
Abstract: An engine for driving the compressor of an air conditioner system which is powered by the heat of the exhaust manifold of a vehicle internal combustion engine. The engine of the invention includes a closed cylinder with a piston dividing the cylinder into two compartments, and with the piston rod extending beyond one end of the cylinder to power both the air conditioner compressor pump and a liquid pump that supplies the engine with pressurized liquid. The inlet port of the engine is located on a cylinder wall midway between the cylinder ends, with bores in the piston linking the inlet port with each cylinder compartment at the position of the cylinder that reduces the particular compartment to its minimum volume. Each end of the cylinder is surrounded by a heated exhaust jacket so that the liquid fed into the cylinder compartment is vaporized to expand the cylinder compartment and drive the piston. An exhaust port extends from each cylinder end with each exhaust port blocked in turn by a slide rod that extends axially through the cylinder and into each exhaust port. A piston is fixed to the slide block in an auxiliary cylinder chamber inside the piston so that the pressurized gas in one engine cylinder compartment is led by ports in the piston to one of the two auxiliary cylinder compartments to maintain the slide rod in bearing engagement against the exhaust valve opening leading from the pressurized engine cylinder compartment until the piston reaches the end of the expansion stroke. The exhaust gas of the engine is led through a condenser, with the condensate led through the liquid pump and a cooler to the intake port.

Journal ArticleDOI
TL;DR: In this article, a method of measuring the fluctuating velocity of gases at any point in the exhaust system of an operating four stroke internal combustion engine was described, which permits periodic automatic crank angle selection in a preselected engine cycle, discharge and ionization in the region of measurement and finally detection at a known distance.
Abstract: A method of measuring the fluctuating velocity of gases at any point in the exhaust system of an operating four stroke internal combustion engine has been described. The instrument developed permits periodic automatic crank angle selection in a preselected engine cycle, discharge and ionization in the region of measurement and finally detection at a known distance. The time interval between the ionization and detection was used to determine the velocity. The pulsating velocity was measured both for motoring and firing conditions at various crank angles.