Showing papers on "Compression ratio published in 1981"

Closed loop diesel engine control

Abstract: A method and apparatus for achieving optimized efficiency combustion in a diesel internal combustion engine utilizes a cylinder pressure detector which measures peak cylinder pressure relative to crankshaft timing and compares it with a speed-load-timing map comprising several engine parameters including engine speed and engine load in order to compensate for various unknown combustion characteristics of the fuels to be used in compression ignition engines, and automatically adjusts fuel injection timing for optimum efficiency.

Pressure sensor for an internal combustion engine

Abstract: A pressure sensor for an internal combustion engine has a piezoceramic transducer in an operating connection, by way of a plunger, with a membrane, the sensor being secured in a cylinder head of an internal combustion engine with the membrane located within a cylinder. The pressure sensor serves for detecting knock and ping.

Method and apparatus for minimum knock operation of an internal combustion engine on low knock-rated fuel

Abstract: The invention relates to method of, and apparatus for, operating an internal combustion engine on low knock-rated fuels as the primary fuel system in which engine knock is anticipated and suppressed by simultaneously detecting actual engine load conditions that may induce such knock and knock condition that actually are occurring in at least one combustion chamber of the engine. In response to such simultaneous conditions, a small but effective amount of anti-knock fluid is supplied to the engine combustion chambers in an amount and for a time sufficient only to suppress knock to a satisfactory level. Such a system permits the use of more economic fuels, such as gasoline, having a substantially lower knock rating than those normally used in automotive equipment and only small but sufficient anti-knock fluid is added solely when the engine is knocking. Such conditions occur over approximately 5-10 percent of road conditions and can readily be supplied by a 1-2 quart container of anti-knock fluid, such as higher knock-rated gasolines, alcohol or the like for each filling of the fuel tank with 10-20 gallons of less expensive low knock-rated gasoline to improve both economic and energy efficiency.

Timing mechanism for engine brake

Abstract: Hydro-mechanical brake timing means are provided to control the timing of an engine braking system of the gas compression type for an internal combustion engine wherein the engine braking system includes a hydro-mechanical mechanism which opens the exhaust valve near the top of the compression stroke of the engine so that the energy absorbed by the engine during the compression stroke is not returned to the engine during the expansion stroke. In accordance with the present invention, hydro-mechanical means are provided in the exhaust valve actuating mechanism whereby the clearance in that mechanism is reduced to a value which maximizes the retarding power developed by the engine whenever the engine brake is activated.

Measurements in a motored four-stroke reciprocating model engine

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

Gasoline engine combustion -- turbulence and the combustion chamber

Abstract: A research programme has been carried out to investigate the effects of operating gasoline engines with different combustion systems. The results showed that at high compression ratios (13:1) compact combustion chambers allowed an increase in compression ratio of between 1 and 2 one-half numbers for a given fuel quality compared to conventional designs. Fuel economy benefits of about 10% could be achieved by using high ratio compact chambers and lean operation.

Method for improving fuel control in an internal combustion engine

Abstract: A method for improving fuel control in an internal combustion engine employs a pressure ratio to determine the engine's actual volumetric efficiency continuously as the engine is operating. The air/fuel ratio of the engine's combustible mixture is affected by the volumetric efficiency. The volumetric efficiency varies during engine operation. Determination of the actual volumetric efficiency on a real-time basis allows greater accuracy in fuel metering. The pressure ratio used in the determination of the volumetric efficiency is the ratio of the intake and exhaust pressures or the inverse of this ratio. The ratio of pressures is combined with a second factor representative of the forces acting upon the air or air/fuel mixture inducted into the engine. The pressure ratio may be obtained without actual measurement of the pressure in the engine's exhaust conduit.

Knock in Spark Ignition Engines

Abstract: The knocking characteristics of several fuels are studied using a single cylinder test engine with variations in key engine operating parameters. Compression ratio, spark advance, fuel equivalence ratio, exhaust gas recirculation, engine speed, charge inlet pressure and charge inlet temperature were varied to yield a range of engine cylinder pressure-temperature histories as the base for this study. A number of empirical relationships for auto ignition times of isooctane and heptane blends are employed in conjunction with the experimentally obtained pressure-temperature histories to predict onset of knock. The accuracies of the predictions with respect to the experimentally determined knock points are discussed.

Introduction of alcohol-water mixture into gasoline-operated engine

Abstract: Alcohol and water are mixed as liquids in a volume ratio of water to alcohol in the range 0.3-1.0 to 1. The liquid mixture is heated in heat exchanging relation with the exhaust conduit of a gasoline operated internal combustion engine, to convert the mixture to a gaseous state which is then combined with a mixture of gasoline and air for introduction into the engine. The water-alcohol mixture is 3-14 vol. % of the gasoline.

Device for adjusting engine timing

Abstract: The timing of delivery of fuel to a compression ignition engine is determined and adjusted by observing the peak pressure attained in a combustion chamber during a fueled working stroke of the engine This is compared with a derived peak pressure and a timing adjustment made The condition of the engine is taken into account by comparing an actual pressure ratio with a desired pressure ratio, the actual pressure ratio being determined by obtaining a peak pressure signal when fuel is supplied or a pressure signal at a fixed point in the working stroke before fuel is supplied The desired pressure ratio is provided by a circuit to which signals representing engine speed and fuel quantity are supplied

Spark ignition internal combustion engine

Abstract: A spark-ignition internal combustion engine having a combustion chamber, comprises intake and exhaust valves disposed on a cylinder head wall surface and positioned generally symmetrical with each other with respect to the center axis of the bore of an engine cylinder, at least first and second squish areas which are located respectively in first and second sections of the combustion chamber which sections are defined by dividing the combustion chamber into two by a first vertical plane containing the centers of the intake and exhaust valves, and a spark plug whose tip section is disposed on the cylinder head wall surface and positioned in said first section of the combustion chamber thereby enabling use of high compression ratio without causing engine knock.

Method for regulating the operating cycle in an external combustion engine

Abstract: An engine having a working chamber and a combustion chamber and a method for operating it are disclosed. The amount and compression ratio of air entering the combustion chamber are controlled by valves at the working chamber. The maximum possible amount of air is inducted into the working chamber, and then air is discharged until an amount necessary for the existing load on the engine remains. This remaining air is then compressed to a predetermined constant compression ratio at which it enters the combustion chamber. A proportional amount of fuel is supplied, and the resulting combustion gas is then transferred to do work in the working chamber. The amount of combustion gas transferred is sufficient to maintain a substantially constant pressure in the combustion chamber.

Optical engine knock sensing system

Abstract: A sensor (10) optically coupled to the combustion chamber (10') of an internal combustion (IC) engine is kept free from contaminating or dirt deposits, or the like, by subjecting the sensor to mechanical shocks or vibration. The mechanical shocks or vibration are obtained by the engine itself by controlling the engine to operate for a predetermined time period as set by a monostable flip-flop (FF) (18) under controlled knocking conditions, the shock waves within the combustion chamber causing flaking off or dropping off of contaminating deposits. Controlled knocking can be obtained by advancing ignition timing by additional control of an ignition system (19) in a direction of excessive spark advance, or overriding a knocking inhibiting system already present on the engine. The degree of contamination of the sensor can be determined, for example, by integrating the light received over a predetermined angle of rotation of the engine crankshaft and comparing this rotation with the amount of fuel supplied to the engine for combustion, for example by comparison with timing of a fuel injection pulse, or the like.

A LH2 engine fuel system on board - Cold GH2 injection into two-stroke engine with LH2 pump

Abstract: An LH2-tank with a range of 400 km was installed in the rear trunk of a small passenger car in June, 1980 Tests demonstrated the overall feasibility of a hydrogen-fueled car: the tank attained a maximum power 20% to 20% higher than its gasoline counterpart and about twice as high as those of premixed engines There was no backfire or knocking, and a very low NOx emission level was achieved by injecting -30 to -50 C cold hydrogen gas, pressurized by an LH2-pump, into the two-stroke engine The LH2-pump was developed by the Musashi Institute of Technology the barrel and the plunger are made of metal and a durable, low friction material, respectively The plunger clearance was reduced to about 3 microns under operating conditions, thereby making fuel leakage from the plunger clearance negligible Proper tank pressures were obtained according to the pump speed The maximum speed of the car was recorded at 135 km/h Future objectives include the production of an engine with a higher compression ratio through the development of a high pressure pump having a discharge pressure above 6 MPa, and the improvement of the heat insulation performance of the LH2-tank

Insulated diesel engine combustion chamber

Abstract: A diesel engine is provided with extenders or spacers attached to those portions of the cylinder block, cylinder head and piston that define the combustion chamber, the extenders being of substantial axial extent and of low thermal conductivity to insulate the components to which they are attached from the combustion chamber while redefining the combustion chamber surfaces.

Varying geometric compression ratio engine

Abstract: An automotive engine having an automatically adjusted geometric compression ratio, wherein the charge is compressed to maximum permissible values under all throttle settings. This is achieved by a cylindrical valve carrier, raised or lowered by a screw jack, while valve stem contact is maintained by a fast acting hydraulic valve actuator. The compact arrangement provides an engine profile which is not significantly taller than a standard overhead cam engine.

Two stroke cycle engine with increased efficiency

Abstract: A method and apparatus is disclosed for decreasing fuel consumption in a variably loaded, two cycle internal combustion engine Fluid communication is provided between the working cylinder and air chamber during the upward stroke of the engine up to about 85°-105° BTDC, during which time the cylinder gases can flow back into the air chamber reducing engine friction as a result of a delay in the rise of the cylinder gas pressure during compression and a reduction in the peak compression pressure

Calculations and measurements of the flow in a motored model engine and implications for open-chamber direct-injection engines

Abstract: The purposes of this paper are to present and compare computer calculations and measurements of the velocity characteristics of the flow in axisymmetric, four-stroke model engine and with the consequent knowledge of the precision of the calculation method, to report further predictions which are of relevance to open-chamber, direct-injection engines. The calculations are performed with the rpm multi-dimensional prediction method, which solves the governing equations in a flexible curvilinear coordinate frame with turbulence effects represented by a two-equation (k-epsilon) turbulence model. The results are compared with measurements obtained by laser-Doppler anemometry in a plexiglass cylinder with a flat piston, centrally-located valve with 60/sup 0/ seat angle and non-swirling inlet flow, operating at 200 rpm and a compression ratio of 3.5. Moderate overall agreement is obtained between data and predictions, which collectively show that a strong highly-turbulent twin-vortex structure is produced during induction, but commences to decay rapidly around inlet valve closure. The mean motion continues to fall to a low level during compression, but the turbulence intensity attains an approximate constant level of about 0.6 times the mean piston speed, as also observed in other engine configurations. It is concluded that this decay process is one of the motivations for more » inducing longer-lived swirl motions in direct-injection engines and later augmenting these with squish, and it is suggested that calculation methods can assist in optimizing the fluid dynamics in such engines. « less

Compression operated injector with fuel injection control

Abstract: A compression operated diesel fuel injector, for use with an internal combustion engine, is provided with a compression operated piston that is associated with a pump cylinder and plunger to effect pressurization of fuel for discharge from the injector, the piston also defining with the associate injector housing a fuel control chamber. A solenoid actuated valve is operatively positioned to normally block the return flow of fuel from the fuel control chamber to the fuel reservoir for the engine and, a variable flow orifice means is operatively positioned downstream of this valve to control the return fuel flow pressure as a function of engine speed and load to thus regulate the return flow of fuel from the control chamber so as to thereby control engine compression operation of the piston and, accordingly, to correspondingly regulate the rate of fuel injection from the fuel injector.

Three cycle internal combustion engine

Abstract: An axial piston type internal combustion engine of novel three cycle variety, wherein the complete combustion process within the combustion chamber consists of three distinct cycles, accomplished over two distinct strokes of each piston, the three cycles being: the high pressure charging cycle, the power cycle, and the postive total exhaust expulsion cycle. The aspiration is controlled by a rotary disc valve, while the fresh gas charge is pre-compressed to high pressure by a separate high pressure charger. The conventional intake stroke and compression stroke, normally directly or indirectly carried out by the power piston in conventional two stroke or four stroke engines, is entirely divorced from the functions of the power piston and its power train components. Intended to replace conventional engines when high specific output, high power to weight ratio, and economy of operation are paramount.

Fuel supply control system for an internal combustion engine

Abstract: Fuel consumption of a declerating automotive vehicle internal combustion engine is reduced while preventing stalling. In response to a valve for selectively supplying air and fuel to the engine being in a fully closed condition, a first signal is derived. In response to the engine speed dropping below a first predetermined value a second signal is derived. In response to derivation of the first and second signals a controller for the valve is activated. The controller responds to engine and brake responsive parameters of the vehicle for opening the valve in respone to any of: (a) the engine being decelerated under no load, and (b) the brake being abruptly applied and (c) the engine speed dropping below a second value. The second value is less than the first value and is determined in response to the rate of change of engine speed.

Combustion chamber layout for modern Otto engines

Abstract: Since the most efficient way to improve fuel economy in the part-load range is to increase the compression ratio, emphasis is placed on combustion chambers allowing high compression ratios combined with low octane requirements. According to Porsche experience, many demands can be met in the simplest manner by locating the combustion chamber in the piston crown. This configuration offers various advantages over its counterpart installed in the cylinder head. 24 refs.

Method and system of power generation by an internal-combustion engine

Abstract: The invention relates to an internal combustion engine (1) supercharged by an air turbocharger (7, 8) for displacing the exhaust gas, by a bypass duct (13), a compressed air bypass flow rate in the pipe of exhaust gas (12) supplying the turbine (8). This compressed air diverted flow is heated by means of a heat exchanger (14) interposed in the bypass line (13) and traversed by the exhaust gases (15) of the turbine (8) and the bypass flow rate of heated compressed air is injected into the upstream end of the exhaust manifold (4) of the engine. The invention is applicable to diesel engines turbocharged compression ratio and compound engines.

Method of controlling air-fuel ratio in internal combustion engine

Abstract: Method of controlling a control system for an air-fuel ratio of air-fuel mixture supplied to an internal combustion engine so that the proper air-fuel ratio is obtained over the whole operation range including a normal operation region and an accelerating operation mode independently of a decrease in oxygen contents at places of high altitudes. When the accelerating operation region is sensed, a proper power duty, corresponding to a negative pressure at that time, is read out from a data table stored in a read-only memory and added to a duty pulse signal which is then utilized for controlling a fuel supply actuator.

Piston and combustion chamber with improved fuel circulation

Abstract: An internal combustion engine, which has a combustion chamber with a coordinated piston where the combustion chamber is divided into a first and second section, and where the piston has an extension which slides into the second chamber section during the later part of the piston's upward movement, and compresses the fuel-air mixture contained in that chamber section to a pressure somewhat higher than the pressure in the first section. The second chamber wall and the piston extension has two air passages, which are coordinated in such a way that during the last part of the compression cycle, the air passages overlap and provide an escape passage for the fuel-air mixture in the second section which is released suddenly into the first combustion chamber section and sets the fuel-air mixture in that section in a swirling motion, which helps to better mix the fuel and the air, and facilitates the ignition process of a lean mixture when used with a suitably adapted, extended electric spark ignition. The invention is also applicable to an engine of the diesel type and to two cycle engines.