Showing papers on "Compression ratio published in 1989"

Image signal recording apparatus capable of recording compressed image data together with audio data

Abstract: An image signal recording apparatus achieves an orthogonal transform and a compression coding on image data so as to record the resultant data in a recoding medium. There is disposed a selector to select a compression ratio for the compression coding of the data, namely, the compression ratio is selectable. The selected compression ratio data is recorded in the recording medium together with the image data. A playback apparatus reads from the recording medium the compression ratio data together with the image data undergone the compression coding so as to decode the image data by use of the compression ratio data. In consequence, according to these apparatuses, the compression ratio can be arbitrarily set. In addition, the image signal recording apparatus generates recording codes associated with the amounts of the image data and the audio data so as to write the codes in the recording medium. The recording codes are read from the recording medium, so that the remaining amount of the recording medium available for the recording operation is displayed.

Operation control system for internal combustion engine

Abstract: An operation control system for an engine using alcohol fuel or mixed fuel of alcohol and hydrocarbon, or for an engine supplying cooling liquid such as alcohol, water or the like as fuel. Vapor concentration in exhaust gas and an air excess ratio of air-fuel mixture are detected, and a supply rate of alcohol, a water absorption ratio of alcohol or an amount of the cooling liquid is computed on the basis of the vapor concentration and the air excess ratio. Ignition timing, temperature of the coolant, a compression ratio and an air excess ratio are controlled on the basis of the supply rate of alcohol or the water absorption ratio of alcohol. Further, the cooling liquid is supplied which has its amount computed at a heavy load. Thus, operational performance of the engine is improved.

Method for detecting engine misfire and for fuel control

Abstract: Misfire is detected in an internal combustion engine during its starting mode by analyzing the engine speed profile. Average speed is determined for 60° increments of crankshaft rotation. If an increment midway between top dead center positions has a higher speed than the previous increment and a higher speed than cranking speed, combustion occurred, otherwise a misfire occurred. When misfires are detected for a particular cylinder the calculated fuel allotment for that cylinder is reduced in accordance with the number of consecutive misfires for that cylinder.

Combustion by Pulsed Jet Plumes - Key to Controlled Combustion Engines

Abstract: : Pulsed Jet Combustion (PJC) is introduced here as a key element for engines where the progress of combustion is interactively controlled by a microprocessor system Practical realization of PJC presented here involves the use of an 18 mm plug containing a cavity, where a rich mixture is ignited by a conventional spark discharge, closed by a tip with a suitable orifice to form the effluent stream Its performance is determined by tests carried out in a constant volume vessel, simulating the enclosure of a CFR engine at 60 CAD with compression ratio of 7:1, using propane/air mixtures at equivalence ratios of an order of 06, in comparison to that of a flame traversing the charge, a so- called FTC mode, upon Ignition by standard spark discharge under identical geometrical and initial thermochemical conditions The results demonstrate the superiority of PJC for executing the exothermic process of combustion in a lean burn engine

A Comparison of Olefin and Paraffin Autoignition chemistries: A Motored-Engine Study

Abstract: The autoignition chemistries of the olefins 1-butene, 2-butene, isobutene, 2-methyl-2-butene, and 1-hexene and their corresponding paraffins were examined in a motored, single-cylinder engine by measuring stable intermediate species and performing heat-release analyses. The same engine conditions were used for each olefin-paraffin pair, and compression ratio was varied to affect different levels of chemical activity. Experimental measurements for each olefin-paraffin pair are compared with each other and with literature values

Cycle-Resolved LDV Measurements In a Motored Diesel Engine and Comparison with K-ε Model Predictions

Abstract: Cycle-resolved LDV measurements of tangential mean velocities and turbulence intensities were made in a motored, single cylinder, Cummins NH diesel engine at 300 and 600 rpm. The measurements were made at eight locations in a plane 0.9 cm below the cylinder head. The combustion chamber and intake configuration of this low-swirl, low-squish engine were nearly identical to the stock configuration. For improved optical access, however, the compression ratio was lower in the test engine (10:1) than in the production engine (14.5:1). The measured turbulence intensities were compared to values computed with KIVA, an in-cylinder fluid dynamics flow code with a {kappa}-{epsilon} turbulence model. The measurements show that the mean velocity field is three-dimensional before TDC, consisting of both a weak swirling motion and a weak tumbling motion.

Engine with variable compression ratio

Abstract: An internal combustion engine is described in which each combustion chamber (10) in the engine has an associated auxiliary chamber (18), and in which, for low compression ratio operation, the auxiliary chamber (18) is constantly connected to the combustion chamber (10) and, for high compression ratio operation, the auxiliary chamber (18) is connected to the combustion chamber (10) by a one way valve (24, 36, 38, 40) which permits gas flow only in the direction from the combustion chamber (10) towards the auxiliary chamber (18).

Compression release retarding system

Abstract: An improved compression release engine retarder or engine brake stores hydraulic fluid under pressure and then release the fluid at an appropriate time in each engine cycle to displace a slave piston and thereby open the exhaust valves for compression release. In one aspect of the improved brake, the hydraulic fluid is released by a master piston of variable length. The variable length master piston travels a fixed distance to the pressure release point so that the timing of the compression release is precisely controlled and independent of installation and engine component tolerances. In another aspect of the improved brake, an anti-jacking valve ensures that the hydraulic pressure displacing the slave piston and exhaust valves is dissipated thereby preventing the exhaust valves from remaining jacked open. In a further aspect of the improvement, the slave piston establishes and maintains a zero lash clearance with the valve crosshead during braking cycles. A slave piston is also disclosed in which a stroke limiting valve restricts the distance the slave piston can move in one engine cycle.

Internal combustion engine having multiple expansion and compression

Abstract: A staged two-stroke internal combustion engine with reciprocating pistons wherein the cycle comprises a first compression of fresh air possibly followed by a cooling, a second compression of air or of mixture or the injection of fuel (Diesel version), a first expansion producing a useful work, a second expansion also producing a useful work and the exhaust of the combustible gases followed by the scavenging of the remaining gases by fresh air, the engine preferably including an odd number greater than or equal to three cylinders and allowing to increase the power output efficiency and the power-to-swept volume ratio with respect to the four-stroke internal combustion engine.

Optimized high pressure internal combustion engines

Abstract: An improved high pressure, high r.p.m. engine having a single cylinder with opposed pistons reciprocating in the cylinder and each piston being connected to dual connecting rods that are connected to counterrotating crankshafts, the cylinder having a central collar between the heads of the opposed pistons that form a specially configured combustion chamber for high turbulence mixture of air and fuel injected from a plurality of fuel injectors peripherally arranged around the cylinder, the pistons being operated with a cycle phase shift to prolong the period of peak compression and provide a double squish action for improved fuel air mixture, the air being supplied under high compression from a counterrotating turboblower assembly that is in part driven by the engine drive train and in part driven by the expansion gases of the combustion process, the engine being provided with specially designed high pressure pistons that have an axially symmetrical piston head and a spherical bearing mount to a wrist pin assembly having dual rolling wrist pins for eliminating side thrust of the piston head and maximizing the projected surface area for transmission of piston thrust forces from a piston head to the connecting rods and crankshafts.

The Influence of High Pressure Fuel injection on Performance and Exhaust Emissions of a High Speed Direct injection Diesel Engine

Abstract: Conventional direct injection diesel engines for cars or light duty trucks, equipped with injection pumps of conventional types, such as distributor injection pumps and inline injection pumps, and operating at compression ratios of 18-19, are capable of offering a fuel consumption benefit of some 15% compared to chamber diesel engines. In terms of noise and exhaust emissions, and also black smoke characteristics they are significantly inferior to the prechamber engine. They have a specific rated output which is some 20% lower. Only through the use of a compression ratio of 21 and high injection pressures it is possible to measurably diminish the drawbacks in respect of exhaust emissions and, to some extent, in respect of soot emissions. This in no way enhances the noise behaviour. For this reason, it is essential to employ measures such as injection rate shaping or split-injection. Satisfactory engine characteristics are best achieved if a pilot- injection is used. Such a pilo- injection is only feasible with an electronically controlled unit injector.

Control system for and method of controlling an internal combustion engine

Abstract: A control system is provided for controlling the composition of a gas and fuel mixture supplied to an internal combustion engine (10). The output of an engine roughness detector (20, 21) (spark ignition engine) or an exhaust smoke detector (compression ignition engine) is compared (22) with a limit value from a look up table 14) and the result is supplied via a controller (23) to correct (18) the base value of mixture composition from a look up table (13) to a mixture control device (17). The amount of correction is limited by the controller (23) in accordance with a limit value from a look up table (15) so as to prevent the emission of unacceptable levels of oxides of nitrogen by the engine (10).

Measurements and Predictions of the Fuel Consumption and Emission of a Spark Ignition Engine Fuelled with Hydrogen-Enriched Gasoline

Abstract: The effect of the amount of hydrogen addition on the fuel consumption and emission of a spark ignition engine has been studied. Dynamometer test results for a wide range of engine speeds, engine loads, equivalent ratio and hydrogen enrichment under steady state operation are presented, and the engine requirements for minimum b.s.f.c. are specified. A detailed model to simulate a four-stroke cycle of a spark ignition engine fuelled with hydrogen-enriched gasoline was used to predict the optimal amount of hydrogen supplement as well as the corresponding minimum best torque (MBT) optimal throttle position and emissions levels of CO and NOx. It has been shown that a significant reduction in the b.s.f.c, in the order of 20 per cent, is achieved with hydrogen-enriched gasoline for a hydrogen-fuel mass ratio of 6 per cent and equivalence ratio of 0.65. A very smooth operation has been observed under these conditions. The energy conversion gain is prominent at partial loads and depends only to a limited extent on...

Variable compression ratio internal combustion engine

Abstract: A variable compression ratio internal combustion engine having at least one cylinder, a piston disposed in the cylinder and a cylinder head disposed at one end of the cylinder. The cylinder head has a combustion chamber and a piston chamber contiguous with the top of the cylinder. A movable piston disposed in the piston chamber to change the effective volume of the combustion chamber. A closed end of the piston chamber is connected to one of the engine's source of pressurized fluid. A solenoid valve is disposed between the source of pressurized fluid and the piston chamber. Energization of the solenoid valve is controlled by a controller to open the solenoid valve when the combustion chamber has a low pressure to displace the movable piston to increase the compression ratio of the engine and to open the solenoid valve when the combustion chamber has a high or peak pressure to displace the movable piston to decrease the compression ratio.

Pressure Trace Knock Measurement in a Current S.I. Production Engine

Abstract: This paper describes a study in which a spark-plug-mounted pressure transducer and an in-cylinder flush mounted pressure transducer were used to monitor the combustion pressure in a modern four cylinder engine during knocking and normal full load operation over a speed range of 1800 RPM to 4000 RPM. This engine features paid combustion and small knock pressure peaks. Pressure trace knock detection algorithms are compared with the output of the standard knock sensor (accelerometer) mounted on the intake manifold of the engine.

Assessment of variants of the k–ϵ turbulence model for engine flow applications

Abstract: This paper is concerned with simulation of the mean flow and turbulence evolution in a model engine and comparison of the behaviour of certain important turbulence parameters, namely the intensity, length scale and dissipation time scale, as predicted by three variants of the k–ϵ model developed for application to strongly compressible flows. The predictions pertain to the axisymmetric, disc-chamber, four-stroke, Imperial College model engine operating at 200 rpm and compression ratios of 3·5 and 6·7. The paper analyses the predicted variations of these parameters during the induction, compression and expansion strokes and identifies the versions that produce the most consistent and physically plausible variations. The significance, to the turbulence evolution, of the ratio of the turbulence dissipation time scale to the time scale of compression/expansion is also discussed. It is concluded that on these grounds the Morel–Mansour and El Tahry versions are, and the Watkins version is not, suitable for engine applications.

Failsafe method in connection with valve timing-changeover control for internal combustion engines

Abstract: A failsafe method in connection with valve timing-changeover control for an internal combustion engine(1). An abnormality in a control system of the engine is detected. A changeover-instructing signal is generated for changing the valve timing to the low speed valve timing in both of the lower and higher engine speed regions, when the abnormality is detected. When the abnormaiity is detected, the air-­fuel ratio of an air-fuel mixture to be supplied (6) to the engine is enriched when the engine is in a predetermined operating condition determined by the detected value of at least one engine parameter (8,11,19,20). The enriching of the air-fuel ratio of the air-fuel mixture is carried out by multiplying a basic fuel injection period by a correction coefficient or selecting a suitable basic fuel injection period map.

Temperature-sensitive variation of the compression ratio in pistons having variable compression height

Abstract: The invention relates to a piston having a variable compression height and two control chambers connected to each other through a hydraulic system. In order to achieve better cold-start and warm-up behavior, an oil discharge bore from the upper control chamber into the crankcase is closed by a control slide valve in the cold operating state of the engine. The blockage of the oil discharge produces a great compression height and therefore high compression. The control slide valve is connected to an expansible element which maintains it in this closed position when the engine is cold. As the engine warms up, the expansible element, due to its thermal expansion, pushes the control slide valve out of its closed position, so that the discharge of oil can occur progressively more unthrottled with rising temperature. In the warm operating state of the engine the control slide valve clears the oil discharge duct completely, and an unobstructed discharge of oil is ensured.

On the time delay in continuous in-cylinder sampling from IC engines

Abstract: When gas sample is continuously drawn from the cylinder of an internal combustion engine, the sample that appears at the end of the sampling system corresponds to the in-cylinder content sometime ago because of the finite transit time which is a function of the cylinder pressure history. This variable delay causes a dispersion of the sample signal and makes the interpretation of the signal difficult An unsteady flow analysis of a typical sampling system was carried out for selected engine loads and speeds. For typical engine operation, a window in which the delay is approximately constant may be found. This window gets smaller with increase in engine speed, with decrease in load, and with the increase in exit pressure of the sampling system.

Cold-start apparatus and cold-start method

Abstract: A cold-start apparatus for alcohol-fueled internal combustion engines in which a certain quantity of gasoline is injected directly into the combustion chambers upon starting. To assure reliable start-up of the engine with the aid of gasoline, and beyond a predetermined temperature, the engine is operated with only alcohol fuel. In order to make gasoline available for the cold start without entailing a major expense, a gasoline storage and supply device is provided. The supply device includes a piston which divides the housing into a work chamber which is filled with alcohol fuel from a work chamber which is filled with gasoline. As the alcohol fuel in the work chamber cools, the piston is forced by a spring inward into the alcohol filled chamber, causing aspiration of gasoline into the gasoline chamber which upon starting of the engine and a build up of pressure in the alcohol work chamber gasoline line is injectable by means of an alcohol fuel pump, via a gasoline delivery line and a gasoline fuel injection valve into the air intake tube until such time as the engine has attained a sufficiently high temperature then only alcohol is used in operating the engine.

Combustion fault detection apparatus and control system for internal combustion engine

Abstract: A combustion fault detection apparatus for the internal combustion engine (7) is disclosed, in which a signal is generated when each cylinder of the engine (7) is located at a predetermined position, a time interval between cylinders is determined from this signal, and time intervals between cylinders are compared and computed thereby to decide the fact that a combustion fault, if any, has occurred in a specific cylinder alone

Method of operating an engine and measuring certain engine parameters

Abstract: An internal combustion engine having a luminosity probe and an arrangement for measuring certain parameters such as IMEP, combustion chamber pressure, heat release and the like by measuring luminosity in the chamber and adjusting the running parameters of the engine to obtain the desired luminosity. Also disclosed is an arrangement for maintaining uniformity from cycle to cycle in a given combustion chamber and uniformity combustion in the combustion chambers of a multi-chamber engine.

Internal combustion engine with preheating of the intake air, and method of operating the engine

Abstract: The compression ratio of an IC engine is reduced to the lowest value desired in the warmed-up operating state. Taking into account a given optimum combustion gas temperature function the combustion air is acted upon prior to its entry into the combustion chamber of the engine in accordance with the respective operations situation as regards temperature and/or quantity flow.

Variable-compression ratio control device for engine

Abstract: PURPOSE: To prevent unnecessary switching control by setting the setting line of the switching between a low compression ratio and a high compression ratio at least in the low rotation range of an engine to the load side higher than that of a running resistance line during the normal running on a flat road at the high-speed stage gear. CONSTITUTION: When a lock pin 40 buried on a connecting rod 4 is coupled and locked into a hole 24b formed on a piston pin 24 by the hydraulic force P in this device, the hole 24b is provided on the protruded side of an eccentric section 24a, thus a piston 2 is extended relatively to the connecting rod 4, and a high compression ratio state is obtained. When the lock pin 40 is coupled and looked into a hole 24c, a low compression ratio state is obtained on the contrary. The hydraulic force P is controlled by a controller 9 via a solenoid valve 7. The setting line of the switching between a low compression ratio and a high compression ratio at least in the low rotation range of an engine is set to the load side higher than that of the running resistance line during the normal running on a flat road at the high-speed stage gear. COPYRIGHT: (C)1991,JPO&Japio

Leading piston engine with two cylinders interconnected through a transfer port

Abstract: A compression ignition, internal combustion engine has at least one pair of pistons operating in separate cylinders interconnected through a transfer port. Said at least one pair of pistons includes a leading piston linked to a leading crankshaft and operating in a leading cylinder, and a trailing piston linked to a trailing crankshaft and operating in a trailing cylinder. For the purpose of varying the compression ratio, the phase relation between said leading and trailing pistons is varied by means of a phase adjustment mechanism which operatively couples the leading and trailing crankshafts of the engine. The fuel is injected into the leading cylinder by means of a centrally situated multi-hole fuel injector. The clearance volume of the trailing cylinder is at a practical minimum in order to maximize the amount of air available for combustion in the leading cylinder. The combustion bowl in the leading cylinder extends over substantially the whole top surface of the leading piston so as to eliminate the stepwise changes of combustion chamber shape associated with compression ratio variation.

Engine protection device

Abstract: An engine protection device which has a valve assembly supplying engine oil to an hydraulic cylinder which in turn is attached to the throttle of an internal combustion engine or governor of a stationary engine. If the oil pressure drops below a predetermined level, a sensor in the valve unit will cause the oil to drain from the hydraulic cylinder so as to slow down or stop the operation of the engine. In addition to using the oil of the engine itself, air or gas can also be used.

Combustion pressure determn. method for petrol-diesel engine - using acceleration sensors fitted at crankshaft bearings of engine in cylinder axial direction

Abstract: The method measures the accelerations occurring at the respective crankshaft bearings of the engine, which alter corresp. to the combustion pressure. The measurement values and their trend is used for the derivation of input variables, for the combustion chamber dependent regulating operations and/or for the monitoring of the combustion process. The acceleration is measured with the help of one or more acceleration sensors fitted at the crankshaft bearings of the engine, pref. in the axial direction of cylinder axis. USE/ADVANTAGE - Combustion pressure in petrol and diesel engines is determined. reliable measuring and evaluating of combustion pressure in motor vehicle.

Instantaneous heat transfer over the piston of a motored direct injection-type diesel engine

Abstract: In the tests described, the instantaneous heat transfer through the piston was measured in a motored direct injection-type diesel engine. The engine piston was equipped with a fast-response thermocouple on the surface and at a specified distance below the surface thermocouple at a number of locations. In order to record and process the measurement of temperature and cylinder pressure, a personal computer (PC)-based data acquisition system was connected to the probes. The results of the experiment are discussed and compared to the previous results and the predictions made by others. The measured heat flux/engine speed relationship agreed with previous results, although the measurements at various positions and at a range of intake manifold pressures did not check with prior predictions. The discrepancies could be attributed to different engine and operation conditions used. (A) For the covering abstract see IRRD 865952.