Showing papers on "Compression ratio published in 1982"

Optimization of a model internal combustion engine

Abstract: We optimize the operating conditions of a model internal combustion engine to obtain maximal efficiency. The model engine consists of a cylinder equipped with a piston containing a working fluid, coupled to a heat bath and heated by internal combustion with a rate of heating that is very weakly dependent on the temperature and pressure of the working fluid. We consider operation of the piston under the influence of an external pressure. The model engine includes valves allowing the exhaust and intake of the working fluid. It is found that the optimal operation has an optimal compression ratio and an optimal energy to be exhausted with the working fluid. The results are demonstrated with a numerical example. Also presented are optimizations for this system of the average power, and optimization of the work for a given specified average power.

Method and apparatus for producing electrical energy from a cyclic combustion process utilizing coupled pistons which reciprocate in unison

Abstract: Method of and device for producing electric energy from a cyclic combustion process. The device includes two oppositely disposed aligned spark ignited internal combustion engine cylinders axially spaced from each other, means rigidly connecting the pistons so that they reciprocate in unison in their respective cylinders, and a reciprocable electrical linear generator-motor unit driven by said reciprocatory piston system. The generator-motor unit includes a very light coreless (ironless) coil rigidly attached to and reciprocatory with the piston system, the said coil reciprocating through a constant strength magnetic field. The beginning of the combustion process (or cycle) in each combustion chamber takes place at the lowest possible compression ratio sufficient for the initial ignition of the fuel-air mixture, the combustion process proceeding at a diminishing volume under the pressure from the compression- and combustion-forces of the opposite combustion chamber-piston system. The combustion process terminates after some extreme point at an expanding volume, whereby the resulting forces are used for compression in the opposite combustion chamber and there the cycle being repeated, which processes (cycles) are taking place under a positive feed-back relation. Because said feed-back relation is very pronounced, this results in a height velocity and a reciprocating rate of the connected piston system whereby there is induced an electromotive voltage in the coil.

Apparatus for maintaining a diesel engine at a ready to start temperature

Abstract: Apparatus for maintaining a diesel engine at a ready to start temperature includes a sensor responsive to the falling of the engine block temperature to a predetermined low value to actuate the starter for up to a predetermined maximum period of time and to actuate the fuel supply. A sensor responds to the attainment of a predetermined oil pressure corresponding to an engine running condition to de-actuate the starter and continue the actuation of the fuel supply to continue running of the diesel engine. The temperature sensor responds to the raising of the engine block temperature to a predetermined high value to de-actuate the fuel supply and thereby stop the diesel engine.

Knock-free engine control system for turbocharged automotive engine

Abstract: In a turbocharged internal combustion engine, in order to optimize engine torque output spark timing control and boost pressure control are coordinated in such a manner that spark advance angle is adjusted only when the measured boost pressure equals a predetermined value and is allowed to vary only within a specified range advanced from a reference value derived from an empirical memory table on the basis of engine speed and boost pressure. When engine operating conditions are such that spark advance angle would fall outside of the specified range, spark advance angle is then held at the empirical value and boost pressure is adjusted in order to optimize engine torque. The coordinated control system can also be designed to respond to exhaust gas temperature on a first-priority basis, i.e., when exhaust temperature is sensed to be dangerously high, boost pressure is reduced regardless of other engine conditions.

Engine idling speed control system and method for an internal combustion engine

Abstract: Disclosed is an electronic automatic control method and system for controlling an air flow rate for an internal combustion engine of an automotive vehicle. The system includes an open loop control and a feedback control which are selectively effected corresponding to engine condition. The system includes an engine or temperature range within which the system controls engine speed. The given temperature range corresponds to a normal ambient temperature range so as to improve warming up efficiency upon starting engine under cold engine conditions. The system further includes a means for determining a feedback control condition to effect feedback control at a specific engine condition. In the feedback condition, the variable rate of a control duty cycle pulse which is applied to an electrically operative air flow rate adjusting means, is determined corresponding to an actual engine speed and a difference between the actual engine speed and a reference engine speed determined corresponding to the engine or coolant temperature.

Automatic compression adjusting mechanism for internal combustion engines

Abstract: Means for controlling the compression pressure in an internal combustion engine having one or more cylinders and subject to widely varying power output requirements. Received between each crank pin (C) and connecting rod (D) is an eccentric sleeve (F) selectively capable of rotation about the crank pin and/or inside the rod and for latching with the rod (D) to vary the effective length of the connecting rod and thereby the clearance volume of the engine. The eccentric normally rotates inside the connecting rod during the exhaust and intake strokes but a latching pawl (F) carried by the eccentric is movable radially outwardly to latch the rod and eccentric together during the compression and power strokes. A control valve (J) responds to intake manifold pressure to time the supply of hydraulic fluid to move the latch-pawl outwardly, varying the effective rod length to maintain a substantially optimum firing chamber pressure at all intake manifold pressures.

Stratified burn internal combustion engine

Abstract: Controlled amounts of relatively rich mixture and relatively lean mixture are supplied separately to a combustion chamber of an internal combustion engine. The position of the intake valves, exhaust valve and spark plug are such that the rich mixture tends to remain near the spark plug during the compression stroke of the engine and does not disperse throughout the lean mixture. At the time of ignition enriched mixture near the spark plug ignites readily and the flame propagates into and through the lean mixture which fills the remainder of the combustion chamber. Several constructions are disclosed to achieve the desired mixture ratios for various operating conditions of the engine.

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.

Valved prechamber diesel engine and methods of operating

Abstract: A prechamber type diesel engine is provided with a cutoff valve in the throat connecting the prechamber and main chamber of each cylinder and operable in cyclically timed fashion to close and open communication between these chambers. Methods of engine operation are disclosed which utilize the cutoff valve to (1) trap combustion products in the prechamber from the previous expansion stroke for use in mixing with the fresh charge in the following compression stroke to provide internal EGR preferably stratified in the prechamber and (2) permit low compression ratio starting by trapping compression pressure in the prechamber from a previous compression stroke for addition to combustion chamber pressure developed on the following compression stroke to provide a higher cylinder pressure for starting than that provided by the overall compression ratio. Advantages of improved engine efficiency and reduced emission levels are anticipated.

Method and apparatus for controlling the fuel-feeding rate of an internal combustion engine

Abstract: Engine-starting enrichment is decreased gradually, after the engine is completely started, in response to the temperature difference between the present-coolant temperature and the initial-coolant temperature. The initial-coolant temperature is determined to be equal to the present-coolant temperature just when the engine is completely started.

Method of controlling the combustion cycle in a combustion engine

Abstract: In a combustion engine, the amount of working medium is controlled by allowing the engine to suck in an amount of working medium corresponding to full gas operation, of which a portion is then allowed to flow out again without being compressed, while an amount proportional to the current load is retained and compressed, the compression ratio being regulated as a function of the amount of working medium retained. In such an engine there is a movable member (4) for adjusting the compression ratio, the position of said member being controlled by a control means (9). Furthermore, there is at least one spill flow valve (12), the open-time of which is variable as a function of the current load of the engine.

Air-fuel ratio control device for internal combustion engines

Abstract: In an air-fuel ratio control device, a torque detector for detecting torque variations which indicate combustion variations in an engine is mounted at the supporting portions of the internal combustion engine. A detecting signal from the torque detector is introduced into an electronic control unit which controls the amount of injecting fuel, namely the air-fuel ratio. The electronic control unit controls the air-fuel ratio toward the lean side by the signal from the torque detector so that the combustion variations (torque variations) in the engine does not become large.

Electronic control system for an internal combustion engine controlling air/fuel ratio depending on atmospheric air pressure

Abstract: An air fuel ratio control system includes a correction system for correcting air/fuel ratio depending on measured atmospheric air pressure. The correction system has sensors for detecting engine operating conditions. A reference intake manifold pressure corresponding to the detected engine operating condition at sea level is obtained from the engine operating condition. The reference atmospheric air pressure is compared with the measure intake manifold absolute pressure to determine a difference value. Based on the difference, a correction value for controlling the air/fuel ratio is determined.

Fuel supply control system for internal combustion engines, having a function of leaning mixture in an engine low load region

Abstract: A fuel supply control system for use with an internal combustion engine in which a fuel quantity adjusting means which controls the quantity of fuel being supplied to the engine is electrically controlled in response to operating condition of the engine to obtain a desired amount of fuel being supplied to the engine. The system includes means responsive to the outputs of an engine speed sensor and an intake pipe absolute pressure sensor to actuate the above fuel quantity adjusting means to lean a mixture being supplied to the engine when the actual engine speed is higher than a predetermined engine rpm and the actual intake pressure absolute pressure is lower than a predetermined absolute pressure. Preferably, the mixture leaning means may be also responsive to the output of an engine temperature sensor to cause leaning of the mixture when the actual engine temperature is higher than a predetermined engine temperature, simultaneously with fulfillment of the engine speed and absolute pressure requirements.

Premetered pump injector having constant injection pressure, and derivative system

Abstract: A pump injector sends a premetered quantity of fuel to a needle type injector of the type including a piston and a discharge chamber The injector includes a compression piston mechanically controlled by cam or eccentric having any form The compression piston compresses fuel within a compression chamber An injection piston is activated exclusively by the pressure within the compression chamber, opposed by an opposing return spring The injection piston in turn compresses the fuel in an injection chamber designed to feed the injector A pressure regulator limits the pressure in the compression chamber to a high, preset value independent of the speed and load of the engine

Air-fuel ratio control method and apparatus for an internal combustion engine

Abstract: The proportion constant for proportional calculation and/or the integration time-constant for integral calculation with respect to the air-fuel ratio correction factor is changed in accordance with the engine warm-up condition, and the fuel-feeding rate is controlled in accordance with the calculated air-fuel ratio correction factor.

Optimum air-fuel ratio control for internal combustion engine

Abstract: In an air-fuel ratio control system the air-fuel ratio is changed by changing the auxiliary air supply amount in a bypass path with respect to a main path for supplying air to the engine in the vicinity of an optimum air-fuel ratio. Signals representing the operating conditions such as rotational speed of the engine operated at the resulting different air-fuel ratios are detected at a plurality of operating points. The signals thus detected are compared and the fuel injection amount is regulated thereby to correct the air-fuel ratio so that the fuel consumption rate may become optimum.

Method and apparatus for measuring engine compression ratio

Abstract: A method and apparatus for measuring compression ratio and/or clearance volume in an internal combustion engine cylinder wherein the crankshaft angle associated with piston top dead center position is obtained and cylinder pressure is measured at a number of incrementally spaced piston positions, including the TDC position Changes in cylinder volume between the incrementally spaced piston positions are determined from nominal engine design parameters These multiple pressure and volume figures are then employed in a programmed microprocessor to determine the constants γ and k in the polytropic equation for relating cylinder pressure to volume PVsupγ =k Clearance volume VTDC is then determined using the constants γ and k and the measured pressure at TDC Compression ratio is then determined by the fraction (VDP +VTDC)/VTDC, where VDP is total piston displacement volume obtained from nominal engine design parameters

Fuel system for compression ignition engine

Abstract: A fuel system for a compression ignition engine includes a body defining a mounting for a fuel injection nozzle. The body also accommodates a reciprocable piston fuel pump having a piston which is actuable by an engine driven cam. The body also defines a surface which in use locates against a surface on the engine cylinder head. The surface is well removed from the bore in the cylinder head of the engine which contains the injection nozzle. In this manner forces applied to the body during operation of the system are applied to the cylinder head of the engine in an area which is sufficient strong to withstand the forces.

Variable-compression ratio engine

Abstract: PURPOSE:To raise the temperature of exhaust gas to maintain the purifying function of an engine exhaust gas purifier satisfactory by providing a catalytic sensor in the engine exhaust gas purifier so that a device for changing the volume of a combustion chamber is actuated in the direction of decreasing a compression ratio when the exhaust gas is lower than a predetermined temperature. CONSTITUTION:A catalytic type exhaust gas purifier 7 is disposed in an engine exhaust passage 6, and a cylinder 2 is provided with the second cylinder 9 communicated with a combustion chamber 9 and a compression ratio changing piston 10. A control circuit 24 which receives signals from a load sensor 25, a rotational speed sensor 26, a knock sensor 27, etc., computes a compression ratio giving an optimum combustion efficiency, and controls the position of the piston 22 through an actuator 22. The control circuit 24 receives a signal from a catalytic temperature sensor 8 and compensates a signal S6 in the direction of decrease in the compression ratio to lower combustion efficiency when a temperature is lower than a predetermined temperature, so that the temperature of exhaust gas is raised to sufficiently ensure the function of the exhaust gas purifier.

Method and apparatus for supplying fuel to internal combustion engine

Abstract: Method and apparatus for supplying fuel to an internal combustion engine, which engine performs strokes for suction, compression, expansion and exhaust in sequence. The method comprises alternatingly supplying fuel to the engine and suspending the fuel supply to the engine in successive suction strokes. In a heavy load range of operation of the engine, the fuel can be supplied in each of the successive suction strokes. Various different embodiments of the apparatus for performing the above method are disclosed.

Catalytic combustion engines

Abstract: A catalytic combustion engine, each cylinder of which has a pre-combustion chamber communicating through an inclined transfer cylinder to produce swirl around the chamber, and has a pair of spaced parallel or nearly-parallel catalytic screen elements, e.g. gauzes, mounted to both the mouth of the transfer passage and the fuel injector nozzle, so as to be clear of the circumferential swirl path of the gas circulating in the chamber. The minimum spacing between the two catalytic screens should exceed the width of the mouth of the transfer passage. The injector injects a fuel spray between the two catalytic screens which preferably just brushes each screen and impinges on a heater plug. The compression ratio may be much lower than that for a conventional Diesel engine, for example down to 12:1.

Centrifugal governor for internal combustion engine

Abstract: A centrifugal governor ensures a positive engine starting operation as well as a smoke control in the low engine speed range and a usual fuel injection control responsive to an increase in engine speed. A control rod with a rack is operatively connected with a floating lever through a spring biased piston and cylinder assembly, so that the control rod can be freely moved to its maximum fuel injection position during engine starting without being effected by a smoke limiter, which may be associated with the governor for a smoke control purpose. A unique lever mechanism is operable to move the control rod to the maximum fuel injection position during engine starting but, after a predetermined engine speed is reached, yields to a movement of the control rod in a fuel decreasing direction caused by the floating lever through the piston and cylinder assembly.

Optimum control for internal combustion engines

Abstract: In the optimum control for an internal combustion engine wherein the engine is operated by dithering a value of a selected one of engine operating control variables from a value of the selected control variable which is obtained by calculation in accordance with detected values of operating parameters of the engine, and a direction of improving either one of a fuel consumption rate and an output of the engine is decided on the basis of a detected change of an engine operating condition, thereby correcting the calculated value of the selected control variable, during the time period of each dithered engine operation, an engine speed is detected two or more times and used for deciding the direction of a change of the engine speed, thereby providing an improved optimum control method and apparatus for internal combustion engines capable of preventing undesired correction control of the control variable from being effected in response to a change of the engine speed caused by any factor of disturbance.

Preliminary Results on Performance Testing of a Turbocharged Rotary Combustion Engine

Abstract: The performance of a turbocharged rotary engine at power levels above 75 kW (100 hp) was studied. A twin rotor turbocharged Mazda engine was tested at speeds of 3000 to 6000 rpm and boost pressures to 7 psi. The NASA developed combustion diagnostic instrumentation was used to quantify indicated and pumping mean effect pressures, peak pressure, and face to face variability on a cycle by cycle basis. Results of this testing showed that a 5900 rpm a 36 percent increase in power was obtained by operating the engine in the turbocharged configuration. When operating with lean carburetor jets at 105 hp (78.3 kW) and 4000 rpm, a brake specific fuel consumption of 0.45 lbm/lb-hr was measured.

Swash plate engine

Abstract: The swash plate engine is provided with an Aspin type rotary valve system with a variable compression capability. The engine may be of four-piston type or six-piston type. The size of the combustion chambers can be changed from time to time to vary the compression ratio. The engine may also be coupled with an accumulator to store the energy of braking for subsequent acceleration of the engine.

Electronically controlled fuel injection timer

Abstract: A fuel injection timer or regulator for a fuel injection pump is acted upon by a signal of an actual value generator detecting an actual injection time adjustment and by a signal of a desired value generator controlled by operating parameters of a piston internal combustion engine. At least one sensor is arranged at the piston internal combustion engine, with the sensor determining a rate of increase of the combustion pressure in the cylinder at each working stroke, and the desired value generator is controlled in dependence upon the output signal of the sensor.