Showing papers on "Spark (mathematics) published in 1989"

Predictive spark timing method

Abstract: A microprocessor based electronic spark control for an internal combustion engine is programmed to determine spark time using a prediction of engine speed during the spark period in which the next spark should occur and to make the calculations immediately prior to that period. The prediction is based upon the most recent speed information including a reference period value just prior to the next spark period. Reference pulses produced from a crankshaft driven transducer determine the measured reference periods and preferably comprise a plurality of pulses per spark event. One reference period is chosen as a base period and a weighted difference of recent periods is used to adjust the base to predict the spark period. The spark period or the corresponding engine speed is used in calculating the spark angle and the conversion to spark time. A hardware interrupt to the microprocessor causes the calculations to be made when the reference pulse nearest the next spark occurs.

Ignition system with repetitive sparks

Abstract: A repetitive spark distributorless ignition system stops ignition current before the complete discharge of magnetic energy in the ignition coil supplying the spark plug. The ignition coil is then recharged so an additional spark can be applied to the spark plug.

Direct sample introduction of solid material into a pulse-operated MIP

Abstract: To minimize problems caused by sample introduction into a microwave-induced plasma (MIP), we have developed a system consisting of a spark ablation cell and a pulse-operated microwave-induced plasma (pulsed-MIP). An aerosol is generated from solid samples with the use of a spark discharge. The resultant material is swept into a pulsed-MIP. Design and fabrication criteria for the spark source and the spark ablation cell are presented. The combined sources show enhanced precision, stability, signal-to-noise levels, and detection limits relative to direct spark emission. Analytical calibration curves and detection limit data are shown for nickel, manganese, and chromium in steel samples. Time-resolved data are also shown.

Spark Decomposition of SF6: Chemical and Biological Studies

Abstract: This paper presents a methodology which can be used to calculate underground cable ampacities and other cable parameters. Capabilities of the methodology include the ability to model both thermally and electrically the presence of conductors, shields, and neutrals in an underground cable system. Unbalanced phase currents associated with conductors connected in parallel and shied and neutral currents along with the effects of ground connections are calculated from the electrical circuit model and are used in the thermal analysis of the cable system. Temperature dependent parameters are determined based on calculated system temperatures. Solutions of both the thermal and electrical circuit models are performed in an iterative procedure until convergence based on conductor temperature occurs. Results from this procedure include not only the calculation of thermal parameters, such as cable ampacities and system temperatures, but also electrical parameters, such as cable voltage drops and open-circuited shield voltages. The temperature rise of a conductor due to conductor losses is based on the current in the conductor, its electrical resistance, and the thermal circuit through which the heat from the conductor losses flows. The current in the conductor is a result of the applied system voltage, the impedance of the electrical circuit, and the inductive coupling between other system conductors. Certain parameters with a cable system are temperature dependent, such as conductor electrical resistances (losses) and duct air space thermal resistances. System temperatures are usually not known precisely and initial estimates of certain temperature dependent parameters can lead to errors in the calculated results. To overcome this problem, a procedure can be implemented which utilizes calculated system temperatures in an iterative process, which stops when conductor temperatures have converged to a specified value. One such procedure which has been successfully implemented is illustrated as follows:

Measurement and modelling of ignition system energy and its effect on engine performance

Abstract: This study investigates the effect of ignition parameters on the cyclic dispersion and the specific fuel consumption of a carburetted single-cylinder engine. Ignition energy measurements were made on the low- and high-voltage sides of the ignition coil, and the performance was predicted satisfactorily by a simple model with passive elements. The spark energy was varied by changing the spark plug gap and the coil-on-time. The spark energy was measured in a special calorimeter: the aim was to find a correlation between engine performance and the spark energy measured by the calorimeter. The tests were conducted at part load and low speed with a weak mixture, as these conditions are known to give levels of cyclic dispersion. The spark calorimeter showed a higher spark plug conversion efficiency for spark plugs with large gaps. However, the spark plug gap was found to be a more significant determinant of engine performance than the spark energy measured by the calorimeter. The experimental results are preceded by a review of ignition phenomena and their influence on combustion. (A)

Spark plug for an internal combustion engine

Abstract: A spark plug is specified which has an outer housing, a centre electrode (which is electrically insulated from the housing) and a side electrode which has a solid spark plate which is connected to the outer housing by means of three elongated parts The spark plug has a longer life than annular side electrodes of a conventional type

Separated circuit hot spark producing apparatus

Abstract: A spark gap producing apparatus that introduces an auxiliary gap in the electrical path between the spark source and the spark plug of an internal combustion engine is disclosed. The spark apparatus can be permanently installed such that it maintains a reliable auxiliary gap. Alternatively, it may be installed in a motorized form such that it can be computer controlled. the computer would control the gap size and, therefore, the capacitance of the spark gap apparatus. Thus, depending on the efficiency needs of the engine, the computer would compensate. In still another embodiment, the driver himself would have direct manual control over the gap size. Since spark "hotness" is controlled by the gap size, the driver would have complete control over the efficiency and power of the engine.

Self Tuning Optimisation Of Spark Ignition Automotive Engines

Abstract: The paper describes the use of self-tuning control concepts applied to the adaptive optimisation of spark ignition angle of an automotive engine. In particular, it is shown how the control theory concepts of self-adaptive control can be modified in a manner which allows their use in continuously up-dating the map of spark angle as a function of load and speed. Used in this way, the self tuner can account for in-service changes in engine characteristics, changes due to ambient changes and changes in operational conditions. In addition, self-adaption allows the spark controller algorithm to tune itself such that the factory-generated spark map is precisely matched to the exact nature of each individual engine. The paper outlines the basic theory of self-tuning optimisers (also known as extremum controllers) and discusses their performance features with particular reference to their implementation in adaptive spark timing systems. It is shown that the self tuning extremum controller can be made robust even when the signal to noise ratio is less than one.

Automobile electronic control modules communicating by pulse width modulated signals

Abstract: A distributed processing system in an automotive environment achieves enhanced noise immunity and reduces the processing burden and background loop time of the master controller by providing for communication of signals between a master controller and a slave controller by pulse width modulated communication signals. In a preferred embodiment, the communicated signal is a spark advance which is transmitted to an ignition module for implementing spark events in an internal combustion engine. The spark advance pulse width is a linearly decreasing function of spark advance value since increased spark advance is associated with an increase in engine speed. The spark advance is encoded into a pulse width signal according to a method which simplifies decoding of the spark advance information in the ignition module.

Towards a general turbulent combustion model for spark ignition engines

Abstract: The prediction of combustion within spark ignition engines needs to take into account the interaction of turbulent fluctuations. Previous attempts at this used a model in which the chemical processes were supposed infinitely fast and the combustion was controlled by turbulent mixing only. This paper describes their progress in extending such models in two directions.

Collector ring spark monitor for rotary electric machine

Abstract: PURPOSE:To prevent occurrence of serious fault such as grounding of collector ring, by providing a means for integrating input voltage fed from a detection brush and performing alarm processing thereby grasping the degree of damage at a current collecting section or proceeding condition of damage CONSTITUTION:DC current is fed from an exciter 25 through a main circuit brush 18 and a collector ring 17 to a field coil so as to excite the field coil At this time, a detection brush 19 is measuring a brush contact voltage drop caused by commutation spark produced between the brush 18 and the ring 17, and when the voltage drop is higher than a predetermined level, a voltage signal corresponding to the spark number is taken out through signal cables 27, 28 and fed to a signal processing circuit 31 In the circuit 31, input voltage signal is integrated through an integrator 32 and an output signal corresponding to spark number is produced Output signal from the circuit 32 is provided to a display 36 and the degree of commutation spark is indicated by a spark number Output signal from the circuit 32 is compared with a set voltage corresponding to a specific spark signal in a comparator 33, and an alarm is produced when the output signal exceeds the set voltage

Thermodynamic simulation of a turbocharged spark ignition engine for electronic control development

Abstract: A nonlinear dynamic model of an intercooled, turbocharged, spark- ignited engine is developed for the purpose of evaluating microprocessor-based wastegate and ignition control laws. The engine system is thermodynamically modelled and matched to engine data. The microprocessor representation contains the actual algorithms used to implement the control law. (A) For the covering abstract of the conference see IRRD 850768.

Spark timing control

Abstract: A spark timing control for an electronic internal combustion engine ignition system that provides a constant spark advance regardless of engine speed. A series of crankshaft pulses are developed which occur at each 60 degrees of rotation of the crankshaft. The system has a source of constant frequency clock pulses which are counted up by an up-counter during 60 degree periods. The count attained by the up-counter during a 60 degree period is loaded into a down-counter. The up-counter is now counted up at a constant rate from zero and the down-counter is counted down at a constant rate from the count magnitude that was loaded into the down-counter. When the count magnitudes of the two counters are equal, a digital comparator that is connected to the counters develops an output signal that can be used to cause the firing of a spark plug.

Triggering of a vacuum spark source by impact of a low‐energy laser beam on the cathode

Abstract: It is shown that the triggering of a vacuum spark source is easily obtained by focusing onto the cathode a pulsed laser beam of short duration and rather low energy per pulse. The main advantages of this kind of triggering are discussed in comparing with the previous designs based on an auxiliary sliding spark.

Spark advancer for engine

Abstract: PURPOSE:To improve the extent of low speed performance by setting the absolute value of rate to a static variation ignition timing with engine speed in an electronic spark advancer to be smaller than that of a mechanical spark advancer, in case of a device that is one combined with both these mechanical and electronic spark advancers together. CONSTITUTION:A mechanical spark advancer 41 rotates a support block 39 with rotation of a second control lever 18 having a support shaft in common with a first control lever 17 constituting an operating mechanism of a throttle valve 16 of a carburetor 12 for an engine, through which it varies a position of a pulser coil 36 in and around a crankshaft 14 in a way of interlocking a variation in throttle opening. On a signal line extending from an output end of the pulser coil 36, where suchlike mechanical spark advance operation is applied, to an SCR gate, there is provided with an electronic spark advancer (unillustrated herein). And, the absolute value of this electronic spark advancer in rate to a static variation in ignition timing with engine speed is set to be smaller than that of the mechanical spark advancer 41.

An Open Letter to Cost Model Evaluators

Abstract: From time to time we are invited to provide background information for comparative evaluations of parametric cost models. We contribute as best we can, but find often that, despite good intentions and a strong commitment to fairness, the evaluators lack fundamental understanding of the role of parametric models in cost analysis. We then find ourselves faced with writing a letter something like the one that follows. We share this letter with you in the hope that it will spark discussions as to how parametricians, as a community, can act to improve the assessment and presentation of cost model capabilities.

Knocking control device for internal combustion engine

Abstract: PURPOSE:To secure the spark advance stability during the stationary running and prevent the abnormal spark delay at the transient time by counting the number of times when the detected knocking is the discrimination level or above, and delaying the ignition timing by the spark delay quantity corresponding to the number of times. CONSTITUTION:A control device 1 calculates the average value of outputs from a knocking detecting means 37 in the preset interval, sets the coefficient which is made larger as the acceleration state from an acceleration state detecting means such as a throttle sensor 22 is made larger, and multiplies it by the average value to set the discrimination level. The ignition timing control means of the control device 1 discriminates the output from the knocking detecting means 37 with the discrimination level, the number of times when the output is the discrimination level or above is counted, and the ignition timing is delayed by the spark delay quantity corresponding to the number of times. The spark advance stability during the stationary running is secured, transient responsiveness is improved, the abnormal spark delay at the transient time is prevented, and the fuel consumption and drivability can be improved.