Abstract:
A method is provided for determining the ion component following a combustion process in a self-igniting internal combustion engine. At least two electrodes are located inside at least one cylinder, to which electrodes an electrical voltage can be applied, with the voltage being an AC voltage or having an AC voltage component.
Abstract:
An alternating current ignition system which can be used in one of two ways for ion current measurement. On the one hand, an oscillating circuit at the primary end of the ignition coil can be driven such that, after ignition has taken place, an alternating current signal is generated at the primary end; the amplitude of the alternating current signal must be sufficiently low so as not to cause any sparks at the secondary end, but lead to an alternating voltage signal which is modulated in relation to the ionisation degree of the ignition spark gap and thus represents an ion current measurement signal. On the other hand, however, if an auto transformer is used as an ignition coil, the intermediate circuit voltage applying at the primary end will be modulated in the medium-high voltage range of, e.g, 180 V in relation to the degree of ionisation, so that this supply voltage is used as a measurement signal.
Abstract:
A method for determining an operating parameter of an internal combustion engine. An ionic current signal curve at a spark plug of the internal combustion engine is measured for a number of ignitions as a function of time. The measured signal curves are then averaged to obtain an averaged signal curve. A maximum and/or the time of the maximum of the averaged signal curve is determined. Based on the maximum of the average signal curve and/or the time of the maximum of the average signal curve, the operating parameter is calculated.
Abstract:
In a gasoline internal combustion engine with direct fuel injection a spark plug with a center electrode is mounted in the cylinder top so as to project into the combustion chamber. A mass electrode is disposed on the piston so as to project upwardly into the combustion chamber and is movable with the piston toward and from the spark plug center electrode. An ignition system is provided for timely generating a spark between the spark plug electrode and the movable mass electrode for igniting a fuel/air mixture in the combustion chamber. A fuel injector is mounted in the cylinder top and adapted to provide a cone-like fuel beam with an envelope disposed between the spark plug electrode and the mass electrode such that a spark generated between the two electrodes extends through the fuel injection beam envelope.
Abstract:
With a transistor ignition system, in order to generate an ion current measurement signal at the secondary end, the ignition transistor, following an ignition triggering impulse, will be driven such that a saw-toothed collector current results as a primary current, and whose rate of increase is selected such that the quasi-stationary direct voltage generated hereby at the secondary end will not trigger any ignition process. The advantage is that for generating such a measurement signal as well as for its evaluation only a few components are required.
Abstract:
A four-stroke reciprocating-piston internal combustion engine includes a fuel injection device, which is arranged centrally in a combustion space and which introduces the fuel in the form of an injection cone into the combustion space, and includes at least one spark plug for each combustion space, the electrodes of which spark plug are arranged at the edge of the injection cone. At least two spark plugs are provided, of which the second spark plug has a markedly higher spark gap than the first spark plug.
Abstract:
Otto internal-combustion engines having one injector respectively per cylinder for the internal mixture formation can be operated at full load or high partial load by fuel injection in the suction stroke of the piston and, at medium or low partial load, with a compression stroke injection. The compression stroke injection, which is advantageous in this load range, because of low average combustion space temperatures and the tendency to form deposits in the combustion space because of residues of liquid fuel and the resulting impaired operating conditions, can partially be carried out only to a limited degree. In order to provide a process for operating an Otto internal-combustion engine of the above-mentioned type which permits an arbitrary operating period in the medium or low load range, it is provided that, in the operation of the internal-combustion engine with a compression stroke injection, as a function of the time or at least of an operating parameter, independently of the momentary load requirement, a change-over takes place to a suction stroke injection while simultaneously reducing the intake air quantity and, after the conclusion of a certain free-burning interval, a switching-back takes place into the operating mode with the compression stroke injection.
Abstract:
In a method for detecting knocking combustion during the operation of an internal combustion engine with a device for measuring the ionic current, the raw ionic current signal or the evaluated value of the knocking intensity are normalized. This enables the value of the knocking intensity to be reliably compared with a threshold value. The normalization avoids the falsifying influence of large intensity fluctuations of the raw ionic current signal from one combustion cycle to the next without any relation to the true knocking intensity.
Abstract:
A process for recognizing ignition failures in an internal-combustion engine which has two spark plugs per cylinder, based on a measurement of the ionic current at the spark plugs. In this process, the ionic current signals of the two spark plugs are each integrated using an assigned integrator over an entire combustion cycle and the integrator values are compared with one another. Since, in the case of a defective spark plug, an ionic current signal will occur only some time after the ignition (specifically after the arrival of the flame from the ignited spark plug), its integration value is significantly lower than that of the intact spark plug. From this information, the correct operation of the spark plugs is determined.
Abstract:
In a method of controlling adjustable operating parameters of an internal combustion engine with direct fuel injection which includes at least one cylinder having a piston delimiting a combustion chamber, a fuel injector and a spark plug, wherein air supplied to the combustion chamber through an air intake passage forms with the fuel injected by the fuel injector a fuel/air mixture which is compressed and produces a plasma cloud which is then ignited by a spark generated between the electrodes of the spark plug, the ionization degree of the plasma cloud is measured and an ionization signal is formed and supplied to an electronic control unit where it is utilized to control at least one operating parameter of the internal combustion engine.