Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1995-03-06
1996-11-12
Nelli, Raymond A.
Internal-combustion engines
Charge forming device
Fuel injection system
F02P 500
Patent
active
055729738
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for identifying cylinders in internal combustion engines.
BACKGROUND INFORMATION
For cylinder identification, i.e., to detect the compression in one cylinder, for example, cylinder 1 of the engine, during one working cycle, the German Published Patent Application No. 34 31 232 has already disclosed providing two sensor wheels, the first sensor wheel turning at crankshaft speed and the second sensor wheel turning at half of the crankshaft speed, which is the speed of the camshaft. By synchronizing the signals generated in the sensors assigned to the sensor wheels, one is able to exactly identify which stroke of the combustion cycle the engine is in. With this method, when the sensor used to detect camshaft revolution fails, one can no longer identify the exact position of the piston of one cylinder during one combustion cycle because of the missing phase signal.
SUMMARY OF THE INVENTION
In contrast, the method according to the present invention, has the advantage of enabling a cylinder identification even without the existence of phase signals. An additional advantage to be considered is that, in particular, feedback controls performed on individual cylinders, such as a cylinder-selective injection or a cylinder-selective knock control, can be continued even when there is a phase-sensor error. Last of all, it is advantageous that safety measures for an operation under emergency conditions, such as a late ignition-advance angle and mixture-enriching, can be eliminated or can be ended after a short time. Until the time that the reference mark is allocated and, thus, until cylinder identification, it is especially advantageous for safety measures to be activated, and then inactivated after the cylinder identification. It is, thus, advantageous for one ignition signal to be output in every crankshaft revolution, so that one ignition signal then takes place during the compression stroke which can, consequently, trigger a combustion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the correlation between the camshaft and crankshaft signal on the basis of signal patterns.
FIG. 2 shows a flow chart of a first exemplary embodiment of the method according to the present invention.
FIG. 3 illustrates a flow chart of a second exemplary embodiment of the method according to the present invention.
FIG. 4 is a block diagram of an exemplary embodiment of a system for carrying out a method in accordance with the present invention.
DETAILED DESCRIPTION
FIG. 1 depicts the signal patterns from the camshaft sensor NW and from the crankshaft sensor KW as a first and second signal pattern for a multicylinder internal combustion engine 100, as detected by a control unit 50 under normal operational conditions. FIG. 4 shows the arrangement of the engine 100, sensors NW and KW and the control unit 50. The ignition-control signal 1 output at a first cylinder Z1 by the control unit is shown in FIG. 1 as a third signal pattern. All three signal patterns NW, KW and the ignition-control signal 1 are depicted over the arc of crankshaft rotation, the intention being to elucidate, in particular, the range of 0.degree. to 720.degree. (thus, two crankshaft revolutions). As is generally known, the crankshaft of a four-stroke internal combustion engine turns twice around its own axis during one combustion cycle. Accordingly, the piston moves twice in the direction of its top dead center and, in fact, once during the compression stroke and, the other time, during the exhaust stroke. To ensure proper combustion, it is important for the spark plug ignition to take place during the compression stroke and not during the exhaust stroke, since otherwise the induction pipe would be at risk. The crankshaft is usually connected to a sensor wheel, which is comprised of, for example, 60 - 2 teeth, to detect one complete crankshaft revolution. The camshaft of an internal combustion engine turns at half of the crankshaft speed, so that one camshaft revolution is completed for two cra
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Nelli Raymond A.
Robert & Bosch GmbH
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