Internal-combustion engines – Spark ignition timing control – Electronic control
Reexamination Certificate
2002-05-01
2004-12-14
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Spark ignition timing control
Electronic control
C123S436000, C123S406590, C123S643000
Reexamination Certificate
active
06830033
ABSTRACT:
BACKGROUND OF THE INVENTION
In a multi-cylinder internal combustion engine with a crankshaft and a camshaft, the phase relationship of the internal combustion engine is calculated by a control apparatus in dependence on the angular position of the crankshaft or the camshaft. From this, it is provided at what point in time and into which cylinder fuel is injected and when the ignition must be tripped. The angular position of the crankshaft, for example, can be ascertained by means of a crankshaft sensor, which senses the crankshaft, or a disk connected with the crankshaft, with a characteristic surface. The surface can contain, for example, similar marks and a reference mark. The phase relationship of the internal combustion engine is not determinable only through ascertaining the crankshaft angular position, however, since the crankshaft rotates in a four-stroke cycle twice within a working cycle. The phase relationship arises typically with the assistance of a camshaft sensor, which senses a sensing disk connected to the camshaft, the disk having a reference mark. The camshaft rotates only once during the working cycle. Therefore, the control apparatus can recognized the phase relationship of the internal combustion engine from the signal of the camshaft sensor. The control apparatus consequently can perform a synchronization, that is, a clear assignment of fuel injection times and ignition times to the individual cylinders. In the event the camshaft sensor is out of commission or is not provided, the phase relationship must be determined in another manner.
DE 42 30 616 A1 relates to a device for determining the position of a shaft of an internal combustion engine, in which a sensor disk with a reference mark, connected to the shaft, is detected by a sensor, and the output signals are evaluated in a control apparatus. Therefore, immediately after starting-up the internal combustion engine, the position of the shaft is known, the determined position after switching off the internal combustion engine and after running the shaft is input in a memory of the control apparatus, and is used after again turning on the internal combustion engine for determining and input of the first injection during a start phase.
DE 44 18 577 discloses a device for regulating an internal combustion engine. The position of the crankshaft is continuously determined with the assistance of a corresponding sensor from a control apparatus. A phase sensor is not necessary. Instead, the beginning of the injection related to the angular positioning of the crankshaft for an individual cylinder is changed, so that from one working cycle to the next, a rotational change is initiated upon an incorrect phase relationship. These rotational changes are recognized with the help of the evaluation of the signals of the crankshaft sensor and is calculated in the control apparatus, where they are used for phase recognition and subsequently, for phase synchronization.
EP 0 640 762 A1 relates to an electronic engine-control apparatus for an internal combustion engine, which, without a camshaft sensor, performs the synchronization, that is, the specific assignment of fuel injection and ignition to the individual cylinders. Thus, the ignition and fuel injection of the internal combustion engine are operated in groups from starting until achievement of a stabile operating condition. After reaching the stabile operating state, either the ignition or the fuel injection for a selected cylinder takes place. A possible combustion misfire is detected and all cylinders can be correspondingly synchronized.
U.S. Pat. No. 5,425,340 discloses a method that determines the state of the cylinder of an internal combustion engine in its operating cycle. A crankshaft sensor runs a first signal when the upper firing top center is reached in a cylinder. A system for recognizing combustion misfires produces a second signal in the event of a misfire in the cylinders. The method includes many sequential method steps: the fuel injection for a determined reference cylinder is stopped. Combustion misfires in this cylinder are detected. From the time difference between the time of stopping the fuel injection and the occurrence of the combustion misfire, the time of the ignition or top dead center (TDC) of the reference cylinder is provided.
DE 198 44 910 relates to another device for phase recognition of an internal combustion engine, in which only a crankshaft sensor is provided. The phase signal is acquired through suppression of injection for a selected cylinder and simultaneous rotational speed analysis. If the expected rotational speed process is adjusted with several suppressed injections for the same cylinder, it can be concluded that the synchronization is correct. If these parameters are not fulfilled, the synchronization incorrect at 360° crankshaft angle and an un-synchronization takes place.
In the state of the art, a number of methods and devices for recognizing combustion misfires are known.
DE 198 14 732 A1 relates to a method for determining rotational speed, in particular combustion misfire recognition.
DE 41 38 765 A1 concerns a method and a device for determining a process instability value of an internal combustion engine on the basis of time, in which the crankshaft strokes over determined dial sectors (time segments).
SUMMARY OF THE INVENTION
The method for phase recognition in an internal combustion engine of the present invention has the advantage that a synchronization can take place without a camshaft sensor, especially, when the sensor is not working. Thus, a breakdown of the car driven by the internal combustion engine is avoided upon a defect of the camshaft sensor. In addition, the method of the present invention produces a substantially smaller loss of ease or comfort than the processes for phase recognition in the state of the art, for example, which includes an injection suppression, since combustion misfires are prevented. In addition, the invention method is useable with both odd and even numbers of cylinders. By repeating the method steps several times, the correct phase relationship can be accurately recognized.
These advantages are achieved through a process for phase recognition in an internal combustion engine with a number of cylinders in a suitable operating area, whereby a crankshaft sensor serves to determine the angular position of the crankshaft, a control apparatus calculates the signals of the crankshaft sensor, and the control apparatus in dependence on the angular position of the crankshaft triggers an injection or ignition impulse. The inventive method includes the following steps:
A) Setting two ignition points for each cylinder, respectively, near the top dead center (TDC) of the applicable piston;
B) Adoption of a phase relationship;
C) Changing the &lgr;-value for at least one cylinder;
D) Injecting at the selected point in time once or several times per working cycle in each cylinder;
E) Detecting rotational speed changes of the internal combustion engine by means of at least one working cycle; and
F) Distinguishing with the aid of the time point of the rotational speed changes or by the absence of rotational speed changes whether the phase relationship adopted in Step B is correct or incorrect.
Method step A means that a doubled ignition output takes place. The ignition is triggered in each cylinder near the two top dead center (TDC)s of the applicable piston. A working cycle of a four-stroke internal combustion engine includes four strokes. These are compression, expansion, exhaust, and suction strokes. During operation of these four strokes, the piston reaches the top dead center (TDC) twice within a working cycle. In the ignition TDC, which lies between the compression and expansion strokes, the ignition is triggered during normal operation of the internal combustion engine. In the second TDC (gas changing or load changing TDC), which lies between the exhaust and suction strokes, no ignition is triggered in normal operation of the internal combustion engine. The ignition in both TDC's
Castro Arnold
Gimie Mahmoud
Robert & Bosch GmbH
Striker Michael J.
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