JPH0658115A - Method of automatically adjusting angular position between at least two driven and coupled shaft - Google Patents

Abstract

PURPOSE: To provide a method for controlling a camshaft adjuster, which has a precise, short responsive time for continuously adjusting a random intermediate position of a camshaft. CONSTITUTION: A control circuit 9 having a regulator 5 and measured value detectors 6, 7 is provided. Positions of a crankshaft 11 and a camshaft 12 are transmitted as measured value signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides an electrically actuatable valve responsive to a control signal through which an adjusting mechanism for adjusting a camshaft can be controlled. The invention relates to a method for automatically adjusting the angular position between at least two drive-coupled shafts, in particular a crankshaft and a camshaft, in an internal combustion engine.

[0002]

2. Description of the Related Art Camshafts used in internal combustion engines are
The gas exchange valve is operated according to the shape of the cam of the camshaft. Defining the valve control time is a compromise, especially with regard to the rated power and torque requirements. It is known to perform a phase shift of the control time in order to optimize the control time. That is, in the case of an internal combustion engine having a double camshaft, the position of the camshaft used for the intake valve or the exhaust valve is
It is displaced by a predetermined crank angle with respect to the crankshaft. As a result, the valve overlap between the intake valve and the exhaust valve changes. Control time optimization in an internal combustion engine with only one camshaft used for the intake valve and the exhaust valve is based on a simultaneous shift of both control times.
al phase shift).
These two methods can be used selectively in a cylinder row in an internal combustion engine having combustion chambers arranged in opposed V shapes. The angle between the two cylinder rows may be up to 180 ° (horizontally opposed engine).

Generally, when using a double camshaft, the respective control times for the intake valve and the exhaust valve can be shifted independently of one another with respect to the crankshaft (dual indep).
end phase shift).

In all engine types, a structure is known in which an intermediate shaft is used as a connecting member between a crankshaft and a camshaft. Thereby, for example, the transmission ratio is realized in two stages. In this case, the phase of this intermediate shaft can be adjusted, which influences the control time of the gas exchange valve as already mentioned.

A control method for the stepless adjustment of a camshaft drive is described in German patent application DE-A 40 40 40
It is known from the specification of 06950. In this camshaft drive, the crankshaft position and the camshaft position are continuously compared in relation to the rotational speed.
The measurement signal is supplied to the difference former. The difference former processes the measurement signal and transmits it to the control unit. The output signal of this control unit serves as an adjustment signal for the mechanical control section.

However, such a known control method, which operates exclusively in relation to the speed of rotation, requires frequent signal conversions, which in turn requires a great deal of effort.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for controlling a camshaft adjustment mechanism which has a precise and short response time so that any intermediate position of the camshaft can be continuously adjusted. Is to provide.

[0008]

In order to solve this problem, the method of the present invention is provided with a control circuit having an adjuster and a measured value detector, and a position signal between the crankshaft and the camshaft is measured value signal. I tried to transmit as.

[0009]

According to the method described in claim 1 of the present invention,
A continuous or two-point camshaft adjustment can be obtained. By this camshaft adjustment, the instantaneous position between the crankshaft and the camshaft can be accurately obtained, and the difference angle can be measured. This difference angle serves as the base for continuous camshaft adjustment. According to the invention, a control circuit is provided which has a regulator and a measured value detector. This measurement value detector enables accurate measurement value detection. This measurement value detection is performed by evaluating the time difference between the trigger pulses of the crankshaft and the camshaft. By adjusting to the set value, a stepless and precise adjustment of the adjusting mechanism and thus advantageously a short response time is possible. Dedicated sensor technology for both signals can be used, or the signals processed by conventional engine processing systems can be used. The number of pulses depends on the various internal combustion engine types. In the case of a 4-cylinder or 8-cylinder internal combustion engine, 1, 2 or 4 crankshaft trigger pulses are processed by 1, 2 or 4 camshaft pulses, whereas Or 1
In the case of a two-cylinder internal combustion engine, 1, 3 or 6 pulses are processed by 1, 3 or 6 camshaft pulses. In this case, the correspondence of the number of pulses can be freely selected. The method according to the invention comprises the engine target value,
In other words, rotational torque characteristics, consumption, exhaust gas emission,
And further improve the riding comfort.

In a refinement of the method according to the invention, the angular position of the crankshaft is used as a reference value for the control, and the detected camshaft position is taken as evaluable position information for the camshaft to be adjusted. Be done.

The placement of another characteristic pulse on the camshaft trigger wheel leads to cylinder identification. The trigger wheel may comprise 2 + 1, 3 + 1 or 4 + 1 marks, the additional mark position correspondence must be clear with respect to the angle mark. The formation of other effective signals used in engine processing systems is possible.

The basic precondition for obtaining each adjustment of the adjusting mechanism is that at the beginning of the program after the working voltage has been applied, the adjusting mechanism must ensure that it is in the defined rest / end position. It is that you are. Moreover, at this position, the angle of difference between the crankshaft pulse and the camshaft pulse must be within the set range, and the adjusting mechanism does not perform the adjusting movement within this tolerance range.
This detected value is regarded as the basis for each subsequent adjustment of the camshaft.

In the method according to the invention, the angle of difference between the crankshaft position and the camshaft position at the start of the system is also determined by sliding averaging via several measurements, preferably eight. 0.1 °
It is specified by the KW resolution. The rotation speed is calculated in the same manner. Then, after the end of the starting process, the difference angle is defined from the instantaneous values of the position positions of the crankshaft and the camshaft.

The present invention is provided with an electric hydraulically operated proportional valve, a switching valve or a rapid timing control valve formed by positive or negative overlap of control edges as an inflow control part or an outflow control part. And is advantageous. This is advantageous because the control member is held at each intermediate position, which in turn ensures accurate detection of the measured value as well as a fine adjustment of the required angle of difference between the crankshaft position and the camshaft position. Be done.

Furthermore, according to the invention, the regulator controls a hydraulic valve, preferably a proportional valve, in a pulse-width modulated manner. That is, the proportional valve is operatively connected at a frequency of about 300 Hz and for different lengths of time.
This increases the proportional valve current and operation as the actuation connection time increases due to the increased on / off ratio.

The regulator used in accordance with the present invention calculates the on / off ratio in relation to the detected angular difference with respect to the desired camshaft position from information in a plurality of program sequences. This is defined by a programmable number of angular windows of varying width.
This window is arbitrarily selectable and represents the deviation between the target value and the actual value. Each of these angle windows corresponds to a factor having a different value, which factor is multiplied by a constant. This product is the instantaneous intermediate position on / off ratio file of the proportional valve. Depending on the control direction, i.e. the approximate direction of the target angle to the actual angle,
This product is added to or subtracted from the mid-angle position.

In a further implementation of the method according to the invention, a sensor is provided for detecting the measured value for the position position of the crankshaft and the camshaft and for detecting the rotational speed. It is also possible to reproduce the crankshaft position and / or the camshaft position and process the signals produced by the engine processing system or other external device.

Advantageously, the control circuit is designed as follows. Ambient conditions such as supply voltage and supply pressure change, ambient temperature that affects the viscosity of the pressure medium changes,
Especially if the piston provided in the adjusting mechanism leaks or changes, the control circuit, without additional sensors,
It is ensured that the stable position of the adjusting mechanism is retained. Furthermore, the control circuit according to the invention can carry out the distinction and reset according to the case of the system, which forms the basis of the control method.

According to the invention, a PI regulator is provided as regulator, and instead of this PI regulator, in relation to the requirements of the control section in terms of control merit and optimization of settling time. , P regulators, PD regulators, PID regulators or regulators with a fuzzy structure modified from the above types can be used. Such regulators are connected to an operating part, the operating capacity of which is designed in such a way that stepless adjustment or positioning of the proportional valve is guaranteed in the respective required position. There is.
According to the invention, a PID regulator may alternatively be used.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a circuit for carrying out the method according to the invention. Only a crankshaft 11, a crank transmission 10, and a camshaft 12 are schematically shown in the internal combustion engine 1. This internal combustion engine is equipped with an adjusting mechanism 3. To the side of this adjusting mechanism, the piston 14 is also shown enlarged and also schematically. A pressure medium pump 16 is used to pressure-load this piston 14. To this end, the internal combustion engine 1
Advantageously, a pressure-medium pump for pressure-circulation lubrication is used which is provided in the. A control circuit 9 is provided for the continuous fine adjustment of the piston 14. This control circuit mainly comprises a proportional valve 8, a regulator 5 and sensors 6, 7 for measuring measured values. The sensor 6 used for the crankshaft 11 and the sensor 7 used for the camshaft 12 are provided to measure the difference angle between the position of the crankshaft 6 and the position of the camshaft 7. The control circuit 9 can be expanded by a sensor for detecting the number of rotations, for example. Alternatively, separate sensors may be used for the detection of the rotational speed and the rotational position. This measurement signal is processed by the regulator 5 and compared with the setpoint,
This defines the on / off ratio, that is, the electromagnetic switching type proportional valve 8 is operated. Via this proportional valve, the regulated and metered pressure medium flow is guided towards the piston 14 in order to achieve a continuous adjustment of the angular position of the camshaft 12. Furthermore, it is advantageous if the proportional valve 8 is formed by a positive overlap of the control edges. That is, when the angular position detected by the sensors 6 and 7 provided on the crankshaft 11 and the camshaft 12 is reached, the proportional valve 8 is moved to the central position, and at this central position, the positive overload of the control edge is exceeded. Due to the wrap, all connections are broken, which locks the piston 14 in place. The displacement of the piston 14 caused by the leak is detected by the control circuit 9 and adjusted automatically. In this case, another sensor is not used.

In addition, the regulator is provided with one or more inputs and outputs, which serve to exchange data with other systems. This means that it receives a setpoint value, detects certain operating conditions that give rise to a special function of the regulator, such as the termination of regulation or the earliest possible start-up of the end position, or, for example, for engine processing systems. Advantageously, it is used to form an effective signal for external devices, such as cylinder identification. This adjuster 5
In the exemplary embodiment, it is further provided with a data interface 4 through which basic parameter settings or parameter changes of the very main variables used in the regulator can be carried out.

[Brief description of drawings]

1 diagrammatically shows a circuit for carrying out the method according to the invention, FIG.

[Explanation of symbols]

1 internal combustion engine, 3 adjusting mechanism, 4 data interface, 5 regulator, 6,7 sensor, 8 proportional valve, 9 control circuit, 10 crank transmission mechanism, 1
1 Crankshaft 12 Camshaft 14 Piston, 16 Pressure medium pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Dirk Heinzen, Federal Republic of Germany Nacharoth-Viblink Verde Telegraph 1

Claims (11)

[Claims] 1. A valve, which is electrically operable and responsive to a control signal, enables a control mechanism for the adjustment of a camshaft to be controlled, by means of which a drive connection in an internal combustion engine is provided. In a method for automatically adjusting the angular position between at least two axes, in particular between a crankshaft and a camshaft, a control circuit having an adjuster and a measured value detector is provided, the position of the crankshaft and the camshaft being provided. Method for automatically adjusting the angular position between at least two drive-coupled axes, characterized in that the position is transmitted as a measurement signal. 2. A differential angle can be defined by using at least one trigger mark provided on each of the crankshaft and the camshaft, and the differential angle is defined as a base for continuous adjustment of the adjusting mechanism. Used as, claim 1
The method described. 3. The angular position of the crankshaft is used as a reference value for control, and the detected position of the camshaft is regarded as evaluable position information for the camshaft to be adjusted. The method according to claim 1 or 2. 4. The differential angle between the crankshaft position and the camshaft position and the number of revolutions are defined by a sliding average value formation through several measurements at system start-up. The method according to any one of 3 to 3. 5. The method as claimed in claim 1, wherein the valve is an electrohydraulic proportional valve formed by a positive overlap of the control edges. 6. The method of any of claims 1-5, wherein the regulator controls the proportional valve in a pulse width modulated manner, and an on / off ratio defines operation of the proportional valve based on the results of a plurality of program sequences. The method according to item 1. 7. The control action of the regulator can be influenced by the angular difference of the instantaneous position of the camshaft with respect to the desired desired value. Method described in section. 8. The method according to claim 1, wherein the sensor detects the measured value and the first sensor is assigned to the crankshaft and the second sensor is assigned to the camshaft. . 9. The method according to claim 1, wherein a control circuit is used which automatically adapts to changing ambient conditions or leakages occurring in the adjusting mechanism. 10. The method according to claim 1, wherein the function of the regulator corresponds to the PI regulator. 11. The method according to claim 1, wherein the regulator allows the proportional valve to be held in each position or to be adjusted steplessly.