CN1198801A - Method for determing phase of four-stroke internal combustion enjine - Google Patents

Abstract

Disclosed are methods to determine the phase angle of a four stroke internal combustion engine with an odd number of cylinders and without a camshaft detector. According to said methods, recognition of phase angle occurs by emission of a first signal from a crankshaft angle sensor presenting a singularity whereby said signal is placed in relation to a second signal, which is for example a speed signal or an output signal of an inlet-manifold air-pressure sensor and the shape of the second signal is evaluated in the range of singularity of the first signal. As this signal shape is variable according to whether the crankshaft is in first or second revolution, the phase angle can be determined precisely.

Description

Method for determining phasing of 4-stroke internal combustion engines

According to the classification of the main claims, the invention relates to a method for determining the phasing of a 4-stroke internal combustion engine with an odd number of cylinders.

current technology

For multi-cylinder internal combustion engines with a crankshaft and at least one camshaft, after synchronization (depending on the detected position of the crankshaft or camshaft), the controller of the internal combustion engine calculates which cylinder should be injected with fuel at which point in time and at which At what time and in which cylinder is the ignition switched off? In conventional internal combustion engines, the angular position of the crankshaft is usually determined by means of sensors. The sensor scans a disc attached to the crankshaft and sends a corresponding signal to the controller. The disc has a characteristic surface, such as a plurality of identical corner marks and fiducial marks on the surface.

Since the crankshaft makes two revolutions and the camshaft only one revolution in one working stroke of a 4-stroke internal combustion engine, the phase of the internal combustion engine cannot be determined unambiguously from the crankshaft sensor signal alone. The position of the camshaft is usually also determined by means of the camshaft's own sensor, a so-called phase sensor, which scans a uniquely marked disk coupled to the camshaft. Each revolution of the camshaft generates a pulse signal, which is also processed in the controller.

From the international application WO 87/05971 is known a device for cylinder recognition or a device for recognition of the working stroke of an internal combustion engine with an odd number of cylinders, which is sufficient without a camshaft sensor. In this regard, in the internal combustion engine controller, the signal provided by the crankshaft sensor (this signal is a pulse for one revolution of the crankshaft, that is, two pulses for one revolution of the camshaft) and the second signal (such as a periodic fluctuation in the working stroke of the internal combustion engine) signal) connected. This periodic fluctuating signal is either the output signal of the speed sensor or the output signal of the intake pipe pressure sensor. Due to the conditions of an internal combustion engine with an odd number of cylinders and the fixed phase relationship between the crankshaft and the camshaft, a working stroke recognition can be carried out by means of a simple logical connection of the crankshaft signal and the second signal, because during this rotation of the crankshaft, periodically The fluctuating second signal must be "high", while it must be "low" during another rotation of the crankshaft. In known devices, the working stroke detection is carried out by means of this simple logical relationship between the two signals. However, it is not recommended to deal with such characteristic signal changes in this way.

Advantages of the invention

The inventive method for determining the phase of a 4-stroke internal combustion engine having the features of claim 1 has the advantage that the engine can be synchronized without knowledge of the camshaft position. This also applies to systems where the phase relationship between the crankshaft and camshaft can be varied. If this advantage is to be achieved, the phase can be determined by correlating the characteristic signal provided by the crankshaft sensor with a second signal which fluctuates during the combustion stroke and which has cylinder-specific characteristics. In this process, the course of the second signal is studied to determine the phase when the characteristics of the first signal are present. Since this method is only used for internal combustion engines with an odd number of cylinders, a different profile of the second signal than that of the second crankshaft revolution results when the behavior of the first signal occurs during the first crankshaft revolution. The reason is that the cylinders in the first crankshaft revolution are in a different stroke than the second crankshaft revolution, so that the torque of the internal combustion engine is different, which has an effect on the profile of the second signal, for example on the rotational speed The change process and the intake pipe pressure change process have an effect. This effect is measurable and can be considered for cylinder identification. Therefore, the second signal will be the output signal of the speed sensor or the intake pipe pressure sensor.

Further advantages of the invention result from the measures specified in the other claims. In addition, since the variation process of the second signal and the absence of the minimum value or maximum value of the second signal are related to the characteristics of the first signal, the invention also shows a special advantage, that is, it is not difficult to solve the first and the second signal when determining the phase. The phase difference between the second speed signals.

The invention also has the advantage that the method for determining the phasing can be carried out during start-up, ie before the first firing of the cylinders. Early determination of the phasing is possible because the different strokes have a different effect on the rotational speed or the intake manifold pressure even without ignition.

For systems without camshaft sensors, the sensors as well as the electronics, camshaft wheels and corresponding cable connections can be saved. Three plugs, processing circuits for sensors and a computer plug can be saved on the engine controller. Also, the area of the printed circuit board can be reduced. In the absence of a camshaft sensor, diagnostic and error handling measures for this sensor can be dispensed with, thereby increasing the usability of the overall system. These savings are implemented without adversely affecting the exhaust performance or starting performance of the internal combustion engine. A further advantage is that the method used causes no additional run-time load on the controller software, since the synchronization is completed before the engine is started, so there are no run-time restrictions on the computer system.

Attached picture

Embodiments of the invention are illustrated in the drawings and described in detail in the description that follows.

describe

The components of an internal combustion engine control system required to describe the invention are schematically presented in FIG. 1 . The sensor disk is indicated by 10, which is fixedly coupled to the crankshaft 11 of the internal combustion engine and has a plurality of angular markings 12 of the same type on its circumference. In addition to these same type of angle markings 12 there are also reference markings 13 , which are realized, for example, by two default angle markings.

The sensor disc 10 is scanned by a receiver 14 (eg an inductive receiver or a Hall sensor). The voltage pulses of the signal S1 generated in the receiver when the angle mark is passed are processed and further processed in a suitable manner in the internal combustion engine control unit 15 .

In addition to the crankshaft 11, the internal combustion engine usually has at least one camshaft, which is indicated by 25 in FIG. The angular position of the camshaft 15 is not taken into account in the control system of the internal combustion engine described in FIG. 1 . In order to keep the communication between the crankshaft 11 and the camshaft 15 synchronized, a second signal fluctuating periodically during the combustion cycle is processed in the controller. This second signal S2 , which measures the pressure in the intake tract of the internal combustion engine, can be obtained by means of the sensor 17 . In principle, other fluctuating parameters in the combustion process can also be processed.

Other input parameters required for internal combustion engine control or adjustment can also be transmitted to the controller 15. Only the input parameter "ignition start" signal is introduced in Fig. 1, when the connector K115 of the ignition switch is connected to the ignition switch 18 This signal is provided and indicates to the controller 15 that the internal combustion engine is on.

The controller 15 itself comprises at least one central computer device 19 and memory 20 . The control signals for the injection and ignition of the corresponding components of the internal combustion engine, not shown in detail, are formed in the control unit 15 . These signals are given via outputs 21 and 22 of the controller 15 . Usually, the controller voltage is supplied from a battery 23 via a switch 24 which is switched on during operation of the internal combustion engine or during a possible coasting phase. Signal processing and processing described later are performed in the controller 15 .

The angular position of the crankshaft 11 can be obtained at any time during the operation of the internal combustion engine by using the control system described in FIG. 1 . During start-up, at the latest after one revolution of the crankshaft 11 , a characteristic in the signal S1 occurs, which corresponds to the reference mark of the crankshaft. Since the arrangement between the crankshaft 11 and the camshaft 25 is generally known as the arrangement between the position of the camshaft and the position of each cylinder of the internal combustion engine, it is therefore possible for the phase to be based on a reference only when a characteristic signal is present. The recognition of markers is kept in sync.

In the inventive system (which should have no phase sensor, or no camshaft sensor, i.e. no sensor for determining the position of the camshaft 25), there is the problem that the reference mark signal provided by the crankshaft sensor has multiple meanings, since the crankshaft is It rotates twice in one working cycle, while the camshaft 25 only rotates once. Therefore, in the controller 15, the signal S2 (for example the rotational speed signal or the output signal of the intake manifold pressure sensor) is processed and added to the signal S1, which signal has the characteristics of the cylinder position. Signal S2 , or a characteristic of this signal, is associated with signal S1 , and the course of signal S2 is especially processed when a reference mark or characteristic of signal S1 occurs.

Such a processing arrangement is possible because for an internal combustion engine with an odd number of cylinders, not every revolution of the crankshaft has the same relationship. For an internal combustion engine or motor, the engine position (hereinafter abbreviated as M1) of another multi-cylinder cylinder within a certain stroke is different from the second possible engine position M2. This can be explained with the aid of a three-cylinder engine as follows:

For example, for engine position M1:

Cylinder 1 is on the compression stroke,

Cylinder 2 is on its intake stroke,

Cylinder 3 is on the exhaust stroke.

For engine position M2:

Cylinder 1 is on the exhaust stroke,

Cylinder 2 is on working stroke,

Cylinder 3 is on its intake stroke.

From this arrangement it is clear that for the two engine positions M1 and M2, one cylinder is on the intake and exhaust strokes at a time, but the third cylinder is either on the working stroke, or on the compression stroke. While the compression stroke is affected by the speed resistance, the working stroke causes the speed to increase. Thus, the course of the rotational speed and the course of the intake manifold pressure during the first revolution of the crankshaft differ in a characteristic manner from the course of the course during the second revolution of the crankshaft. Therefore, the speed change process and the intake pipe pressure change process in the environment of the reference mark or the characteristic environment of the signal S1 are the criteria of the engine position, which can be considered as a substitute for the camshaft signal, and at the same time generate identification signals that describe the engine position M1 and M2 .

Not only in the process of processing the speed change, but also in the processing of the pressure signal must be determined according to the number of cylinders and the valve control time of the engine, the sign conversion of the slope of the second signal, or the second signal in the environment of the reference mark, that is, the characteristic environment of the signal S1 Is min/max processing the best way to identify phases. The second signal is derived in terms of time to determine sign transitions or to perform minimum/maximum processing such that slope and/or maximum/minimum values are obtained. Determine exact engine-specific measuring points for speed or intake manifold pressure determination.

As the measurements illustrate, when the internal combustion engine or engine is started, the controller can directly recognize the actuation of the starting device. Both the speed profile and the intake manifold pressure profile are used as signal S2 for synchronization. In addition, signal processing can be carried out before the first injection or ignition, in the unfired operating state after the engine starts to rotate. During the first revolution of the unignited revolution, not only the speed profile but also the intake manifold pressure profile are characteristic for the first or second crankshaft revolution. After normal operation of the engine, especially at high engine speeds or speed changes, it is possible to disregard the use of the speed change process for determining the engine position. Once synchronization is required at work, it must be done by means of intake pipe pressure signal processing.

If the inventive method is used in a system with a camshaft sensor, it can be used as an emergency operation when a defective camshaft sensor is detected.

A combination of using the inventive method directly after start-up and taking into account the output signal of the camshaft sensor for phase determination under normal operating conditions is also possible.

Claims (7)

1. the feature of method that is used to determine to have 4 stroke IC engine phase places of odd number cylinder number is, in characteristic range, studied the change procedure of secondary signal, this signal all is very typical for the first lap and second circle that bent axle rotates at every turn, in this method, formed first signal with characteristic, this specific character can be predesignated, that crank shaft angle had and be associated with the secondary signal that forms by speed probe output signal and/or intake manifold pressure sensor output signal, in the characteristic range of first signal, formed identification signal by the secondary signal processing.

2. according to claim 1, be used for determining that the method feature of phase place is, in cylinder of internal-combustion engine, implement this method before the igniting first time when starting.

3. the method feature according to claim 1 or 2 is, the processing of secondary signal (S2) has comprised the identification or the processing of the minimum/maximum in the characteristic environment of first signal (S1) of signal slope symbol transition.

4. the method feature according to claim 3 is, depends on the decision of the cylinder of internal-combustion engine number and/or the controller in valve control time, whether carries out signal processing by means of the slope of secondary signal or by means of the minimum/maximum processing.

5. the method feature according to one of aforementioned claim is, determines that the distinctive measuring point of motor is to measure rotating speed and/or suction press.

6. the method feature according to one of aforementioned claim is, in running, under time of predesignating or condition, further carry out determining or check of phase place, in this course, be in operation and only handle the output signal of intake manifold pressure sensor when determining phase place.

7. the method feature according to one of aforementioned claim is, in case when controller detects signal processing circuit defectiveness under phase detector or its, implement this method in having the internal-combustion engine of phase detector, to carry out emergency operating.

Images