WO1988007631A1

WO1988007631A1 - Arrangement for determining the ignition angle in combustion engines

Info

Publication number: WO1988007631A1
Application number: PCT/DE1988/000198
Authority: WO
Inventors: Wolfgang PICKAVÉ; Klaus Roland Kuhn
Original assignee: Siemens Aktiengesellschaft
Priority date: 1987-03-30
Filing date: 1988-03-28
Publication date: 1988-10-06
Also published as: KR890700758A; DE3710521A1; EP0356436A1

Abstract

In an arrangement for determining the ignition angle in combustion engines, the cylinder movements are proportional to a rotation of the crankshaft which can be determined by measurement, and a reference angle region (R) is indicated by at least two marks on the circumference of a disc integral with the crankshaft. The upper dead centre of at least one cylinder can be derived from the marks. To ensure accurate measurement of the ignition angle in combustion engines, which is not possible by adapting any conventional upper dead centre sensors, the ignition angle is determined by measuring a time and using a reference angle to derive the ignition angle in real time by simple mathematical operations. The invention is used mainly in vehicle test stands.

Description

- Λ -

Arrangement for determining the ignition angle in internal combustion engines

Technical field

The invention relates to an arrangement for determining the ignition angle in internal combustion engines, in which the cylinder movements are proportional to a crankshaft rotation that can be measured and in which at least two markings on the circumference of a disk firmly connected to the crankshaft are used Reference angle range is specified, the top dead center of the at least one cylinder being derivable from the markings.

State of the art

With known arrangements of this type (cf. Siemens magazine 47 (1973), number 8, pages 603 to 608, Herbert Lücke: "New sensors for automotive electronics"), the ignition angle is usually determined by the rotation of the crankshaft by the Piston movements caused by the cylinders of the internal combustion engine can be derived. The ignition angle is defined here as

Angle of rotation of the crankshaft between the ignition point and the top dead center of a cylinder. The optimal setting of the ignition angle is extremely important for the function and service life of the engine and for maintaining optimal exhaust gas values.

A cost-effective and quick determination of the ignition angle is made possible with appropriate sensors, which detect the rotation of the crankshaft, and evaluation electronics, which further process the measured values. Although special sensor fiducials for top dead center are dispensed with for reasons of space and saving, May exist for the determination of dynamic ignition angles in the development of internal combustion engines as well as for production, sales and service workshops with at least the accuracy of conventional devices.

Presentation of the invention

The invention has for its object to provide an arrangement for the precise determination of the ignition angle in internal combustion engines, in which a conventional top dead center sensor adaptation is no longer available and the ignition angle measurement is therefore no longer possible with external devices.

This object is achieved in an arrangement of the type specified at the outset with the features of the characterizing part of claim 1.

With the invention, the determination of the ignition angle can advantageously be traced back to a pure time measurement, with a relatively large time base. This is a time measurement which, in accordance with one embodiment of the invention, is based on the advantages of the incremental information of the rotating ring gear and its angular assignment accuracy of the teeth with one another and makes full use of them. The increased resolution of non-integer intermediate states between the gear rim periods is interpolated by time measurement. The evaluation can be carried out using a relatively simple and likewise exact calculation which can be carried out with the electronics present in almost every test device for internal combustion engines.

The invention can advantageously be used in internal combustion engines in which there is an electrical connection between the sensor and an electronic control unit for ignition, fuel injection, etc. Here, a high-ohmic intermediate adaptation can be implemented without difficulty. The ignition signals occurring during the ignition events can easily be either from the common ignition line or from the cylinder-specific ignition lines, for example using trigger pliers. The previously usual fixed reference marks for the top dead center of a cylinder can therefore be omitted.

The reference angle measuring method, which can be carried out with the arrangement according to the invention in accordance with the subclaims, makes it possible to use highly precise gear rim (or segment) angle relationships with an error of + _ 0.01 ° for determining the ignition angle. The position of the reference angle can be created so that the ignition event times tcc.n_ coincide with the

Superimpose reference angle times t _{R over} time in actual operation. With the division according to the invention of two time periods determined almost simultaneously during a rotation angle process which is subject to out-of-roundness, as is customary in crankshaft revolutions with process-dependent accelerations or decelerations, the corresponding system error of the measuring arrangement is minimized. Depending on the design of the disk, the advantageous width of the reference angle can be selected for optimal determination of the ignition angle, for example at

Sprocket disks by a suitable number of tooth periods (here six tooth periods) and in the case of segment disks by selecting either raised or non-raised segments as reference time periods.

The dynamic firing angle determination of a plurality of cylinders in the firing order of the engine, for example via predetermined angular increments, can be carried out in real time with the use of appropriate standard test equipment using the existing evaluation electronics. In this way, the characteristic diagram programs running in the control units of the engine could be better dynamically optimized and possible knocking and other controls could be checked for their correct function in a cylinder-specific manner. The accuracy of the measurement in this arrangement according to the invention therefore no longer depends on the number of sprocket teeth per crank angle revolution, but it is the accuracy of the through the tooth period π designed reference angle, which is determined with the help of time measurement, is now decisive. This mechanical accuracy is very high. The time resolution is, for example, 200 kHz, ie 5 μsec event resolution. This means a measurement uncertainty of the dynamic ignition angle in the speed range of 20 - 4000 rpm of + 0.113 °, which is very low.

Brief description of the drawing

The invention is explained with reference to the figures, in which FIG. 1 shows a basic arrangement for determining the ignition angle, FIG. 2 shows a rolled-up toothed ring on the circumference of a crankshaft washer,

FIG. 3 markings for multi-cylinder engines,

Figure 4 shows an embodiment for a segment marking and Figure 5 shows another embodiment with segment marking for a six- and eight-cylinder engine.

WAYS OF IMPLEMENTING THE INVENTION / INDUSTRIAL APPLICABILITY

In the arrangement shown in FIG. 1, a ring gear disk ZKS is shown, which is connected to the crankshaft of an internal combustion engine (not shown here) and thus executes a rotary movement proportional to the cylinder movements of the internal combustion engine. In connection with the toothed ring disk ZKS, a toothed ring ZK is attached, in which each tooth period represents an angular increment. Via a sensor S

- For example, a magnetic sensor - the passage of the tooth flanks or the markings can be detected and evaluated with a test device PG. In conjunction with the ignition pulse of an ignition coil ZS, which is detected by means of trigger pliers TZ, an angle determination of all ignition angles of all cylinders "in spite of ring gear dryness" is possible continuously in real time. In Figure 2, a ring gear ZK according to Figure 1 is shown unrolled. A first reference mark is located on the left end of the rolled-up ring gear; this is the offset marking for the top dead center 0T of a first cylinder or a first cylinder of the second crankshaft revolution or a synchronization point SP, which is emphasized by the fact that the two previous teeth have been left out. At the right end there is the mark for the top dead center 0T of the first cylinder, at which the preceding six tooth periods 1 ... 6 are defined as the reference angle R. The time span in the passage through this area is designated t _R. The ignition timing ZZP is also indicated in FIG. 2; the time span between the ignition timing ZZP and the top dead center OT is here with t. designated.

The ignition angle σc to be calculated is thus obtained

c = -. 36 ^ZL R1 assuming that a tooth period is 6 "and thus the reference angle range is 36 °. The pulse sequence for determining the reference angle R is shown in a simplified manner under the rolled-up ring gear.

In FIG. 3, a sprocket sequence, as occurs in a four-cylinder engine, is shown in unrolled form, only the tooth or pulse flanks necessary for determining the reference angles R 1 ... R 4 being specified here. The synchronization point SP is again marked on the left, the ignition follows

(Ignition timing ZZP) of the first cylinder and the time period t ,, j subsequently the reference angle time t _{R1 of} this first cylinder. The ignition angle determination can be carried out here as in the exemplary embodiment according to FIG. 1. The ignition of the second cylinder and the detection of the reference angle time t _R2 and the time period t ₂ ^{from the} ignition event to follow immediately after to top dead center 0T2 of the second cylinder. The same is shown for the third and fourth cylinders. It is therefore possible to carry out a cylinder-specific ignition angle determination cC -, ... oc A in the ignition sequence of the engine in real time,

In the exemplary embodiment according to FIG. 4, a segment disk SS is provided, on which instead of the teeth there are segments with an enlarged radius, in which the right flank is the top dead center OT of a first cylinder and the left flank the area of the reference angle R to top dead center Represents TDC of the first cylinder. In this embodiment, the reference angle is R = 55 °. Opposite this segment, a second segment for a second cylinder is arranged in the order of the cylinders. In addition to this exemplary embodiment of the ring gear disk ZKS, a pulse diagram of the detected time periods t _Λ and t _R can be seen, the ignition timing ZZP lying here within the reference angle time t _R , but this does not change the evaluation calculation according to FIG. 2. The detection of the time period and the determination of the ignition angle is done in the same way for the second cylinder and is also identical to the detection of the ignition angle oc of the third and fourth cylinders.

FIG. 5 shows segmented disks SS for a six-cylinder engine and an eight-cylinder engine. In the case of the six-cylinder engine, a segment for the ignition angle measurement of the first and fourth cylinders with the top dead centers 0T1 and 0T4 as well as a segment for the second and fifth cylinder and a further one for the third and sixth cylinder are specified. The segments for determining the ignition angle are given in an equivalent form in the right embodiment for the eight-cylinder internal combustion engine.

4 claims

5 figures

Claims

1. Arrangement for determining the ignition angle in internal combustion engines, in which the cylinder movements are proportional to a crankshaft rotation that can be measured and

- in which a reference angle range (R) is indicated by at least two markings on the circumference of a disk which is firmly connected to the crankshaft, the top dead center (TDC) of the at least one cylinder being deduced from the markings, that is to say that,

that a time period for the passage of a predetermined number or the spacing of markings can be determined as a reference variable with a sensor (S), a counting device and evaluation electronics which is fixedly attached in the region of the rotating disc (KWS; SS), the predetermined number of markings or the distance between the markings indicating a reference angle (R), - that the ignition timing (ZZP) can be detected with a further sensor and

- That in the evaluation device, the reference time period (t _R ) and the time period (t ^) between the ignition point (ZZP) and the time of the passage through the top dead center (OT)

Determination of the ignition angle oC ₇ according to the equation

cC

^ z = t R

is used.

2. Arrangement according to claim 1, d a d u r c h g.e k e n n - z e i c h n e t,

that the rotating disc is a ring gear disc (ZKS), in which there is a ring gear (ZK) on the ring gear disc (ZKS) and in which each tooth marks a predetermined angular range, - And that a synchronization point (SP) is formed by omitting the previous teeth, the locations of the top dead centers (TDC) of the cylinders are derived by counting predetermined numbers of teeth.

3. Arrangement according to claim 1, d a d u r c h g e k e n n ¬ z e i c h n e t,

- That the rotating disc is a segment disc (SS), in which there is at least one radially or axially raised segment on the circumference of the disc (KWS), the

Circumferential section of the segment indicates the reference angle (R) and a segment edge indicates the respective top dead center (OT).

4. Arrangement according to one of the preceding claims, d a - d u r c h g e k e n n z e i c h n e t,

- That it is in the sensors (S) for detecting the passage of the teeth or segments to magnetic sensors.