DE2631323A1 - ELECTRONIC EARLY IGNITION SYSTEM FOR COMBUSTION ENGINES - Google Patents

Description

Fabbrica Italiana Magneti Marelli S.p.A. , Via G-uastalla 2,

Milano

Electronic pre-ignition system for internal combustion engines.

The present invention relates to an electronic system for adjusting the pre-ignition in combustion engines.

The purpose of the present invention is to provide one new electronic system for variable adjustment of the pre-ignition according to any puncture made by one or more Mutable is dependent.

Another object of the invention is to provide one variable adjustment system for the ignition, which allows from one pre-ignition function to another by simply changing the function values stored in a memory to pass over.

The present invention solves this problem in that a first series of continuous pulses is generated at a frequency which is independent of the rotational speed of the internal combustion engine, that a second series of continuous pulses of a frequency proportional to the rotational speed of the engine in question is generated, that reference pulses with one of the rotational speed of the engine in question proportional F _r FREQUENCY

60988 5/08 12

_ ₂ _ 263 7 3 2 3.

be generated that the pulses of the first series during the running between two successive reference pulses Period of time are counted that the number of pulses thus paid first series are codified according to the predetermined pre-ignition function that starting from each reference pulse, the pulses of the second series between two successive reference pulses are counted, and that the pulse number thus obtained with compared to the coded value of the impulse number of the first series is, and that a control pulse is triggered as soon as the value of the counted number of pulses of the second series is coded Value of the number of pulses of the first series becomes the same.

According to a preferred embodiment, the coding function, which determines the adjustment of the pre-ignition, entered into a memory, which thus the respective conditions contains corresponding pre-ignition function

Further advantages and features of the pre-ignition adjustment system emerge from the following description and the attached documents Drawings illustrating a preferred embodiment of the invention.

Fig. 1 is a block diagram of electronic equipment by which the pre-ignition system is realized according to the invention;

Fig. 2 gives a graphical representation of the function of the Apparatus according to FIG. 1 for three different angular speeds of the internal combustion engine o The

6 0 9 8 8 5/0812

three angular velocities are u; ' _o , CC ^ and £ 3 ^, where cj ^ j> cc ^ > CG c ^ * »

Fig. $ Illustrates the in a memory of the apparatus according to FIG. 1 entered function for adjusting the pre-ignition (coding function).

Referring to Fig. 1, R denotes a shaft of the internal combustion engine referred gear, with A and B are two input circuits of the electronic adjustment system of the pre-ignition, which are connected to the gear in question.

The gear has two groups of teeth. The first R _- . consists of a plurality of teeth
a single tooth

a plurality of teeth and the second Rp has at least

The first input circuit A speaks when passing the teeth of the group of teeth R ^. and gives a series of impulses at output 1 sen according to the rotational speed of the wheel R (see Fig. 2a). The second input scarf speaks in the same way device B with its response organs on the teeth of tooth group R and emits 2 reference pulses at the output, which also have a frequency dependent on the rotational speed of the wheel R. In the example shown, the reference pulses in the top dead center (PMS) of the drive

It can be seen that the circuits A and B are a signal reversal

609885/0812

cause shaping, in which the by the load or response organs emitted signals are converted into sharp impulses. It is also evident that the finding of the top dead center by means of a corresponding selection of the number of teeth Rp and / or by appropriate choice and arrangement of the number of response organs of circuit B can be made.

With CK a pulse generator or clock is called, which generates a series of pulses of a frequency that is independent of the speed of rotation of the wheel R (see Fig. 2c) is. This series is hereinafter referred to as the "first pulse series". In the example shown, this is the pulse frequency constant.

The number of pulses of the first pulse series is counted by a first counter C1, which is reset to full by means of the reference pulses arriving at its input 3, so that the counts of the counter during the time periods t ^ -tp ^ t ¹ ^ -t ¹ ₂ etc. between two consecutive reference pulses, that is, between two consecutive dead centers (EMS) (see FIG. 2d).

The value which corresponds to the number of pulses counted by C1 (see N _x ., ET ¹ ,, and N ¹ ',. According to FIG. 2d) is entered into a transit memory MT each time a reference pulse is applied to input 4 of this memory ( see the times t ^ or to ^s t ¹ ^ etc. according to FIG. 2d).

60988 5/0812

The transmission of the information from Cl to the memory MT takes place, before the count carried out by Cl is deleted by the reference pulse which serves to reset it Input 3 is created o

Other values can also be sent to the input of the transit memory MT be entered by means of the feeder 5, which other the motor or the adjustment system of the ignition represent parameters of interest «)

The value given by the memory MT is applied to a read-only memory Ml, which is based on the code entered on his Output supplies a corresponding value.

This code corresponds to the pre-ignition law (pre-ignition function), which is desired and it is evident that if this law is to be changed, the entry of the code must be changed accordingly

In FIG. 3, for example, a function f (N) of N is plotted, which represents a desired pre-ignition law. By coding in the read-only memory, the values N ^, N ¹ ^, N ¹¹ ^ etc. are stored by MT and sent to ML are applied (see Fig. 2e) the respective values fC ^), f (N · ,,), f (N '' ,,) etc. (see Fig. 2fD assigned ·

The pulses supplied by A, hereinafter referred to as the "second pulse series" are counted by the second counter Op,

- 6 - "■" 60.98.8 5/0812 ■

which by means of the reference pulses applied to its input 6 is reset to zero. Since the impulses supplied by A and also by B are proportional to the motor speed the end count of G2 remains when the motor speed changes constant (see N2 of FIG. 2g).

It is obvious that every pulse counted by Cp is one Fraction of the angle between two consecutive references- impulses.

A comparator CM compares the value of the pulses counted by C2 with the value supplied by the memory ML, which in turn is determined by that of Gj. counted value is determined in the immediately preceding cycle.

The comparator reaches the G _r ößedes signal from Cp that of the memory ML · SOFC signal / IRD at the output 7, a control pulse is generated, which can be used for the discharge of the ignition coil.

The operation of the device to carry out the preignition is explained below. At the moment t ^ of the arrival of the reference pulse (see Fig. 2b) the counter Cl has counted a number of pulses of the first pulse series and is reset to zero (see Fig. 2d). Before resetting to zero, however, the with N ^. denoted count value of your transit store MT which transmits the same up to time t ^ (see Fig.

609885/0812

. 263-323

2e) stores in which the following reference pulse arrives.

According to a particular solution, this transmission is carried out by means of the leading edge of each reference pulse, while the Resetting the counter C- to zero by means of the reverse Plank of the pulse is controlled.

The value Nl is applied from the memory MT to a read-only memory ML which, starting from the time t 1 to the time t p, supplies a value at the output which corresponds to f (N 1) (see FIG. 2f). The value f (Nl) is determined by the puncture of the Pig · 3, which is entered in the memory ML. Likewise starting from time ty. the counter C2 counts the pulses of the second pulse series (see Pig. 2g). As soon as this count leads to an electrical value which is equal to the value f (Nl) supplied by ML, the comparator CM supplies a control signal to the output 7

In the pig. 2g is designated by t £ the moment in which this compensation is achieved and the control signal for the speed u> c <ies motor is then given. -

From the foregoing, it follows that the count of Cp im Moment to is compared with the value f (N,) which is provided by ML im Time t, is delivered, a value that corresponds to the count of

609885/081 2

C ^ in the cycle immediately preceding the period t ^ -tp corresponds to, where the motor speed &> «? as constant and is considered lying below ^.

The function at the speed UJ ₄ is now taken into account: At the time t ~, the counter CL counted a lower number of pulses than on the occasion of the working cycle before ty ^{due to the increased speed (see N 1} , of FIG. 2d), so that the signal delivered to MT at time t ~ (see descending step at time t _? according to FIG. 2e) is smaller, while the signal delivered by ML corresponds to the course given by the curve in FIG Time t ~ according to Fig. 2f). The moment of triggering of the control signal in the cycle following tp is accordingly determined by the comparison between the value of the count of Cp from time tp s t '^ and the value f (W' ^) ( See Fig. 2g) When changing from the speed (O ^ to the speed CO £ , the number of pulses counted by C, between two successive reference pulses falls further (see N ¹ '. during the period \ " ", - f 'p ^of Figo 2d) u nd this reduces the new value sent by MT to ML, which in turn calls up the new value f (N '' ^).

The comparator is now the control signal as soon as the value of the count of C ₂ from time t ^{1 1} ^ from the value f (K ^{"1 1} ^) has been reached, an event that in M _o ment t * '(see Figure 2g) occurs.

609885/081 2

It should be emphasized that, if this signal is used to trigger the discharge of an ignition coil, the advance of the ignition takes place according to the speed of the engine according to a special law (see Fig. 2g), which is determined by the function f (N) of Fig 3 which has been entered into the memory ML. If the speed CjJο is changed over to Cj, the Y pre-ignition angle decreases compared to the pre-ignition angle at CnSq , because f (N ¹ O ^ f (EL), while it increases when a change is made from (Sj ^ to Φ * , because in this case f (N ¹ ^) ^ f (N ^). It is obvious that, depending on the particular requirements, the ignition advance curve can be changed by changing the function f (N) accordingly.

This peculiarity represents a very important feature of the invention » because it is sufficient to simply change the entries in the memory ML accordingly in order to achieve the desired pre-ignition curve · This has the advantage over the known pre-ignition devices that the other circuits of the device remain unchanged when switching from one engine with certain characteristics to another engine with different characteristics is passed over.

The circuits used in the device according to FIG. 1 are known and their detailed description can therefore be omitted. In particular, OK is a common oscillator and Cl and 02: are two

- 10 -

60 988 8/08 12

common binary counters, for example of the RCA 4-024 type. the Memories MT and ML can be of the Motorola 14-508 and Intel 1702 be.

Patent claims

609885/0812

Claims (4)

Claims (i) y Electronic system for ignition advance in internal combustion engines, characterized in that a first series of continuous pulses is generated at a frequency which depends on the rotational speed of the internal combustion engine is independent that a second series of continuous pulses one of the speed of rotation of the motor in question proportional frequency is generated that reference pulses with one of the speed of rotation of the motor in question proportional frequency are generated that the pulses of the first series during the are counted between two successive reference pulses running time period that the counted number of pulses first series codified according to the specified pre-ignition function that, starting from each reference pulse, the pulses of the second series between two successive ones Reference pulses are counted, and that the pulse dial thus obtained is compared with the coded value of the pulse number of the first series, and that a control pulse is triggered becomes as soon as the value of the counted number of pulses of the second series equals the coded value of the number of pulses of the first series soon it will 2) device for an electronic system according to claim 1, characterized by a pulse generator (CK) which supplies the first series of pulses with a frequency which is independent of the - 12 - 609885/0812 The speed of the internal combustion engine is a rotatable element, which is carried along by the motor shaft and has two groups of teeth, the first of which has a plurality of teeth (E1) and the second of which has at least one tooth (R2) having, a first input circuit (A) which is actuated by the teeth of the first group of teeth of the rotating member and on its output (1) the second series of pulses with a frequency proportional to the rotational speed of the internal combustion engine delivers, a second input circuit (B), which of the or the Teeth of the second group of teeth is actuated and at its output (2) reference pulses (PMS) with one of the speed of the internal combustion engine supplies proportional frequency, a first counter (Cl), which the pulses of the first series of pulses counts during the period between two consecutive reference pulses, a T _r ansitspeicher (MT), which at each reference pulse stores the value corresponding to the number of counted by the first counter (Cl) pulses, the zero reset occurs of the latter in the transmission of the relevant value to the transit memory (MT), a Read-only memory (ML), into which the _{value stored by the T r} ansit memory (MT) is entered, and which delivers a value that corresponds to the pre-ignition law entered, a second counter (02), which counts the pulses of the second series based on each Reference pulse counts, - 13 609885/081 2 - and a comparator (GM) which ver & lightly ver & lightly the value of the number of pulses counted by the second counter (C2) with the value supplied by the read-only memory (ML) at each preceding reference pulse and emits a control signal as soon as
both values become the same. 3) Apparatus according to claim 2, characterized in that the transit memory (MT) also registers further values corresponding to other parameters, which are for the engine and / or the ■ pre-ignition s system come into consideration. 4) Device according to claim 2, characterized in that in the
Read memory (ML) corresponding to a changed pre-ignition function corresponding other memory values are entered 60 9 8 85/0812