DE3425187A1 - METHOD AND DEVICE FOR CONTROLLING THE COMBUSTION PROCESS - Google Patents

Description

VT JJii »111JH. UL CARPENTER

3425187 'V- PATENT AGENCIES

european patent attorneys

Dipl.-Ing. H. Leinweber (ΐ93ο-7β) Dipl.-Ing. Heinz Zimmermann Dipl.-Ing. A. Gf. v. Wengersky Dipl.-Phys. Dr. Jürgen Kraus

Rosental 7, D-8000 Munich 2

2. Ascent (Kustermann-Passage) Telephone (089) 2 60 39 89 Telex52 8191lepatd
Te! Egr.-Adr. Leinpat Munich

the 9th JUU 1961

Our reference Zm / GO 84046 kr ρ

Nuno Ryberg Mousinho de Figueiredo, Nybytorpsvägen 4, 64 Djursholm, Sweden

Method and device for controlling the combustion process in an internal combustion engine

- * - The invention relates to a method for Control of the combustion process in an internal combustion engine and a device for carrying out this method .

In particular, the invention relates to such a method in which successive adjustments lungs under at least one variable variable influencing the combustion process as a function of the instantaneous values of two different operating parameters of the engine

O the guidance through individual setpoints of the size for a multiple

number of different sub-areas of the working range of the engine is provided, which are determined by predetermined intervals of the values of the two operating parameters.
5

In practice, these two engine operating parameters usually consist of intake pressure and the speed of the engine. Furthermore, there is the variable subject to the successive adjustments Size usually from the ignition point, i.e. the moment when an ignition spark is generated in one Cylinder of the engine. This moment can either be determined by a relative time or particularly typically by the Angular position of a rotating part of the motor can be set. Procedures of the above type can however, alternatively or in addition, contain settings of other variable sizes that are made one after the other, which influence the combustion process in the internal combustion engine. In particular, they can be used to run successive adjustments of the supply of a liquid or a liquid mixture to the Serve combustion chambers of the engine. In engines equipped with a device for injecting water into the Combustion chambers are provided, the method can also be used to control this water injection.

When controlling the combustion process in an internal combustion engine according to a method of the above Art, it must be ensured that the motor does not run in for any appreciable period of time enters an impermissible operating state and is therefore exposed to the risk of damage. Also is it is often desirable to exclude operating states of the engine that do not pose a risk of damage to the Motor, but undesirable for other reasons, for example with regard to environmental requirements are.

- ί-

In the prior art, the problem of excluding an undesirable operating state of the Engine is usually solved by choosing the setpoints of the variable quantity in a way that which offers a reasonable margin of safety. However, this known solution leads to a considerable one Reduction of the maximum power of the engine.

The invention is based on the object of providing an improved method of the type mentioned at the beginning create, by which the occurrence of an undesirable operating condition of the engine for any appreciable period of time is prevented without any unnecessary and excessive degradation in engine performance.

According to the invention, this object is achieved with a method of the type mentioned in that the setting of the size within each of at least some of the sub-areas of the engine's working range depending on at least one within of the relevant sub-area of the work area own limit value for the size is limited, whereby the Limit value is chosen such that a transition of the engine into an undesirable operating condition is excluded is.

The proposed limitation of the setting of the variable size can be a function of at least a predetermined fixed own limit value for each affected sub-area of the work area of the Engine. Alternatively or additionally, however, it can be changed depending on at least one variable own limit value can be executed for each such sub-area of the work area. By doing The last-mentioned case can be the method according to the invention preferably the method steps of detecting the

any occurrence of at least one selected type of undesirable engine operating condition as well as a use of the eventual detection of such an occurrence to establish a changeable one Have limit value for the relevant sub-area of the work area.

Examples of undesirable operating conditions, their recording and use to determine the "LQ Changing limits can be worthwhile, engine knocking, undesirable temperature conditions within of the engine and undesired conditions of the exhaust gases, for example with regard to their composition.

2g The invention also relates to an apparatus for controlling the combustion process in an internal combustion engine, which has an adjusting device to carry out successive settings at least one influencing the combustion process

OQ the variable size depending on the instantaneous values two different operating parameters of the motor under the guidance of individual setpoints of the Has size for a plurality of different sub-areas of the working range of the engine, which by predetermined Intervals of the values of the two operating parameters are specified. This is according to the invention Device characterized in that the setting of the size within the setting device each from at least some of the sub-areas

ο «the working range of the motor depending on at least one specific limit value for the size within the relevant sub-area of the work area can be limited, the limit value being selected in such a way that a transition of the engine into an undesired operating mode

GP condition is excluded.

Further features, details and advantages of the invention emerge from the following description and the drawing, all of which are not mentioned in the text with regard to an essential disclosure of the invention Details are expressly pointed out. Show here:

Fig. 1 is a block diagram of an exemplary first embodiment of the invention Device, and

2 is a block diagram of an exemplary

second embodiment of the device according to the invention.
15th

In the following description, the devices shown are first explained to the effect that they for controlling the combustion process in an internal combustion engine by executing successively Adjustments of the ignition timing are used during the operation of the engine. This is followed by another Brief description explaining how the devices shown can be carried out one after the other Fuel supply settings for one Motor can be used.

In Fig. 1, the reference numeral 10 denotes an internal combustion engine or an internal combustion engine, which can be formed, for example, by a four-cylinder four-stroke engine. The engine 10 is with a Intake pressure sensor 11, an engine speed sensor 12 and a camshaft position sensor 13 are provided. In Fig. 1 these sensors and the four spark plugs 14 of the engine are shown sjcihematically with: dashed lines. ''

The transmitters 11, 12 and 13 are connected to a signal conditioner

* ■ 3Λ25187

stage 15 connected, in which the output signals of these encoders of any type of shaping or conversion may be subjected to any further use of these signals required in view of the intended use is.

The spark plugs 14 are connected to a driver circuit 24 by means of conventional ignition cables, which gives the spark plugs the required high voltage pulses feeds.

Numeral 16 denotes an ignition timing adjusting circuit, which sequentially depends on the ignition point during the operation of the engine from the prevailing values of the intake pressure and the engine speed. The ignition timing circuit 16 has an address decoder 17 and a setpoint memory 18, a limit value memory 19, an adder 20, a correction value unit 21 for an adjustable correction value and a comparison and Selection unit 22.

For a variety of different sub-areas of the engine's working range, the different intervals the values of the intake pressure and the engine speed are individual nominal values for the ignition point permanently stored in binary form in the setpoint memory 18. In the same way are individual limit values for the ignition point for at least some of these sub-areas of the engine's operating range permanently stored in binary form in the limit value memory. The different sub-areas of the work area of the motor can be achieved through a matrix-like division of the entire work area into a large number are formed by separate matrix areas, each of which has a given value interval for the suction pressure

and represents a given value interval for the engine speed.

The address decoder 17 is from the signal shaping stage 15 with information about the current intake pressure and the current engine speed supplied. Based on this information, the address decoder determines within which sub-area of the working range, the motor works and addresses the two memories 18 and 19 as a function of this Ignition time limit value of the relevant sub-range of the working range, which is stored in the limit value memory 19 is then available at a first input of the comparison and selection unit 22 while the setpoint value of the ignition point stored in the setpoint memory 18 for this sub-range of the working range is fed to an input of the adder 20, which at the same time at its other input of the Correction value unit 21 receives a positive or negative adjustable correction value. The adder 20 generates a value representing the sum of the relevant setpoint and the correction value. This The sum value is available at the other input of the comparison and selection unit 22.

The purpose of the correction value unit 21 is to provide a quick and easy correction if necessary to enable all setpoint values stored in the memory 18, for example during the transition from one type of fuel to another fuel variety.

The comparison and selection unit 22 is used to compare the supplied corrected setpoint value the applied limit value and making a selection between these two values. If the correct

tr

The yawed setpoint deviates from the limit value in an impermissible manner, the limit value is selected. If but instead of this, the corrected setpoint value deviates from the limit value in a permissible manner, the setpoint value becomes chosen. If the two values are the same, there is no need to make a choice between them. Suitable circuitry provided in unit 22 will establish the selected value for the ignition timing Cached in this unit until ig as a result of a change in the suction pressure and / or the engine speed, which is a shift from a sub-range of the engine's operating range to a includes another part of the work area, a changed ignition timing is required.

The by means of the above setting circuit

determined and stored in the unit 22 value for the ignition timing is through the intermediary of a general with 23 designated synchronization circuit for controlling the generation of high voltage pulses used in the driver circuit 24. In the embodiment shown in FIG 23 three different units, namely a control unit 25, a down counter 26 and an arithmetic unit 27. The value selected by the unit 22 for the ignition timing by the the desired ignition point expressed approximately by a certain angular position of the camshaft of the motor corresponding angle can be determined, the arithmetic unit 27 is fed to the Difference between a constant higher angle value and that corresponding to the desired ignition point Angle value calculated. The difference value formed in this way in the unit 27 is used in a down counter 26 entered. The control unit 25 is loaded with synchronization pulses from the unit 15.

which are derived from the camshaft position sensor 13. As a result, every time the Camshaft an angular position corresponding to the constant higher angular value stored in the unit 27 reached, causes the control unit 25 to generate a sequence of pulses which one of the for each rotation of the camshaft through an angle of 1 ° at the prevailing engine speed Time have a corresponding time interval. These pulses are fed from the unit 25 to the down counter 26, which, when it has counted down to zero, applies a trigger pulse to the driver circuit 24. The driver circuit 24 then supplies a high-voltage ignition pulse for one of the spark plugs 14. 15th

In the device described above and shown in FIG. 1, the ignition timing becomes responsive controlled to constant setpoints and constant limit values, which are permanently stored in memories 18 resp. 19 are stored. In Fig. 2 is an alternative

Embodiment shown in which the ignition timing is controlled in response to variable limit values instead of constant limit values. Since most of the device shown in FIG. 2 corresponds to the device from FIG. 1, the following description of the device shown in FIG. 2 is limited only to explaining the differences between this device and the embodiment according to FIG.
30th

In addition to the various units of Fig. 1, the apparatus ι> shown in FIG. 2, further comprising a Grenzwerteinstelleinheit 28 and an additional encoder 29 on the motor 10. This transmitter 29 can consist, for example, of a knock transmitter, which has a possible occurrence of engine knocking

Output signal generated. The unit 28 is with the comparison and selection unit 22 connected to this unit information about the selected and to receive the value of the ignition point stored in it. Furthermore, the unit 28 is also connected to the unit 15, in order to send a control signal derived from the converter 29 in the event of engine knocking receive. If such a control signal is received by means of the unit 15, the unit 28 issues a new one Limit value in the area of the limit value memory 19 addressed by the decoder 17. This new limit can preferably consist of the sum of the value received by the unit 22 and a constant term, for example a binary "1". As a result, the limit value stored in the memory 19 becomes one after the other changed gradually until no knocking occurs in the engine 10 any more. Provided that those shown in FIGS. 1 and 2 are shown Devices for carrying out successive adjustments to the fuel supply for the Engine 10 are used instead of the ignition point, the reference numeral 14 represents in place of the four spark plugs four fuel injectors.

These fuel injectors 14 are controlled by driver circuit 24 which applies appropriate electrical drive pulses to them.

Then, reference numeral 16 denotes a fuel supply adjusting circuit which controls the fuel supply one after the other depending on the prevailing intake pressure and the prevailing engine speed adjusts.

The values stored in the memories 18 and 19 consist of setpoint values and limit values for the Fuel supply.

The value selected by the unit 22 can be used in

a moment desired to initiate fuel injection into a cylinder of the engine, expressed by an angle corresponding to a certain angular position of the camshaft. After a fuel injection has been initiated into the cylinder, this injection can be ended at a subsequent point in time corresponding to a constant angular position of the camshaft.
10

Alternatively, fuel injection can be used at a constant angular position of the camshaft, while they are instead under the action of the setting circuit 16 is terminated.

The additional transmitter 29 shown in FIG. 2 can, for example, also serve to prevent any occurrence display impermissible CO level in the exhaust gas. This allows the device to such Control of fuel injection can be used, that the exhaust gas is kept at an acceptable CO content.

The invention is not based on the embodiments described above and shown in the drawing limited. In particular, it should be noted that, if desired, the device without further can be modified so that there is an individual control for each cylinder of the engine supplies.

List of reference symbols

Method and device for controlling the combustion process in an internal combustion engine

10 internal combustion engine

11 suction pressure transducer

12 engine speed sensors

13 Camshaft position sender

14 Spark plug or fuel injector

15 signal conditioning stage

16 ignition timing adjustment circuit or fuel supply adjustment circuit

• ic 17 address decoder

18 setpoint memory

19 limit value memory

20 adders

21 Correction value unit

2Q 22 comparison and selection unit

23 Synchronization Circuit

24 driver circuit

25 control unit

26 down counter

27 arithmetic unit

28 Limit value setting unit

29 additional encoder

Claims (11)

Claims Method for controlling the combustion process in an internal combustion engine, in which according to-5 mutually occurring settings of at least one changing the combustion process influencing Size depending on the instantaneous values of two different operating parameters of the Motor under the guidance of individual setpoint values of the size for a plurality of different sub-areas of the working range of the engine are provided by predetermined intervals of the values of the two operating parameters are set, characterized in that the setting of the size within -15 half of each from at least some of the sub-areas of the engine's working range as a function of at least one specific limit value within the relevant sub-range of the working range for the size is limited, whereby the limit value of the- .. kind is chosen that a transition of the engine into a undesirable operating conditions are excluded. 2. The method according to claim 1, characterized in that that depending on the setting of the size of at least one predetermined fixed own limit value for each affected sub-area of the work area of the engine is running. 3. The method according to claim 1 or 2, characterized in 30 characterized in that the setting of the size depending on at least one changeable own Limit value is executed for each affected sub-area of the working range of the motor. 4. The method according to claim 3, characterized in that that any occurrence of at least one selected type of undesirable operating condition of the engine and any detection of such an occurrence to determine a variable Limit value is used for the affected sub-area of the work area. 5. The method according to claim 4, characterized in that that detects any occurrence of engine knock and any detection of such occurrence is used to determine a variable limit value. 6. The method according to claim 4 or 5, characterized in that any occurrence is undesirable Temperature conditions in the engine are sensed and the detection of any such occurrence for determination a variable limit value is used. 7. The method according to any one of claims 4 to 6, characterized in that it detects any occurrence of undesirable conditions in the exhaust gases of the engine and any detection of such an occurrence to determine a variable threshold is used. 8. Device for controlling the combustion process in an internal combustion engine, which has an Adjusting device for carrying out successive settings as a function of at least one variable that influences the combustion process of the instantaneous values of two different operating parameters of the engine under the guidance by individual setpoint values of the size for a plurality of different sub-areas of the working area of the ι Has motor, which is determined by predetermined intervals of the values of the two operating parameters are, characterized in that the setting of the size by the setting device (16) within each of at least some of the sub-areas of the engine's working range depending on of at least one specific limit value within the relevant sub-range of the working range can be limited for the size, the limit value being chosen such that a transition of the motor is excluded in an undesirable operating condition. 9. Apparatus according to claim 8, characterized in that the adjusting device (16) the setting of the size as a function of at least one predetermined fixed own limit value for each affected part of the working range of the motor can be limited. 10. Apparatus according to claim 8 or 9, characterized characterized in that the setting device (16) adjusts the size as a function of at least a changeable own limit value for each be-OK affected part of the working range of the engine can be limited. 11. The device according to claim 10, characterized in that a detection device (29) is provided ο «is through which a possible occurrence of at least one selected type of undesired operating condition of the engine is detectable and one of the detection means (29) actuatable device (28) for determining and storing variable own limit values oc for the size for different sub-areas of the working range of the engine.