DE3933654A1 - Automatically detecting number of working cylinders of motor vehicle - repeatedly checking ratio of engine to wheel speed against ignition rate to assumed number of cylinders - Google Patents

Abstract

A method of automatically detecting the number of cylinders of a vehicle engine involves measuring the vehicle speed and drive wheel revolution rate nR during a constant speed period and the number E of ignition or injection pulses per unit time for all cylinders. The ratio nM/nR is determined from 2E/(Z.nR), where nM is the engine speed and Z the assumed number of cylinders. This is compared with stored ratios and the process repeated with different values of Z until agreement is reached. USE/ADVANTAGE - Drive slip controllers for automatic engine type encoding for programming according to vehicle type after first journey.

Description

State of the art

For traction controllers with engine intervention used for vehicles with un different cylinder numbers different ECUs, each on one Number of cylinders are tailored. This requires many control unit variants. It It is also possible to code the control units for the respective engine type.

Advantages of the invention

The invention enables the automatic recognition of the number of cylinders, which then is stored in the ASR control unit and thereby the ASR control unit after a the first drive programmed to the type of vehicle in which it was installed.

It is now also possible in the context of the exchange, a control unit a vehicle to remove it and then repair it in any vehicle to install.

It is via sensors or signals from other systems in the ASR control unit the Engine speed, throttle position, and vehicle speed detected.  

At an operating point where the torque converter does not torque conversion performs, the ratio of engine speed to Antriebsachsendrehzahl calculated.

This operating point can be identified by different methods, z. B.

• 1. by evaluation of the characteristic field M _M = f (n _M ) with DK as a parameter. The intersection of the characteristic of a desired engine speed with the Ordi nate gives the desired operating point.
• 2. by checking whether the relation (n _M : n _Rad ) = [(n _M + Δn _M ): (n _wheel + Δn _wheel )] is satisfied in a time interval t 1 <t <t 2.
  Here, t₁ is the time within which mechanical compensation processes (Drehschwindungen the drive train) have subsided and t₂ the time in which the vehicle must drive at a constant speed.

About the relationship

can be determined in known possible transmission ratios, the number of cylinders become.

figure description

Annex of Fig. 1, an embodiment of the invention will be explained.

Here is a traction control system comprising transducers 1, 2 and 3 , which supply the speed of the driven wheels and at least one non-driven wheel corresponding signals to a control unit 4 . When spin tendency of the driven wheels controls this brake pressure control valves 5 and 6 for the brakes of the driven wheels and / or an actuator 7 z. B. for the throttle so that the tendency to spin eliminated or the spin is prevented ver.

A block 8 , via the terminal 9, a signal corresponding to the engine speed and line 10, a vehicle speed corresponding signal is supplied, now determined under certain circumstances, the number of cylinders of the ve hicle, in which the ASR is installed and stores the number of cylinders in the control unit from, so that this can take into account the number of cylinders in an engine intervention. In block 8 , the various possible Übersetzungsver ratios are stored in a table.

An example of the sequence of this recognition within the block 8 can be seen from the flowchart of FIG .

In the first program step, it is checked whether v _F is constant for a time t <t _min . The time t _min is to be chosen so that during this time a coupling process is closed.

In the second program step, the check is made whether the throttle angle for the selected speed has a value at which the engine neither a Drag or torque generated, d. H. the converter is inactive.

In the third program step is for a first assumed number of cylinders Z, z. B. Z = 4 the ratio between engine and wheel speed according to the relationship

calculated. Here, E is the number of injection pulses or firing pulses per Time unit.

In the 4th program _step , the calculated ratio i _{4Z is compared} with the actual translations stored in a _table . If the calculated translation is identical to a stored one, then a jump is made to program step 6 for storing the number of cylinders with which the translation was calculated.

If the computed translation is not identical to a stored one, the program continues with program step 5.

In the 5th program step, the next number of cylinders z. B. Z = Z + 1 = 5 selected and jumped back to the program point 3, where again the translation for the new Number of cylinders is calculated and in program step 4 again a plausibility examination.

In the 6th program step, the last number of cylinders, where an agreement mood between calculated and a stored gear ratio he has saved.

Now follows a numerical example for a specific vehicle. This one has the following translations

Translation gear Total ratio (stored) with final drive i _a = 2.93 2.48 7,266 1.48 4,336 1.00 2,930 0.73 2,139

The overall translations are stored in a memory. Now the speed 60 km / h and the second gear is assumed; the vehicle have 6 cylinders.

The number E of injection pulses at 60 km / h and 2nd gear are calculated to:

can be calculated from the vehicle speed v _F and the tire circumference = U _R = 2 m.

It follows:

You get used

This results in the engine speed to:

The program now runs as follows:

First program step

It is checked continuously whether the vehicle speed for a before certain time is constant.

This condition should be fulfilled at 60 = km / h, after which the above calculations be performed.

2. Program step

For 60 km / h, a DK angle of less than x degrees is considered an indication that the converter is inactive.

3. Program step

For the first assumed number of cylinders Z = 4 and the measured number of injection pulses calculates the gear ratio.

4. Program step

Since the calculated gear ratio with no stored translation 7,3 / 4,3 / 2,9 / 2,1 is identical, the next number of cylinders is selected by continues with program step 5.

5. program step

Z = Z + 1 = 4 + 1 = 5

3. Program step 2. Run

For Z = 5 results

4. Program step 2. Run

Since the calculated gear ratio with no stored translation is identical, the next number of cylinders is selected by using program step 5 is continued.

5. program step

Z = Z + 1 = 5 + 1 = 6  

3. Program step 2. Run

For Z = 6 results

4. Program step 3. Pass

Since the calculated gear ratio with the stored translation of 2. Ganges is identical, the program step 6 is continued.

6. Program step

The number of cylinders 6, at which there is a match between the calculated and a stored translation has been accepted.

Claims (4)

1. A method for automatically detecting the number of cylinders of a motor vehicle engine, characterized

• a) that in a period of constant vehicle speed these and the associated drive wheel speed n _{R are} determined,
• b) that the number E of firing or injection pulses per unit of time is determined for all cylinders together,
• c) that according to the relationship where Z is an assumed number of cylinders, a translation is determined, (n _M = engine speed)
• d) that this is compared with the known and stored translations, and
• e) that in case of inequality of the compared values with a new assumed number of cylinders, the steps c) and d) are repeated or
• f) that in case of equality of the compared values, the assumed number of cylinders is stored as existing number of cylinders.

2. The method according to claim 1, characterized in that the detection only is triggered when there is no torque conversion between the engine output and the wheel follows. 3. The method according to claim 2, characterized in that this state with the aid of the characteristic field engine torque M _M = f (n _M ) with the position of the throttle flap DK is determined as a parameter. 4. The method according to claim 2, characterized in that this condition by checking if the condition is satisfied during a period of time is determined.