JPH0797951A - How to change the idling speed supplementarily afterwards - Google Patents

Abstract

PURPOSE: To posteriorly and supplementarily increase the initially set idling rotating speed by a simple method by calculating an additional air quantity according to the difference between the actual rotating speed of an engine and the target rotating speed and the minimum rotating speed. CONSTITUTION: In the step S1, according to the engine rotating speed N and the throttle valve opening, the basic air value BLW is read out. In the step S2, according to a coolant temperature TKW or the like, an additional air value ZTLW is read out. In the step S3, according to the sum of the basic air value and the load air value, the temperature correction and the load corrected air value TLW are calculated. In the step S4, according to the coolant temperature, the idling target rotating speed NSOLL is calculated. In the step S5, the idling target rotating speed is subtracted from the minimum rotating speed NMIN to calculate the rotating speed difference NDIFF. In the step S6, according to the rotating speed difference, an additional air quantity ALW is calculated. In the step S7, the additional air value is added to the air value to calculate the final air value GLW.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control unit having an idling adjustment unit in which combustion air supplied to an engine is combined with an air preliminary control function of a type controlled by an adjustment element. Regarding post-complementary changes.

[0002]

2. Description of the Related Art In modern engine control systems, idling speed is controlled during idling.
This is usually done via a continuously operating regulating element, which regulates the amount of combustion air supplied to the engine during and near idling (idling air regulating element). The control of the intake air flow is, for example, German Patent Application No. 3019
As described in No. 608, this is done with feedback depending on engine operating conditions or with an open loop control circuit. For the purpose of reducing control,
Even in the region of the idling adjustment unit, the required intake air amount depending on the engine operating condition is set and adjusted by the preliminary control to an air value which almost corresponds to the actually required value. Fine adjustment is then carried out by means of a speed control, which controls the idling air adjusting element accordingly depending on the difference between the actual speed and the target speed.

At this time, for example, because of a manufacturing tolerance, a resonance phenomenon, or because of riding comfort, the engine speed is set to an excessively low value by an engine control unit in an actually operating vehicle. It may be necessary to supplementarily increase the set idling speed. In addition, the engine control unit itself may require an increase in idling speed, for example, when a large number of current loads are turned on and connected during idling, which significantly reduces the voltage of the vehicle power supply. is there.

In this case, the air preliminary control value for the idling air amount must be adjusted for each newly set and adjusted rotational speed.

[0005]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a simple and memory-saving method by which the initially set idling speed can be increased subsequently. It is in.

[0006]

SUMMARY OF THE INVENTION According to the invention, the task is to set the minimum number of revolutions in a complementary manner, depending on the actual number of revolutions and the difference between the target number of revolutions and the minimum number of revolutions. This is solved by calculating the added air amount and controlling the idling air adjustment element depending on the sum of the air amount required to reach the target rotation speed and the added air amount.

That is, the above-mentioned problems are solved by setting the smallest effective adling rotational speed, so-called "minimum rotational speed", for all engine operating parameters. This minimum rotation speed is stored in a non-volatile memory (for example, so-called EEPROM) that can be changed from the outside. If engine operating parameters occur such that the target speed is higher than this minimum speed, the idling speed is adjusted to this higher value. In other cases, the idling speed is set to the above minimum speed value.

[0008]

SUMMARY OF THE INVENTION It is insignificant to generate the additional required air quantity, which may be required by the introduction of a minimum speed, by the addition of a fixed quantity, i.e. the air reserve control characteristic. It is meaningless to simply move the curved region in parallel. Since the air pre-control value is dependent on the cooling medium temperature, the corrected air pre-control value thus obtained is only correct for the cooling medium temperature. On the other hand, it is not desirable to store one unique characteristic curve that depends on the cooling medium temperature for each possible minimum number of revolutions, due to storage location problems.

Another problem arises because the idling air adjusting element is controlled in a region other than the idling region for the purpose of controlling the rotational speed when the load changes and during the switching process, for example. Therefore, in addition to the first air pre-control value, which depends on the cooling medium temperature,
Still another air preliminary control value that depends on the engine speed and the throttle valve opening is determined. These preliminary control values are used for the above processes (load change, switching process, etc.).
That is, it is adjusted to the idling target rotational speed that is originally stored without considering the minimum rotational speed.

In this case, the additional air precontrol based on a given minimum speed must not have the same effect in all speed ranges. As a result, for example, in the central or upper rotational speed range, the rotational speed characteristic at the time of switching is disadvantageously extended. That is, the increase of the air preliminary control value due to the setting of the minimum rotation speed should be performed only in the rotation speed range near the minimum rotation speed.

This problem is solved by the method according to the invention as follows. That is, a further air value depending on the following two parameters is added to the air preliminary control value calculated from the operating parameter, that is, the rotation speed, the throttle valve opening, and the cooling medium temperature. That is, A. Difference between minimum speed and target idling speed stored in memory B. The engine speed parameter A determines the additional air value that depends on the difference between the minimum speed and the idling target speed stored in the memory.

The parameter B reduces the added air value at relatively high engine speeds.

The combination of both parameters is performed in the two-dimensional characteristic curve area.

Next, the present invention will be described in more detail with reference to the drawings.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the case of FIG. 1, the idling target speed NSOLL is shown by a solid line depending on the cooling medium temperature TKW. In this case, it can be seen that the target rotational speed NSOLL decreases from a presettable initial value to a presettable final value as the cooling medium temperature TKW rises. When the minimum rotation speed NMIN as indicated by the broken line in the horizontal direction is set from the outside or by the engine control unit itself, the target rotation speed is reduced to this minimum rotation speed even if the cooling medium temperature rises. Not (dashed line).

FIG. 2 shows, in the same format as that described above, the time-dependent characteristic of the air amount LW required to reach the target rotational speed NSOLL, depending on the cooling medium temperature TKW (solid line). Since the target rotation speed NSOLL decreases as the cooling medium temperature TKW increases, the required air amount LW also decreases accordingly. However, when the minimum speed is introduced, the air quantity decreases only to the minimum air quantity LWMIN, which is necessary for it to maintain the minimum speed (dashed line) (dashed line).

FIG. 3 shows an example of the characteristic curve of the additional air value ALW depending on the engine speed N and the difference between the minimum speed NMIN and the target speed NSOLL. The target speed NSOLL is here the rotation that occurs when the idling air-conditioning element is controlled with the amount of air determined from the characteristic curve region, depending on the cooling medium temperature and possibly the additional engine load. Let it be a number.

What can be seen here is that the minimum speed NMIN
The additional air amount ALW increases as the difference between the target rotational speed NSOLL and the target rotational speed NSOLL increases, and the minimum rotational speed can be maintained even if the difference between these rotational speeds increases. On the other hand, the added air amount ALW decreases as the engine speed N increases. The reason is that the increase in the air amount is desired only in the region near the idling.

Further in FIG. 4, a flow chart of the method according to the invention is illustrated. In starting this method step (A), in method step S1, the basic air value BLW is read from the characteristic curve region depending on the actual engine speed N of the internal combustion engine and the actual throttle valve opening α.

In method step S2, the additional air value ZTLW is obtained from another characteristic curve region. This value is
It depends on the cooling medium temperature TKW and possibly on the additional load that is actually switched on and off, for example in a heating and cooling system.

In method step S3, the basic air value B
A temperature-corrected and load-corrected air value TLW is formed from the sum of LW and the additional air value ZTLW.

In the method step S4, the idling target speed NSOLL is determined as a function of the cooling medium temperature TKW and the additional load actually connected.

Next, in method step S5, the idling target rotational speed NSOLL obtained as described above is subtracted from the externally set minimum rotational speed NMIN to form a rotational speed difference NDIFF.

Further, in method step S6, the added air value ALW is read from the characteristic curve area portion depending on the magnitude of the rotational speed difference NDIFF and the actual rotational speed. If the minimum engine speed NMIN is less than or equal to the target engine speed NSOLL, this added air value ALW is equal to zero.

In method step S7, this added air value is added to the air value TLW previously calculated, so that the final air value GLW is obtained.

Then, in method step S8, the idling air conditioning element is controlled in accordance with the calculated final air value GLW.

[0027]

According to the present invention, there is provided a simple and memory-saving method in which the initially set idling speed can be complementarily changed afterwards.

[Brief description of drawings]

FIG. 1 is a characteristic diagram of a target idling engine speed that depends on a cooling medium temperature.

FIG. 2 is a diagram showing a required air amount depending on a cooling medium temperature.

FIG. 3 is a diagram showing an actual example of a transition characteristic of an added air value.

FIG. 4 is a flow chart of a method according to the present invention.

[Explanation of symbols]

 NSOLL Target idling speed NMIN Minimum speed TKW Cooling medium temperature LW Final air value LWMIN Minimum air amount ALW Additional air value NDIFF NSOLL speed difference N Engine speed

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02D 45/00 376 B

Claims (8)

[Claims] 1. An engine control section having an idling adjustment section in which combustion air supplied to an engine is controlled by an adjustment element and combined with an air pre-control function, to change the idling speed supplementarily afterwards. In the method, the minimum rotation speed (NMIN) is supplementarily set afterwards, and the added air amount depends on the actual rotation speed and the difference (NDIF) between the target rotation speed (NSOLL) and the minimum rotation speed (NMIN). (ALW) is calculated, and the idling air adjustment element is controlled depending on the sum of the air amount required to reach the target rotation speed (NSOLL) and the added air amount (ALW). , A method to change the idling speed supplementarily afterwards. 2. When the target speed (NSOLL) is greater than or equal to the minimum speed (NMIN),
The method of claim 1, wherein the additive air volume (ALW) is zero. 3. The method according to claim 1, wherein the minimum speed (NMIN) is externally set. 4. The method according to claim 1, wherein the minimum speed (NMIN) is stored in a non-volatile memory. 5. The method according to claim 1, wherein the minimum engine speed (NMIN) can also be set by the engine controller itself. 6. The method according to claim 1, wherein the highest rotational speed of the plurality of simultaneously set minimum rotational speeds is used. 7. The method according to claim 1, wherein the operating quantity on which the idling speed depends is the cooling medium temperature (TKW) and the additional load actually connected. 8. The method of claim 7, wherein the additional load comprises an air conditioner, an automatic transmission, or a combination of both.