JP2003120366A - Torque control method for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved method for torque control on an internal combustion engine. SOLUTION: The method measures the viscosity of a lubricant used to lubricate an internal combustion engine, detects an adjustment level necessary to reach target torque according to a basic value of a stored characteristic map, corrects the adjustment level necessary to reach the target torque according to the measured viscosity of the lubricant used to lubricate the internal combustion engine, and controls an adjusting element of the internal combustion engine with the corrected adjustment level.

Description

Detailed Description of the Invention

[0001]

The invention relates to a method for controlling the torque of an internal combustion engine according to the preamble of the independent claims,
And a control device for controlling a fuel injection device of an internal combustion engine, and a computer program for implementing the method.

[0002]

2. Description of the Related Art The control of today's internal combustion engines is mainly carried out by electronic control units. The control device controls various adjusting elements depending on various operating parameters and load demands or target torques. In this case, for example, the temperature of the lubricant (lubricating oil) used to lubricate the internal combustion engine,
The rotational speed of the internal combustion engine and the temperature or humidity of the surrounding air are constantly detected.

The adjusting elements of an internal combustion engine operating on the Otto principle are, for example, throttle valves, injection valves, ignition devices and the like. In order to be able to properly take into account the complex relationship between the operating parameters of the internal combustion engine and the adjustment amount of the adjusting element for controlling the internal combustion engine, usually a plurality of characteristic maps are filed in the control device. There is. These characteristic maps are based on measured values which are measured according to the type of internal combustion engine.

A target torque is usually set as a guide amount for controlling the internal combustion engine.

[0005]

The object of the present invention is to provide an improved method for controlling the torque of an internal combustion engine.

[0006]

According to the present invention, the above-mentioned problems can be solved by the following method. That is, the viscosity of the lubricant used to lubricate the internal combustion engine is measured, and the adjustment amount required to reach the target torque is detected based on the basic value of the stored characteristic map of the internal combustion engine, The amount of adjustment required to reach the target torque is corrected based on the measured viscosity of the lubricant used to lubricate the internal combustion engine and the adjusting elements of the internal combustion engine are controlled by the corrected amount of adjustment It is solved by the method of doing.

[0007]

In the method according to the invention, the basic value of the adjustment quantity stored in the characteristic map is corrected by taking into account the measured viscosity of the lubricant of the internal combustion engine. Thereby, the internal combustion engine controlled by the method of the invention produces the desired target torque with higher accuracy. This provides advantages in all vehicle functions and assemblies in which the target torque is used as the guide quantity. Examples of such functions and assemblies are anti-slip control, vehicle electronic stability control and automatic transmission control.

The cost of implementing the method of the present invention is
It only takes to measure the viscosity of the lubricant and to take the measured viscosity into account accordingly. Thereby, the method of the invention can be used very inexpensively.

In a variant of the invention, the adjustment quantity required to reach the target torque is detected taking into account the drag torque of the internal combustion engine, and when the drag torque is detected, the measured viscosity is Is configured to be considered. This drag torque is a torque that must be generated in order to drive the structure of the internal combustion engine at a predetermined rotation speed and a predetermined temperature. This drag torque is a parameter for the internal friction of the internal combustion engine. In many engine controls, the drag torque is further added to the target torque to calculate the required internal torque of the internal combustion engine.
The amount of fuel to be injected depends on this internal torque of the internal combustion engine and is calculated in consideration of other operating parameters.

Furthermore, the advantages of the method according to the invention are further enhanced if the basic value of the adjustment variable read from the characteristic map is adapted during starting or during operation of the internal combustion engine. As a result, variations in mass production of the internal combustion engine, as well as changes during operation of the internal combustion engine, are taken into account in the control method of the internal combustion engine according to the invention. This ensures that the quality of the internal combustion engine control remains substantially constant over the life of the internal combustion engine.

In a further refinement of the invention, at least one further operating parameter of the internal combustion engine is detected and the measured viscosity and said at least one further operating parameter are compared with a set reference value, The one or more adjustment amounts are corrected and / or the output signal is formed. by this,
For example, an undesired operating state of the internal combustion engine can be identified and appropriate adjusting means can be provided to eliminate it.

The identification of such operating conditions by comparing the lubricating oil viscosity and a number of further operating parameters with the values under normal operating conditions of the internal combustion engine is intended to identify such operating conditions, for example during a cold start. This is the case when the λ value is decreased and when the viscosity of the lubricant of the internal combustion engine is decreased. This situation occurs, for example, when the engine is cold and fuel is deposited on the inner wall of the cylinder and washed by the lubricating film. If cold start is repeated many times, the fuel flows into the engine oil, which causes the viscosity of the engine oil to decrease. At temperatures above 40 ° C., fuel evaporates from the engine oil and reaches the combustion chamber again via crankcase ventilation. As a result, the λ value becomes smaller than 1, that is, the mixture becomes “too rich”. This is corrected by reducing the injection quantity via the λ control. This means that the injection quantity increases during cold start and decreases during hot operation.

Similarly, due to the reduced viscosity of the lubricant, defects in the sealing of the cylinder head of the internal combustion engine can also be identified. This is because the cooling water flowing into the lubricant deteriorates the viscosity of the lubricant.

It is also detected that excess lubricant may be present in the internal combustion engine, for example by a decrease in viscosity of the lubricant at a given temperature and a simultaneous misfire. If excess lubricant is present in the internal combustion engine,
The crankshaft spins idle in the lubricant and the lubricant foams. As a result, the viscosity of the lubricant is reduced and at the same time a large amount of lubricant reaches the internal combustion engine during the intake stroke via the crankcase ventilation. Lubricant does not ignite as easily as fuel, resulting in misfire. Therefore, from the measured viscosity and the occurrence of misfire, it can be inferred that excess lubricant is present in the internal combustion engine.

The predictive power of this detection method is further improved if the λ value of the exhaust gas of the internal combustion engine is additionally used to detect the presence of excess lubricant in the internal combustion engine.

Of course, the present invention is not limited to such a combination of operating parameters and measured lubricant viscosity. Other combinations can also be used to detect said operating conditions and generate corresponding output signals or to eliminate said operating conditions by using one or more adjusting elements. .

[0017]

Other advantages and advantageous embodiments of the invention are:
It is set forth in the following figures and description and in the claims.

The only figure shows, in the form of a block circuit diagram, by way of example, how the measured lubricating oil viscosity η _{o el} is taken into account when detecting the drag torque M _schlepp .

Usually, the drag torque M
_{The schlepp} is _{detected depending} on the target torque M _soll and the rotational speed of the internal combustion engine not shown here. Detection drag torque which depends on the target torque M _{so ll} and rotational speed is performed by the first characteristic map 1. The output amount of the characteristic map 1 is M in this figure.
_Shown as _{schlepp, Gru ndwert} . Of course, drag torque M _{schlepp, Gr
Other} parameters may also be considered when detecting _undwerts . These parameters are indicated by arrows P ₁ , P ₂ , P ₃ in the figure.

The drag torque is the target torque M of the internal combustion engine.
The method according to the invention also measures the viscosity η _oel of the lubricant of the internal combustion engine (not shown), since it is not only dependent on the _soll and the rotational speed. Via characteristic curve 3 or a second characteristic map not shown here,
A correction value is detected, and this correction value is added to the output values M _{schlepp, Grundwert} of the characteristic map 1.
The result of this addition is the corrected drag torque M
It is _schlepp , and the influence of the viscosity of the lubricating oil is sufficiently accurately considered in this drag torque. This corrected drag torque M _{sc hlepp} can be further processed in the engine control, not shown here, which is located in the higher order. For example, if the required fuel injection amount should be detected depending on the target torque M _soll set by the driver, the corrected drag torque M
Knowledge of _schlepp is required. Of course, the corrected drag torque M _schlepp can advantageously be used for other functions of vehicle control or engine control, for example for anti-slip control, electronic stability programs, etc.

[Brief description of drawings]

FIG. 1 is a block circuit diagram for detecting a drag torque in consideration of a lubricating oil viscosity.

[Explanation of symbols]

1 1st characteristic map 3 Characteristic curve M _soll target torque η _oel Lubricating oil viscosity M _schlepp Drag torque M _{schlepp, Grundwert} characteristic map 1
Output amount P ₁ , P ₂ , P ₃ other operating parameters

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI Theme Coat (reference) F02D 45/00 376 F02D 45/00 376A (72) Inventor Klaus Reith-Muller Federal Republic of Germany Bad Rappenau Heinheimer Strasse 47 F term (reference) 3G084 BA02 BA13 BA31 DA12 DA26 DA28 EA08 FA20 FA24 FA29 FA32 FA33 3G301 HA01 JA23 JB10 LB01 MA11 NB18 PA17Z PC09Z PD02Z PE00Z PE01Z PE06Z PE08Z

Claims (10)

[Claims] 1. A method for controlling the torque of an internal combustion engine, wherein the viscosity of the lubricant used to lubricate the internal combustion engine (η
_ol ) is measured, and the adjustment amount required to reach the target torque (M _soll ) is detected based on the basic value (M _{schlepp, Grundwert} ) of the stored characteristic map (1) of the internal combustion engine. The amount of adjustment required to reach the torque (M _soll ) is corrected on the basis of the measured viscosity (η _ole ) of the lubricant used to lubricate the internal combustion engine, the corrected amount of internal combustion A method characterized by controlling a regulating element of an engine. 2. The amount of adjustment required to reach the target torque (M _soll ) is detected in consideration of the drag torque (M _schlepp ) of the internal combustion engine, and the drag torque (M _schlepp ) is detected. In case, consider the measured viscosity (η _{o el} ),
The method of claim 1. 3. The method according to claim 1, wherein the basic value of the adjustment amount read from the characteristic map is adapted at the time of starting or during operation of the internal combustion engine. 4. At least one further operating parameter of the internal combustion engine is detected, the measured viscosity (η _ol ) and the at least one further operating parameter (P ₁ , P ₂ ,
By comparing the P ₃₎ with a predetermined reference value, one or more corrected adjustment amount, and / or to form an output signal, any one process of claim 1 to 3. 5. The mass (m _E ) of the fuel to be injected when the λ value of the exhaust gas of the internal combustion engine and the viscosity (η _oel ) of the lubricant of the internal combustion engine are reduced with respect to the normal state at a predetermined temperature. The method of claim 4, wherein 6. When the viscosity (η _oel ) of the lubricant of the internal combustion engine is decreased with respect to the normal state at a predetermined temperature and, at the same time, a misfire occurs, an excessive amount of the lubricant is present in the internal combustion engine. 6. The method according to claim 4 or 5, which outputs a signal instructing. 7. The method according to claim 6, wherein the lambda value of the exhaust gas of the internal combustion engine is additionally used to detect the presence of excess lubricant in the internal combustion engine. 8. A control device for a fuel injection system of an internal combustion engine, characterized in that it is suitable for carrying out the method according to any one of claims 1 to 7. 9. Computer program, characterized in that it is suitable for carrying out the method according to any one of claims 1 to 7. 10. The computer program according to claim 9, wherein the computer program is stored in a storage medium, in particular a CD-ROM.