JP5426068B2 - Method for operating internal combustion engine and internal combustion engine - Google Patents

Description

  The invention relates to a method for operating an internal combustion engine according to the preamble of claim 1. The invention also relates to an internal combustion engine according to the preamble of claim 11.

  A known common rail internal combustion engine actually includes at least one fuel injector for each cylinder, and each fuel injector has an injection nozzle and a solenoid valve. The solenoid valve is closed in an unpowered or no-current state, and no fuel is sent to the corresponding cylinder of the internal combustion engine via the injection nozzle. On the other hand, when the solenoid valve is supplied with power, the solenoid valve opens and fuel injection into the corresponding cylinder starts. The opening time of the solenoid valve determines the fuel injection amount into the cylinder of the internal combustion engine together with the fuel pressure of the internal combustion engine. In the case of a common rail internal combustion engine, the fuel pressure is the same for all cylinders and hence for all fuel injectors. is there. That is, in the case of a common rail internal combustion engine, fuel pressure is generated by a pump and supplied to each fuel injector through a common pressure distributor (rail). In order to actually operate an internal combustion engine, it is known to obtain the same open time for all solenoid valves of the internal combustion engine, and hence all the fuel injectors, in relation to the fuel pressure and the injection amount and the characteristics of the fuel injector of the internal combustion engine. It is. At that time, the opening time for each cylinder of the fuel injector, and hence the solenoid valve, is obtained from the same fuel injector opening time for all the cylinders based on the individual correction characteristic diagrams for each cylinder of the internal combustion engine. For this reason, it is possible to individually match the fuel injection amount to each cylinder of the internal combustion engine and to guarantee the desired load distribution over a plurality of cylinders of the internal combustion engine.

  In practice, the individual correction characteristic diagrams for each cylinder are typically constant, i.e. always the same, over the entire operating period of the internal combustion engine. However, since the characteristics of the cylinder change over the operation period of the internal combustion engine due to, for example, different wear, there is a disadvantage that a deviation occurs in a desired load distribution over a plurality of cylinders of the internal combustion engine when the same cylinder-specific correction characteristic diagram is always used. There is.

  Starting from this point, the object of the present invention is to provide a new method of operating an internal combustion engine and a corresponding internal combustion engine.

  This problem is solved by the operation method of the internal combustion engine according to claim 1. In the present invention, the correction characteristic diagram for each cylinder is automatically adapted based on the exhaust gas temperature measured for each cylinder during operation of the internal combustion engine.

  The present invention proposes to automatically adapt the correction characteristic diagram for each cylinder based on the exhaust gas temperature measured for each cylinder during operation of the internal combustion engine. As a result, a self-learning or adaptive correction characteristic diagram is generated for each cylinder of the internal combustion engine, and a desired load distribution can be maintained in each cylinder of the internal combustion engine over the entire operation period of the internal combustion engine. The correction characteristic diagram of the cylinder is adapted to the actual state of the cylinder, and the adaptation is performed automatically or spontaneously based on the exhaust gas temperature measured in the cylinder. For this reason, the operation of the internal combustion engine can be remarkably improved.

  In an advantageous embodiment of the present invention, when the internal combustion engine is in a steady operation state, the exhaust gas temperature of each cylinder is measured, and an average temperature value is obtained from the exhaust gas temperature of each cylinder, and measured for each cylinder. Calculate the temperature difference for each cylinder between the exhaust gas temperature for each cylinder and the temperature average value, and find the correction value for the open time of each fuel injector for each cylinder according to the temperature difference for each cylinder. Based on the value, the corresponding correction value characteristic diagram for each cylinder is automatically adapted.

  An internal combustion engine according to the invention is defined in claim 11.

  Advantageous embodiments of the invention emerge from the dependent claims and the following description. Next, examples of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these.

  Hereinafter, the present invention will be described in detail with reference to FIG. FIG. 1 is a block diagram or signal flow diagram of a method for operating a multi-cylinder internal combustion engine according to the present invention. The internal combustion engine is preferably a common rail diesel engine. The method according to the invention is divided in principle into three main steps 10, 11, 12 which will be described in detail below. The main steps 10 and 11 are conventionally known operation procedures of the internal combustion engine, and the main step 12 includes details of the operation method of the internal combustion engine according to the present invention.

  In step 13 of the main step 10 of the method according to the invention, the fuel injection quantity for each operating cycle is queried, and in step 14 the fuel pressure of the internal combustion engine is queried. The operating parameters of the internal combustion engine inquired in steps 13 and 14, that is, the fuel injection amount and the fuel pressure for each operating cycle are the same for all the cylinders, and are supplied as input amounts to the characteristic diagram 15 of the fuel injector of the internal combustion engine. . FIG. 15 of the fuel injector gives the open time of the fuel injector of the internal combustion engine in step 16 based on the fuel injection quantity and fuel pressure for each operating cycle which is the same for all cylinders. This open time is the same for all cylinders, and thus for all fuel injectors or for the solenoid valve of each fuel injector.

Further, in steps 13 and 14 of the main step 11 of the method according to the present invention, the fuel injection amount for each operating cycle and the fuel pressure of the internal combustion engine are respectively inquired, and the inquired operating parameters of the internal combustion engine are the same for all cylinders. And supplied to the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder. Here, N corresponds to the number of cylinders of the internal combustion engine, and hence the number of correction characteristic diagrams of each cylinder. The correction characteristic diagrams 17 _{1 to} 17 _{N for} each cylinder are based on the same operating parameters for all cylinders inquired in steps 13 and 14, and in step 18, the fuel injectors of the corresponding cylinders or the opening of each fuel injector are Gives the correction value for each cylinder with respect to time. In all fuel injectors prepared in step 16 of main step 10, the correction values for each cylinder with respect to the open times of the corresponding fuel injectors prepared in step 18 are added to the same open time, and thus in step 19, all fuel injectors are added. For each cylinder. Accordingly, as a result of step 19, an open time for each cylinder is provided to each fuel injector or solenoid valve of each cylinder, thus determining the fuel injection time for each cylinder individually, and a plurality of cylinders of the internal combustion engine. A predetermined load distribution is set.

It should be noted that, in general, the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder with respect to a certain number of characteristic operating points indicate the recording or correction value for each cylinder with respect to the open time of each fuel injector of the corresponding cylinder. Have. The characteristic operating point is defined by a predetermined fuel injection amount and fuel pressure for each operation cycle. When an operation parameter not drawn by a characteristic operation point in the correction characteristic diagram is inquired in steps 13 and 14, interpolation or extrapolation is performed on the characteristic operation point drawn in the correction characteristic diagram with respect to the operation parameter. I do.

  That is, in order to obtain the opening time of each cylinder with respect to the fuel injector of the cylinder, as described above, the main step 10 is based on the fuel injection amount for each operating cycle, the fuel pressure, and the characteristic diagram of the fuel injector of the internal combustion engine. Find the same open time for all fuel injectors. This open time is calculated in the main step 11 using the correction value for each cylinder determined based on the fuel injection amount for each operation cycle, the fuel pressure, and the correction characteristic diagram for each cylinder.

The present invention automatically adapts the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder based on the exhaust gas temperature measured in each cylinder during the operation of the internal combustion engine in the main step 12 of the operation method of the internal combustion engine. Propose that. This results in an adaptive or self-learning cylinder-specific correction characteristic diagram 17 _{1 to} 17 _N which ensures the maintenance of the desired distribution of operation across the cylinders of the internal combustion engine during the entire operation of the internal combustion engine. To do.

  In step 20 of the main step 12, it is checked whether the internal combustion engine is in a steady operation state. Therefore, in step 21, the operation parameters important for fuel injection of the internal combustion engine are inquired. The operating parameters important for fuel injection of the internal combustion engine are at least one of the fuel injection amount, the fuel pressure, and the rotational speed of the internal combustion engine, particularly for each operation cycle. In step 20, it is checked whether the operating parameters important for fuel injection are substantially constant over a predetermined time or within a predetermined limit value. When this is true, it is determined that the internal combustion engine is in a steady operation state, and the routine proceeds to step 22 of the main step 12.

  The characteristic quantity of the internal combustion engine inquired or detected in steps 23 and 24 is supplied to step 22 as an input quantity. That is, in step 23, the exhaust gas temperatures of all cylinders of the internal combustion engine are obtained, and the corresponding exhaust gas temperatures of the respective cylinders are supplied to step 22 as input amounts. In step 24, the temperature average value is obtained from the exhaust gas temperature for every cylinder measured in step 23. This average value is supplied as an input amount to step 22 in the same manner as the exhaust gas temperature for each cylinder. In step 22, the temperature difference for each cylinder between the exhaust gas temperature for each cylinder inquired in step 23 and the temperature average value calculated in step 24 is detected.

  From this temperature deviation calculated for each cylinder, a correction value for the corresponding open time of the fuel injector is obtained for each cylinder of the internal combustion engine in step 25 of the main step 12, and for this purpose, for each cylinder The temperature deviation is calculated with the proportionality queried in step 26. This proportionality is preferably the same for all cylinders, but may be different for each cylinder. The correction value for each cylinder determined in step 25 for the corresponding open time of the fuel injector is determined in particular by the fuel injection amount and / or the fuel pressure for each operating cycle, and the corresponding steady operation confirmed in steps 20 and 21. Valid for points.

The correction value for each cylinder obtained in step 25 for the corresponding open time of the fuel injector is preferably related to the correction value average value for each cylinder in step 27, and the correction for each cylinder calculated in this step 25. The average value is provided or queried at step 28 of the main step 12. Accordingly, in step 27, a correction value deviation for each cylinder between the correction value for each cylinder of the open time for the fuel injector calculated in step 25 and the correction value average value for each cylinder prepared in step 28 is detected. In relation to the correction value deviation for each cylinder, the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder are automatically adapted.

Based on the correction value deviation for each cylinder from the correction value average value prepared in Step 27 and the operating point of the internal combustion engine determined in Steps 20 and 21, in order to adapt the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder, Perform reverse interpolation or reverse extrapolation. Thus, the recording of the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder is automatically adapted. That is, as described above, the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder with respect to a certain characteristic operating point defined by the predetermined fuel pressure and the predetermined fuel injection amount for each operation cycle, the corresponding fuel injectors of the cylinders The information used as a correction value for each cylinder with respect to the open time is recorded. However, the correction value or correction value deviation for each cylinder obtained in the main step 12 is usually obtained for operating points not drawn in the correction characteristic diagrams 17 _{1 to} 17 _N. In the case of reverse interpolation or reverse extrapolation, in the main step 12, the correction characteristic for each cylinder or the correction value deviation is recorded for the characteristic operation point in the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder adjacent to the operation point for which the correction value or correction value deviation is obtained. Or adjust the correction value.

When performing reverse interpolation or extrapolation, the recorded or corrected value of the characteristic operating point that is located near the operating point of the main step 12 is more strongly matched than the recorded or corrected value of the characteristic operating point that is located further away. Change it. This reverse interpolation or reverse extrapolation is executed in step 29 of the main step 12. Thus, finally, the recorded or corrected values in the correction characteristic diagrams 17 _{1 to} 17 _N are automatically adapted. It should be noted that at the time of reverse interpolation or extrapolation, step 29 uses the filtered values of operating parameters, that is, the fuel injection amount and fuel pressure for each operating cycle. For this purpose, an average value of the operating parameters is obtained over the time zone considered in step 21 where the operating parameters are substantially constant or located within a predetermined limit value.

In step 30 of the main step 12 of the method according to the invention, the state of the sensor used for detecting the exhaust gas temperature for each cylinder is queried. In subsequent step 31, it is checked whether or not the corresponding sensor is operating normally. At this time, the adjustment of the correction characteristic diagrams 17 _{1 to} 17 _N for each cylinder in step 29 is performed only when it is confirmed in step 31 that the sensor is operating normally. In other cases, the correction characteristic diagrams 17 _{1 to} 17 _N are not adapted.

  In the step 25 of the main step 12 of the present invention, the correction value obtained in the step 25 is preferably considered in terms of a maximum value or a limit value. Specifically, when the correction value exceeds each maximum value, the maximum value The value is used as a correction value. This maximum or limit value is constant over the entire operating state of the internal combustion engine. However, in step 25 it is advantageous to take into account the limit value or maximum value relating to the operating point or operating load and thus the fuel injection quantity.

  In the present invention, the cylinder exhaust gas temperature measured in step 23 is offset. Such an offset for the cylinder of the internal combustion engine is prepared in step 32 and added to the exhaust gas temperature of the corresponding cylinder measured in step 23. This offset can have various magnitudes for all cylinders of the internal combustion engine.

  Therefore, according to the method of the present invention, during the operation of the internal combustion engine, the correction characteristic diagram for each cylinder is automatically or spontaneously applied in an adaptive sense based on the exhaust gas temperature measured for each cylinder during the operation of the internal combustion engine. Adapt. For this reason, it is possible to compensate for the various wears that occur during operation of the internal combustion engine of the components for each cylinder of the internal combustion engine, thus maintaining the desired load distribution for the multiple cylinders of the internal combustion engine throughout the operation. In that case, a uniform load distribution can be set on the one hand over all the cylinders of the internal combustion engine, and on the other hand, a load distribution can be set which varies for each cylinder. The greater the load in the cylinder range, the more fuel is injected into the cylinder and the higher the exhaust gas temperature generated in the cylinder.

  The detection of the open time for each cylinder of the fuel injector of the cylinder of the internal combustion engine in the main steps 10 and 11 and the adaptation or adaptation of the correction characteristic diagram for each cylinder in the main step 12 are performed separately from each other but in parallel or simultaneously. This allows continuous adaptation of the correction characteristic diagram to changing conditions or states of the internal combustion engine on the one hand, and rapid detection of the open time for each cylinder of the fuel injector on the other hand even under unsteady operating conditions. It is.

The block diagram of the operating method of the internal combustion engine based on this invention.

Explanation of symbols

10-12 main steps, 13, 14, 16, 18-32 steps, 15 Fuel injector characteristic diagram

Claims (6)

At least one fuel injector is attached to each cylinder;
In relation to the fuel injection amount, fuel pressure and the characteristic diagram of the fuel injector of the internal combustion engine, the same open time is obtained for all fuel injectors, and the same open time, fuel injection amount, fuel pressure in all fuel injectors And based on the individual correction characteristic diagram for each cylinder, the open time for each cylinder of the fuel injector is obtained,
At least one of the fuel injection amount per operation cycle, the fuel pressure, and the rotation speed of the internal combustion engine, which are important operating parameters for fuel injection of the internal combustion engine, is substantially constant over a predetermined time or within a predetermined limit value. When determining that the internal combustion engine is in a steady operation state,
When the internal combustion engine is in a steady operation state, the exhaust gas temperature of each cylinder is measured, and the correction characteristic diagram for each cylinder is automatically adapted based on the measured exhaust gas temperature,
Determine the average temperature of the exhaust gas temperature for each measured cylinder, measured the temperature deviation for each cylinder of the temperature mean value and exhaust gas temperature of each cylinder is calculated and related to the temperature deviation of each cylinder for each cylinder Then, the correction value of the open time of the fuel injector is obtained, and the correction characteristic diagram for each cylinder is automatically adapted based on this correction value ,
The maximum value or limit value in the correction value is determined, and when the correction value exceeds the maximum value, the maximum value is used as the correction value, and the limit value or maximum value is related to the fuel injection amount. A common rail type multi-cylinder internal combustion engine operating method. An average value of correction values of all cylinders is obtained, a correction value deviation between the correction value and the average value is calculated for each cylinder, and a correction characteristic diagram for each cylinder is automatically adapted in relation to the correction value deviation. The method of claim 1 wherein: The reverse interpolation and the extrapolation are performed on the basis of the correction value or correction value deviation for each cylinder and the obtained fuel injection amount and fuel pressure in order to adapt the correction characteristic diagram for each cylinder. The method according to 1 or 2 . Records or corrects the correction characteristic diagram for each cylinder at the characteristic operating point that is located close to the operating point for which the correction value or correction value deviation for each cylinder was obtained, and records or corrects it at the characteristic operating point that is located further away. 4. A method as claimed in claim 3 , characterized in that the fit is stronger than the value. It is characterized by checking whether or not the sensor for detecting the exhaust gas temperature for each cylinder is operating normally, and applying the correction characteristic chart for each cylinder only when the sensor is operating normally. The method according to one of claims 1 to 4 . For at least one cylinder, the method according to one of claims 1 to 5, characterized in that providing a measured offset in the exhaust gas temperature.

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