Method For Regulating The Total Injection Mass During A Multiple Injection Operation

Abstract

A method for controlling the total injection mass per working cycle during a multiple injection operation of a fuel injector of an internal combustion engine is provided. In the method, an injection mass difference is determined from individual injection pulse to individual injection pulse, and transferred to the next individual injection pulse, in stepwise fashion. The injection mass difference remaining in the penultimate individual injection pulse is transferred to the final individual injection pulse to achieve a total injection mass with improved tolerance.

Claims

1. A method for controlling a total injection mass per working cycle during a multiple injection operation of a fuel injector of an internal combustion engine, the method comprising: determining an individual quantity signal of individual injection pulses of the multiple injection; calculating a respective injection mass of an individual injection pulse (individual injection pulse SETPOINT mass); measuring an actually injected individual injection pulse mass (first individual injection pulse ACTUAL mass) of the first individual injection pulse using an operating parameter of the internal combustion engine; determining an injection mass difference D.sub.1 between the SETPOINT and ACTUAL mass of the first injection pulse; measuring an actually injected individual injection pulse mass of a further individual injection pulse using an operating parameter of the internal combustion engine; transferring the injection mass difference D.sub.1 to the actually injected individual injection pulse mass of the further individual injection pulse; and determining the remaining difference in relation to the individual injection pulse SETPOINT mass of the further individual injection pulse, wherein the corresponding differences are determined and transferred up until a penultimate individual injection pulse, and the remaining difference D.sub.n−1 of the penultimate individual injection pulse then obtained is transferred to the individual injection pulse ACTUAL mass of the final individual injection pulse of the multiple injection.

2. The method of claim 1, further comprising: controlling the individual injection pulses.

3. The method of claim 2, further comprising controlling quantity equalization at coil injectors.

4. The method as of claim 1, wherein the method is used in Otto-cycle engines.

Description

DESCRIPTION OF DRAWINGS

[0014] FIG. 1 shows an exemplary schematic flow diagram of a method for controlling a total injection mass.

[0015] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0016] A method according to the disclosure will be explained based on a multiple injection of a fuel injector of an Otto-cycle engine. The multiple injection is made up here of n individual injections within one working cycle.

[0017] In a first step of the method, which is identified by block 1 in FIG. 1, an individual quantity signal of the individual injection pulses of the multiple injection is determined. In a second step identified by block 2, this results in a calculation of a respective injection mass of an individual injection pulse to obtain an individual injection pulse SETPOINT mass.

[0018] Furthermore, in a third step identified by block 3, an actually injected individual injection pulse mass is measured as a first individual injection pulse ACTUAL mass of the first individual injection pulse, where this is done by measuring a suitable operating parameter of the internal combustion engine.

[0019] In a fourth step identified by block 4, the SETPOINT and ACTUAL masses of the first individual injection pulse are compared with one another, and a corresponding difference D.sub.1 between the two is determined.

[0020] This difference D.sub.1 is transferred in a fifth step identified by block 5 to an actually injected individual injection pulse mass of the next individual injection pulse, which was determined in the same way as in the third step. There then follows again a comparison between the SETPOINT and ACTUAL mass, where a difference D2 is obtained. This is then transferred again to the individual injection pulse mass of the next individual injection pulse.

[0021] The method is carried out in this way up until the penultimate individual injection pulse. The remaining difference D.sub.n−1 then determined in accordance with a sixth step identified by block 6 is transferred in a seventh step identified by block 7 to the individual injection pulse mass of the final individual injection pulse. Overall, a total injection mass of the multiple injection is thus obtained with which an improved tolerance of the total quantity of the fuel mass per working cycle can be achieved. The injection operation of the final individual injection is denoted by 8 in FIG. 1.

[0022] The examples described and illustrated here may for example involve 8 individual injection operations. If, for example, a difference D.sub.1 of the injection mass of 5% is determined in the case of the first individual injection pulse, this difference of 5% is applied to the second pulse. If a difference of 4% is determined in the case of the second pulse, the 4% is applied to the third pulse, until, in this way, a difference of 1% remains in the case of the penultimate pulse (7th pulse), for example. This is then transferred to the 8th pulse, such that the desired compensation with regard to the total injection mass is achieved in this way.

[0023] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.