Method and motor controller for multiple injections with quantity correction for an internal combustion engine

Abstract

A method for injecting a predetermined total fuel quantity via multiple injections using a fuel injector having a solenoid drive for an internal combustion engine of a motor vehicle is disclosed. The method includes determining a first target injection quantity to be injected per injection to inject the total fuel quantity throughout a series of consecutive injections; and performing a first subseries of consecutive injections, where the fuel injector is actuated according to the first target injection quantity. The method also includes determining a first fuel quantity injected during the first subseries of injections; determining a second target injection quantity to be injected per injection in a second subseries of consecutive injections, to inject the total fuel quantity throughout the first subseries and the second subseries of consecutive injections; and performing the second subseries of injections. The fuel injector is actuated according to the second target injection quantity.

Claims

1. A method for injecting a predetermined total fuel quantity via multiple injections using a fuel injector having a solenoid drive for an internal combustion engine of a motor vehicle, the method comprising: determining a first target injection quantity to be injected per injection to inject the total fuel quantity throughout a series of consecutive injections; carrying out a first subseries of consecutive injections, wherein the fuel injector is actuated according to the first target injection quantity; determining a first fuel quantity injected during the first subseries of injections; determining a second target injection quantity to be injected per injection in a second subseries of consecutive injections, to inject the total fuel quantity throughout the first subseries and the second subseries of consecutive injections; and carrying out the second subseries of injections, wherein the fuel injector is actuated according to the second target injection quantity, wherein the second subseries includes less injections than the first subseries, and wherein the second target injection quantity is equal to a difference between the predetermined total fuel quantity and the determined first injected fuel quantity divided by a number of injections in the second subseries.

2. The method of claim 1, wherein the first subseries and the second subseries together form a multiple injection process in which a temporal interval between two successive injections is the same.

3. The method of claim 2, wherein the temporal interval is so short that a magnetization of the solenoid drive from a preceding injection cannot be completely dissipated.

4. The method of claim 1, wherein the second subseries contains a single injection, or wherein a second series contains a plurality of injections.

5. The method of claim 1, wherein determination of the first fuel quantity injected during the first subseries of injections includes an estimate of the injected fuel quantity based on a measured current curve.

6. A computer program with computer-executable commands which, when they are executed by a processor, are configured to perform the method of claim 1.

7. The method of claim 1, wherein determination of the first fuel quantity injected during the first subseries of injections includes an estimate of the injected fuel quantity based on a measured voltage curve in the solenoid drive.

8. A motor controller for an internal combustion engine of a motor vehicle, the motor controller configured to perform a method for injecting a predetermined total fuel quantity via multiple injections using a fuel injector having a solenoid drive for an internal combustion engine of a motor vehicle, the method comprising: determining a first target injection quantity to be injected per injection to inject the total fuel quantity throughout a series of consecutive injections; carrying out a first subseries of consecutive injections, wherein the fuel injector is actuated according to the first target injection quantity; determining a first fuel quantity injected during the first subseries of injections; determining a second target injection quantity to be injected per injection in a second subseries of consecutive injections, to inject the total fuel quantity throughout the first subseries and the second subseries of consecutive injections; and carrying out the second subseries of injections, wherein the fuel injector is actuated according to the second target injection quantity, wherein the second subseries includes less injections than the first subseries, and wherein the second target injection quantity is equal to a difference between the predetermined total fuel quantity and the determined first injected fuel quantity divided by a number of injections in the second subseries.

9. The motor controller of claim 8, wherein the first subseries and the second subseries together form a multiple injection process in which a temporal interval between two successive injections is the same.

10. The motor controller of claim 9, wherein the temporal interval is so short that a magnetization of the solenoid drive from a preceding injection cannot be completely dissipated.

11. The motor controller of claim 8, wherein the second subseries contains a single injection, or wherein a second series contains a plurality of injections.

12. The motor controller of claim 8, wherein determination of the first fuel quantity injected during the first subseries of injections includes an estimate of the injected fuel quantity based on a measured current curve.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a block diagram of an exemplary method for injecting a predetermined total fuel quantity by multiple injection with a fuel injector.

(2) Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

(3) FIG. 1 shows a block diagram of an exemplary method 100 for injecting a predetermined total fuel quantity by multiple injection with a fuel injector having a solenoid drive for an internal combustion engine, such as a petrol engine of a motor vehicle.

(4) Firstly, block 110 designates a first target injection quantity which is to be injected per injection in the multiple injection process in order in total to inject the predetermined total fuel quantity. This may take place such that the first target injection quantity is determined as the predetermined total fuel quantity divided by the total number of injections in the multiple injection process. If the total number is for example equal to eight, then the first target injection quantity is equal to one-eighth of the predetermined total fuel quantity.

(5) Block 120 designates a first subseries of successive injections, where the fuel injector is actuated such that the previously determined first target injection quantity is injected per injection. The first subseries includes the majority of the total provided injections, for example six or seven of the total of eight injections.

(6) Since, with short temporal intervals (pauses) between the individual injections, residual magnetization may be present in the solenoid drive of the fuel injector, this actuation of the fuel injector may lead to different (e.g., larger) actual injection quantities in at least some of the injections.

(7) To solve this problem, at block 130, the first fuel quantity injected during the first subseries of injections is determined, for example by determining opening and closing times based on measured curves of current and voltage in the solenoid coil.

(8) With knowledge of the fuel quantity injected so far, at block 140, a second target injection quantity is determined which is to be injected per injection in a second subseries of successive injections directly following the first subseries, in order, in the second subseries of injections, to inject the necessary remaining quantity of fuel so that overall, the total fuel quantity is injected throughout the first subseries and second subseries of successive injections.

(9) At block 150, the second subseries of injections is carried out, where the fuel injector is actuated according to the second target injection quantity.

(10) It should be noted that the first and second subseries of injections follow one another directly, and that there is no additional pause between the two subseries. In other words, the second target injection quantity is determined in the course of the total injection process.

(11) The first subseries and the second subseries thus together form a multiple injection process in which the temporal interval between two successive injections is the same. Here the temporal interval is so short that a magnetization of the solenoid drive from the preceding injection cannot be completely dissipated.

(12) The second subseries of injections contains the last injection or last injections in the total multiple injection process.

(13) In some implementations, at block 140, the second target injection quantity is calculated as the difference between the predetermined total fuel quantity and the determined first injected fuel quantity divided by the number of injections in the second subseries.

(14) This determination, carried out at block 130, of the first fuel quantity injected during the first subseries of injections includes, in some examples, an estimate of the injected fuel quantity based on a measured current curve and/or a measured voltage curve in the solenoid drive.

(15) The method according to the disclosure may be implemented directly in a motor controller, for example in the form of a computer program. Here it is particularly advantageous that no additional hardware, such as special sensors or injectors, are required which would increase the total cost of the system.

(16) 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.