Method and device for operating a fuel pump

Abstract

A fuel pump of a motor vehicle includes: a pump stage configured to induce fuel from a fuel tank; an electric motor configured to drive the pump stage; and control electronics configured to supply the electric motor with electrical current. The control electronics includes a memory storing a low temperature start program and a standard start program. The control electronics are connected to a temperature sensor and a selector configured to select the start program depending on the sensed temperature.

Claims

1. A fuel pump (3) of a motor vehicle, comprising: a pump stage (5) configured to induce fuel from a fuel tank (7), wherein the fuel is diesel fuel; an electric motor (4) configured to drive the pump stage (5); and control electronics (6) configured to supply the electric motor (4) with electrical current, wherein the control electronics (6) includes a memory (9) storing a low temperature start program, a count of a number of false starts of the fuel pump determined by the control electronics (6), and a standard start program, the control electronics (6) being connected to a temperature sensor (10) and a selector configured to: in a case in which the number of false starts of the fuel pump stored in the memory (9) is below a predetermined threshold, start the low temperature start program at an envisaged low temperature of the fuel, the envisaged low temperature being the Cold Filtering Plugging Point (CFPP) temperature, and select the standard start program above the envisaged temperature, and in a case in which the number of false starts of the fuel pump stored in the memory (9) indicates plural false starts at or above the predetermined threshold number of false starts, start the low temperature start program regardless of the temperature of the fuel, wherein control in accordance with the temperature sensor (10) is based at least in part on temperature differences and thermal time constant differences constants between the control electronics (6) and the fuel pump.

2. The fuel pump as claimed in claim 1, wherein the control electronics (6) comprises the temperature sensor (10).

3. The fuel pump as claimed in claim 1, wherein an ohmic resistance of a phase of the electric motor (4) is used to determine the temperature of the fuel pump (3).

4. A method for operating a fuel pump (3) of a motor vehicle, comprising: supplying, by control electronics (6) having a memory (9), an electric motor (4) with electric current, the control electronics (6) being connected to a temperature sensor (10); driving, by an electric motor (4), a pump stage (5) that sucks fuel from a fuel tank (7), wherein the fuel is diesel fuel; detecting, by the control electronics (6), false starting of the fuel pump (3); counting a number of false starts of the fuel pump occurring and storing the count in the memory (9); selecting, by the control electronics (6), such that: in a case in which the number of false starts of the fuel pump stored in the memory (9) is below a predetermined threshold, starting a low temperature start program at an envisaged low temperature of the fuel, the envisaged low temperature being the Cold Filtering Plugging Point (CFPP) temperature, and selecting a standard start program above the envisaged temperature, and in a case in which the number of false starts of the fuel pump stored in the memory (9) indicates plural false starts at or above the predetermined threshold of false starts, starting the low temperature start program regardless of the temperature of the fuel, wherein control in accordance with the temperature sensor (10) is based at least in part on temperature differences and thermal time constant differences constants between the control electronics (6) and the fuel pump.

5. The method as claimed in claim 4, wherein a higher current level for energizing the electric motor (4) is selected in the low temperature start program than in the standard start program.

6. The method as claimed in claim 4, wherein the low temperature start program has a longer time duration than the standard start program.

7. The method as claimed in claim 4, wherein a temperature threshold is specified as the envisaged low temperature and in total two temperature-dependent start programs are selectable.

8. The method as claimed in claim 4, wherein the control electronics (6) are disposed on the electric motor (4), the method further comprising measuring the temperature of the control electronics (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention allows numerous embodiments. For a further explanation of its basic principle, one of the embodiments is represented in the figures and will be described below. In the figures:

(2) FIG. 1 shows a fuel pump for supplying an internal combustion engine, and

(3) FIG. 2 shows schematically a method for starting the fuel pump.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(4) FIG. 1 shows an internal combustion engine 1 with an engine controller 2 and with a fuel pump 3. The fuel pump 3 comprises a pump stage 5 activated by an electric motor 4 and control electronics 6 for activating the electric motor 4. The pump stage sucks fuel from a fuel tank 7 and delivers the fuel to the internal combustion engine 1. The control electronics 6 and the engine controller 2 comprise a data connection 8.

(5) Furthermore, the control electronics 6 comprise a memory 9 for various programs and a temperature sensor 10. The fuel pump 3 carries a flow of fuel, so that the temperature sensor 10 of the control electronics 6 measures the temperature of the fuel.

(6) FIG. 2 shows schematically a method for starting the fuel pump 3. In a first step S1, the start of the method is carried out with the desired start of the internal combustion engine 1. In the step S2, the temperature is measured by the temperature sensor 10. Depending on the temperature, in the step S3 a start program is selected from the memory 9 and is started. If the measured temperature is lower than a provided threshold value, a low temperature start-up program is started in the step S4.

(7) Following execution of the low temperature start-up program, an operating program for operating the fuel pump 3 is started in the step S5. However, if the temperature is higher than the provided threshold value, a standard start program is started in the step S6. If control electronics 6 detect no false start in the step S7, the transition to the operating program takes place. If there are false starts of the fuel pump 3, the false starts are counted in the step S8 and, if the number of false starts exceeds an envisaged sum, the low temperature start program is started in the step S9. Then a change is made to the operating program.

(8) Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.