DE102012214705A1 - Method for generating a clock signal for a vehicle electrical system of a vehicle - Google Patents

Abstract

The invention relates to a method for generating a clock signal (4) for an on-board network (34) of a vehicle, comprising: - receiving a wirelessly transmitted signal (10) with time information, and - generating the clock signal (4) with a time information dependent Clock period (8).

Description

The invention relates to a method for generating a clock signal for an electrical system of a vehicle, to methods for using the clock signal and to control devices for carrying out the specified methods.

Like from the DE 32 164 12 C2 As is known, in order to measure the charge level of an electrical energy source, the current supplied or discharged to the electrical energy source must be integrated in time.

In order to carry out measurements of the electrical current delivered by the electrical energy source to an electrical consumer in a motor vehicle, a current sensor can be connected in series between the electrical energy source and the electrical consumers. Such a current sensor is for example from the DE 10 2011 078 548 A1 known.

It is an object of the present invention to improve the charge measurement.

The object is solved by the features of the independent claims. Preferred developments are the subject of the dependent claims.

• – Empfangen eines drahtlos übertragenen Signal mit einer Zeitinformation, und
• – Erzeugen des Taktsignals mit einer von der Zeitinformation abhängigen Taktperiode.

According to one aspect of the invention, a method for generating a clock signal for an electrical system of a vehicle comprises the steps:

• Receiving a wirelessly transmitted signal with a time information, and
• Generating the clock signal with a dependent of the time information clock period.

The specified method is based on the consideration that the above-mentioned charge level could be formed over a numerical integration of the detected electrical current over time. Based on this consideration, the invention recognizes, however, that for the numerical integration of the time interval of the individual nodes within the numerical integration must be precisely defined in order to keep the integration error as low as possible and to calculate the charge level accurately. Although the time interval of the interpolation points could be specified via a clock generator, such as an oscillator, a clock generator can not generate the time interval between the interpolation points with an accuracy that would be necessary for the numerical integration of the electric current over a comparatively long period of time to perform the required accuracy and output the charge level with a small error.

With the specified method, it is therefore proposed to carry out the numerical integration based on a temporal reference source which has sufficient accuracy over a comparatively long period of time.

Such a reference source are wirelessly transmitted signals carrying appropriate time information with them.

The time information may for example be the frequency, ie the carrier frequency, of the wireless signal itself. If, for example, a wirelessly transmitted signal of a radio station is received, then this wireless signal can be assigned to the corresponding radio transmitter and subsequently the carrier frequency of the radio transmitter can be determined on the basis of the known radio transmitter. If the carrier frequency is known, the clock signal based on the carrier frequency can be generated with sufficient accuracy.

However, the wirelessly transmitted signal is particularly preferably a radio-transmitted time signal into which the time information is modulated. Such signals may be, for example, a Global Positioning System signal, GPS signal for short, or a timer signal known in Europe, for example, under the name DCF77 signal. The advantage of these signals is that they can carry the modulated time information with any accuracy. In the case of the two examples mentioned above, the information is accurate to the atomic clock and therefore represents a reliable reference source for numerical integration even over the years.

In a further development, the specified method comprises the step of generating the clock signal with an oscillator controlled based on the time information. Such a controlled oscillator will be understood below to mean a tunable oscillator circuit or a tunable frequency generator. These can be arbitrarily, for example as a digitally controlled oscillator, called DCO for short, as a numerically controlled oscillator, called NCO for short, or as a voltage-controlled oscillator, called VCO for short. Suitable circuits for the controlled oscillators are, for example, phase-locked loops or also Wien-Robinson bridges.

In an additional development, the specified method comprises the step of generating the clock signal with a local oscillator when the wirelessly transmitted signal is not available. In this way, for example, driving with a vehicle can be bridged by a tunnel without the clock signal would fail.

• – Messen einer physikalischen Größe, und
• – numerisches Integrieren der gemessenen physikalischen Größe über die Zeit basierend auf zeitlichen Abständen zwischen den Takten des Taktsignals.

According to a further aspect of the invention, a method for using a clock signal, which has been generated with a specified method for generating a clock signal for a vehicle electrical system, comprises the steps:

• - Measuring a physical quantity, and
• Numerically integrating the measured physical quantity over time based on time intervals between the clocks of the clock signal.

By using the above-described clock signal in numerical integration, measurement values to be determined by numerical integration over time can be determined accurately and reliably over a longer period of time.

In a preferred refinement, the physical variable is an electrical current flowing from or to an electrical energy source in the electrical system of the vehicle, so that the numerical integration of the electric current results in the charge state of the electrical energy source. In this way, the state of charge of the electrical energy source can be determined with high accuracy. As a further advantage of the specified method, the possibility arises at a given tolerance for the charge state to exploit them in the technical quality of the current sensor. Thus, these tolerances can now be played with a lower-cost current sensor, whereby the charge measurement can be carried out more economically even with the same quality. In other words, by the specified method, the accuracy requirements for the current sensor can be relaxed, thereby significantly reducing costs, without limiting the accuracy of the charge detection of the electrical energy source.

• – Erzeugen einer absoluten Zeitangabe basierend auf dem Taktsignal, und
• – Verknüpfen der gemessenen und numerisch integrierten physikalischen Größe und/oder der gemessenen physikalischen Größe mit der absoluten Zeitangabe.

In a further development, the specified method comprises the steps

• Generating an absolute time based on the clock signal, and
• Linking the measured and numerically integrated physical quantity and / or the measured physical quantity with the absolute time specification.

Since the absolute time is calculated based on a wirelessly transmitted signal, it is the same in different locations, such as in different vehicles. In this way, the measured and numerically integrated physical quantities associated with the absolute time indication and / or the measured physical quantities recorded at different locations can be correlated with one another, which increases the evaluation possibilities of these variables.

• – Synchronisieren einer ersten elektrischen Vorrichtung im Bordnetz mit einer zweiten elektrischen Vorrichtung basierend auf dem Taktsignal.

According to a further aspect of the invention, a method for using a clock signal, which has been generated with a specified method for generating a clock signal for an on-board network of a vehicle, comprises the step:

• - Synchronizing a first electrical device in the electrical system with a second electrical device based on the clock signal.

Since the clock signal itself is used for synchronization in the vehicle electrical system, further synchronization costs are eliminated.

The two electrical devices can be arranged in two different vehicles, so that electrical devices in two different vehicles can be operated synchronously with each other. However, the second electrical device is preferably arranged in the electrical system of the vehicle.

According to a further aspect of the invention, a control device is set up to carry out a method according to one of the preceding claims.

In a development of the specified control device, the specified device has a memory and a processor. The specified method is stored in the form of a computer program in the memory and the processor is provided for carrying out the method when the computer program is loaded from the memory into the processor.

According to a further aspect of the invention, a computer program comprises program code means for performing all the steps of one of the specified methods when the computer program is executed on a computer or one of the specified devices.

According to another aspect of the invention, a computer program product includes program code stored on a computer-readable medium and, when executed on a data processing device, performs one of the specified methods.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings, in which:

1 a schematic diagram of a circuit for carrying out a method for generating a clock signal, and

2 show a schematic diagram of another circuit for carrying out a method for generating a clock signal.

In the figures, the same technical elements are provided with the same reference numerals and described only once.

It will open 1 Reference is made to a schematic diagram of a circuit 2 for carrying out a method for generating a clock signal 4 shows.

The clock signal 4 is in the present embodiment in a tunable oscillator 6 generated, for example, as a known to those skilled fed-back phase loop, called phase locked loop, may be executed. The tunable oscillator 6 receives a reference frequency for tuning 8th , which in the present embodiment consists of a wirelessly transmitted signal 10 via a receiver 12 is won.

The wirelessly transmitted signal 10 can be any signal from which a periodicity can be derived which is used to set the clock signal 4 suitable is. In the present embodiment, this wirelessly transmitted signal 10 from a satellite 14 for sending GPS signals or from an antenna 16 emitted to send time synchronization signals.

In a manner known to those skilled in the GPS signals contain time information on the basis of which the position of a receiver of the GPS signals can be determined. Details can be found in the relevant state of the art. In the present embodiment, the timing information of the GPS signals may also be used to generate the clock signal 4 be used by a period of the clock signal 4 is aligned with the time course of this time information. For this, the GPS signal is first from an antenna 18 in the receiver 12 receive and from the time course of the time information, the reference frequency 8th in a demodulator 20 demodulated. Subsequently, the clock signal 4 with the tunable oscillator 6 based on this reference frequency 8th generated.

Alternatively, to generate the clock signal 4 a time synchronization signal known to those skilled in the art may also be used. Such a time synchronization signal is sent, for example, in Western Europe by the long-wave transmitter DCF77 in the district Mainflingen in Mainhausen and provides most radio controlled clocks with the exact legal time applicable in Germany. This time synchronization signal therefore contains, in the same turnout as the GPS signals, one or more time information, from whose time course in the manner described above analogously the clock signal 4 can derive.

Alternatively, but could also be the carrier frequency of the wireless signal transmitted 10 even to generate the clock signal 4 will be used for the sake of brevity.

The generated clock signal 4 can then via a clock input 22 a circuit 24 to calculate a charge level 26 be supplied to a vehicle battery not shown. In this circuit 24 be from the circuit 24 Received readings for a stream 28 from or to the vehicle battery powered by a current sensor 30 was measured in time to the charge level 26 based on the clock signal 4 integrated. The integration could, for example, run numerically.

The calculated charge level 26 can then via a communication interface 32 in a wiring system 34 a vehicle are fed, in which the vehicle battery, not shown, is arranged.

It will open 2 Reference is made, which is a schematic diagram of another circuit 2 for carrying out a method for generating a clock signal 4 shows.

The circuit 2 of the 2 works until the clock signal is generated 4 analogous to the circuit of 1 ,

Should, however, the clock signal 4 fail because, for example, no wireless signal transmitted 10 is available, then the time of unavailability of the wirelessly transmitted signal 10 through an internal oscillator 36 but do not meet the high tolerance requirements for the generation of the clock signal 4 needs, like the tunable oscillator 6 , For a comparatively short period of time this is justifiable, for example, when calculating the charge level. The bridging can be realized by the clock signal 4 from the internal oscillator 36 for example, via a switch 38 is switched on.

Subsequently, the clock signal 4 distributed to a variety of electronic devices that need a tact for their functionality. The advantage is that these electronic devices all by the clock signal 4 sync, so there is no need for further synchronization.

In addition to the circuit already described 24 to calculate a charge level 26 one not further illustrated vehicle battery can be to these electronic devices of the current sensor 30 or a voltage sensor 40 belong.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3216412 C2 [0002]
• DE 102011078548 A1 [0003]

Claims (10)

Method for generating a clock signal ( 4 ) for a vehicle electrical system ( 34 ) of a vehicle, comprising: - receiving a wirelessly transmitted signal ( 10 ) with a time information, and - generating the clock signal ( 4 ) with a clock period dependent on the time information ( 8th ). Method according to claim 1, wherein the wirelessly transmitted signal ( 10 ) is a radio-transmitted time signal into which the time information is modulated. Method according to claim 1 or 2, comprising generating the clock signal ( 4 ) with an oscillator based on the time information ( 6 ). Method according to one of the preceding claims, comprising generating the clock signal ( 4 ) with an auxiliary oscillator ( 36 ) when the wirelessly transmitted signal ( 10 ) not available. Method of using a clock signal ( 4 ) produced by a method according to any one of the preceding claims, comprising: - measuring a physical quantity ( 28 ), and - numerically integrating the measured physical quantity ( 28 ) over time based on time intervals between clocks of the clock signal ( 4 ). Method according to claim 5, wherein the physical quantity ( 28 ) is an electrical current flowing from or to an electrical energy source in the electrical system of the vehicle, so that the numerical integration of the electric current is the state of charge ( 26 ) of the electrical energy source.  Method according to claim 5 or 6 comprising: Generating an absolute time based on the clock signal, and Linking the measured and numerically integrated physical quantity and / or the measured physical quantity with the absolute time specification. A method of using a clock signal generated by a method according to any of claims 1 to 4, comprising: - synchronizing a first electrical device ( 24 ) in the electrical system with a second electrical device ( 30 . 40 ) based on the clock signal. The method of claim 8, wherein the second electrical device ( 30 . 40 ) is arranged in the electrical system.  Control device adapted to perform a method according to any one of the preceding claims.

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