JP2012188020A - Cable arrangement structure, and moving-body electric system having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable arrangement structure that reduces the effect of noise in a communication between two electronic devices even in a complicated electromagnetic environment, and also to provide a moving-body electric system having the same.SOLUTION: The cable arrangement structure is mounted on a vehicle and electrically connects an ECU 10 to a sensor 20. The apparatus includes a main line 30 and an auxiliary line 40, which serve as the cable, for sending the same signal from at least one of the electronic devices as the other of the electronic devices. The main line 30 and the auxiliary line 40 to which the same signal is sent are arranged at positions where a distance from a ground potential part 51 is different from each other.

Description

  The present invention relates to a cable arrangement structure that is mounted on a mobile body and electrically connects two electronic devices, and to a mobile electronic system having this arrangement structure.

  Conventionally, there has been an electronic control device disclosed in Patent Document 1. The electronic control device includes an analog signal input circuit unit. The analog signal input circuit unit is electrically connected to an analog sensor provided outside the electronic control device via a power supply line and a signal line.

The analog signal input circuit unit includes a current limiting circuit unit, an integrating circuit unit, a current limiting resistor, a signal noise absorption circuit, and a first bypass capacitor. The capacitance C1 and the parasitic inductance L1 of the first bypass capacitor are set in a range of 7 × 10 ⁶ <1 / [2π√ (L1 × C1)] <35 × 10 ⁶ .

JP 2006-140345 A

  According to the electronic control device disclosed in Patent Document 1, noise in a frequency band (7 MHz to 35 MHz) induced in a cable (power line or signal line) by a strong transmission radio wave of a portable wireless device used in the vicinity is generated. It can escape to the ground line via the bypass capacitor. Further, other noise generated in the cable can be removed through the signal noise absorption circuit and the integration circuit unit in the analog signal input circuit unit. Therefore, an electronic control device having excellent noise resistance can be obtained.

  However, in the electronic control device disclosed in Patent Document 1, it is necessary to provide a circuit such as a bypass capacitor, a signal noise absorption circuit, and an integration circuit unit in order to remove noise superimposed on the cable.

  Further, the frequency of noise that can be taken by this bypass capacitor is determined by the characteristics of the bypass capacitor. Therefore, when the frequency of the noise to be countermeasured is known, the noise countermeasure can be achieved by adjusting the characteristics of the bypass capacitor.

  However, in a complicated electromagnetic environment, not only the frequency of noise to be countermeasured is wide, but also sudden noise (noise whose frequency is not known) may occur. Therefore, in a complicated electromagnetic environment, it is necessary to increase the number of bypass capacitors by the amount of noise (frequency) to be countermeasured, which increases costs. Furthermore, even if the number of bypass capacitors is increased, there are cases where the effect cannot be expected for sudden noise (noise whose frequency is not known).

  The present invention has been made in view of the above problems, and a cable arrangement structure capable of reducing the influence of noise in communication between two electronic devices even in a complicated electromagnetic environment, and this arrangement It is an object to provide a mobile electronic system having a structure.

  Since the moving body changes its electromagnetic environment as it moves, the electromagnetic environment tends to be complicated. That is, the electromagnetic environment is likely to be complicated with respect to the mounting environment of the electronic device mounted on the moving body. Therefore, noise that is difficult to specify a frequency (that is, an unknown frequency) is likely to be superimposed on a signal communicated between electronic devices mounted on the moving body.

  Accordingly, in order to achieve the above object, the cable arrangement structure according to claim 1 is mounted on a movable body and is used as a cable for electrically connecting two electronic devices, from at least one electronic device to the other electronic device. Including a plurality of cables through which the same signal is transmitted. And the impedance of each cable can be made different by arrange | positioning the several cable to which this same signal is transmitted in the position where distance with a ground potential part differs mutually. Therefore, it is possible to reduce the probability that noise of the same frequency is simultaneously superimposed on the signals flowing through the cables.

  That is, even if noise is superimposed on a signal flowing in any of a plurality of cables, it is possible to suppress the noise having the same frequency as this noise from being superimposed on a signal flowing in another cable. In other words, it becomes easy to communicate at least one signal with no noise superimposed between the two electronic devices. Therefore, in the cable arrangement structure according to the first aspect, the influence of noise in communication between two electronic devices can be reduced even in a complicated electromagnetic environment.

  Further, the frequency of noise superimposed on the signal flowing through the cable is greatly affected by the frequency characteristics of the cable. Further, the frequency characteristics of this cable change depending on the length of the cable.

  Therefore, as described in claim 2, the plurality of cables that are transmitted at the same signal and are arranged at different positions from the ground potential portion have different lengths from each other. The frequency characteristics can be made different. That is, the noise (frequency) that is easily superimposed differs for each cable. Therefore, the influence of noise between the two electronic devices can be further reduced.

  In order to achieve the above object, a mobile electronic system according to a third aspect has the cable arrangement structure according to the first aspect. That is, it is possible to reduce the probability that noise of the same frequency is simultaneously superimposed on the same signal flowing in each cable. Therefore, even if noise is superimposed on a signal flowing in any of a plurality of cables, it is possible to suppress the noise having the same frequency as this noise from being superimposed on a signal flowing in another cable. In other words, it becomes easy to communicate at least one signal with no noise superimposed between the two electronic devices.

  And an electronic device becomes easy to employ | adopt the signal on which noise is not superimposed by selecting one signal employ | adopted as a received signal based on the noise amount in the several signal received via each cable. Therefore, in the mobile electronic system according to claim 3, the influence of noise in communication between two electronic devices can be reduced even in a complicated electromagnetic environment.

  Further, as this selection means, as shown in claim 4, a signal smaller than the threshold is adopted as a received signal by comparing the amount of noise with the threshold and selecting a signal determined to be smaller than the threshold. be able to.

  Further, when the received signal is adopted by comparing the noise amount with the threshold value as described above, the noise amount of the signal received first is calculated and the signal received first by the selecting means as shown in claim 5. If it is determined that the amount of noise exceeds the threshold, the amount of noise of the next received signal may be calculated. By doing in this way, when the noise amount of the signal received previously is smaller than a threshold value, it is not necessary to calculate the noise amount for all received signals, which is preferable because the processing can be simplified.

  However, it is possible that the noise amounts of a plurality of signals received via each cable all exceed the threshold value. When all the threshold values are exceeded in this way, as shown in claim 6, by comparing the noise amounts of a plurality of received signals and selecting a signal having the smallest noise amount, at least one signal ( The signal having the smallest noise amount among the plurality of signals having the noise amount exceeding the threshold value can be adopted as the received signal.

  Further, as the selection means, as shown in claim 7, a threshold value or the like is used by comparing the noise amounts of a plurality of signals received via each cable and selecting a signal having the smallest noise amount. Therefore, it is possible to select a signal as a received signal.

  In addition, since the effect | action and effect of the invention which concerns on Claim 8 are the same as that of the above-mentioned invention based on Claim 2, description is abbreviate | omitted.

It is a block diagram which shows an example of the cable arrangement | positioning structure of the vehicle electronic system in embodiment of this invention. It is a block diagram which shows the other example of the cable arrangement | positioning structure of the vehicle electronic system in embodiment of this invention. It is a flowchart which shows the processing operation of the vehicle electronic system in embodiment of this invention. It is a block diagram which shows an example of the cable arrangement | positioning structure of the vehicle electronic system in the modification 1. It is a block diagram which shows an example of the cable arrangement | positioning structure of the vehicle electronic system in the modification 2. 10 is a flowchart showing a processing operation of the vehicle electronic system in Modification 3. 10 is a flowchart showing a processing operation of the vehicle electronic system in Modification 4.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, as an example, an example in which the mobile electronic system and the cable arrangement structure of the present invention are applied to a vehicle (four-wheeled vehicle) is adopted.

  As shown in FIG. 1, a vehicle electronic system (mobile electronic system) 100 in the present embodiment includes an ECU (electronic control unit) 10, a sensor (electronic device) 20, and an ECU (electronic device). A main line (cable) 30 and an auxiliary line (cable) 40 that electrically connect the sensor 10 and the sensor 20 are provided.

  The ECU 10 corresponds to the electronic device of the present invention. The ECU 10 is mainly configured by a microcomputer including a CPU, a ROM, a RAM, a backup RAM, and the like (all not shown), and performs various processes by executing various control programs stored in the ROM. It is something to execute. The ECU 10 communicates with the sensor 20 via the main line 30 and the auxiliary line 40. That is, the ECU 10 receives (acquires) a sensor signal (signal) that is a detection result of the sensor 20 via the main line 30 and the auxiliary line 40. That is, the ECU 10 receives (acquires) the sensor signal for each main line 30 and each auxiliary line 40 (each cable). In addition, although detailed description is abbreviate | omitted here, ECU10 performs a predetermined | prescribed process according to this sensor signal.

  The sensor 20 corresponds to the electronic device of the present invention. The sensor 20 performs a detection operation and transmits a sensor signal as a detection result to the ECU 10 via the main line 30 and the auxiliary line 40. The sensor 20 transmits (outputs) the same sensor signal to the main line 30 and the auxiliary line 40 when transmitting a sensor signal to the ECU 10. Therefore, when external noise (high-frequency noise) does not affect, the same sensor signal communicated between the ECU 10 and the sensor 20 flows through the main line 30 and the auxiliary line 40. However, when external noise is superimposed on the sensor signal due to external noise (high-frequency noise), even if the sensor 20 transmits (outputs) the same sensor signal to the main line 30 and the auxiliary line 40, the main line 30 and the auxiliary line Different signals may flow on the line 40.

  The main line 30 and the auxiliary line 40 correspond to the cable of the present invention. For example, a wire harness (in other words, a cable harness) can be employed as the main line 30 and the auxiliary line 40. That is, a cable in which a plurality of electric wires such as a power supply line, a ground line, and a signal line are bundled and covered with an insulator can be employed. Hereinafter, the main line 30 and the auxiliary line 40 are also simply referred to as a wire harness.

  As described above, the same sensor signal from the sensor 20 to the ECU 10 is transmitted (output) to the main line 30 and the auxiliary line 40. Therefore, apart from the main line 30 which is a wire harness that electrically connects the ECU 10 and the sensor 20, the same sensor signal as that of the main line 30 is transmitted from the sensor 20, and the ECU 10 and the sensor 20 are electrically connected. An auxiliary wire 40 that is a wire harness to be connected is provided.

  The main line 30 and the auxiliary line 40 are arranged at positions where the distances from the ground potential portion (for example, the body of the vehicle) in the vehicle are different from each other. Preferably, the main line 30 and the auxiliary line 40 may be arranged at positions where the distance from the ground potential portion (for example, the body of the vehicle) in the vehicle is different from each other in the whole (full length) of the main line 30 and the auxiliary line 40.

  For example, as shown in FIG. 1, the main line 30 and the auxiliary line 40 are arranged at different positions from the ground potential portion 51. That is, the main line 30 and the auxiliary line 40 are arranged such that the distance between the auxiliary line 40 and the ground potential unit 51 is closer than the distance between the main line 30 and the ground potential unit 51. In other words, the auxiliary line 40 is disposed at a position closer to the ground potential portion 51 than the main line 30. That is, the main line 30 is arranged at a position farther from the ground potential portion 51 than the auxiliary line 40.

  In addition, as shown in FIG. 2, the main line 30 and the auxiliary line 40 are located at the same distance from the ground potential portion 53, and the auxiliary line 40 and the auxiliary line 40 are located at a distance greater than the distance between the main line 30 and the ground potential portion 52. They are arranged so that the distance from the ground potential portion 52 is closer. That is, the main line 30 and the auxiliary line 40 are arranged at positions where the distance from the ground potential unit 53 is the same, but the distance from the ground potential unit 52 is different.

  By the way, the electromagnetic environment in the engine compartment and the passenger compartment of the vehicle is an extremely complicated electromagnetic environment due to the influence of on-board equipment and external noise. Further, since the electromagnetic environment of the vehicle changes as the vehicle moves, the electromagnetic environment tends to be complicated. That is, the electromagnetic environment is likely to be complicated with respect to the mounting environment of the ECU 10 and the sensor 20 mounted on the vehicle. Therefore, noise that is difficult to specify (that is, an unknown frequency) is easily superimposed on a signal communicated between the ECU 10 and the sensor 20 mounted on the vehicle.

  Therefore, as described above, by arranging the main line 30 and the auxiliary line 40 at positions where the distance from the ground potential portion is different from each other, the parasitic capacitance between each wire harness and the ground potential portion is different. The impedance can be made different. Therefore, it can be paraphrased that the main line 30 and the auxiliary line 40 are arranged at positions where the impedances are different from each other. Therefore, the method of superimposing noise on each wire harness (main line 30 and auxiliary line 40) is definitely different. Therefore, it is possible to reduce the probability that noise of the same frequency is simultaneously superimposed on the sensor signals flowing through the main line 30 and the auxiliary line 40.

  That is, even if noise is superimposed on a sensor signal flowing in one of the plurality of wire harnesses (for example, main line 30), noise having the same frequency as this noise flows in another wire harness (for example, auxiliary line 40). It is possible to suppress superimposition on the sensor signal. In other words, it becomes easy to communicate at least one signal on which no noise is superimposed between the ECU 10 and the sensor 20. Therefore, in the cable arrangement structure of the present invention, the influence of noise in communication between the ECU 10 and the sensor 20 can be reduced even in a complicated electromagnetic environment.

  That is, in this embodiment, a bypass capacitor specialized for noise in a specific frequency band is not used as in the prior art. Therefore, it is possible to deal with noise from several MHz to several GHz without limiting the noise frequency. That is, it is possible to reduce the probability that noise of the same frequency in the range of several MHz to several GHz is simultaneously superimposed on the sensor signal flowing on the main line 30 and the sensor signal flowing on the auxiliary line 40. Therefore, it becomes a particularly effective noise countermeasure in a complicated electromagnetic environment where the noise frequency cannot be specified.

  In the present embodiment, an example in which the ECU 10 and the sensor 20 are electrically connected by the two wire harnesses of the main line 30 and the auxiliary line 40 is employed, but the present invention is limited to this. is not. ECU10 and sensor 20 should just be connected with a plurality of wire harnesses. In other words, the ECU 10 and the sensor 20 may be electrically connected with two or more wire harnesses, or may be electrically connected with three or more wire harnesses.

  However, the same signal is transmitted (output) from the sensor 20 to the plurality of wire harnesses that electrically connect the ECU 10 and the sensor 20. The plurality of wire harnesses to which the same signal is transmitted need to be arranged at positions where the distance from the ground potential portion of the vehicle is different from each other.

  That is, in the cable wiring structure of the present invention, the same signal is transmitted from at least one electronic device (sensor 20) to the other electronic device (ECU 10) as a wire harness that electrically connects the ECU 10 and the sensor 20. Including a plurality of wire harnesses. That is, in addition to the main line 30 that is a wire harness that electrically connects the ECU 10 and the sensor 20, the main line 30 includes one or a plurality of auxiliary lines 40 that are wire harnesses that electrically connect the ECU 10 and the sensor 20. 30 and the auxiliary line 40 transmit the same signal from at least one electronic device (sensor 20) to the other electronic device (ECU 10). And if the several wire harness to which the same signal is transmitted is arrange | positioned in the position where the distance with the ground electric potential part in a vehicle mutually differs, the objective of this invention can be achieved.

  In other words, the present invention is an arrangement structure of a wire harness (cable) that is mounted on a moving body and electrically connects two electronic devices, and a plurality of wire harnesses are provided between the two electronic devices, The plurality of wire harnesses transmit the same signal from at least one electronic device, and the plurality of wire harnesses to which the same signal is transmitted are located at different distances from the ground potential portion in the moving body. If it is arrange | positioned, the objective of this invention can be achieved.

  Here, the processing operation of the vehicle electronic system will be described with reference to FIG.

  The vehicle electronic system in the present embodiment has an arrangement structure of the wire harness (main line 30 and auxiliary line 40) as described above. Further, the ECU 10 calculates a noise amount in a plurality of sensor signals received via the main line 30 and the auxiliary line 40 (noise amount calculating means). Further, the ECU 10 selects one signal to be adopted as a reception signal from a plurality of sensor signals received via the main line 30 and the auxiliary line 40 based on the calculated noise amount (selection means).

  Specifically, the processing operation as shown in the flowchart of FIG. 3 is executed.

  First, in step S10, the ECU 10 receives a sensor signal from the sensor 20 (signal reception). Next, in step S11, the ECU 10 calculates the noise amount (A) of the sensor signal (that is, the main line signal) received via the main line 30 (noise amount calculating means).

There are various methods for measuring the amount of noise. Here, as an example, the SN ratio (signal-to-noise ratio) is used as an index of the amount of noise. That is, the SN ratio is calculated as the noise evaluation amount. Specifically, the formula S / N = Ps / Pn = (Vs / Vn) ² , (Ps = signal power, Pn = noise power, Vs = effective value of signal voltage (current), Vn = noise voltage (current) (Effective value).

  Next, in step S12, the ECU 10 compares the noise amount (A) of the main line signal with the noise amount threshold value (C), and determines that A <C, the process proceeds to step S13, where A <C If not (A ≧ C), the process proceeds to step S14 (selection means). When it is determined that the noise amount (A) of the main line signal is smaller than the threshold value (C), it can be considered that no noise is superimposed on the main line signal or there is no significant influence due to the noise. Therefore, in step S13, the ECU 10 employs a main line signal having a noise amount (A) smaller than the threshold value (C) as a reception signal (main signal use, selection means). That is, the ECU 10 employs a sensor signal (main line signal) received via the main line 30 as a detection result of the sensor 20 (a signal output from the sensor 20, that is, a sensor signal not affected by noise).

  On the other hand, in step S14, the ECU 10 calculates the noise amount (B) of the sensor signal (that is, the auxiliary line signal) received via the auxiliary line 40 (noise amount calculating means). Next, in step S15, the ECU 10 compares the noise amount (B) of the auxiliary line signal with the threshold (C) of the noise amount, and if it is determined that B <C, the ECU 10 proceeds to step S16, and B < If it is determined that it is not C (B ≧ C), the process returns to step S10 (selection means). When it is determined that the noise amount (B) of the auxiliary line signal is smaller than the threshold value (C), it can be considered that no noise is superimposed on the auxiliary line signal or there is no significant influence due to the noise. Therefore, in step S16, the ECU 10 employs an auxiliary line signal whose noise amount (B) is smaller than the threshold value (C) as a reception signal (auxiliary line signal utilization, selection means). That is, the ECU 10 employs a sensor signal (auxiliary line signal) received via the auxiliary line 40 as a detection result of the sensor 20 (a signal output from the sensor 20, that is, a sensor signal not affected by noise).

  By doing in this way, it becomes easy for ECU10 to employ | adopt the signal on which noise is not superimposed. Therefore, in the vehicle electronic system of the present invention, the influence of noise in communication between the ECU 10 and the sensor 20 can be reduced even in a complicated electromagnetic environment.

  That is, in this embodiment, a bypass capacitor specialized for noise in a specific frequency band is not used as in the prior art. Therefore, it is possible to deal with noise from several MHz to several GHz without limiting the noise frequency. That is, it is possible to reduce the probability that noise of the same frequency in the range of several MHz to several GHz is simultaneously superimposed on the sensor signal flowing on the main line 30 and the sensor signal flowing on the auxiliary line 40. Therefore, it becomes a particularly effective noise countermeasure in a complicated electromagnetic environment where the noise frequency cannot be specified.

  Further, by comparing the noise amount with the threshold value and selecting the sensor signal determined that the noise amount is smaller than the threshold value, a sensor signal smaller than the threshold value can be adopted as the reception signal.

  Further, in this way, when the noise amount of one sensor signal is calculated and it is determined that the noise amount of this sensor signal exceeds the threshold value, the noise amount of the other sensor signal is calculated, and the sensor signal By determining whether the amount of noise exceeds the threshold, if the noise amount of the sensor signal calculated first is smaller than the threshold, it is not necessary to calculate the amount of noise for all received sensor signals, simplifying the process This is preferable.

  Here, the noise amount (A) of the sensor signal (main line signal) first received via the main line 30 is compared with the threshold (C), and then the sensor signal (auxiliary signal) received via the auxiliary line 40 is compared. The example in which the noise amount (B) of the line signal) is compared with the threshold value (C) is adopted, but the present invention is not limited to this. For example, the noise amount of the sensor signal received first may be compared with the threshold value (C), and then the noise amount of the sensor signal received next may be compared with the threshold value (C). Therefore, the noise amount (B) of the sensor signal (for example, auxiliary line signal) first received via the auxiliary line 40 is compared with the threshold (C), and then the sensor signal (for example, main line) received via the main line 30 is compared. The noise amount (A) of the signal) may be compared with the threshold value (C). In this case, when it is determined that the noise amount of the first received sensor signal is smaller than the threshold value, it is not necessary to calculate the noise amount for the next received sensor signal, which is preferable because the processing can be simplified.

  In addition, noise amounts (A and B) are calculated for all received sensor signals (main line signal and auxiliary line signal), and each noise amount (A, B) is compared with a threshold value (C). A sensor signal having a noise amount smaller than C) may be adopted as the received signal. In this case, the noise amount (A and B) of all sensor signals (main line signal and auxiliary line signal) may be smaller than the threshold value (C). In this case, it can be considered that no noise is superimposed on all the sensor signals or that there is no significant influence due to the noise. Therefore, any one sensor signal can be employed as the reception signal.

  When it is determined that both the noise amount (A) of the main line signal and the noise amount (B) of the auxiliary line signal exceed the threshold value (C) (the threshold value (C) has been reached) (NO in step S15). In the case of determination), noise is superimposed on the main line signal and the auxiliary line signal, and it can be considered that there is a significant influence due to the noise. That is, noises with different frequencies may be simultaneously superimposed on the sensor signal on the main line 30 and the sensor signal on the auxiliary line 40. In this case, the sensor signals (main line signal and auxiliary line signal) are temporarily not used (that is, a standby state is established until a new sensor signal is received). Alternatively, processing such as noise removal may be performed.

  When the ECU 10 and the sensor 20 are electrically connected by three or more wire harnesses that transmit the same sensor signal from the sensor 20, the ECU 10 calculates the noise amount in the order in which the received sensor signals are received. The comparison with the threshold value (adopting a sensor signal whose noise amount is smaller than the threshold value) may be repeated. Further, the ECU 10 calculates the noise amount of the main line signal and compares it with a threshold value (adopts a sensor signal whose noise amount is smaller than the threshold value), and then calculates the noise amounts of a plurality of auxiliary line signals and compares them with the threshold value. (A sensor signal whose noise amount is smaller than a threshold is adopted) may be repeatedly performed. Further, the ECU 10 calculates a noise amount for all the received sensor signals (three or more), compares each noise amount with a threshold value (C), and has a sensor signal with a noise amount smaller than the threshold value (C). May be adopted as the received signal.

(Other embodiments)
The frequency of noise superimposed on the sensor signal flowing through the wire harness is greatly influenced by the frequency characteristics of the wire harness. Moreover, the frequency characteristic of this wire harness changes with the length of a wire harness.

  For example, with 1.5 [GHz] noise (high frequency noise), one wavelength is 20 [cm]. Therefore, a wire harness having a length multiplied by 20 [cm] is easily affected by high-frequency noise of 1.5 [GHz], but a wire harness having a length less than 20 [cm] is affected. It is hard to receive.

The relationship between noise frequency and wavelength is apparent from wavelength λ [m] = (3 × 10 ⁸ ) / frequency f [Hz]. An example of noise frequency and wavelength is shown below. For noise with a frequency of 1.0 [GHz], one wavelength is 30 [cm]. For noise with a frequency of 1.09 [GHz], one wavelength is 27.5 [cm]. For noise with a frequency of 2.0 [GHz], one wavelength is 15 [cm]. For noise with a frequency of 3.0 [GHz], one wavelength is 10 [cm]. For noise with a frequency of 6.0 [GHz], one wavelength is 5 [cm].

  Therefore, the main line 30 and the auxiliary line 40 that are transmitted at the same signal and are located at different positions from the ground potential portion may have different lengths. That is, in the cable arrangement structure and the vehicle electronic system in the above-described embodiment, the length of the main line 30 and the length of the auxiliary line 40 may be different from each other.

  For example, when the length of the main line 30 is 40 [cm], noise of 1.5 [GHz] is likely to be superimposed. In this case, the length of the auxiliary line 40 is set to 45 [cm]. That is, between the ECU 10 and the sensor 20, a 45 [cm] auxiliary line 40 that is 15 [cm] longer than the main line 30 is added as a wire harness for transmitting the same sensor signal as that of the main line 30 from the sensor 20. That is, the main line 30 and the auxiliary line 40 are configured to transmit the same sensor signal from the sensor 20, are arranged at positions different from each other in the distance from the ground potential portion, and have different lengths.

  In this example, the main line 30 has a characteristic that 1.5 [GHz] noise is easily superimposed, but 1.1 [GHz] noise is difficult to be superimposed. On the other hand, the auxiliary line 40 has a characteristic that noise of 1.5 [GHz] is not easily superimposed, but noise of 1.1 [GHz] is easily superimposed. Thus, the main line 30 and the auxiliary line 40 have different frequencies of noise that are easily superimposed.

  Thus, the frequency characteristics of the main line 30 and the frequency characteristics of the auxiliary line 40 can be made different by making the length of the main line 30 and the length of the auxiliary line 40 different. That is, noise (frequency) that is easily superimposed on the main line 30 and the auxiliary line 40 can be made different. Therefore, the influence of noise between the ECU 10 and the sensor 20 can be further reduced.

  In addition, it is preferable that the method for determining the length of the auxiliary line 40 is determined based on the upper limit of the noise frequency to be countered. For example, when the frequency of noise to be countered is 2 [GHz], the length of the auxiliary line 40 is obtained by additionally extending the length of one wavelength of the noise to the main line 30. As a result, the frequency characteristics of the main line 30 and the auxiliary line 40 are different up to a band of 2 [GHz], and the noise component superimposed on the sensor signal flowing on the main line 30 and the noise component superimposed on the sensor signal flowing on the auxiliary line 40 are also included. Will be different. In this way, by adjusting the length of the auxiliary line 40, the method of noise superposition is changed in the range of several MHz to several GHz. Therefore, it is possible to take measures against noise of several MHz to several GHz. That is, it is possible to reduce the probability that noise of the same frequency in the range of several MHz to several GHz is simultaneously superimposed on the sensor signal flowing on the main line 30 and the sensor signal flowing on the auxiliary line 40.

  In addition, although the technique which makes this main line 30 and the length of the auxiliary line 40 differ can be implemented in combination with the above-mentioned embodiment, it is also possible to implement independently.

  That is, it is an arrangement structure of a cable that is mounted on a moving body (for example, a vehicle) and electrically connects two electronic devices (for example, the ECU 10 and the sensor 20), and at least one electronic device (for example, a sensor) is used as the cable. 20) includes a plurality of cables (for example, main line 30 and auxiliary line 40) through which the same signal is transmitted to the other electronic device (for example, ECU 10). The distance between the moving body and the ground potential portion may be the same.

  As described above, since the electromagnetic environment of the vehicle changes as the vehicle moves, the electromagnetic environment tends to be complicated. That is, the electromagnetic environment is likely to be complicated with respect to the mounting environment of the ECU 10 and the sensor 20 mounted on the vehicle. Therefore, noise that is difficult to specify a frequency (that is, an unknown frequency) is easily superimposed on a signal communicated between the ECU 10 and the sensor 20 mounted on the vehicle.

  Therefore, in this way, the main line 30 and the auxiliary line 40 to which the same signal is transmitted have different lengths, and are arranged at the same distance from the ground potential portion in the moving body, thereby overlapping each other. This makes it possible to vary the noise (frequency) that is easily generated. Therefore, it is possible to reduce the probability that noise of the same frequency is simultaneously superimposed on the signals flowing through the main line 30 and the auxiliary line 40.

  That is, even if noise is superimposed on a signal flowing in one of a plurality of cables (for example, main line 30), noise having the same frequency as this noise is superimposed on a signal flowing in another cable (for example, auxiliary line 40). Can be suppressed. In other words, it becomes easy to communicate at least one signal on which no noise is superimposed between the ECU 10 and the sensor 20. Therefore, the influence of noise between the ECU 10 and the sensor 20 can be reduced. Further, a bypass capacitor specialized for noise in a specific frequency band is not used as in the prior art. Therefore, it is possible to deal with noise from several MHz to several GHz without limiting the noise frequency.

(Modification 1)
Here, as Modification 1, an example in which an engine ECU 10 and an intake pressure sensor 20 are employed as electronic devices will be described as shown in FIG. In other words, a specific example of the cable arrangement structure and the vehicle electronic system in the above-described embodiment will be described as a first modification. Accordingly, the processing operation in the vehicle electronic system is the same as that in the above-described embodiment, and thus the description thereof is omitted. In addition, the contents described in the above-described embodiment can be appropriately applied to the cable arrangement structure and the vehicle electronic system in the first modification.

  As mentioned above, the electromagnetic environment surrounding the vehicle is complex, especially the electromagnetic environment within the engine compartment. For example, in addition to the engine 200, spark plug, motor, and the like mounted in the engine compartment, the influence of external radio waves from a mobile phone or the like can be considered, and it is difficult to grasp the actual state of noise.

  Therefore, it is preferable to apply the cable arrangement structure and the vehicle electronic system of the present invention in the engine compartment. As an example, as shown in FIG. 4, the present invention can be applied to a wire harness that electrically connects the engine ECU 10 and the intake pressure sensor 20.

  As shown in FIG. 4, the intake pressure sensor 20 is mounted on the engine 200. On the other hand, engine ECU 10 is mounted at a position different from engine 200. The engine ECU 10 and the intake pressure sensor 20 are electrically connected by a main line 30 and an auxiliary line 40. The same sensor signal is transmitted (output) from the intake pressure sensor 20 to the main line 30 and the auxiliary line 40. Further, the main line 30 and the auxiliary line 40 are arranged at positions where the distance from the ground potential portion 54 is different. That is, the main line 30 and the auxiliary line 40 are arranged such that the distance between the auxiliary line 40 and the ground potential unit 51 is longer than the distance between the main line 30 and the ground potential unit 54. In other words, the auxiliary line 40 is disposed at a position farther from the ground potential portion 51 than the main line 30. That is, the main line 30 is arranged at a position closer to the ground potential portion 51 than the auxiliary line 40. As a result, the same effects as those of the above-described embodiment can be obtained.

(Modification 2)
Here, as a second modification, as shown in FIG. 5, an example in which an ABS (Anti-lock Braking System) ECU (electronic device) 10 and a wheel speed sensor (electronic device) 20 are employed as electronic devices will be described. In other words, a specific example of the cable arrangement structure and the vehicle electronic system in the above-described embodiment will be described as a second modification. Accordingly, the processing operation in the vehicle electronic system is the same as that in the above-described embodiment, and thus the description thereof is omitted. In addition, the contents described in the above-described embodiment can be appropriately applied to the cable arrangement structure and the vehicle electronic system in the second modification.

  In the modification 2, as shown in FIG. 5, the wheel speed sensor 20 is mounted in each tire (wheel) of the vehicle. On the other hand, the ABS ECU 10 is mounted in the vehicle interior. The ABS ECU 10 and the wheel speed sensor 20 are electrically connected by the main line 30 and the auxiliary line 40. The same sensor signal is transmitted (output) from each wheel speed sensor 20 to the main line 30 and the auxiliary line 40. For example, the wheel speed sensor 20 provided on the left front wheel and the ABS ECU 10 are electrically connected. The same sensor signal is transmitted (output) from the wheel speed sensor 20 to the main line 30 and the auxiliary line 40. Further, the main line 30 and the auxiliary line 40 are arranged at positions where the distance from the ground potential portion 55 is different. As a result, the same effects as those of the above-described embodiment can be obtained.

(Modification 3)
In the above-described embodiment, when the noise amounts of a plurality of sensor signals all exceed the threshold, the sensor signals (main line signal and auxiliary line signal) are temporarily not used, noise removal, etc. Although the example which performs a process was employ | adopted, this invention is not limited to this.

  The vehicle electronic system of the present invention may execute the processing operation shown in the flowchart shown in FIG. 6 (Modification 3).

  Note that steps S20 to S26 in the flowchart shown in FIG. 6 are the same as steps S10 to S16 in the flowchart shown in FIG.

  That is, in the determination process of step S25, when it is determined that the noise amount (B) of the auxiliary line signal has reached the threshold value (C) (B <C is not satisfied), the process proceeds to step S27.

  In step S27, the ECU 10 compares the noise amount (A) of the main line signal with the noise amount (B) of the auxiliary line signal, and if it is determined that A <B is not satisfied (A ≧ B), the ECU 10 proceeds to step S26. If it is determined that A <B, the process proceeds to step S28.

  In step S26, the ECU 10 uses the sensor signal (auxiliary line signal) received via the auxiliary line 40 as the detection result of the sensor 20 (the sensor signal output from the sensor 20, that is, the sensor signal not affected by noise). adopt. On the other hand, in step S28, the ECU 10 uses the sensor signal (main line signal) received via the main line 30 as the detection result of the sensor 20 (the sensor signal output from the sensor 20, that is, the sensor signal not affected by noise). adopt.

  In this way, when the noise amounts of the plurality of sensor signals received via the respective cables (main line 30 and auxiliary line 40) all exceed the threshold, the noise amounts of the received plurality of sensor signals are compared to determine the noise. You may make it select the sensor signal with the smallest quantity.

  By doing in this way, even if it is a case where the noise amount of the several sensor signal received via each cable (the main line 30 and the auxiliary line 40) has all exceeded the threshold value, at least 1 sensor signal (noise amount) Can be adopted as a received signal.

(Modification 3)
In the above-described embodiment, an example of selecting a sensor signal to be employed by comparing the noise amounts of a plurality of sensor signals with threshold values is employed, but the present invention is not limited to this.

  The vehicle electronic system of the present invention may execute the processing operation shown in the flowchart shown in FIG. 7 (Modification 4).

  First, in step S30, the ECU 10 receives a sensor signal from the sensor 20 (signal reception). Next, in step S31, the ECU 10 detects the noise amount (A) of the sensor signal (that is, main line signal) received via the main line 30 and the sensor signal (that is, auxiliary line signal) received via the auxiliary line 40. Noise amount (B) is calculated (noise amount calculating means).

  Next, in step S32, the ECU 10 compares the noise amount (A) of the main line signal with the noise amount (B) of the auxiliary line signal, and if it is determined that A = B, the process proceeds to step S33. If it is determined that it is not = B, the process proceeds to step S34.

  In step S33, the ECU 10 employs a sensor signal (main line signal) received via the main line 30 as a detection result of the sensor 20 (a sensor signal output from the sensor 20, that is, a sensor signal not affected by noise). .

  On the other hand, in step S34, the ECU 10 compares the noise amount (A) of the main line signal with the noise amount (B) of the auxiliary line signal, and determines that A <B, the process proceeds to step S35, where A < If it is determined that it is not B (A ≧ B), the process proceeds to step S36.

  In step S35, as in step S33, the ECU 10 detects the sensor signal (via the main line 30) as the detection result of the sensor 20 (the sensor signal output from the sensor 20, that is, the sensor signal not affected by noise). Main line signal) is adopted.

  In step S36, the ECU 10 uses the sensor signal (auxiliary line signal) received via the auxiliary line 40 as the detection result of the sensor 20 (the sensor signal output from the sensor 20, that is, the sensor signal not affected by noise). adopt.

  Thus, the noise amount of a plurality of signals received via each cable (main line 30 and auxiliary line 40) may be compared to select a signal with the smallest noise amount. In this way, a signal as a received signal can be selected without using a threshold value or the like.

  In the above-described embodiments and modifications, the example in which the mobile electronic system and the cable arrangement structure of the present invention are mounted on a vehicle (four-wheeled vehicle) is adopted, but the present invention is not limited to this. Absent. For example, the object can be achieved even when applied to a moving body such as a two-wheeled vehicle (motorcycle), a ship, an airplane, and a railway.

  Further, as described above, an ECU (engine ECU, ABS ECU) and a sensor (intake pressure sensor, wheel speed sensor) have been described as examples of the electronic device, but the present invention is not limited to this. For example, wheel speed sensor, acceleration sensor, yaw rate sensor, steering angle sensor, temperature sensor, air flow meter, O2 sensor, A / F sensor, engine control temperature sensor (water temperature sensor / intake air temperature sensor), oil temperature sensor, tire Air pressure sensor, auto air conditioner sensor (outside air sensor, solar radiation sensor, inside air sensor, suction temperature sensor, refrigerant pressure sensor, water temperature sensor), auto light sensor, liquid level sensor, rain sensor, exhaust gas detection sensor (CO, HC, CO2) Gas sensor), throttle position sensor, crank position sensor, cam position sensor, knock sensor, accelerator position sensor, steering sensor, yaw rate sensor, height control sensor, wheel speed sensor, torque sensor for electric power steering, supersonic sound Sensor, touch sensor, also various types of sensors, such as for navigation angular velocity sensor can be adopted. Further, various actuators such as an ABS actuator, an air bag, and an electronic slot can be employed. When an actuator is employed as the electronic device, a noise amount calculation function (noise amount calculation means) and a signal selection function (selection means) are mounted on the actuator.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the embodiment mentioned above at all, and various deformation | transformation are possible in the range which does not deviate from the meaning of this invention.

  10 ECU (Electronic Device), 20 Sensor (Electronic Device), 30 Main Line (Cable), 40 Auxiliary Line (Cable), 51-54 Ground Potential Unit, 100 Vehicle Electronic System (Mobile Electronic System), 200 Engine

Claims (8)

A cable arrangement structure that is mounted on a moving body and electrically connects two electronic devices,
The cable includes a plurality of cables that transmit the same signal from at least one electronic device to the other electronic device,
The cable arrangement structure, wherein the plurality of cables to which the same signal is transmitted are arranged at positions different from each other in the distance from the ground potential portion in the moving body.   2. The cable arrangement structure according to claim 1, wherein the same signal is transmitted, and the plurality of cables arranged at different positions from the ground potential portion have different lengths. Two electronic devices mounted on the moving body;
A cable for electrically connecting the two electronic devices,
The cable includes a plurality of cables that transmit the same signal from at least one electronic device to the other electronic device,
The plurality of cables to which the same signal is transmitted are arranged at positions where the distance from the ground potential portion in the moving body is different from each other,
Of the two electronic devices, an electronic device that receives a signal via the cable,
A noise amount calculating means for calculating a noise amount in a plurality of signals received via each cable;
Based on the amount of noise, from a plurality of signals received via each cable, selection means for selecting one signal to be adopted as a received signal;
A mobile electronic system comprising:   The mobile electronic system according to claim 3, wherein the selection unit compares the amount of noise with a threshold and selects a signal determined to be smaller than the threshold.   The noise amount calculation means calculates the noise amount of the first received signal, and when the selection means determines that the noise amount of the first received signal exceeds the threshold, the next received signal The mobile electronic system according to claim 4, wherein a noise amount of the signal is calculated.   The selection means compares the noise amounts of the plurality of received signals when the noise amounts of the plurality of signals received via the cables all exceed a threshold value, and the signal having the smallest noise amount is compared. The mobile electronic system according to claim 4, wherein the mobile electronic system is selected.   4. The mobile electronic system according to claim 3, wherein the selection unit compares the noise amounts of a plurality of signals received via the cables and selects a signal having the smallest noise amount.   The plurality of cables that are transmitted at the same signal and are arranged at different distances from the ground potential portion have different lengths. The described mobile electronic system.

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