JPH09216541A - Vehicular sensor signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a wire harness between an on-vehicle sensor and an on- vehicle electric equipment. SOLUTION: This device is the processing device of plural onvehicle sensor signals in a vehicular electric equipment system. The plural sensor signals are inputted in a specific electronic control unit for processing only that signal respectively and various electric equipment (EFI, ABS, car navigator) required respective sensor signals are connected to this electronic control unit ECU by a digital communication system. In the ECU, the preprocessing of respective sensor signals and the digital conversion are carried out and its processing information is distributed to respective electric equipment through the digital communication system. For example, a tire air pressure, vehicular travel direction are calculated by four wheels car speed and the data is transmitted to the car navigator by the said pre-processing. Thereby, the car navigation with high precision can be carried out.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vehicle electrical component,
For example, car navigation system (hereinafter referred to as car navigation system)
The present invention relates to a device that processes signals from various sensors mounted on a vehicle in a system such as a wheel speed sensor (rotation speed sensor).

[0002]

2. Description of the Related Art Today's vehicles are equipped with high-grade electronic components such as an electronically controlled injection device (EFI), an anti-lock brake device (ABS), and a car navigation system along with the progress of car electronics. A large number of various sensors are required, and the number of such sensors is increasing. FIG. 5 shows an example of today's in-vehicle electrical components and in-vehicle sensors required for them. In the figure, the sensor corresponding to "o" in the lateral direction of each electrical component is a sensor required for that electrical component.

Under such circumstances, each electric component (EFI,
ABS, etc.), as shown in FIG.
Generally, necessary sensors (wheel speed sensors, etc.) are connected by a wire harness a, and each electric component processes each sensor signal to perform various controls. In the figure, Sn is a meaning that the required sensor is provided as appropriate, a _n is the wire harness (hereinafter, the same).

At this time, even if each electric component requires the same sensor signal, one sensor is connected to each electric component through a wire harness. Also, the necessary sensors are connected to each electrical component. That is, when sensors with the same function are provided in duplicate (duplicate mounting)
There is also.

However, as described above, the number of electric wires in the wire harness a from each sensor is increasing, and the wire harness a from each sensor is becoming more complicated as the number of electric components mounted on the vehicle increases. This complication of the wire harness a causes difficulty in securing the harness routing path. Also, the redundant mounting of the above sensors is useless.

As a solution to the problem, Japanese Patent Laid-Open No. Hei 7 (1998)
In No. 1234883, a plurality of stations to which a plurality of sensors and a control device (electrical equipment) are selectively connected are coupled by a multiplex communication line, and each sensor is provided to at least one station of the plurality of stations. A centrally connected system is disclosed. That is, in this system, since the wire harness from each sensor to each station (electrical component) can be omitted, the above problem can be solved and the cost can be reduced.

However, in this system,
The electrical equipment to which each sensor is connected centrally connects, for example, each sensor arranged in the engine room to an EFI that requires the signal, and configures a parameter (sensor signal) supply device in the EFI. The device supplies the collected sensor signal to other electrical components that need it. In this case, the EFI must perform the engine control, which is the original function, in addition to supplying the sensor signal to each electric component after the necessary processing, and therefore the processing of the collected signal is limited. Further, if the both processes are to be carried out smoothly, the ability of the CPU must be improved, which leads to an increase in cost.

Under the above circumstances, it is an object of the present invention to simplify the wire harness while minimizing the cost increase of the current electrical equipment.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 is a processing device for a plurality of vehicle-mounted sensor signals in an electric system for a vehicle, wherein the plurality of sensor signals are transmitted as signals. Input to each specific electronic control unit that performs only processing, various electronic components that require each sensor signal are connected to this electronic control unit by a digital communication system, and each electronic control unit outputs each sensor signal. The pre-processing and the digital conversion thereof are performed, and the processing information is distributed to each of the electrical components via the digital communication system.
As the pre-processing, judgment / calculation of tire pressure, traveling direction, traveling speed, traveling acceleration, traveling angular velocity, traveling angular acceleration, tire slip degree, traveling distance, vehicle turning angle, etc. can be considered.

As described above, since the electronic control unit (ECU) for processing only the sensor signal is provided and the sensor signal is processed by this ECU and the necessary sensor signal is distributed to each electric component, the processing capacity of the ECU is sufficient. Therefore, the processing can be advanced. Further, since the respective sensor signals can be communicated only by the wire harness from the ECU to the electric components, the wire harness for sensor signal communication can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the plurality of sensor signals are respective rotation speed signals of the front and rear wheels, and the electrical component is a car navigation device, an antilock brake device, or It is configured as an anomaly indicator (meter).

As described above, when four rotation speed signals of the front wheels and the rear wheels are input to the ECU (see FIG. 2), the difference in the rotation speeds of the wheels (tires) is taken to determine whether the tire pressure is good or bad. And the traveling direction of the vehicle can be determined. That is, for example, as shown in FIG. 3, the rotation speeds of the wheels when traveling straight at a constant speed are C1, C2, C3, and C4, and {{(C1 + C
4)-(C2 + C3)} / (C1 + C2 + C3 + C
4)} is calculated, and if all the tire pressures are equal, at a certain vehicle (running) speed, the rotational speeds of the wheels are equal. Therefore, the value of the expression is 0. If the air pressure of the tire represented by C1 decreases, the radius from the center to the ground decreases, and at the same traveling speed, the number of rotations becomes larger than that of other wheels. Instead, the air pressure defect can be determined. At this time, in reality, each tire has wear, variations in air pressure within an appropriate range, slip, and the like. Therefore, a tire air pressure defect is determined in consideration of these factors. If the tire pressure is poor, it will be sent to the anomaly indicator to display that fact.

When the vehicle is traveling straight ahead, the rotation speeds of the wheels are equal (C1 = C2 = C3 = C4), but when the vehicle turns, the outer wheels are better than the inner wheels.
As the vehicle travels a longer distance, the wheel rotation speed increases. For example, in FIG. 3, C1 <C2, and it can be seen that the vehicle turned left. By calculating the difference between them, the turning angle is calculated,
The vehicle traveling direction is determined based on this turning angle. At this time, in reality, there are tire wear, slip, defective air pressure, and the like, so the vehicle turning angle (turning angle) is calculated in consideration of these factors. If the vehicle traveling direction is known, it can be used as a substitute for a gyro sensor in a car navigation system or the like (claims 3 and 4).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment is shown in FIG. 1, in which required components of the on-vehicle sensors shown in FIG. 5 are arranged at required positions, and the respective sensors are connected to an ECU by a wire harness a. Based on the sensor signals, the ECU performs pre-processing such as the above-mentioned pass / fail of the tire pressure and the traveling direction of the vehicle, and converts the sensor signal and the pre-processed value into a digital signal capable of multiplex communication, and the EFI, the car navigation, the meter. And so on. The multiplex communication is described in the above-mentioned publication, Japanese Patent Laid-Open No. Sho-6.
Well-known appropriate means described in, for example, JP-A 1-229195 is adopted.

At this time, the sensor signal and the preprocessed value are EC
Instead of directly transmitting from U to each electric component (ABS or the like), as shown in FIG. 2, it may be transmitted from another electric component. In the figure, the vehicle traveling direction is transmitted to the meter via the car navigation, and the air pressure is transmitted via the ABS. In this way, the communication path from the ECU to the meter for such information can be reduced. AB
In many cases, the S, car navigation system and meter require a communication path between them to display their contents.

[0016]

Since the present invention is configured as described above and is provided with the ECU dedicated to sensor signal processing, it is possible to significantly reduce the wire harness connecting each electric component and each sensor.

If the four-wheel vehicle speed is input to the ECU and various processing is performed and the processing data is distributed to the ABS, the car navigation system, and the meter, it is more accurate than the ABS that uses the one-wheel vehicle speed. Can be performed without increasing the wire harness (see FIG. 2).

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment.

FIG. 2 is a schematic diagram of another embodiment.

[Fig. 3] Explanatory view of four-wheel vehicle speed detection action

FIG. 4 is a schematic view of a conventional example.

[Fig. 5] Relationship table between in-vehicle sensor and in-vehicle electrical components

[Explanation of symbols]

 ECU Electronic control unit ABS Anti-lock brake device EFI Electronic control fuel injection device C1, C2, C3, C4 Wheel rotation speed a Wire harness

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Okamoto 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi In Harness Institute of Technology Co., Ltd. (72) Hiroe Ikeda 1-7 Kikuzumi, Minami-ku, Nagoya No. 10 Stock Company Harness Research Institute

Claims (4)

[Claims] 1. A processing device for a plurality of vehicle-mounted sensor signals in a vehicle electrical system, wherein the plurality of sensor signals are input to specific electronic control units that perform only the signal processing, and the electronic control units are provided with the above-mentioned Various electrical components that require each sensor signal are connected by a digital communication system, the electronic control unit performs preprocessing and digital conversion of each sensor signal, and the processed information is passed through the digital communication system. And a sensor signal processing device for a vehicle, wherein the sensor signal processing device is distributed to each of the electrical components. 2. The sensor signal for a vehicle, wherein the plurality of sensor signals are respective rotation speed signals of front and rear wheels, and the electrical component is a car navigation device, an antilock brake device, or an abnormality indicator. Processing equipment. 3. The electronic control unit is characterized in that the tire air pressure is calculated based on the rotation speed signals of the front and rear wheels, and the abnormality of the tire air pressure is transmitted and displayed on the abnormality indicator. The vehicle sensor signal processing device according to claim 2. 4. The electronic control unit is adapted to determine a traveling direction of a vehicle on the basis of respective rotational speed signals of the front and rear wheels, and to transmit the processing information to the car navigation device. Item 2. The vehicle sensor signal processing device according to Item 2.