Patent ID: 12261910

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all combinations of the features described in the embodiments are necessarily indispensable to the solution of the invention.

FIG.1illustrates a configuration example of a sensor system10according to one embodiment of the present invention. The sensor system10detects a physical quantity such as pressure or temperature in the ambient environment, and outputs a signal indicating a detection result to a control device20. The sensor system10may include a harness for transmitting the signal to the control device20. The harness is, for example, a wire, or may be a wiring other than a wire.

The control device20processes the signal received from the sensor system10. The control device20may control another device based on the processing result of the signal. The control device20is an engine control device (ECU) for controlling a vehicle engine, and the sensor system10is a pressure sensor for detecting pressure of any region of the engine as one example. The control device20may control the vehicle engine based on the signal from the sensor system10.

The sensor system10includes a plurality of sensor devices100for detecting physical quantities. The physical quantity is, for example, pressure, temperature, moisture or the like of the ambient environment, but it is not limited thereto. One sensor device100may detect one type of physical quantity or may detect a plurality of types of physical quantity. In the example ofFIG.1, the sensor system10includes a first sensor device100-1and a second sensor device100-2. The respective sensor devices100may be devices implemented in circuit boards different from each other. The circuit board in this specification may be a semiconductor substrate, a printed substrate, a flexible substrate or the like.

Each sensor device100has a physical quantity sensor112, a processing circuit110, a terminal115and a terminal117. In the identical sensor device100, the physical quantity sensor112and the processing circuit110may be implemented on the identical circuit board.

The physical quantity sensor112detects a physical quantity such as pressure and temperature. The physical quantity sensor112may output an electrical signal according to the detected physical quantity. For example, the physical quantity sensor112is a pressure sensor. The physical quantity sensor112may have a detection unit where the electrical resistance value changes according to the detected pressure value, and output an analog electrical signal according to the electrical resistance value.

The processing circuit110generates a signal including the detection result of the physical quantity sensor112. The processing circuit110may have an AD converter113for converting the analog signal from the physical quantity sensor112to a digital signal, and a logic circuit114for processing the digital signal. In this example, the signal output by the processing circuit110-1of the first sensor device100-1is referred to as a first signal S1, and the signal output by the processing circuit110-2of the second sensor device100-2is referred to as a second signal S2. Further, the first signal S1includes first data D1indicating the detection result of the physical quantity sensor112-1of the first sensor device100-1, and the second signal S2includes second data D2indicating the detection result of the physical quantity sensor112-2of the second sensor device100-2and the first data D1.

In this example, the logic circuit114-1of the first sensor device100-1outputs the first signal S1to the second sensor device100-2. The second sensor device100-2extracts the first data D1included in the input first signal S1. The processing circuit110-2may have a decoder116-2for extracting the first data D1from the first signal S1. In the decoder116-2, information indicating which bit of the first signal S1corresponds to the first data D1may be preset.

The logic circuit114-2of the processing circuit110-2generates and outputs the second signal S2that includes the first data D1extracted by the decoder116-2and the second data D2indicating the detection result of the physical quantity sensor112-2to the control device20. The control device20extracts the first data D1and the second data D2by decoding the second signal S2. According to such a configuration, the number of the harnesses connected to the control device20can be reduced. Particularly, when a plurality of sensor systems10are connected to the control device20, if each sensor device100is connected to the control device20, the number of the harnesses will become large. In contrast, according to this example, one sensor system10is connected to the control device20by one harness. Therefore, the number of the harnesses connected to the control device20where the harnesses tend to concentrate can be reduced.

In this example, the first signal S1and the second signal S2are digital signals. The processing circuit110-2may generate the second signal S2that complies with the protocol identical to that of the first signal S1. As one example, the protocol is a SENT protocol.

Each of the first signal S1and the second signal S2may have a plurality of data slots for storing data. The slot may be a group of bits in a signal. For example, a predetermined range of bits of the first signal S1and the second signal S2are assigned to the data slot. The decoder116-2extracts the first data D1from the data slots of the first signal S1. The logic circuit114-2may store the first data D1extracted by the decoder116-2and the second data D2in different data slots of the second signal S2.

FIG.2illustrates one example of a data format of the first signal S1and the second signal S2. The data format is information indicating a role assigned to each slot of the signal.

In this example, the first signal S1includes one or more messages M1, and the second signal S2includes one or more messages M2. Each message M has a synchronous slot Sync, a state slot Sta, a first data slot Data1, a second data slot Data2, and an error correction slot CRC.

The synchronous slot Sync is a slot indicating the boundary between the message and another message. The synchronous slot Sync of this example is arranged in the beginning of the message M and stores a predetermined data value. The state slot Sta stores the data indicating the state of any device of the sensor system10, or the state of a signal S. The state slot Sta may store error data when an abnormality are detected in any device of the sensor system10, may store data indicating the type of the physical quantity of the data stored in the data slot Data or the type of the physical quantity sensor112and so on, or may store data indicating a coefficient by which the data value is to be multiplied to calculate the upper limit value, the lower limit value, the physical quantity or the like of the data stored in the data slot Data. The state slot Sta may also store data indicating the version of the protocol of the signal S.

The first data slot Data1and the second data slot Data2store the data according to the physical quantity detected by the physical quantity sensor112. The error correction slot CRC stores data such as CRC codes for correcting data errors in the message.

The logic circuit114-1of this example stores the first data D1in any data slot of the first signal S1(the first data slot Data1in the example ofFIG.2). The decoder116-2extracts the first data D1from the first signal S1. The logic circuit114-2stores the first data D1in any data slot of the second signal S2(the first data slot Data1in the example ofFIG.2), and stores the second data D2in another data slot (the second data slot Data2in the example ofFIG.2).

In this way, the second signal S2including the first data D1and the second data D2can be generated. The processing circuit110-1and the processing circuit110-2may be circuits for processing the signals according to the identical protocol (for example, a SENT protocol).

FIG.3illustrates one example of a data format of the second signal S2. In this example, although the data format of the second signal S2is described, the first signal S1also has a data format identical to that of the second signal S2. The second signal S2of this example includes n messages M2-1to M2-n(where n is an integer number equal to or greater than 2).

Each of the n messages has two or more fast data slots and slow data slots. In this example, the first data slot Data1and the second data slot Data2correspond to two fast data slots. Also, some bits of the state slot Sta correspond to the slow data slot SD. InFIG.3, the state slots Sta1to Stan of the respective messages are shown side by side. As indicated by the dashed lines, the respective state slots Sta1to Stan include the slow data slots SD1to SDn.

The second signal S2is a signal where the predetermined data are divided and stored in the slow data slots of two or more messages M. In this example, the predetermined data are divided and stored in each of the slow data slots SD1to SDn of the n messages M2-1to M2-n. The control device20may detect slow data by combining each bit of the n slow data slots SD1to SDn included in the second signal S2. That is, one fast data is detected from one message, and one slow data is detected from a plurality of messages. Therefore, the slow data has a slower transmission speed of the data than that of the fast data.

The processing circuit110-1of this example stores the first data D1in the fast data slots of the first signal S1. Also, the processing circuit110-2stores the first data D1and the second data D2in the fast data slots of the second signal S2. The first data D1and the second data D2may be the data indicating pressure values.

The processing circuit110-2may store data indicating a physical quantity of a different type from the first data D1and the second data D2in the slow data slots of the second signal S2. For example, the processing circuit110-2stores data indicating temperature in the slow data slots. The temperature may be the temperature detected by the first sensor device100-1or may be the temperature detected by the second sensor device100-2. In this case, at least one of the first sensor device100-1and the second sensor device100-2has a temperature sensor.

According to such a configuration, the data whose detection period is desired to be shortened and the data whose detection period may be relatively long can be transmitted by an identical signal. For example, in the case where the engine is desired to be controlled to follow the pressure fluctuations at a high speed, but may follow the temperature fluctuations at a relatively low speed, the configuration of this example is effective.

As one example, the processing circuit110-2of the second sensor device100-2may store the data of the physical quantity such as temperature in the slow data slots of the second signal S2. In this case, the decoder116-2may not extract the slow data of the first signal S1. Therefore, the circuit scale of the decoder116-2can be reduced. The processing circuit110-1of the first sensor device100-1may or may not store the data in the slow data slots of the first signal S1. In any case, the decoder116-2may not extract the slow data of the first signal S1.

Also, the decoder116-2may extract the data of the data slots preset as the slots for storing the first data D1among the plurality of fast data slots. The circuit scale of the decoder116-2can be reduced by not extracting data of the other data slots.

The processing circuit110-1may also store error data of a predetermined bit value instead of the first data D1in the fast data slots when an abnormality is generated in the first sensor device100-1. In this way, the error data can be extracted by the decoder116-2with a small circuit scale. The processing circuit110-1may also store the error data in the state slot Sta. In this case, the decoder116-2also preferably extracts data of the state slot Sta. The processing circuit110-2may store the error data in the state slot Sta of the second signal S2when an abnormality is generated in any of the first sensor device100-1and the second sensor device100-2.

FIG.4illustrates another configuration example of the sensor system10. The sensor system10of this example is different from the example described inFIG.1toFIG.3in that the logic circuit114-1of the first sensor device100-1outputs the first signal S1together with a clock signal CLK synchronized with the first signal S1. The sensor system10has the same configuration as that of the example described inFIG.1toFIG.3other than the configuration related to the clock signal CLK.

The decoder116-2of the second sensor device100-2receives the first signal S1and the clock signal CLK. The decoder116-2extracts the value of each bit in the first signal S1by sampling the first signal S1according to the clock signal. According to such a configuration, the value of the first signal S1can be detected with high precision.

The second sensor device100-2may output the clock signal synchronized with the second signal S2together with the second signal S2to the control device20. The period of the second signal S2may be identical to or may be different from that of the first signal S1.

FIG.5Aillustrates another configuration example of the sensor system10. The sensor system10of this example is different from the respective examples described inFIG.1toFIG.4in that the first sensor device100-1has a decoder116-1and a terminal117-1, and each of the sensor devices100has a memory118and a terminal119. That is, the first sensor device100-1has a configuration identical to that of the second sensor device100-2. The other configurations are the same as any example described in theFIG.1toFIG.4.

In this example, one device of the sensor devices100for outputting the signal S to another sensor device100is referred to as a master side device, and the other device of the sensor devices100for outputting the signal to the control device20is referred to as a slave side device. In the example ofFIG.1toFIG.4, the first sensor device100-1is the master side device, and the second sensor device100-2is the slave side device. According to the configuration shown inFIG.5A, any sensor device100can function as the master side device, and also can function as the slave side device. In the example ofFIG.5A, the first sensor device100-1is the slave side device, and the second sensor device100-2is the master side device. The memory118of each of the sensor devices100stores setting information indicating whether the device is the master side or the slave side, and the logic circuit114of each of the sensor devices100may read the setting information Smst indicating that the corresponding sensor device100is the master side, or the setting information Sslv indicating that the corresponding sensor device100is the slave side from the memory118. The terminal119may store the setting information indicating whether each of the sensor devices100is the master side or the slave side in the memory118from outside. Also, the setting information indicating whether each of the sensor devices100is the master side or the slave side may also be input to the logic circuit114directly from outside instead of being stored in the memory118. The harness for connecting each device is provided corresponding to the setting information. The sensor system10may also include a switching unit for switching the output terminal of which sensor device100to connect to the harness of the control device20according to the setting information. Also in this case, since the master side device and the slave side device have an identical physical shape and internal structure, the colors and shapes of their exteriors may also be different to distinguish between the two. Also, when the master side device and the slave side device are connected in reverse, each of the sensor devices100or the control device20may also output an error signal.

The logic circuit114set as the master side stores the data from the corresponding physical quantity sensor112in the signal S. The logic circuit114set as the slave side stores the data from the corresponding decoder116and the data from the corresponding physical quantity sensor112in the signal S. According to such a configuration, each of the sensor devices100can function as a device of any of the master side and the slave side.

FIG.5Bhas only one of the sensor devices100used in the example ofFIG.5A. In this case, the sensor device100outputs a third signal S3. The sensor device100of this example includes a memory118, as is the case with the second sensor device100-2shown inFIG.5A. In the memory118, the setting information indicating that the sensor device100is used alone may be stored. The logic circuit114may read the setting information Ssgl indicating that the sensor device100is used alone from the memory118. The terminal119may store the setting information indicating that the device is used alone in the memory118from outside. The logic circuit114generates the third signal S3based on the data from the physical quantity sensor112.

The data for calibrating the output of the physical quantity sensor may be stored in the memory118described in theFIG.5AandFIG.5B. Also, the memory118can use a rewritable non-volatile memory such as a flash memory.

As described above, the sensor device100that can function as the master side or the slave side can also be used alone. Therefore, the sensor device100can be selectable to be the master side, the slave side or alone. Therefore, the logic circuit114includes a first generation function as a function when used as the slave side, for generating the second signal that includes the first data from the first signal input from outside and the second data indicating the detection result of the physical quantity sensor. Furthermore, the logic circuit114includes a second generation function as a function when used as the master side or alone, for generating the third signal that includes the second data indicating the detection result of the physical quantity sensor. Moreover, the three usage aspects can be switched by the setting information stored in the memory118. It is noted that the setting information in the case of functioning as the master side may also be the same as that of the case of being used alone.

FIG.6illustrates an exemplary arrangement of the first sensor device100-1and the second sensor device100-2. The first sensor device100-1and the second sensor device100-2of this example detect the gas pressure inside a gas pipe40for the intake gas or the exhaust gas of the vehicle engine to pass. In the gas pipe40, a filter30is provided to remove foreign substances and so on included in the gas passing through the gas pipe40. The first sensor device100-1detects the gas pressure inside the gas pipe40of the upstream side of the filter30. The second sensor device100-2detects the gas pressure inside the gas pipe40of the downstream side of the filter30. The upstream and the downstream refer to the positions along the flowing direction of gas. Clogging of the filter30and so on can be detected by detecting the gas pressure of the two positions sandwiching the filter30. Also, the distance between the sensor devices can be shortened and the length of the harness can be shortened, by combining the two sensor devices near the filter30as the first sensor device100-1and the second sensor device100-2. Also, the related two pressure values can be included in one signal and transmitted to the control device20.

FIG.7illustrates one example of the sensor system200. The sensor system200of this example includes a plurality of sensor systems10described inFIG.1toFIG.6. That is, the sensor system200includes a plurality of pairs of the first sensor device100-1and the second sensor device100-2. Normally, the greater the number of sensor devices100, the more harnesses are concentrated in the control device20. According to this example, since the sensor system10including two sensor devices100is connected to the control device20by one harness, the number of the harnesses connected to the control device20can be halved.

While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations or improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention.

The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order.