Electronic communication system and signal transmission method

Abstract

Provided is an electronic communication system and a signal transmission method, which can improve responsiveness when a control unit mounted on a vehicle is woken up from a low power consumption state. The electronic communication system includes a higher control unit and a vehicle control unit that controls a function unit mounted on a vehicle, the vehicle control unit is connected to the higher control unit through a lower communication line, a plurality of higher control units are connected to each other through a higher communication line, the higher control unit is started from a sleep state in response to receiving a first wake-up signal from the vehicle control unit through the lower communication line, the higher control unit determines a first transmission period based on a time required for other higher control units connected through the higher communication line to be started, and periodically transmits a second wake-up signal to the other higher control units at the determined first transmission period.

Description

Technical Field

[0001] This invention relates to electronic communication systems and signal transmission methods. Background Technology

[0002] In recent years, the functionality of vehicles has been continuously increasing. For example, research and development results related to improving fuel efficiency, which contributes to energy efficiency, have been applied to vehicles, and the functionality of ECUs (Electronic Control Units) that control engines and motors has been continuously developing. Along with such technological development, there is a tendency to increase the number of ECUs installed in vehicles, and there is a demand for more efficient communication between ECUs. For example, Patent Document 1 discloses a method in which, in an in-vehicle network system composed of LANs such as CAN (Controller Area Network), the transmission cycle of communication messages is changed to a preset transmission cycle based on the vehicle status.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-28547 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in vehicles with multiple ECUs, the power consumption of the ECUs cannot be ignored if all ECUs are always running. Therefore, it is considered to put the ECUs into a low-power state, such as sleep mode. However, ECUs in a low-power state need to be woken up before performing any actions. Therefore, there are concerns about reduced responsiveness if the ECUs are put into a low-power state.

[0008] The present invention was made in view of the following background, and its purpose is to improve the responsiveness of the control unit mounted in the vehicle when it is woken up from a low power consumption state.

[0009] Methods for solving problems

[0010] One way to achieve the above objective is an electronic communication system comprising: a vehicle control unit that controls functional units mounted on a vehicle; and a higher-level control unit connected to the vehicle control unit via a lower-level communication line, wherein a plurality of the higher-level control units are interconnected via the higher-level communication line, the higher-level control unit activating from a dormant state in response to receiving a first wake-up signal from the vehicle control unit via the lower-level communication line, the higher-level control unit determining a first transmission period based on the time required for other higher-level control units connected via the higher-level communication line to activate, and periodically transmitting a second wake-up signal to the other higher-level control units at the determined first transmission period.

[0011] The effects of the invention

[0012] According to the above structure, the responsiveness of waking up the higher-level control unit can be improved by using an electronic communication system including a control unit mounted in the vehicle. This allows the control unit to go into sleep mode without compromising signal transmission responsiveness. Therefore, by appropriately putting the control unit mounted in the vehicle into sleep mode, the energy efficiency of the vehicle's electronic communication system can be improved. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the vehicle control system.

[0014] Figure 2 This is a diagram illustrating a specific structural example of a vehicle control system.

[0015] Figure 3 This is a flowchart illustrating the operation of the vehicle control system.

[0016] Figure 4 This is a schematic diagram illustrating an example of the operation of a vehicle control system.

[0017] Figure 5 This is a timing diagram illustrating an example of the operation of a vehicle control system.

[0018] Figure 6 This is a timing diagram illustrating an example of the operation of a vehicle control system.

[0019] Label Explanation

[0020] 1: Vehicle control system (electronic communication system); 2: Central ECU (upper-level control unit); 11: Area A-ECU (upper-level control unit); 13: Area B-ECU (upper-level control unit); 33: TCU (vehicle control unit); 35: IVI-ECU (vehicle control unit); 41: Driver assistance ECU (vehicle control unit); 44: Camera; 50: ECU (vehicle control unit); 51: FI control unit (vehicle control unit); 52: Motor control unit (vehicle control unit); 53: BATT control unit (vehicle control unit); 54: Shift control unit (vehicle control unit); 57: Transmission unit; 60: ECU (vehicle control unit); 70: ECU (Vehicle Control Unit); 72: Lighting Control Unit (Vehicle Control Unit); 76: Electric Door Control Unit (Vehicle Control Unit); 77: A / C Control Unit (Vehicle Control Unit); 78: PW Control Unit (Vehicle Control Unit); 81: Entry Control Unit (Vehicle Control Unit); 82: Lighting Device; 83: Sensor; 84: Communication Unit; 91, 91A, 91B, 91C: Processor; 93, 93A, 93B, 93C: Memory; 94A, 94B, 94C: Startup Time Data; 95A, 95B, 95C: Identification Data; 96, 96A, 96B, 96C: Communication Unit; 97, 97A, 97B, 97C: Communication Unit; V: Vehicle. Detailed Implementation

[0021] Figure 1 This is a diagram showing the vehicle control system 1. Figure 2 This is a diagram showing a specific structural example of the vehicle control system 1.

[0022] The vehicle control system 1 consists of multiple ECUs that control the functional units mounted on the vehicle V. In the vehicle control system 1, the driving and various functions of the vehicle V are realized by controlling the functional units of the vehicle V. In this disclosure, the vehicle control system 1 corresponds to an example of an electronic communication system.

[0023] The vehicle V equipped with the vehicle control system 1 is, for example, a four-wheeled automobile. The specific form of the vehicle V is not limited. The vehicle V can also be an autonomous two-wheeled vehicle or other mobile entity. The vehicle V can be a vehicle using an internal combustion engine as its drive source, an electric vehicle using a motor as its drive source, or a hybrid vehicle using both an internal combustion engine and a motor.

[0024] Figure 1 The ECU included in the vehicle control system 1 is generally shown in... Figure 2 The figures show specific examples of the ECU of the vehicle control system 1. These figures illustrate an example of various ECUs mounted on a vehicle V and devices controlled by the ECU. They are not intended to limit the vehicle V, which is the subject of this disclosure, to possess [the ECU]. Figure 1 and Figure 2The vehicle control system 1 shown includes all ECUs and all functional units described below. For example, it does not have... Figure 2 The ECU shown is part of the vehicle V, and it is equipped with an ECU that is not in Figure 2 The vehicle V with the ECU shown is also an object of this disclosure. Furthermore, this disclosure is not intended to limit its application to functional units connected to the ECU as objects of control.

[0025] The vehicle control system 1 includes a central ECU 2 for overall control and information processing of the vehicle V. The central ECU 2 is connected to communication lines including communication lines B1, B2, and B10. The central ECU 2 functions as a gateway managing the transmission and reception of communication data between these communication lines. In this disclosure, the central ECU 2 corresponds to an example of a higher-level control unit.

[0026] The central ECU2 is connected to area A-ECU11 via communication line B1 and to area B-ECU13 via communication line B2. Area A-ECU11 and area B-ECU13 are further connected to one or more ECUs.

[0027] For example, ECU11 in area A is connected to ECUs 50A, 50B, 50C... via communication line B20. ECU13 in area B is connected to ECUs 60A, 60B, 60C... via communication line B30. Hereinafter, ECUs 50A, 50B, 50C... will be referred to as ECU50 without distinction, and ECUs 60A, 60B, 60C... will be referred to as ECU60 without distinction. ECU50 is the ECU controlled by ECU11 in area A, and ECU60 is the ECU controlled by ECU13 in area B.

[0028] Area A-ECU11 manages the transmission and reception of communication data between central ECU2 and ECU50. Area B-ECU13 manages the transmission and reception of communication data between central ECU2 and ECU60.

[0029] Additionally, the central ECU2 is connected to ECUs 70A, 70B, etc., via communication line B10. ECUs 70A and 70B are referred to as ECU70 without distinction. ECU70 can be considered the ECU controlled by the central ECU2.

[0030] The central ECU2 is connected to the TCU (Telematics Control Unit) 33 via communication line B3. The TCU 33 is a wireless communication device equipped with a communication antenna (not shown) and communication circuitry, capable of performing wireless data communication via cellular communication methods such as LTE (Long Term Evolution) and 5G (5th generation mobile communication). The TCU 33 is an example of a functional unit controlled by the central ECU2.

[0031] Additionally, the central ECU2 is connected to camera 44 via communication line B4. Camera 44 captures images of the interior or exterior of vehicle V. Camera 44 can be, for example, an MVC (Multi-View Camera) system containing multiple cameras. The central ECU2 can control camera 44 to perform image capture, acquire, and analyze the images captured by camera 44.

[0032] Figure 2 An example structure of a vehicle control system 1, including specific examples of ECUs 50, 60, and 70, is shown. Figure 2 In this example, the central ECU2 is connected to the IVI (In-Vehicle Infotainment) ECU35 via communication line B10. The IVI-ECU35 connects to the vehicle's navigation system, various cameras including a rear-view camera, audio players, monitors, touch panels, buttons and switches, speakers, microphones, and other in-vehicle equipment. The IVI-ECU35 controls the in-vehicle equipment to provide various information and entertainment to the occupants of vehicle V. For example, the IVI-ECU35 controls the start or stop of in-vehicle equipment, and other ECUs output data detected by sensors to the in-vehicle equipment.

[0033] Communication line B10, which is connected to the central ECU2, is connected to the driver assistance ECU41. The driver assistance ECU41 performs control to automatically park the vehicle V in a parking position, or assists the driver when parking the vehicle V. Functional components controlled by the driver assistance ECU41 include, for example, various cameras, monitors, touch panels, steering mechanisms, braking mechanisms, and accelerator devices mounted on the vehicle V.

[0034] Area A-ECU11 is connected to the FI (Fuel Injection) control unit 51, the motor control unit 52, the BATT (Battery) control unit 53, and the shift control unit 54 via communication line B20. These are examples of ECU50 and can be referred to as the functional units controlled by Area A-ECU11.

[0035] The fuel injection unit 51 controls the fuel injection quantity and timing in the internal combustion engine mounted on the vehicle V. Functional units controlled by the fuel injection unit 51 may include electronic fuel injection devices, and may also include sensors. Examples of sensors include O2 sensors, knock sensors, camshaft angle sensors, crankshaft angle sensors, intake air temperature sensors, and exhaust air temperature sensors.

[0036] The motor control unit 52 controls the rotational speed of the motor mounted on the vehicle V. Functional units controlled by the motor control unit 52 include an inverter circuit that supplies drive current to the motor, and may also include various sensors. The BATT control unit 53 performs control related to the driving battery mounted on the vehicle V. The BATT control unit 53 performs charging control, discharging control, and remaining charge management for the driving battery. The driving battery, a functional unit controlled by the BATT control unit 53, is the power source for driving the vehicle V. This driving battery is separate from the starting battery that supplies power to various parts of the vehicle control system 1, and is mounted on the vehicle V to supply drive power to the motor. The driving battery may be, for example, a lithium-ion secondary battery, a lithium polymer battery, a nickel-metal hydride battery, an all-solid-state battery, or other secondary batteries, and may also be a capacitor. In addition to the driving battery, functional units controlled by the BATT control unit 53 may also include a regeneration mechanism that uses the driving energy of the vehicle V to generate regenerated electricity. In contrast, the starting battery of vehicle V is a secondary battery that supplies power to various parts of the vehicle control system 1 when the power supply to vehicle V is disconnected, and is charged by the generator installed on vehicle V when vehicle V is in motion. For example, the starting battery is composed of lead-acid battery, other secondary batteries or capacitors.

[0037] The functional unit controlled by the shift control unit 54 is, for example, the transmission device 57. Figure 4 The shift control unit 54 controls the transmission device 57 based on the driving state of the vehicle V and the driver's operation. Examples of transmission devices 57 include stepper AT (Automatic Transmission), CVT (Continuously Variable Transmission), and DCT (Dual Clutch Transmission). Functional components controlled by the shift control unit 54 may also include a gear position sensor, a shift switch, and a shift lever.

[0038] Area B-ECU13 is connected to the headlight control unit 72, power door control unit 76, A / C control unit 77, PW (Power Window) control unit 78, and access control unit 81 via communication line B30. These are examples of ECU60 and can be referred to as functional units controlled by Area B-ECU13.

[0039] The functional part controlled by the headlight control unit 72 is the lighting device 82. Figure 4 The lighting device 82 includes lamps mounted on the vehicle V. Specifically, the lighting device 82 includes headlights, turn indicators, fog lights, brake lights, and reversing lights of the vehicle V, and may also include lamps that illuminate the interior and exterior of the vehicle V.

[0040] The functional components controlled by the electric door control unit 76 include, for example, actuators installed in the opening and closing section of the vehicle V. These actuators may include, for example, a motor for opening and closing the electric sliding door or electric rear door, and an actuator for unlocking the electric trunk lid. Alternatively, the actuators controlled by the electric door control unit 76 may also include actuators for locking and unlocking door locks installed in the opening and closing section. The electric door control unit 76 controls the actuators to unlock and lock the door locks of the vehicle V, and to open and close the electric sliding door or electric rear door.

[0041] The functional unit controlled by the A / C control unit 77 is the air conditioning unit (A / C) of the vehicle V. The A / C control unit 77 controls the air conditioning unit to cool and heat the interior of the vehicle V based on a set target temperature.

[0042] The functional unit controlled by the PW control unit 78 is the electric window device of the vehicle V, specifically, the actuator for opening and closing the window and the encoder for detecting the position of the window.

[0043] The functional units that are controlled by the access control unit 81 include sensor 83. Figure 4 ) and Ministry of Communications 84 ( Figure 4 Sensor 83 is disposed on the exterior or interior of vehicle V to detect a person's approach or contact with vehicle V. Communication unit 84 is a wireless communication device that communicates wirelessly with the FOB key or other electronic key of vehicle V. Access control unit 81 processes user access to vehicle control system 1 from outside the vehicle via sensor 83 and / or communication unit 84, realizing a so-called intelligent entry operation.

[0044] Communication lines B1–B4, B10, B20, and B30 consist of multiple communication transmission paths conforming to various communication standards. They are referred to as communication line B without distinction. Communication line B can be a data transmission path conforming to different communication standards. That is, the specific structure, transmission band, and communication standard of the cable constituting communication line B can be arbitrarily chosen. Examples of communication standards applicable to communication line B include CAN, Ethernet (registered trademark), USB (Universal Serial Bus), LIN (Local Interconnect Network), and LVDS (Low Voltage Differential Signaling), but other standards are also possible. Furthermore, each communication line B in… Figure 1 , Figure 2 as well as Figure 4 It is described as an independent communication line, but its specific structure is not limited. For example, it can be a bus-type structure that connects to multiple devices, or a structure that connects two devices one-to-one.

[0045] The vehicle control system 1 has a cascaded structure that connects multiple ECUs in a hierarchical manner. Specifically, the vehicle control system 1 includes ECUs directly connected to the central ECU 2 via communication lines B1 and B2, as well as ECUs connected to the central ECU 2 via other ECUs. The ECUs connected to the central ECU 2 via other ECUs are referred to as the vehicle control unit. Specifically, the vehicle control unit comprises ECU 50 connected to area A-ECU 11 and ECU 60 connected to area B-ECU 13.

[0046] exist Figure 2 In this example, the FI control unit 51, motor control unit 52, BATT control unit 53, and shift control unit 54 correspond to the vehicle control unit. Additionally, the headlight control unit 72, power door control unit 76, A / C control unit 77, PW control unit 78, and entry control unit 81 correspond to the vehicle control unit. The communication line B20 connecting area A-ECU 11 and the vehicle control unit, and the communication line B30 connecting area B-ECU 13 and the vehicle control unit, are referred to as lower-level communication lines.

[0047] Alternatively, the vehicle control unit may also include an ECU that controls the functions of the vehicle V from among the ECUs that are directly connected to the central ECU2. For example, TCU33, IVI-ECU35, and driver assistance ECU41 may also be included in the vehicle control unit.

[0048] Region A-ECU11 and Region B-ECU13 are directly connected to the central ECU2 and are configured between the vehicle control unit and the central ECU2. Region A-ECU11 and Region B-ECU13 perform adjustments to the communication between the vehicle control unit and the central ECU2. Region A-ECU11 and Region B-ECU13 correspond to an example of a higher-level control unit. The communication lines B1 and B2 connecting the central ECU2, Region A-ECU11, and Region B-ECU13 (which serve as higher-level control units) are called higher-level communication lines. In the higher-level control unit, the central ECU2 can be called the main control unit, and Region A-ECU11 and Region B-ECU13 can be called intermediate control units. The higher-level control unit, intermediate control unit, and main control unit are connected to the vehicle control unit and are the ECUs responsible for transmitting and processing data related to the control of the vehicle control unit.

[0049] The central ECU2, area A-ECU11, area B-ECU13, and other vehicle control units in the vehicle control system 1 can switch their operating states to normal operating states and low power consumption states. Figure 1 The same applies to the various ECUs not shown in the diagram.

[0050] The normal operating state of the vehicle control unit refers to the state in which it controls the functional units that are the objects of its control, and the state in which it is able to control the functional units that are the objects of its control. The normal operating state of the central ECU2, area A-ECU11, and area B-ECU13 refers to the state in which they send and receive control data related to the vehicle control unit and process the control data, and the state in which they are able to execute these actions. In contrast, the low-power consumption state is a state in which power consumption is lower than the normal operating state, and is also known as the sleep state.

[0051] When a wake-up signal is received from any of the communication lines B1-B4 connected to the central ECU2 in a low-power state, the central ECU2 starts up and transitions to its normal operating state. The wake-up signal can be, for example, digital data destined for the central ECU2, or a change in the voltage of communication lines B1-B4 to activate. Communication lines B1-B4 are, for example, one signal line or two differential signal lines of CAN or CAN-FD. In this case, communication lines B1-B4 are recessive in the low-power state of the central ECU2; if any of the communication lines B1-B4 becomes dominant, the central ECU2 detects the wake-up signal and starts up. Alternatively, the wake-up signal can also be a signal that selectively activates the central ECU2.

[0052] Similarly, in the low-power state of region A-ECU11, when any one of the communication lines B1 and B20 connected to region A-ECU11 becomes active, region A-ECU11 detects a wake-up signal and starts up. Additionally, in the low-power state of region B-ECU13, when any one of the communication lines B2 and B30 becomes active, region B-ECU13 detects a wake-up signal and starts up.

[0053] Similarly, the vehicle control unit also starts up and transitions to normal operation when it detects a wake-up signal in a low-power state. For example, the FI control unit 51, motor control unit 52, BATT control unit 53, and shift control unit 54 detect the wake-up signal and start up by sensing a change in the voltage of the communication line B20 from recessive to dominant.

[0054] The wake-up signal that activates the vehicle control unit connected to communication line B20 can also be a signal that selectively activates any one of the following control units: FI control unit 51, motor control unit 52, BATT control unit 53, and shift control unit 54. In this case, FI control unit 51, motor control unit 52, BATT control unit 53, and shift control unit 54 can selectively switch to a low-power state. The same applies to the headlight control unit 72, power door control unit 76, A / C control unit 77, and PW control unit 78 connected to communication line B30.

[0055] In the vehicle control system 1, it is not necessary for all ECUs to be in a normal operating state at all times. For example, when the vehicle V is parked and the power supply to the vehicle V is disconnected, the ECUs of the drive system, such as the FI control unit 51, the motor control unit 52, and the shift control unit 54, can be set to a low-power state. On the other hand, the entry control unit 81 needs to communicate with the FOB key when the driver wants to enter the vehicle V, so it needs to be in a normal operating state or a similar operating state. Therefore, in the vehicle control system 1, each ECU constituting the vehicle control system 1 is individually or in a predetermined number to be transferred to a low-power state. As a result, the power consumption of the vehicle control system 1 can be suppressed. Furthermore, the ECUs in the low-power state can be activated by detecting a wake-up signal flowing through the communication line B and then transferred to the normal operating state.

[0056] The central ECU2, area A-ECU11, area B-ECU13, and other ECUs equivalent to the vehicle control unit require a predetermined time from detecting a wake-up signal to transitioning to their normal operating state. This time is called the startup time. The length of the startup time varies depending on the type, function, and specifications of the ECU.

[0057] like Figure 1 As shown, the central ECU2 has a processor 91A, a memory 93A, and communication units 96A and 97A.

[0058] Communication units 96A and 97A are communication circuits that transmit and receive signals and data via communication lines B1 to B4. Communication units 96A and 97A may be constructed, for example, by an NM-GW (Network Management Gateway). Communication units 96A and 97A can be independent hardware or a single communication circuit.

[0059] Communication unit 96A is connected to communication lines B1 and B2. Communication unit 96A performs communication with area A-ECU 11 and area B-ECU 13. Communication unit 97A is connected to communication lines B3 and B4. Communication unit 97A performs communication with each ECU connected to communication lines B3 and B4.

[0060] The communication unit 96A receives signals transmitted via communication lines B1 and B2. When the central ECU2 is in a low-power state, if a wake-up signal is detected in either communication line B1 or B2, the communication unit 96A notifies the processor 91A. The communication unit 96A has the function of transmitting wake-up signals via communication lines B1 and B2 under the control of the processor 91A.

[0061] The communication unit 96A selects either or both of communication lines B1 and B2 to send a wake-up signal. In this case, the communication unit 96A periodically sends the wake-up signal until the device on the communication target side completes startup and transitions to normal operation. The sending period of the wake-up signal is a preset, predetermined period. This predetermined sending period corresponds to an example of the second sending period in this disclosure. Furthermore, the wake-up signal sent by the communication unit 96A corresponds to an example of the second wake-up signal.

[0062] The transmission period of the wake-up signal by the communication unit 96A is variable according to the control of the processor 91A. For example, the processor 91A determines the transmission period of the wake-up signal by the communication unit 96A. The communication unit 96A repeatedly transmits the wake-up signal at the transmission period specified by the processor 91A. In this case, the period specified by the processor 91A corresponds to an example of the first transmission period in this disclosure.

[0063] Furthermore, the communication unit 96A has the function of transmitting and receiving control data via communication line B1 or communication line B2. The control data is data related to the control of the vehicle control unit. For example, the communication unit 96A transmits and receives control data related to the function of the BATT control unit 53 in controlling the driving battery with area A-ECU 11. This control data is transmitted and received, for example, in the form of CAN or CAN-FD data frames. When transmitting control data via communication line B1 or communication line B2, the communication unit 96A performs transmission according to a control data transmission cycle. The control data transmission cycle is a cycle preset for the communication unit 96A or a cycle specified by the processor 91A; it is not a variable cycle. In this disclosure, the control data transmission cycle corresponds to an example of the fourth transmission cycle.

[0064] The communication unit 97A receives signals transmitted via communication lines B3 and B4. When the central ECU2 is in a low-power state, and a wake-up signal is detected in communication lines B3 and B4, the communication unit 97A notifies the processor 91A. The communication unit 97A has the function of transmitting a wake-up signal via communication lines B3 and B4 under the control of the processor 91A.

[0065] The communication unit 97A selects one or more of communication lines B3 and B4 to send a wake-up signal. In this case, the communication unit 97A periodically sends the wake-up signal until the device on the communication target completes startup and transitions to normal operation. The sending period of the wake-up signal is a pre-set, predetermined period.

[0066] Furthermore, the communication unit 97A has the function of transmitting and receiving control data via communication lines B3 and B4. This control data is transmitted and received, for example, in the form of CAN or CAN-FD data frames. When transmitting control data via communication lines B3 and B4, the communication unit 97A performs transmission according to a control data transmission cycle. The control data transmission cycle is a cycle preset for the communication unit 97A or a cycle specified by the processor 91A; it is not a variable cycle. In this disclosure, the control data transmission cycle corresponds to an example of the fourth transmission cycle.

[0067] Processor 91A may be composed of, for example, a CPU (Central Processing Unit), an MCU (Microcontroller Unit), or an MPU (Microprocessor Unit). Memory 93A is a rewritable, non-volatile storage device that stores programs executed by processor 91 and data processed by processor 91. Memory 93A may be composed of semiconductor storage devices such as flash memory (ROM), solid-state drive (SSD), or magnetic storage devices. Memory 93A may include RAM (Random Access Memory) forming working areas for temporarily storing programs and data. Processor 91A and memory 93A may also be composed of an integrated circuit (IC). Central ECU2 may be an integrated circuit that integrates processor 91A, memory 93A, and communication units 96A and 97A, or it may be a structure where they are separate hardware components.

[0068] The memory 93A stores startup time data 94A and identification data 95A.

[0069] Startup time data 94A indicates the startup time of the ECU connected to the central ECU2 via the host communication line. Figure 1 and Figure 2 In this example, the ECUs connected to the central ECU2 via the host communication line are region A-ECU11 and region B-ECU13. Therefore, the startup time data 94A includes the startup time of region A-ECU11 and the startup time of region B-ECU13.

[0070] Startup time data 94A can also be data pre-recorded with the startup time of region A-ECU 11. In this case, the startup time of region A-ECU 11 included in startup time data 94A is the designed time or the time obtained through measurement. Alternatively, processor 91A can update startup time data 94A by measuring the actual startup time required for region A-ECU 11. In this case, startup time data 94A represents the measured startup time of region A-ECU 11 when it started from a low-power state most recently or last. The startup time of region B-ECU 13 included in startup time data 94A is the same as the startup time of region A-ECU 11.

[0071] Identification data 95A indicates the corresponding function and the destination of the signal and data transmission for the signals and data received by the central ECU2. When a signal or data is received by the communication unit 96A or the communication unit 97A, the processor 91A refers to identification data 95A to determine the ECU and function related to the received signal or data.

[0072] The processor 91A switches the central ECU2 from a normal operating state to a low-power state based on the operating state of the vehicle V. If a wake-up signal is received by the communication unit 96A or 97A in the low-power state, the processor 91A starts up and switches back to the normal operating state.

[0073] Upon receiving a signal or data from communication unit 96A or communication unit 97A, processor 91A refers to identification data 95A to determine the function or ECU associated with the received signal or data. This signal includes a wake-up signal. Processor 91A performs processing based on the received signal or data, and based on the processing result, transmits the signal or data through communication unit 96A or communication unit 97A.

[0074] The processor 91A determines the transmission period of the wake-up signal when it is necessary to wake up other ECUs connected via the host communication line. In this embodiment, this action is performed when waking up region A-ECU11 or region B-ECU13.

[0075] The processor 91A can selectively execute a normal startup function and a high-speed startup function. The normal startup function is the function of sending a wake-up signal at a predetermined transmission cycle. The predetermined transmission cycle is preset for the processor 91A or the communication unit 96A, and the processor 91A will not change it. When executing the normal startup function, the processor 91A instructs the communication unit 96A to send a wake-up signal and specifies the predetermined transmission cycle.

[0076] The high-speed start function works as follows: it determines the transmission period of the wake-up signal corresponding to the start time of the ECU to be woken up, and sends the wake-up signal within the determined transmission period. When executing the high-speed start function, the processor 91A refers to the start time data 94A to determine the transmission period by doubling the start time of the ECU to be woken up, or by doubling the transmission period plus a margin. This transmission period can be longer or shorter than the predetermined transmission period. The processor 91A specifies the period determined based on the start time data 94A to the communication unit 96A and instructs the communication unit 96A to send the wake-up signal.

[0077] Region A-ECU11 includes a processor 91B, a memory 93B, a communication unit 96B, and a communication unit 97B. The functions and structures of the processor 91B, memory 93B, communication unit 96B, and communication unit 97B are the same as those of the processor 91A, memory 93A, communication unit 96A, and communication unit 97A, respectively.

[0078] The communication unit 96B is connected to the communication line B1 to perform communication with the central ECU2.

[0079] The communication unit 97B is connected to the communication line B20. The communication unit 97B performs communication with the ECU 50 through the communication line B20.

[0080] Region B-ECU13 includes a processor 91C, a memory 93C, a communication unit 96C, and a communication unit 97C. The functions and structures of the processor 91C, memory 93C, communication unit 96C, and communication unit 97C are the same as those of the processor 91A, memory 93A, communication unit 96A, and communication unit 97A, respectively.

[0081] The communication unit 96C is connected to the communication line B2 to perform communication with the central ECU2.

[0082] The communication unit 97C is connected to the communication line B30. The communication unit 97C performs communication with the ECU 60 through the communication line B30.

[0083] Memory 93B stores startup time data 94B and identification data 95B. Startup time data 94B represents the startup time of the ECU connected to region A-ECU11 via the host communication line. Figure 1 and Figure 2 In this example, the ECU connected to region A-ECU11 via the host communication line is the central ECU2. Therefore, the startup time data 94B includes the startup time of the central ECU2.

[0084] Memory 93C stores startup time data 94C and identification data 95C. Startup time data 94C represents the startup time of the ECU connected to region B-ECU13 via the host communication line. Figure 1 and Figure 2 In this example, the ECU connected to region B-ECU13 via the host communication line is the central ECU2. Therefore, the startup time data 94C includes the startup time of the central ECU2.

[0085] Startup time data 94B and 94C may be data that pre-records the startup time of the central ECU2. In this case, the startup time of the central ECU2 included in startup time data 94A is the designed time or the time obtained through measurement.

[0086] Alternatively, the processor 91B can also update the startup time data 94B by measuring the actual startup time required for the central ECU2. In this case, the startup time data 94B represents the measured startup time of the most recent or last startup of the central ECU2 from a low-power state. The startup time data 94C can also be the time measured by the processor 91C.

[0087] Hereinafter, processors 91A, 91B, and 91C will be referred to as processor 91 without distinction. Similarly, memories 93A, 93B, and 93C will be referred to as memory 93 without distinction. The startup time data 94A, 94B, and 94C will also be referred to as startup time data 94A, 94B, and 94C, as well as identification data 95A, 95B, and 95C. Furthermore, communication units 96A, 96B, and 96C, and communication units 97A, 97B, and 97C will be referred to as communication unit 96 or communication unit 97 without distinction.

[0088] In the vehicle control system 1, although the ECUs other than the central ECU 2, area A-ECU 11 and area B-ECU 13 are not shown, they have the same structure as the processor 91, memory 93, communication unit 96 and communication unit 97.

[0089] Figure 3 This is a flowchart illustrating the operation of the vehicle control system 1. Figure 3 The operation of the ECU connected to the host communication line is shown. Specifically, it shows... Figure 1 and Figure 2 The diagram illustrates the actions performed by the central ECU2, area A-ECU11, and area B-ECU13 in the structure shown. Specifically, processors 91A, 91B, and 91C are all capable of executing these actions. Figure 3 The actions of the processor 91B will be used as an example to illustrate the process.

[0090] When a wake-up signal is detected by the communication unit 97B in a low-power state (step S11), the processor 91B starts up (step S12). When the processor 91B completes the startup process and transfers to the normal startup function (step S13), it determines the function of the vehicle V related to the wake-up signal detected by the communication unit 97B (step S14).

[0091] In step S14, the processor 91B determines the function associated with the wake-up signal, for example, by identifying the ECU that is the source of the wake-up signal. Alternatively, the processor 91B determines the function associated with the wake-up signal based on data, identification codes, etc., attached to the wake-up signal.

[0092] Based on which function was determined in step S14, the processor 91B determines whether to execute the high-speed startup function (step S15). If the processor 91B determines that the high-speed startup function should not be executed (step S15; no), the processor 91B executes the normal startup function (step S16), and the communication unit 96B sends a wake-up signal at a predetermined transmission cycle (step S17).

[0093] If the processor 91B determines that the high-speed boot function needs to be executed (step S15; Yes), the high-speed boot function is executed. That is, the processor 91B refers to the boot time data 94B (step S18) and determines the transmission period corresponding to the boot time (step S19). The processor 91B transmits a wake-up signal through the communication unit 96B according to the transmission period determined in step S19 (step S20).

[0094] In the high-speed start function, by adapting the wake-up signal transmission cycle to the ECU's start-up time, the time from when the ECU completes the start-up process to when the transmission cycle is reached can be shortened. Therefore, it has the advantage that even when the ECU is in a low-power state, it can perform processes including ECU start-up within a short time. Therefore, the high-speed start function is preferably implemented because short response time is particularly effective for functions of vehicle V.

[0095] The functions that processors 91A, 91B, and 91C perform the high-speed startup function are those that require immediate response to the driver's or passenger's actions. Examples include functions 1 through 5 listed below.

[0096] The first function is as follows: in response to the driver or passenger approaching vehicle V, or performing operations on the doors of vehicle V, the door locks of vehicle V are unlocked. When this function is executed, in the vehicle control system 1, the access control unit 81 detects the approach of the FOB key and the opening / closing operation of the FOB key. The area B-ECU 13, the central ECU 2, and the electric door control unit 76 are activated. Under the control of the electric door control unit 76, the actuator unlocks the door.

[0097] The second function is as follows: when the driver or passenger approaches the vehicle V, or operates the door of the vehicle V, the transmission device 57 becomes operational. In the vehicle control system 1, when the access control unit 81 detects the approach of the FOB key or the opening and closing of the FOB key, the area B-ECU 13, the central ECU 2, the area A-ECU 11, and the shift control unit 54 are activated.

[0098] The third function is as follows: in response to the driver or passenger approaching vehicle V, or operating the doors of vehicle V, the exterior and interior lighting devices of vehicle V are illuminated. This lighting device is equivalent to a lighting device called a welcome lamp. When this function is executed, in the vehicle control system 1, the access control unit 81 detects the approach of the FOB key and the opening and closing of the FOB key. The area B-ECU 13, the central ECU 2, and the headlight control unit 72 are activated, and the welcome lamp is illuminated for a predetermined time under the control of the headlight control unit 72.

[0099] The fourth function is as follows: in response to the driver or the operation of the FOB key, the hazard lamp of vehicle V flashes. When this function is executed, in the vehicle control system 1, the access control unit 81 detects the operation of the FOB key, and the area B-ECU 13, the central ECU 2, and the headlight control unit 72 are activated. Under the control of the headlight control unit 72, the hazard lamp of the lighting device 82 flashes.

[0100] The fourth function is as follows: when the face of a pre-registered driver or passenger is recognized by camera 44, the door locks of vehicle V are unlocked. When this function is executed, in vehicle control system 1, central ECU2 recognizes the face of the pre-registered driver or passenger based on the image captured by camera 44, and central ECU2, area B-ECU13 and electric door control unit 76 are activated. Under the control of electric door control unit 76, the actuator unlocks the door.

[0101] The fifth function is as follows: when the face of a pre-registered driver or passenger is recognized by the camera 44, the welcome lights are illuminated. When this function is executed, in the vehicle control system 1, the central ECU 2 recognizes the face of the pre-registered driver or passenger based on the image captured by the camera 44. The central ECU 2, area B-ECU 13, and headlight control unit 72 are activated, and the welcome lights are illuminated for a specified time under the control of the headlight control unit 72.

[0102] The functions executed by processors 91A, 91B, and 91C as normal startup functions are those that can be performed without hindrance, such as those for driver or passenger operations, even if the response time requires hundreds of milliseconds to several seconds. For example, these are functions related to operations performed by the driver or passenger from a location remote from the vehicle V. Specific examples include functions 6 through 11 listed below.

[0103] The sixth function relates to situations where a driver or passenger uses a smartphone or other communication terminal to send commands to vehicle V via a communication network (not shown), server, etc. More specifically, the sixth function is the function of vehicle V to illuminate or flash the lighting device 82 based on commands from the communication terminal. This function is part of a function known as carfinder. When this function is executed, in vehicle control system 1, TCU 33 receives commands, and central ECU 2, area B-ECU 13, and headlight control unit 72 are activated. Under the control of headlight control unit 72, the lighting device 82 illuminates or flashes.

[0104] The seventh function is as follows: Similar to the sixth function, vehicle V receives a command from the communication terminal, and according to the command, causes the horn of vehicle V to sound. This function is part of a function known as vehicle locator. When this function is executed, in vehicle control system 1, TCU33 receives a command, and central ECU2, area B-ECU13, and a horn control unit (not shown) are activated. Under the control of the horn control unit, the horn sounds.

[0105] The eighth function is as follows: Similar to the sixth function, vehicle V receives an instruction from the communication terminal and, according to the instruction, sends the vehicle V's location information and map data containing the area of ​​vehicle V's location to the terminal device. This function is part of a function known as vehicle locator. When this function is executed, in vehicle control system 1, TCU33 receives the instruction, central ECU2 and IVI-ECU35 are activated, and the location information of vehicle V detected by IVI-ECU35 and the map data held by IVI-ECU35 are sent to the terminal device via TCU33.

[0106] The ninth function is as follows: Similar to the sixth function, vehicle V receives an instruction from the communication terminal and, according to the instruction, sends the photographic image captured by camera 44 to the terminal device. When this function is executed, in vehicle control system 1, TCU 33 receives the instruction, central ECU 2 is activated, central ECU 2 acquires the photographic image from camera 44, and, according to the instruction, the photographic image from camera 44 is sent to the terminal device via TCU 33.

[0107] The 10th function is as follows: Charging of the driving battery begins at a pre-set date and time via the vehicle V's timed reservation function. This timed reservation function is achieved, for example, by using the RTC (Real Time Clock) built into the IVI-ECU 35 to keep track of the date and time specified by the touch panel operation. When this function is executed, in the vehicle control system 1, the IVI-ECU 35 detects the arrival of the scheduled date and time, and the central ECU 2, area A-ECU 11, and BATT control unit 53 are activated. Under the control of the BATT control unit 53, charging of the driving battery begins.

[0108] The 11th function is as follows: Using the vehicle V's timed reservation function, the air conditioning unit can be started or stopped at a pre-set date and time. When this function is executed, in the vehicle control system 1, the IVI-ECU 35 detects the arrival of the scheduled date and time, and the central ECU 2, area B-ECU 13, and A / C control unit 77 are activated. Under the control of the A / C control unit 77, the air conditioning unit starts or stops operating.

[0109] The functions 1 through 11 mentioned above are just one example of the functions possessed by vehicle V. For other functions of vehicle V, processor 91 can also select and execute high-speed start function and normal start function according to the function.

[0110] Figure 4 This is a schematic diagram illustrating an example of the operation of vehicle control system 1. Figure 4 In the diagram, arrows indicate the startup sequence of the ECUs in vehicle control system 1. Figure 4 The startup sequence P1 shown represents the sequence related to the second function mentioned above, and the startup sequence P2 represents the sequence related to the sixth function.

[0111] As shown in the startup sequence P1, when executing the second function, the control unit 81 is activated by detection by sensor 83 or communication unit 84, triggering the activation of region B-ECU 13. Next, region B-ECU 13 activates central ECU 2, which in turn activates region A-ECU 11. Region A-ECU 11 then activates shift control unit 54, thereby enabling shift control unit 54 to control the transmission device 57.

[0112] The startup sequence P1 is an example of the functionality of the object used for high-speed startup.

[0113] As shown in the startup sequence P2, when performing the 6th function, the central ECU2 is started when the TCU33 receives an instruction, which in turn wakes up the area B-ECU13. The area B-ECU13 then wakes up the headlight control unit 72, which in turn causes the lighting device 82 to light up or flash.

[0114] Startup sequence P2 is an example of the functionality of an object that typically starts up.

[0115] Figure 5 This is a timing diagram illustrating an example of the operation of vehicle control system 1, and is related to... Figure 4 This is an example of the high-speed startup function corresponding to the startup sequence P1.

[0116] Figure 5 (a) shows the action of entering the control unit 81. Figure 5 (b) shows the operation of region B-ECU13. Figure 5 (c) shows the operation of the central ECU2. Figure 5 (d) shows the operation of region A-ECU11. Figure 5 (e) shows the operation of the shift control unit 54. Furthermore, in Figure 5 and Figure 6 For ease of understanding, the diagrams and explanations of the transmission delay of the vehicle control system 1 and the processing delay inside the ECU are omitted.

[0117] The entry control unit 81 is activated in response to detection by the sensor 83 or the communication unit 84, and begins sending a wake-up signal D to the communication line B20. The transmission of the wake-up signal D is repeated repeatedly from time T1, for example, at a period of 20 milliseconds. The transmission period of the wake-up signal D by the entry control unit 81 is a preset period. In this disclosure, the transmission period of the wake-up signal D corresponds to an example of the third transmission period. In this disclosure, the wake-up signal D corresponds to an example of the first wake-up signal.

[0118] Region B-ECU13 is activated at time T1 by detecting the wake-up signal D. The activation time of Region B-ECU13 is... Figure 5 In this example, the time is 32 milliseconds. Region B-ECU13 detects the wake-up signal D immediately after its startup is complete (at time T3) and, in response to the wake-up signal D, sends a wake-up signal E to the central ECU2. The wake-up signal E in this disclosure corresponds to an example of the second wake-up signal.

[0119] Region B-ECU13 selects either the high-speed start function or the normal start function based on the wake-up signal D received at time T3 after startup. Figure 5 In the example, the high-speed start function is selected. Region B-ECU13 determines the transmission cycle of the wake-up signal E based on the start time of the central ECU2 as represented by start time data 94C. For example, in Figure 5In the example, the startup time of the central ECU2 is 140 milliseconds. In this case, if the transmission period of the wake-up signal E is set to 70 milliseconds or 140 milliseconds, then the wake-up signal E will be received by the central ECU2 immediately after startup. The transmission period of the wake-up signal E has an upper limit depending on the specifications of the ECU and communication line B, therefore... Figure 5 In the example, the transmission period of the wake-up signal E is 70 milliseconds. Furthermore, to improve the reliability of the operation, it is preferable to include a certain margin in the transmission period. Therefore, region B-ECU13 sets the transmission period of the wake-up signal E to 75 milliseconds. In this case, central ECU2 detects the wake-up signal E at time T5, 10 milliseconds after central ECU2 completes startup, and sends the wake-up signal F to region A-ECU11. The time from central ECU2's startup completion to the detection of the wake-up signal E is essentially a loss of time without processing. By executing the high-speed startup function, the waiting time LT1 related to the startup of central ECU2 can be suppressed to 10 milliseconds.

[0120] The central ECU2 selects either the high-speed start function or the normal start function based on the wake-up signal E received at time T5 after startup. Figure 5 In the example, the high-speed start function is selected. The central ECU2 determines the sending cycle of the wake-up signal F based on the start time of region A-ECU11 represented by start time data 94A.

[0121] exist Figure 5 In the example, the start-up time of zone A-ECU11 is 170 milliseconds. In this case, if the sending period of the wake-up signal F is set to 45 milliseconds, 85 milliseconds, or 170 milliseconds, the waiting time can be shortened. To suit the constraints of the upper limit and margin of the sending period, the central ECU2 sets the sending period to 50 milliseconds. In this case, zone A-ECU11 detects the wake-up signal F at time T9, 30 milliseconds after zone A-ECU11 has finished starting, and sends the wake-up signal G to the shift control unit 54. The waiting time LT2 from the completion of zone A-ECU11's start-up to the detection of the wake-up signal F is 30 milliseconds, which is sufficiently short compared to the start-up time of zone A-ECU11.

[0122] exist Figure 5In the example, the central ECU2 can also send a notification signal W indicating startup completion to the area B-ECU13 upon startup completion. In this case, the area B-ECU13 can also detect the startup time of the central ECU2 based on the notification signal W and update the startup time data 94C. Similarly, the area A-ECU11 can also send a notification signal W to the central ECU2 upon startup completion, in which case the central ECU2 can also update the startup time data 94A based on the notification signal W.

[0123] Figure 6 This is a timing diagram illustrating an example of the operation of vehicle control system 1, and is related to... Figure 4 The startup sequence P2 corresponds to an example of a typical startup function.

[0124] Figure 6 (a) shows the action of TCU33. Figure 6 (b) shows the operation of the central ECU2. Figure 6 (c) shows the operation of region B-ECU13. Figure 6 (d) shows the operation of the headlight control unit 72.

[0125] After receiving the instruction via the communication function, TCU33 begins transmitting the wake-up signal H in communication line B3. The transmission of the wake-up signal H is repeated repeatedly, for example, at a period of 100 milliseconds, starting from time T11. The transmission period of the wake-up signal H by TCU33 is a predetermined period, a fixed period determined according to the specifications of TCU33 and communication line B3. This transmission period corresponds to an example of the third transmission period in this disclosure. The wake-up signal H corresponds to an example of the first wake-up signal in this disclosure.

[0126] Central ECU2 starts up upon detecting wake-up signal H at time T11. The startup time of central ECU2 is... Figure 6 In this example, the time is 140 milliseconds. At time T13 after the central ECU2 has completed its startup, it detects the wake-up signal H and, in response to the wake-up signal H, sends a wake-up signal I to region B-ECU13. In this disclosure, wake-up signal I corresponds to an example of the second wake-up signal.

[0127] exist Figure 6 In this example, the central ECU2 selects the normal startup function. The central ECU2 uses 80 milliseconds as the predetermined transmission period for the wake-up signal I. The central ECU2 transmits the wake-up signal I at 80-millisecond intervals.

[0128] Region B-ECU13 detects wake-up signal I at time T13 and starts up, completing the startup process after 170 milliseconds. In response to detecting wake-up signal I at time T16, Region B-ECU13 begins sending wake-up signal J to the vehicle lighting control unit 72.

[0129] exist Figure 6 In the example, the waiting time LT3 from the start of central ECU2 to the detection of wake-up signal H is 60 milliseconds. Additionally, the waiting time LT4 from the start of region B-ECU13 to the detection of wake-up signal I is 70 milliseconds. These waiting times are... Figure 5 The examples are long.

[0130] In vehicle control system 1, for functions requiring rapid response to driver and passenger operations, area A-ECU 11, area B-ECU 13, and central ECU 2 perform a high-speed start function. By performing the high-speed start function, waiting time is shortened, enabling rapid response. By reducing the waiting time for the ECU to wake up from a low-power state, the convenience of the driver and passengers is not compromised even when the ECU is switched to a low-power state. Therefore, the power consumption of vehicle control system 1 can be effectively suppressed by enabling the ECU to actively switch to a low-power state. Furthermore, for functions in vehicle control system 1 that allow for a slight delay, area A-ECU 11, area B-ECU 13, and central ECU 2 perform a normal start function. This reduces the processing load on central ECU 2, area A-ECU 11, and area B-ECU 13, as well as the transmission load on communication line B, ensuring operational stability.

[0131] Furthermore, the ECUs in the vehicle control unit other than the central ECU2, area A-ECU11, and area B-ECU13 send wake-up signals at a predetermined transmission cycle. This predetermined transmission cycle is determined based on the specifications of each ECU and communication line B, and is not changed. These ECUs are connected to communication line B, which serves as a shared bus for multiple ECUs. Therefore, by maintaining the unchanged transmission cycle, stable bus communication can be ensured, thus guaranteeing reliability.

[0132] exist Figure 6 In this example, zone B-ECU13 can also send a notification signal W to central ECU2 upon completion of startup. Central ECU2 can also detect the startup time of zone B-ECU13 based on the notification signal W and update the startup time data 94A.

[0133] The above embodiments illustrate a specific example of the application of the present invention and do not limit the way the invention is applied.

[0134] In the above embodiment, the structure in which the central ECU2, area A-ECU11, and area B-ECU13 can selectively perform high-speed start function and normal start function has been described, but this is only one example. For example, the central ECU2 may also be configured to perform only the normal start function. Alternatively, it may be configured such that ECUs that do not share a bus with other ECUs can selectively perform high-speed start function and normal start function.

[0135] Furthermore, the structure of the vehicle control system 1 shown in the above embodiment is one example, and various changes can be made to the type of ECU, the number of ECUs, and the structure of the device controlled by the ECU in the vehicle control system 1. Figure 3 The step units shown are divided according to the main processing content to facilitate understanding of the actions in the vehicle control system 1, and are not limited by the method or name of the processing unit division. They can also be divided into more step units based on the processing content. Alternatively, a single step unit can contain more processing steps. The order of the steps can also be changed appropriately.

[0136] Furthermore, the contents described in this embodiment can be combined appropriately. For example, structures 1 to 7 described below can be combined with any other structures.

[0137] The above implementation supports the following structures.

[0138] (Structure 1) An electronic communication system comprising: a vehicle control unit that controls functional units mounted on a vehicle; and a higher-level control unit, wherein the vehicle control unit is connected to the higher-level control unit via a lower-level communication line, and a plurality of the higher-level control units are interconnected via the higher-level communication line, wherein the higher-level control unit starts from a dormant state in response to receiving a first wake-up signal from the vehicle control unit via the lower-level communication line, and determines a first transmission period based on the time required for other higher-level control units connected via the higher-level communication line to start, and periodically transmits a second wake-up signal to the other higher-level control units in accordance with the determined first transmission period.

[0139] According to the electronic communication system of Structure 1, by including the control unit mounted in the vehicle, the responsiveness when waking up the upper control unit can be improved. Therefore, the upper control unit can be put into sleep mode without compromising its responsiveness. Thus, by appropriately putting the control unit mounted in the vehicle into sleep mode, the energy efficiency of the vehicle's electronic communication system can be improved.

[0140] (Structure 2) The electronic communication system of Structure 1, wherein the upper control unit switches and executes the normal start function and the high-speed start function as needed by the vehicle control unit sending the first wake-up signal. When executing the normal start function, the upper control unit sends the second wake-up signal at a predetermined second transmission cycle. When executing the high-speed start function, the upper control unit determines the first transmission cycle, which is different from the second transmission cycle, based on the time required for the other upper control units to start.

[0141] According to the electronic communication system of Structure 2, it is possible to selectively execute a high-speed startup function that determines the transmission period of the wake-up signal based on the startup time required by the upper control unit, and a normal startup function that sends the wake-up signal at a predetermined transmission period. Therefore, for functions requiring rapid response, the high-speed startup function can be used to improve responsiveness. Furthermore, regarding other functions, by utilizing the normal startup function, the processing load of the upper control unit and the transmission load in the communication line can be reduced, thereby improving operational stability. Therefore, both operational stability and rapid response can be achieved.

[0142] (Structure 3) An electronic communication system of Structure 1 or Structure 2, wherein the upper control unit determines the first transmission cycle based on the time required for the other upper control units to start in the past.

[0143] According to the electronic communication system of Structure 3, the transmission period of the wake-up signal can be determined based on the actual start-up time of the upper control unit. Therefore, an appropriate transmission period can be determined in correspondence with the state of the upper control unit.

[0144] (Structure 4) An electronic communication system of any one of Structures 1 to 3, wherein the upper control unit determines the first transmission cycle in such a way that the time required for the other upper control units to start in the past becomes the time obtained by doubling the first transmission cycle.

[0145] According to the electronic communication system of Structure 4, by setting a transmission cycle suitable for the time required for the upper control unit to start, the waiting time from the start of the upper control unit to the processing corresponding to the wake-up signal can be effectively shortened. Therefore, the responsiveness of the upper control unit in a low-power state can be further improved.

[0146] (Structure 5) An electronic communication system of any one of Structures 1 to 4, wherein the vehicle control unit transmits the first wake-up signal at a predetermined third transmission cycle, the upper control unit is capable of transmitting the second wake-up signal at a variable first transmission cycle, and the upper control unit transmits the second wake-up signal after performing the action of determining the first transmission cycle.

[0147] According to the electronic communication system of structure 5, the transmission period of the wake-up signal can be varied by the upper-level control unit, thereby improving responsiveness. Furthermore, since the vehicle control unit transmits the wake-up signal at a predetermined transmission period, it is possible to configure multiple vehicle control units to share a lower-level communication line. Therefore, both improved responsiveness and efficient communication line structure in the electronic communication system can be achieved.

[0148] (Structure 6) An electronic communication system of any one of Structures 1 to 5, wherein the upper control unit transmits a data frame containing control data of the vehicle control unit at a predetermined fourth transmission cycle, and transmits the second wake-up signal at the first transmission cycle.

[0149] According to the electronic communication system of Structure 6, the transmission period of the wake-up signal can be changed, and data frames, which account for the majority of the communication traffic in the communication line, are transmitted with a fixed transmission period. This improves responsiveness when starting from a low-power state and enables communication stabilization.

[0150] (Structure 7) A signal transmission method in an electronic communication system, wherein a higher-level control unit and a vehicle control unit that controls functional units mounted on a vehicle are connected via a lower-level communication line, and multiple higher-level control units are interconnected via a higher-level communication line. In the signal transmission method, the higher-level control unit is activated from a dormant state by sending a first wake-up signal from the vehicle control unit to the higher-level control unit via the lower-level communication line. The higher-level control unit determines a first transmission period based on the time required for other higher-level control units connected via the higher-level communication line to activate, and periodically sends a second wake-up signal to the other higher-level control units in accordance with the determined first transmission period.

[0151] According to the signal transmission method of structure 7, the responsiveness when waking up the upper control unit mounted in the vehicle can be improved. Therefore, the upper control unit can be put into sleep mode without compromising its responsiveness. Thus, by appropriately putting the control unit mounted in the vehicle into sleep mode, the energy efficiency of the vehicle's electronic communication system can be improved.

Claims

1. An electronic communication system, comprising: The vehicle control unit controls the functional units mounted on the vehicle; and Upper control unit, The vehicle control unit is connected to the upper-level control unit via a lower-level communication line, and multiple upper-level control units are interconnected via upper-level communication lines. The host control unit has a storage unit that stores the startup time required for other host control units connected to it via the host communication line. The upper-level control unit starts from the hibernation state in response to receiving a first wake-up signal from the vehicle control unit via the lower-level communication line. The upper-level control unit switches between and executes the normal start function and the high-speed start function based on the vehicle control unit that sent the first wake-up signal. When the upper-level control unit performs the normal startup function, it periodically sends a second wake-up signal to the other upper-level control units at a predetermined second transmission cycle. When the upper-level control unit executes the high-speed start function, it determines a first transmission period that is different from the second transmission period based on the time required for the other upper-level control units to start up, which is stored in the storage unit, and periodically sends the second wake-up signal to the other upper-level control units in the determined first transmission period.

2. The electronic communication system according to claim 1, wherein, The storage unit stores the startup time required for each of at least two other upper-level control units connected to the upper-level control unit via the upper-level communication line. The upper control unit determines the first transmission cycle based on the other upper control units that are the destination of the second wake-up signal, and on the time required for the other upper control units that are the destination to start up, which is stored in the storage unit.

3. The electronic communication system according to claim 1 or 2, wherein, The upper control unit determines the first transmission cycle based on the time required for the other upper control units to start in the past.

4. The electronic communication system according to claim 1, wherein, The upper-level control unit determines the first transmission cycle in such a way that the time required for the other upper-level control units to start in the past becomes the time obtained by doubling the first transmission cycle.

5. The electronic communication system according to claim 1, wherein, The vehicle control unit sends the first wake-up signal at a predetermined third transmission cycle. The upper control unit can send the second wake-up signal with a variable first transmission period, and the upper control unit sends the second wake-up signal after performing the action of determining the first transmission period.

6. The electronic communication system according to claim 1, wherein, The upper control unit sends a data frame containing control data of the vehicle control unit in a predetermined fourth transmission cycle, and sends the second wake-up signal in the first transmission cycle.

7. A signal transmission method in an electronic communication system, wherein a higher-level control unit and a vehicle control unit that controls functional units mounted on a vehicle are connected via a lower-level communication line, and multiple higher-level control units are interconnected via a higher-level communication line. In the signal transmission method, The upper control unit is activated from its sleep state by sending a first wake-up signal from the vehicle control unit to the upper control unit via the lower communication line. The host control unit has a storage unit that stores the startup time required for other host control units connected to it via the host communication line. The upper-level control unit switches between and executes the normal start function and the high-speed start function based on the vehicle control unit that sent the first wake-up signal. When the upper-level control unit performs the normal startup function, it periodically sends a second wake-up signal to the other upper-level control units at a predetermined second transmission cycle. When the upper-level control unit executes the high-speed start function, it determines a first transmission period that is different from the second transmission period based on the time required for the other upper-level control units to start up, which is stored in the storage unit, and periodically sends the second wake-up signal to the other upper-level control units in the determined first transmission period.

Images