Patent Application
20080068128
Referring to
A vehicle-based electronic control unit (ECU) 16 for controlling passive entry functions is mounted within the vehicle structure of the vehicle 10 such as in a junction box 18 of the vehicle 10. The ECU 16 is coupled to a plurality of low frequency (LF) antennas 20 disposed at various locations of the vehicle for communicating with a portable communication device 18 that is typically carried by a user of the vehicle 10 for allowing the user access to the interior region 11 of the vehicle. The plurality of LF antennas 20 may be located in a driver side vehicle door 13, a passenger side vehicle door 14, a driver side mirror 22, a passenger side mirror 24, an engine compartment 26, or a trunk compartment 28. The plurality of LF antennas 20 are coupled to the ECU 16 via respective communication lines.
The portable communication device 18 is a portable electronic device that is capable of receiving an interrogation signal, such as a wake-up signal, from the ECU 16 and is responsive to the wake-up signal by broadcasting a response signal to the ECU 16. Preferably, the portable communication device 18 is a remote keyless entry (RKE) fob. The RKE fob typically broadcasts RF signals to a vehicle-based ECU 16 in response to a user actuating one of the plurality of switches commonly disposed on the face of the RKE fob for remotely actuating various vehicle entry functions such as unlocking and locking the vehicle doors, unlatching a trunk latch, or for activating and deactivating a vehicle alarm system 30.
The ECU 16 is enclosed by the housing 31 for protecting the ECU 16 from environmental conditions and debris. Preferably, the housing 31 is produced from a plastic or similar material which does not interfere or at least a portion of the housing 31 does not interfere with the broadcast of the signals to and from the ECU 16. Moreover, the housing 31 is mounted within the interior region structure 11 such that the interior structure or at least a part of the interior structure thereof is unshielded at low electromagnetic frequencies for allowing the broadcast of the communication between the ECU 16 and the exterior region 12 of the vehicle 10.
The LF transmitter 42 is coupled to the single antenna 34 disposed within the ECU 16. Preferably, the single antenna 34 is integrated within a printed circuit board 50 of the ECU 16. Integrating the single antenna 34 within the ECU 16 eliminates the requirement for additional wiring which would be required to couple the LF transmitter 42 to the single antenna 34. The RF receiver may be coupled to an RF antenna disposed external to the ECU. In an alternative embodiment, the both the LF transmitter 42 and the RF receiver 44 are coupled to the single antenna 34 for transmitting LF signals and receiving RF signals.
The wake-up signal generated by the LF transmitter 42 and broadcast by the LF antenna 34 typically has a transmission range of 2.5 m. Locating the ECU 16 centrally within the center console of the instrument panel 16 (shown in
Referring to
The portable communication device 18 carried by the user includes an LF receiver (not shown) coupled to a LF antenna (not shown) and a microcontroller (not shown) for receiving the wake-up signal from the ECU 16. An omni directional antenna is commonly used so that the wake-up signal broadcast by the ECU 16 may be detected by the LF antenna within the portable communication device 18 regardless of the orientation of the portable communication device 18; however, a 2D or a one dimensional antenna may be used. Preferably, the wake-up signal includes a preamble followed by a patterned signal. If the patterned data of the broadcast wake-up signal matches the data stored in the portable communication device 18, the microcontroller within the portable communication device 18 is woken up. Energizing the microcontroller only after the determination that matching data patterns are present assists in maintaining the longevity of the battery (not shown) that powers the microcontroller. Alternatively, the wake-up signal may not be patterned and the microcontroller may waken each time an energy field of sufficient magnitude or random noise is present.
The portable communication device 18 carried by the user attempting to access the vehicle 10 receives and validates the wake-up signal. Upon validation, the microcontroller within the portable communication device 18 will be fully energized. The microcontroller within the portable communication device 18 will control the broadcast of a response signal to the ECU 16 in the vehicle 10 in response to the receiving the wake-up signal.
The response signal broadcast by the portable communication device 18 is received by the RF receiver 44 of the ECU 16. The authenticity of the response signal is determined by the controller 40 of the ECU 16. If the controller 42 determines the response signal is valid, then the controller 40 commands a door control module (not shown) to unlock the corresponding vehicle door.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
