JP2001040921A - Smart entry system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of the battery of a portable transceiver without increasing the number of component elements of the portable transceiver. SOLUTION: The transmission period of a question signal 2 is extended according to staying time during which a driver is situated in a vehicle's transmission and reception area when getting off the vehicle, so that a portable transceiver 10 requires much greater power in transmitting an answer signal 5 to the vehicle than in receiving the question signal 2 from the vehicle. Therefore, consumption of the battery 17 of the portable transceiver 10 can be reduced by reducing the number of times of unnecessary transmission and reception between a vehicle side transceiver 1 and the portable transceiver 10, without increasing the number of component elements of the portable transceiver 10 nor decreasing convenience.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology of a remote unlocking boarding system (keyless entry system) for controlling locking and unlocking of a door lock of a vehicle, and particularly to a door without operating a switch provided on a key. The present invention relates to a smart entry system that controls the smart entry.

[0002]

2. Description of the Related Art A keyless entry system which locks and unlocks a door by a switch provided on a key is known. As a next-generation type of this system, a key switch is eliminated, and the driver carrying the portable transceiver will unlock the door only by approaching the vehicle door, and lock the door only by moving away from the vehicle door. There is.

In this system, a transmitter / receiver is mounted on a vehicle, and a transmitter / receiver of the vehicle automatically transmits a signal to a portable transmitter / receiver.
The interrogation signal is transmitted periodically. The portable transceiver carried by the driver receives the interrogation signal and returns a response signal corresponding to the interrogation signal to the vehicle. This response signal is received by the vehicle-side transceiver, and it is determined whether the received response signal corresponds to the interrogation signal. If it is determined that the response is correct, the door is unlocked.

When the driver gets off the vehicle, an inquiry signal is transmitted from the vehicle, and since there is no response from the portable transceiver, it is detected that the driver has left the vehicle, and the door is locked. Do. In this way, the door can be locked and unlocked completely hands-free.

[0005]

A problem with the portable transceiver in such a system is that the portable transceiver must always be able to receive the interrogation signal from the vehicle. The power of the built-in battery (battery) is always consumed. Thus, the system life is limited by the battery life of the portable transceiver. In order to improve the convenience of the system, it is necessary to extend the life of the portable transceiver.

As a method of extending the life of a portable transceiver, a technique as disclosed in Japanese Patent Application Laid-Open No. Hei 10-46891 has been disclosed. This is achieved by providing a timer circuit in the portable transceiver and operating the transceiver unit according to the time period of the power pulse output from the timer circuit, that is, by intermittently operating the transceiver circuit of the portable transceiver with the timer circuit. It is intended to reduce the average power consumption of the transmitter / receiver.

In such a method, a timer circuit for controlling the transmission / reception circuit is required, which not only complicates the circuit configuration but also restricts the key in a limited space in a key grip (grip) as in a keyless system. There is a problem that it is very difficult to configure a timer circuit in addition to the transceiver.

It is an object of the present invention to extend the battery life of a portable transceiver without increasing the components of the portable transceiver.

[0009]

The present invention employs the technical means described in the claims to solve the above-mentioned problems.

According to the first aspect, when the driver gets off the vehicle, the transmission period of the interrogation signal is lengthened according to the staying time of the driver in the transmission / reception area of the vehicle.
When a driver is in the transmission / reception area of the vehicle, the vehicle needs to use much more power when transmitting a response signal to the vehicle than when receiving an inquiry signal from the vehicle. By reducing the number of transmissions and receptions between the transceiver and the portable transceiver, the battery consumption of the portable transceiver can be suppressed without increasing the number of components of the portable transceiver and without impairing the convenience.

According to the second aspect, the vehicle-side transceiver transmits the interrogation signal according to the transmission / reception operation time of the vehicle-side transceiver during the period of receiving the response signal to the interrogation signal from the portable transceiver. Includes means to increase the interval between occurrences,
It is possible to reliably recognize the presence of the driver and extend the generation interval of the interrogation signal.

According to a third aspect of the present invention, the means is configured to extend the interval of generating the interrogation signal in accordance with the number of generations of the interrogation signal of the vehicle-side transceiver. The intermittent time can be adjusted without using any means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a system configuration of a smart entry system according to an embodiment of the present invention.

As shown in FIG. 1, a vehicle-side transceiver 1 includes a transmission antenna 3 for transmitting an interrogation signal 2, a driver circuit 4 for supplying a current to the transmission antenna 3, and a response signal 5 from a portable transceiver 10. Antenna 6 for receiving the
A tuner 7 for demodulating the received response signal 5; a memory 8 for storing an encryption code for restoring the interrogation signal 2 transmitted from the encrypted response signal 5 from the portable transceiver 10; The ECU 9 controls the elements.

Further, the portable transceiver 10 includes a receiving antenna 11 for receiving the interrogation signal 2 from the vehicle-side transceiver 1,
A tuner 12 for demodulating the signal, a memory 13 storing an encryption code for encrypting the interrogation signal 2, a driver circuit 14 for transmitting the response signal 5 to the vehicle-side transceiver 1, and a transmission antenna 15 And an ECU 16 for controlling each component, and a battery 17 for supplying power to each component
Consists of

The operation of each component will be described by taking as an example a case where a driver gets on a vehicle. The vehicle-side ECU 9 drives the driver circuit 4 according to an arbitrary question code, and transmits the question signal 2 from the transmission antenna 3 by radio waves. The transmission from the vehicle is automatically and periodically performed with a different interrogation signal 2 each time.

A driver having the portable transceiver 10 approaches a transmission / reception area where mutual communication is possible and enters the transmission / reception area (for example, within a range of 1 to 2 m).

Here, the transmission / reception area is one of the transmission strength from the vehicle-side transceiver 1 and the reception sensitivity of the portable transceiver 10, or the transmission strength from the portable transceiver 10 and the reception sensitivity of the vehicle-side transceiver 1. Has been determined by

When entering the transmission / reception area, the portable transceiver 10 receives the interrogation signal 2 from the vehicle-side transceiver 1 by the reception antenna 11, demodulates the signal by the tuner 12, and inputs the signal to the ECU 16. The ECU 16 uses the demodulated interrogation signal 2 and the encryption code stored in the memory 13 to determine the response signal 5 according to a predetermined encryption algorithm.
Generate The ECU 16 drives the driver circuit 14 in response to the response signal, and transmits the response signal 5 via the transmission antenna 15.
Outgoing.

The vehicle-side transceiver 1 receives a response signal 5 transmitted from the portable transceiver 10 by a receiving antenna 6 and a tuner 7.
, Demodulated and input to the ECU 9.

The vehicle-side ECU 9 decodes the input response signal 5 using an encryption algorithm, and if the decoded result matches the transmitted inquiry signal 2, the authorized driver (portable transceiver 10) approaches. Recognize and unlock the door.

When the driver gets into the vehicle, the sensor (not shown) detects that the driver is in the vehicle, and the vehicle-side transceiver 1 stops emitting the interrogation signal 2.

Next, a case where the driver gets off the vehicle will be described. The vehicle-side transceiver 1 starts to generate the interrogation signal 2 by detecting that the driver is not in the vehicle or that the driver has left the seat by a sensor (not shown). Therefore, the interrogation signal 2 is transmitted from the vehicle in the same manner as when riding,
A response signal 5 from the portable transceiver 10 corresponding to the inquiry signal 2 is received. While receiving the response signal 5 from the driver (portable transceiver 10), the vehicle-side ECU 9 always repeats transmission and reception at certain time intervals, and does not lock the door.

This is because it is more convenient not to lock the door while in the transmission / reception area because the driver may try to get into the vehicle immediately after getting off the vehicle.

When the driver exits the transmission / reception area, the vehicle EC
After U9 cannot obtain a correct response signal, vehicle E
The CU 9 locks the door.

In this way, the door can be locked and unlocked without pressing the key switch.

If the driver stops in the transmission / reception area when the user gets off the vehicle, the driver always recognizes that the driver has left the transmission / reception area. It is necessary to repeat transmission and reception between and. At this time, in this embodiment, the transmission period of the interrogation signal 2 from the vehicle-side transceiver 1 is increased according to the staying time of the driver in the transmission / reception area of the vehicle, and the intermittent time T of the interrogation signal 2 is increased. Thus, the battery consumption of the portable transceiver 10 is suppressed.

Next, the control operation will be described. FIG. 2 is a flowchart of the embodiment of the present invention.

The control for reducing the battery consumption will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG.

When the driver gets off the vehicle, the vehicle ECU 9 detects this and sets the intermittent time T to the initial value αsec, sets the transmission counter N to N = 1, and transmits the first interrogation signal 2.

When the response signal 5 from the portable transceiver 10 can be received, the transmission counter N is set to a specified number m.
If the number of transmissions is equal to or less than m, the transmission counter N is incremented as N = N + 1, and the interrogation signal 2 is transmitted again at the intermittent time T = α.

When the number of transmissions (transmission counter N) becomes larger than m, the intermittent time T is lengthened by a constant value and the transmission of the interrogation signal 2 is repeated. As a method, a constant value β with respect to the previous value α is used as an equal difference (α + β) or an equal ratio (αγ).
(Α, β> 0) or a constant value γ (γ> 1). When the response signal 5 disappears, the vehicle-side ECU 9 locks the door, resets the intermittent time T and the transmission counter N to the initial values T = αsec, N = 1, and shifts to a normal unlocking wait. This makes it possible to lengthen the intermittent time T every m transmissions.

The effect of this embodiment is that if the interval (ie, the intermittent time) of the interrogation signal 2 transmitted from the vehicle-side transceiver 1 when getting off the vehicle is immediately increased, the interrogation signal 2 is not transmitted during the intermittent time, and Since the transceiver 10 cannot be detected, responsiveness when the driver leaves quickly deteriorates. On the other hand, in the present embodiment, the battery life can be extended without deteriorating the responsiveness (without deteriorating the convenience) by gradually increasing the intermittent time T, and the number of times of battery replacement can be reduced. Can be.

In the above-described embodiment, the intermittent time T is lengthened by a constant value β (or γ) every m times the interrogation signal 2 is transmitted. The same effect can be obtained even if the intermittent time T is increased according to the elapsed time immediately after getting off the vehicle.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a system configuration of a smart entry system according to an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle-side transceiver 2 Interrogation signal 10 Portable transceiver

Claims (3)

[Claims] 1. A vehicle-mounted transceiver mounted on a vehicle, which automatically and periodically transmits an interrogation signal, while a portable transceiver carried by a driver transmits the interrogation signal. In the smart entry system that locks and unlocks the vehicle door by determining whether the received response signal corresponds to the inquiry signal, In this case, the transmission period of the interrogation signal is made longer according to the staying time of the driver in the transmission / reception area of the vehicle. 2. The system according to claim 1, wherein the vehicle-side transceiver is configured to receive a response signal from the portable transceiver in response to the interrogation signal. 2. The smart entry system according to claim 1, further comprising means for lengthening the length of the smart entry. 3. The apparatus according to claim 2, wherein the means is configured to increase an interval between generations of the interrogation signal in accordance with the number of times the interrogation signal is generated by the vehicle-side transceiver.
The smart entry system according to 1.