Lock control apparatus for use in vehicle

A vehicle lock controller that is easily used. The controller is installed in a vehicle having a plurality of doors and controls locking of the doors through communication with a portable device. The controller includes transmitting circuits, each provided in association with a corresponding one of the doors to output a request signal and request the portable device to transmit a response signal. A control unit is connected to the transmitting circuits to intermittently output the request signal from each of the transmitting circuits at a predetermined cycle. The control unit determines a priority order of the transmitting circuits to set the predetermined cycle of the request signal output from each transmitting circuit in accordance with the priority order.

BACKGROUND OF THE INVENTION

The present invention relates to a lock control apparatus for use in a vehicle, and more particularly, to an apparatus for locking and unlocking a door of a vehicle without using a mechanical key.

In addition to improvement in basic performance and security, automobiles are nowadays required to be operated with more ease. To achieve such an object, a vehicle lock control system provided with a smart entry function has been proposed. The smart entry function automatically unlocks a door of a vehicle when the owner (driver) of the vehicle approaches the vehicle and locks the door when the driver moves away from the vehicle.

For example, as shown inFIG. 1, a vehicle lock control system51of the prior art includes a portable device52and a lock controller53, which is installed in the vehicle50. The lock controller53includes a control unit54, which is arranged in the passenger compartment, and first to fifth to transmitting circuits56ato56e,each of which is arranged on one of a plurality of (five) doors55ato55eof the vehicle50.

The control unit54intermittently transmits a request signal having a predetermined frequency from the transmitting circuits56ato56ein respective areas A1to A5. When the portable device52enters any one of the first to fifth areas A1to A5and receives the request signal, the portable device52transmits a radio wave signal (ID code signal) including an ID code in response to the request signal. When the control unit54receives the radio wave signal, the lock controller53compares the ID code included in the wireless signal with a stored ID code and unlocks the door when the two ID codes match. When the portable device52is separated from the first to fifth areas A1to A5and the radio wave signal cannot be received, the lock controller53locks the door. Thus, the driver does not have to perform any operations to lock or unlock the door. This makes it easier to operate the vehicle.

Referring toFIG. 2, in the prior art, the first to fifth transmitting circuits56ato56esequentially output the request signal so that only one request signal is output at any given time. In other words, the request signal is output from only one of the transmitting circuits56ato56eat any given time. Thus, the control unit54may confirm which one of the transmitting circuits56ato56egenerated the request signal to which the ID code signal was transmitted in response and acknowledge the door that the portable device52is located near. This unlocks only the door55ato55ethat is near the portable device52.

However, in the vehicle lock control system51of the prior art, the first to fifth transmitting circuits56ato56esequentially output the request signal. Thus, when the time for a single output of the request signal is represented by Δt, the cycle time T in which the request signal is output from all of the transmitting circuits56ato56eis represented by 5×Δt. For example, when the output time Δt is 0.3 seconds, the cycle time T is about 1.5 seconds. Thus, for example, if the driver enters the request signal output area A1of the first transmitting circuit56aimmediately after the first transmitting circuit56aoutputs the request signal, the driver must wait 1.5 seconds before the door is unlocked. Accordingly, in the vehicle lock control system51of the prior art, the communication response between the portable device52and the lock controller53is not satisfactory. Thus, the door may not be unlocked immediately even if the driver tries to open the door.

SUMMARY OF THE INVENTION

One aspect of the present invention is a vehicle lock controller installed in a vehicle having a plurality of doors to control locking of the doors through communication with a portable device. The vehicle lock controller includes a plurality of transmitting circuits, each provided in association with a corresponding one of the doors to output a request signal and request the portable device to transmit a response signal. A control unit is connected to the transmitting circuits to intermittently output the request signal from each of the transmitting circuits at a predetermined cycle. When receiving the response signal from the portable device, the control unit unlocks the door corresponding to the transmitting circuit that outputs the request signal to which the response signal is transmitted in response. The control unit determines a priority order of the transmitting circuits to set the predetermined cycle of the request signal output from each transmitting circuit in accordance with the priority order.

Another aspect of the present invention is a vehicle lock controller installed in a vehicle having a plurality of doors to control locking of the doors through communication with a portable device. The vehicle lock controller includes a plurality of transmitting circuits, each provided in association with a corresponding one of the doors to output a request signal and request the portable device to transmit a response signal. A control unit is connected to the transmitting circuits to intermittently output the request signal from each of the transmitting circuits at a predetermined cycle. When receiving the response signal from the portable device, the control unit unlocks the door corresponding to the transmitting circuit that outputs the request signal to which the response signal is transmitted in response. The control unit detects how often each door is used and stops the output of the request signal from transmitting circuits that are seldom used when a voltage value of a battery installed in the vehicle becomes lower than a predetermined threshold value.

A further aspect of the present invention is a method for controlling locking of a plurality of doors for a vehicle through communication with a portable device. The vehicle includes a plurality of transmitting circuits, each provided in association with a corresponding one of the doors to output a request signal and request the portable device to transmit a response signal. The method includes intermittently outputting the request signal from each of the transmitting circuits at a predetermined cycle, and when receiving the response signal from the portable device, unlocking the door corresponding to the transmitting circuit that output the request signal to which the response signal is transmitted in response. The method also includes setting the priority order of the transmitting circuits and setting the cycle of the request signal output from each transmitting circuit in accordance with the priority order.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3is a schematic plan view of a vehicle2provided with a vehicle lock control system1according to a preferred embodiment of the present invention. The vehicle lock control system1includes a portable device11, which is carried by an owner (driver) of the vehicle2, and a lock controller21, which is installed in the vehicle2.

As shown inFIG. 4, the portable device11includes a receiving circuit12, a transmitting circuit13, and a microcomputer14. The receiving circuit12is connected to the microcomputer14. The lock controller21transmits a request signal to the receiving circuit12. When receiving the request signal, the receiving circuit12demodulates the request signal to a pulse signal and provides the pulse signal to the microcomputer14.

The transmitting circuit13is connected to the microcomputer14and transmits an ID code signal, which is provided from the microcomputer14. More specifically, the transmitting circuit13modulates the ID code signal to a radio wave having a predetermined frequency (in the preferred embodiment, 314 MHz) and transmits the modulated radio wave. The receiving circuit12is connected to a receiving antenna15, and the transmitting circuit13is connected to a transmitting antenna16. The receiving circuit12receives the request signal via the receiving antenna15, and the transmitting circuit13transmits the ID code signal via the transmitting antenna16.

The microcomputer14is a central processing unit (CPU) including a ROM and a RAM (none of which are shown). When receiving the request signal from the receiving circuit12, the microcomputer14generates a transmission signal (ID code signal), which includes a predetermined ID code, and provides the ID code signal to the transmitting circuit13.

The lock controller21includes first to fifth transmitting circuits22ato22eand a control unit23.

As shown inFIG. 3, the first transmitting circuit22ais located in a right front (driver's) door3a,and the second transmitting circuit22bis located in a front left door3b.The third transmitting circuit22cis located in a rear right door3c,and the fourth transmitting circuit22dis located in a rear left door3d.The fifth transmitting circuit22eis located in a hatch (back door)4.

As shown inFIG. 4, the first to fifth transmitting circuits22ato22eare respectively connected to transmitting antennas24ato24e.The transmitting circuits22ato22econvert the request signal provided from the control unit23(more specifically, a microcomputer26) to a radio wave or a magnetic signal and transmit the converted signal from the respective antennas24ato24eto predetermined areas around the vehicle2.

Referring toFIG. 3, the first transmitting circuit22atransmits the request signal to area A1, which is defined near the driver's door3a,and the second transmitting circuit22btransmits the request signal to area A2, which is defined near the front left door3b.The third transmitting circuit22ctransmits the request signal to area A3, which is defined near the rear right door3c,and the fourth transmitting circuit22dtransmits the request signal to area A4, which is defined near the rear left door3d.The fifth transmitting circuit22etransmits the request signal to area A5, which is defined near the back door4. Accordingly, mutual communication between the portable device11and the lock controller21is enabled in the areas A1to A5, in which the request signal is transmitted. In the referred embodiment, the request signal is transmitted as a radio wave at 134 kHz.

The control unit23is located near the middle of the vehicle2and connected to the transmitting circuits22ato22e.As shown inFIG. 4, the control unit23includes a receiving circuit25and the microcomputer26.

The receiving circuit25receives the ID code signal transmitted from the portable device11via an antenna27, demodulates the ID code signal to a pulse signal, and generates an input signal. The input signal is provided to the microcomputer26.

The microcomputer26is a CPU, which includes a ROM and a RAM (none of which are shown), and has a non-volatile memory26a.The memory26astores a predetermined ID code (hereinafter referred to as reference ID code). The microcomputer26provides the first to fifth transmitting circuits22ato22ewith the request signal in different cycles, generates only one request signal at any given time, and provides the request signal to only one of the transmitting circuits22ato22eat any given time.

When receiving the request signal, the transmitting circuits22ato22econvert the request signal to a radio wave and transmits the converted radio wave to the areas A1to A5via the transmitting antennas24ato24e,respectively. Thus, the transmitting circuits22ato22eintermittently transmits the request signals to the corresponding areas A1to A5.

The microcomputer26is connected to door courtesy switches31, a battery32and a door lock drive device33. The door courtesy switches31are each arranged in one of the doors3ato3dand4and used to detect whether the associated door3ato3dand4is opened. The battery32is a conventional battery installed in the vehicle2. The door lock drive device33includes an actuator for driving the door locks and controls the actuator with an electric signal.

The ID code signal is transmitted from the portable device11in response to the request signal from one of the transmitting circuits22ato22e.When receiving the input signal (ID code signal) from the receiving circuit25, based on the input timing, the microcomputer26determines the transmitting circuit22ato22ethat transmitted the request signal to which the ID code signal was transmitted in response. The microcomputer26compares the ID code included in the ID code signal with a reference ID code to perform ID code verification. When the two ID codes match, the microcomputer26provides the door lock drive device33with a drive signal so that the door3ato3dor4corresponding to the transmitting circuit22ato22ethat transmitted the request signal to which the ID code signal was transmitted in response is unlocked. When the receiving circuit25does not receive the ID code signal or the two ID codes do not match, the microcomputer26provides the door lock drive device33with a drive signal so that the doors3ato3dand4are locked or remain locked.

The memory26aof the microcomputer26stores parameters that determine the output pattern of the request signal sent to the first to fifth transmitting circuits22ato22e.In the preferred embodiment, the memory26astores parameters so that in the initial setting, the output cycle of the request signal becomes longer in the order of the first transmitting circuit22a,the second transmitting circuit22b,the fifth transmitting circuit22e,the fourth transmitting circuit22d,and the third transmitting circuit22c.Thus, the microcomputer26provides the first transmitting circuit22awith the request signal having the shortest cycle and the third transmitting circuit22cwith the request signal having the longest cycle.

The microcomputer26determines a priority order of the first to fifth transmitting circuits22ato22e.The first transmitting circuit22ais given the highest priority, and the third transmitting circuit22cis given the lowest priority.

More specifically, referring toFIG. 5, the cycle time of the request signal output from the first transmitting circuit22ais represented by T1. The cycle time T1is three times greater than the output time Δt of the request signal (3×Δt). For example, if the output time at is 0.3 seconds, the cycle time T1is about 0.9 seconds.

Therefore, the cycle time T1is shorter than the cycle time T in the prior art by 0.6 seconds. During period ΣT1(5×T1) in which the microcomputer26provides the first transmitting circuit22awith the request signal five times, the microcomputer26provides the second transmitting circuit22bwith the request signal four times. During the same period ΣT1, the microcomputer26provides the request signal to the fifth transmitting circuit22ethree times, the fourth transmitting circuit22dtwice, and the third transmitting circuit22conce at predetermined timings. The microcomputer26constantly provides one of the first to fifth transmitting circuits22ato22ewith the request signal.

In the preferred embodiment, the cycle time T1of the request signal provided to the first transmitting circuit22ais three times greater than the output time Δt of the request signal. During the output cycle T1, when the request signal is not provided to the first transmitting circuit22a,the request signal is provided to two of the second to fifth transmitting circuits22bto22e.As shown inFIG. 5, the request signals are repeatedly provided to the transmitting circuits22ato22ein a cycle during period ΣT1.

In the vehicle lock control system1, when the owner (driver) of the portable device11approaches the driver's door3a,mutual communication is performed between the portable device11and the lock controller21most frequently. When the driver approaches the rear right door3c,mutual communication is performed between the portable device11and the lock controller21least frequently. Since the driver uses the driver's door3amost frequently, the convenience for locking and unlocking the door is improved.

The microcomputer26of the lock controller21obtains the usage frequency of each of the doors3ato3dand4based on the communication with the portable device11and the activation of the corresponding door courtesy switches31. More specifically, when detecting the opening of the doors3ato3dand4from the activation of the courtesy switches31, the microcomputer26determines which one of the areas A1to A5the portable device11is located in. The microcomputer26counts the number of times each of the doors3ato3dor4is opened when the portable device11is located in the respective areas A1to A5and stores the counted numbers in the memory26a.

For example, when the portable device11is located in area A1, which is near the driver's door3a,and the driver's door3ais opened, the microcomputer26determines that the driver's door3ahas been used and counts the opening of the driver's door3a.When the front left door3bis opened but the portable device is located in area A1, the microcomputer26does not count the opening of the front left door3b.

The microcomputer obtains the usage frequency of each of the doors3ato3dand the back door4based on the usage number recorded in the memory26a.For example, in the past ten usages, if the driver's door3ahas been used four times, the front left door3bhas been used three times, the back door4has been used twice, the rear left door3dhas been used once, and the rear right door3chas never been used, the microcomputer26determines that the driver's door3ais most frequently used and the rear right door3cis least frequently used.

The microcomputer26changes the initially set output pattern of the request signal based on the usage frequency. More specifically, based on the usage frequency of the doors3ato3dand4, the microcomputer26determines the priority order from the transmitting circuit corresponding to the most frequently used door (in this case, the first transmitting circuit22a) to the transmitting circuit corresponding to the least frequently used door (in this case, the third transmitting circuit22c). The microcomputer26provides transmitting circuits having a higher priority with a request signal having a shorter cycle and transmitting circuits having a lower priority with a request signal having a longer cycle.

Therefore, if, for example, the back door4is used most frequently and the usage frequency decreases in the order of the driver's door3a,the rear right door3c,the rear left door3d,and the front left door3b,the microcomputer26sets the request signal of the fifth transmitting circuit22eto have the shortest output cycle. Then, the microcomputer26increases the output cycle of the request signal for the remaining transmitting circuits in the order of the first transmitting circuit22a,the third transmitting circuit22c,the fourth transmitting circuit22d,and the second transmitting circuit22b.In other words, the microcomputer26is provided with a learning function for automatically adjusting the output cycle of the request signal for the first to fifth transmitting circuits22ato22ein accordance with the history of the usage frequency of the doors3ato3dand4.

The microcomputer26calculates the relative usage frequency rate of each of the doors3ato3dand4. More specifically, the microcomputer26calculates the usage frequency rate based on the counted usage number of each of the doors3ato3dand4recorded on the memory26a.For example, the usage frequency rate in the above example is 40% for the driver's door3a,30% for the front left door3b,20% for the back door3a,10% for the rear left door3d,and 0% for the rear right door3c.In this case, the microcomputer26provides the first transmitting circuit22awith the request signal during 40% of the period ΣT1and the second transmitting circuit22bwith the request signal during 30% of the period ΣT1. Further, the microcomputer26provides the fifth transmitting circuit22ewith the request signal during 15% of the period ΣT1, the fourth transmitting circuit22dwith the request signal during 10% of the period ΣT1and the third transmitting circuit22cwith the request signal during 5% of the period ΣT1. Thus, as a usage frequency of a certain one of the doors3ato3dand the back door4increases, the request signal is generated at a high frequency when the person carrying the portable device11moves near or away from that door3ato3dor4.

Further, the microcomputer26monitors the voltage value of the battery32based on a signal provided from the battery32. Referring toFIG. 6, when the voltage value of the battery32becomes less than a predetermined threshold value, the microcomputer26reduces the percentage the output time of the request signal occupies during a predetermined period time (period ΣT2inFIG. 6). More specifically, the microcomputer26provides the first transmitting circuit22awith a request signal during cycle time T1. When the request signal is provided to the first transmitting circuit22aten times during period ΣT2(10×T1), the microcomputer26provides the second transmitting circuit22bwith the request signal four times.

Further, during period ΣT2, the microcomputer26provides the fifth transmitting circuit22ewith the request signal three times at a predetermined timing, the fourth transmitting circuit22dwith the request signal twice at a predetermined timing, and the second transmitting circuit22bwith the request signal once at a predetermined timing. In other words, the microcomputer26decreases the number of times the request signal is provided to the second to fifth transmitting circuits22bin comparison to when the voltage value of the battery32is greater than or equal to the threshold value. Thus, as shown by arrows P inFIG. 6, there are times (blank periods) when the request signal is not output to any one of the transmitting circuits22ato22ewhen the voltage value of the battery32becomes less than the threshold value. This reduces the amount of power consumed to generate the request signal.

In the preferred embodiment, when the voltage value of the battery32is greater than or equal to the threshold value, the total number the request signal is output during period ΣT2is set to thirty times. However, when the voltage value of the battery32is less than the threshold value, the total number the request signal is output during period ΣT2is set to twenty times. Thus, in comparison to when the voltage value of the battery32is greater than or equal to the threshold value, the power amount consumed when outputting the request signal is reduced by 33%.

The lock controller21of the preferred embodiment has the advantages described below.

(1) The output cycle of the request signals output from the first to fifth transmitting circuits22ato22ediffers in accordance with a priority order that is determined by the initial setting or by the usage frequency of the doors3ato3dand4. The first transmitting circuit22a,which has high priority, outputs the request signal with a short output cycle. The third transmitting circuit22c,which has a low priority, outputs the request signal with a long output cycle. Thus, the first transmitting circuit22aenables immediate mutual communication between the lock controller21and the portable device11. Accordingly, the associated door is readily locked and unlocked. Since the locking and unlocking of the doors is performed with a quick response during normal usage of the vehicle2, the vehicle lock control system1is easy to use.

(2) The output cycles of the request signals output from the first to fifth transmitting circuits22ato22eare automatically changed in accordance with the usage frequency of the corresponding doors3ato3dand back door4. The output cycle of the request signal is short for the first transmitting circuit22acorresponding to the driver's door3a,which is frequently used. In other words, when a certain one of the doors3ato3dand4is used frequently, the locking and unlocking response of the certain one of the doors3ato3dand4becomes quicker when the person carrying the portable device11approaches or moves away from the door. Thus, during normal usage of the vehicle2, the locking and unlocking of the door is performed with a high response. This makes it easier to use the vehicle lock control system1.

(3) When the voltage value of the battery32becomes lower than a predetermined threshold value, the ratio of the total output time of the request signal that occupies a predetermined period (ΣT2) decreases. This reduces the consumed amount of power of the battery32for the generation and output of the request signal and suppresses battery drainage.

Referring toFIG. 7, when the voltage value of the battery32becomes lower than a predetermined threshold value, the output cycle of the request signal for the first transmitting circuit22amay be adjusted so that it has a cycle time T2, which is longer than cycle time T1. As shown inFIG. 7, the cycle time T2is five times greater than the output time Δt of the request signal. During a period ΣT3(5×T2) in which the first transmitting circuit22aoutputs the request signal five times, the microcomputer26outputs the request signal four times from the second transmitting circuit22a.Further, during period ΣT3, the microcomputer26outputs the request signal from the fifth transmitting circuit22ethree times, the fourth transmitting circuit22dtwice, and the third transmitting circuit22conce at predetermined timings. The total number of times the request signal is output is fifteen times. In this case, the maximum number of times the request signal may be output during ΣT3is twenty-five. This produces blank periods as shown by arrows P inFIG. 7and reduces the consumed power amount of the battery32by 40%.

A second threshold value lower than the first threshold value, which is compared with the voltage value of the battery32, may further be set. If the voltage value of the battery32becomes lower than the second threshold value, the output of the request signal from transmitting circuits having low priority (in this case, the fourth transmitting circuit22dand the third transmitting circuit22c) may be stopped. The broken lines ofFIG. 8represent request signals of which output has been stopped. This further reduces the consumed power amount of the battery32and further suppresses battery drainage.

The stopping of the request signal output may be applied to the prior art example shown inFIG. 2and the example shown inFIG. 7. When applied to the prior art example, the request signal is normally output from the first to fifth transmitting circuits22ato22eat the timings shown inFIG. 2. When the voltage value of the battery32becomes lower than the predetermined threshold value, the output of the request signal from transmitting circuits22ato22ehaving low priority is stopped. In this case, the priority is determined from the usage frequency of the corresponding doors3ato3dand4.

When the stopping of the request signal output is applied to the example ofFIG. 5, the request signal is normally output from the first to fifth transmitting circuits22ato22eat the timings shown inFIG. 5. When the voltage value of the battery32becomes lower than the predetermined threshold value, the output of the request signal from low priority transmitting circuits (in this case, the fourth transmitting circuit22dand the third transmitting circuit22c) is stopped.

When the stopping of the request signal output is applied to the example ofFIG. 7, the output of the request signal from low priority transmitting circuits (in this case, the fourth transmitting circuit22dand the third transmitting circuit22c) is stopped if the voltage value of the battery32becomes lower than the second threshold value.

Parameters related with the output cycle of the request signal do not necessarily have to be recorded on the memory26a.For instance, in the prior art example ofFIG. 2, the priority order of the transmitting circuits does not have to be determined in the initial setting of the output cycle and may be set by means of the learning function, which is based on the usage frequency of the doors3ato3dand4.

In the above embodiments, parameters are recorded on the memory26aof the microcomputer26to determine the priority order of the first to fifth transmitting circuits22ato22e.However, for example, setting registration switches may be arranged in the passenger compartment of the vehicle2to enable the user to set the priority order of the transmitting circuits22ato22e.

Instead of decreasing the output number of the request signal, the output intensity of the request signal may be decreased in low priority transmitting circuits. This would also decrease the consumed power amount of the battery32.

The learning function for automatically adjusting the output cycle of the request signal may be eliminated and the output control of the request signal of the first to fifth transmitting circuits22ato22emay be performed based on only the initial setting. This reduces the processing load of the microcomputer26.

All of the doors3ato3dand4do not necessarily have to be provided with a transmitting circuit, and the number of the transmitting circuits is not limited.

Each of the transmitting circuits22ato22emay be arranged at any location as long as the request signal can be output in the corresponding areas A1to A5.