Keyless vehicle lock system

A keyless lock system for a vehicle includes a card for transmitting a radio signal, at least one onboard antenna for receiving the radio signal, and a control unit for allowing and preventing keyless lock and unlock operations in dependence on the existence or nonexistence of the card in a predetermined area near the antenna. The control unit monitors the position of at least one monitored door, and produces a card warning signal each time the monitored door is closed if the card is absent in the vehicle.

BACKGROUND OF THE INVENTION 
The present invention relates to a vehicle keyless lock system for 
controlling one or more door locks and/or a vehicle control lock such as a 
steering lock without using any key. 
Japanese Patent Provisional (KOKAI) Publications Nos. 63-1765 and 63-4182 
disclose vehicle keyless lock o systems which enable the driver of a 
vehicle to unlock a vehicle door or a steering system merely by pushing a 
request switch if the driver carries a card for radiating radio waves, on 
the person. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a keyless vehicle lock 
system which can avoid troubles due to keyless operations, and improve the 
vehicle's safety. 
It is another object of the present invention to provide a keyless vehicle 
lock system which is speedy, accurate and resistant to noise in 
determining the position of an entry card for radiating radio waves. 
According to the present invention, a keyless lock system for a vehicle 
comprises a portable communicating means, an onboard communicating means, 
a primary (detecting) means, a final (controlling) means, and a (main) 
controlling means. 
The portable communicating means (such as an entry card) transmits a cipher 
code signal, and the onboard communicating means (such as an antenna 
connected with a circuitry) receives the code signal. The primary means 
senses the position of at least one monitored door of the vehicle to 
determine whether the monitored door is in a closed state or in an open 
state. The final means produces a first (card) warning signal in response 
to a first alarm command signal of the controlling means. The controlling 
means produces an automatic request signal when the door is moved between 
the open state and the closed state, ascertains the existence of the 
portable means by receiving the code signal through the onboard 
communicating means when the automatic request signal is produced, and 
produces the alarm command signal to command the final means to produce 
the warning signal if the portable communicating means is absent. 
Therefore, this keyless lock system can prevent the loss of the portable 
communicating means by producing the warning signal when the door is 
operated. Especially, the control system can prevent the portable 
communicating means from being carried away by a passenger. 
According to another aspect of the present invention, a keyless lock system 
for a vehicle comprises a portable communicating means for transmitting 
microwaves, an onboard communicating means for receiving microwaves from 
the portable communicating means, an actuating means for actuating at 
least one lock unit of the vehicle in response to an actuation command 
signal, and a controlling means for calculating a distance between the 
portable communicating means and the onboard communicating means by using 
a microwave propagation time (or propagation delay), determining, in 
dependence on the calculated distance, whether the portable communicating 
means is in a predetermined area or not, and producing the actuation 
command signal to actuate the lock unit only when the portable 
communicating means is in the predetermined area. Therefore, this keyless 
lock system can locate the portable communicating means accurately and 
speedily without being readily influenced by elecromagnetic noise waves 
and metallic obstructions.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 shows an arrangement of various functional means used in the first 
embodiment. The arrangement shown in FIG. 1 approximately corresponds to 
the invention claimed in original Claim 13. 
As shown in FIG. 1, the keyless lock control system of the first embodiment 
comprises a portable communicating means PCM, an onboard communicating 
means OCM, a primary (detecting) means PM, a final (controlling) means FM, 
and a controlling means CM. The portable communicating means PCM comprises 
a pocket device which is an entry card in this embodiment, and the onboard 
communicating means OCM comprises one or more antennas. Both communicating 
means are designed to perform radio communication. The primary means PM 
comprises various switches and sensors. The final means FM comprises a 
warning means WM for producing a warning signal to the driver, and an 
actuating means AM for actuating one or more lock units of the vehicle. 
The controlling means CM receives signals from the primary means PM and 
controls the final means FM by sending one or more command signals in 
accordance with the input signals sent from the primary means PM. The 
controlling means CM of this embodiment comprises a condition 
discriminating means DM for receiving the signals from the primary means 
PM, and produces at least one request signal, and a request examining 
means EM which receives the request signal, determines whether the 
portable means is present in a predetermined area or not, and produces the 
command signal in dependence on the result of the determination. 
In this embodiment, the primary means PM comprises a door position sensing 
means DPSM which comprises a first door position switch DPSW1 for 
detecting the position of a monitored door MD of the vehicle and a second 
door position switch DPSW2 for detecting the position of a controlled door 
CD of the vehicle. The primary means PM further comprises first and second 
request switch RSW1 and RSW2, and a vehicle control main selector switch 
VCSW which is connected with a steering system SS, an accessory system AS 
and an ignition system IG of the vehicle. The primary means PM further 
comprises a door lock sensing means DLSM and a vehicle state sensing means 
VSSM connected with an automatic transmission AT of the vehicle. 
In the final means FM of this embodiment, the warning means WM may 
comprises a first warning device WD1 for producing a first warning signal 
and a second warning device WD2 for producing a second warning signal, and 
the actuating means AM comprises a first lock actuator LA1 for actuating a 
first lock unit LU1 and a second lock actuator LA2 for actuating a second 
lock unit LU2. 
In the controlling means CM, the discriminating means DM comprises first 
and second door condition discriminating means DDM1 and DDM2; and first, 
second and third switch condition discriminating means SDM1, SDM2 and 
SDM3. The examinining means EM comprises an automatic request examining 
means AREM; and first and second switch request examining means SREM1 and 
SREM2. 
In this embodiment, the pocket device of the portable communicating means 
PCM is an entry card 21, as shown in FIG. 2. The card 21 can transmit a 
predetermined cipher code signal. 
As shown in FIG. 2, the onboard communicating means OCM comprises a door 
control antenna 23, a trunk control antenna 25 and an ignition control 
antenna 27 which are all mounted on the vehicle. The door antenna 23 is 
mounted on a front door on the driver seat's side near the outside handle. 
The door antenna 23 can receive the code signal when the driver stands 
near the driver door with the card 21. It is optional to provide another 
antenna on the other front door. The trunk antenna 25 is a built-in 
antenna located inside a rear bumper of the vehicle. The trunk antenna 25 
can receive the code signal when the driver stands with the card 21 near a 
trunk lid of the vehicle. The ignition control antenna 27 is located 
outside a steering lock unit near the driver's seat. 
A control unit 29 is connected with each of the antennas 23, 25 and 27. The 
control unit 29 includes an antenna selector circuit 31 for selectively 
making conneciton to any one of the antennas 23, 25 and 27, a duplexer 
circuit 33, a receiving (receiver) circuit 35, a transmitting 
(transmitter) circuit 37, and a control section 39. The duplexer circuit 
33 connects the receiving circuit 35 with the selector 31 during a 
receiving period, and connects the transmitting circuit 37 with the 
selector 31 during a transmitting period. The control section 39 includes 
a central processing unit of a microcomputer, and serves as the 
controlling means CM. The control section 39 receives the code signal from 
the card 21 through one of the antennas 23, 25 and 27, and sends the code 
signal through an input and output circuit 47 to a steering lock unit 49. 
The control section 39 is connected through a reset circuit 41 with an 
interface circuit 43. The control section 39 is further connected through 
an interface circuit 45 with a buzzer 46 serving as the warning means WM, 
and various switches of the primary means PM. 
The peripheral devices connected with the interface circuit 45 are at least 
one door position switch DPS, at least one door lock switch DLS, a vehicle 
speed sensor VSS, an automatic transmission position switch ATS, and a 
vehicle control main selector switch VCSW including an ignition switch IGS 
which is connected with a battery BTT. In this embodiment, there are 
provided a plurality of door position switches DPS for sensing the 
positions of all the doors of the vehicle. The door position switches are 
connected in parallel to each other between a ground and the interface 
circuit 45. On the other hand, the interface circuit 43 is connected with 
at least one door request switch DRS and a trunk request switch TRS 
provided in the trunk lid of the vehicle. In this embodiment, the door 
request switch DRS is located on the driver's front door near the outside 
door handle. It is optional to provide another door request switch in the 
other front door. 
The steering lock unit 49 has a control section 51 which includes a central 
processing unit of a microcomputer. The control section 51 receives the 
cipher code signal and other information from the control unit 29 through 
an input and output circuit 53, and performs various control operations to 
lock and unlock the steering system of the vehicle. The control section 51 
is connected through a reset circuit 55 with a key request switch KRS. The 
key request switch KRS is further connected through the interface circuit 
43 with the reset circuit 41. When the key request switch KRS is switched 
on, then the reset circuit 55 resets the control section 51 to a 
prescribed state, and at the same time the reset circuit 41 resets the 
control section 39 to a prescribed state. The control section 51 is 
further connected with a memory section 57 which stores request codes for 
requesting various information items from the control unit 29. 
The steering lock unit 49 further includes a checking section 59 which is 
connected with the control section 51, and a memory section 61 for storing 
cipher code data. The checking section 59 collates the cipher code signal 
sent from the card 21 through the control unit 29, with the cipher code 
data stored in the memory section 61. If the cipher code signal of the 
card 21 is in complete agreement with the code data of the memory section 
61, then the checking section 59 sends an agreement signal to the control 
section 51. A driver circuit 63 is connected with the control section 51 
and a latch solenoid 65. The control section 51 actuates the latch 
solenoid 65 through the driver circuit 63 in accordance with the agreement 
signal of the checking section 59. A switch SWH is put in a closed state 
only when the selector switch is in an ACC position or a spare key is 
inserted in a key hole formed in the steering lock unit. 
The steering lock unit 49 further includes a steering locking means for 
locking the steering system of the vehicle, a steering unlocking means for 
unlocking the steering system, and an inhibiting means for preventing the 
unlocking operation of the steering unlocking means. (These means are not 
shown in the figures.) The driver circuit 63 and the latch solenoid 65 
serve as a releasing means for cancelling the inhibition of the inhibiting 
means. When the agreement signal is produced by the checking section 59, 
the control section 51 actuates the latch solenoid 65 to cancel the 
inhibition of the inhibiting means. 
The keyless lock control system of the first embodiment is operated as 
shown in FIGS. 3A, 3B and 3C. 
(A) The driver can enter the vehicle as follows: 
At a step S1 shown in FIG. 3A, (the controlling means of) the keyless lock 
control system determines wether the ignition switch IGS is in the on 
state or not. If it is not, the control system proceeds to a step S2 to 
determine whether the vehicle control main selector switch VCSW is in the 
ACC position for turning on the electric accessory system of the vehicle. 
If the answer of the decision step S2 is negative, then the control system 
proceeds to a step S3 shown in FIG. 3B through a connector point B. At the 
step S3, the control system determines whether the key request switch KRS 
is in the on state or not. If the key request switch KRS is in the off 
state, then the control system determines at a step S11 whether the door 
request switch DRS is in the on state or not. When the driver pushes the 
door request switch DRS (to a request position), the door request switch 
DRS is turned on, and the control system proceeds to a step S13. 
At the step S13, the control unit 29 carries out communication with the 
card 21 which is held by the driver standing near the driver's door. The 
control unit 29 transmits an interrogation signal from the door antenna 23 
to the card 21 when the door request switch DRS is switched on, and the 
card 21 transmits the code signal automaticaly when the card 21 receives 
the correct interrogation signal. At a step S15, the control system 
compares the code signal of the card 21 with the stored code data to note 
points of disagreement, and determines whether the correct card 21 exists 
in a predetermined door operating area. For example, the door operating 
area is an area near the outside handle of the driver's door. If the card 
21 is absent in the predetermined door operating area, then the control 
system returns from the step S15 to the step S1 through a connector point 
X. If the correct card 21 is detected in the door operating area, then the 
control system proceeds to a step S17 to determine whether the doors are 
in the closed state or not. If at least one door is not in the closed 
state, then the control system produces, at a step S19, a door warning 
signal to warn the driver that the doors are not closed securely. From the 
step S19, the control system returns to the step S1 through the connector 
point X. When the answer of the step S17 is affirmative, then the control 
system proceeds to a step S21 to determine whether the driver's door is in 
the locked state or not. If the door is in the locked state, then the 
control system proceeds to a step S23 to determine whether the control 
system is in a low sensitivity mode or not. If it is, the control system 
proceeds to a step S25 to restore the sentivity to a normal level, and 
perform a predetermined check operation; and then returns to the step S1 
through the connector point X. If the control system is not in the low 
sensitivity mode but in a normal mode, then the control system proceeds 
from the step S23 to a step S27. At the step S27, the control system 
delivers a door unlock command signal to the door lock actuator, and by so 
doing unlocks the driver's door. Then, the control system returns from the 
step S27 to the step S1 through the connector point X. In this way, the 
driver having the card 21 can open the driver's door and enter the 
vehicle. 
The door request switch DRS corresponds to the second request switch RSW2 
shown in FIG. 1; the step S11 corresponds to the second switch condition 
discriminating means SDM2; and the steps S13, S15, S21 and S27 correspond 
to the second switch request examining means SREM2. The door lock switch 
DLS serves as the door lock sensing means DLSM. 
(B) The keyless lock control system of the first embodiment enables the 
driver to start the engine as follows: 
When the vehicle main selector switch VCSW is not turned to the accessory 
(ACC) position, and the ignition switch is still in the off state, the 
control system reaches the step S3 through the steps S1 and S2 and the 
connector point B. When the driver pushes the key request switch KRS, then 
the key request switch KRS is turned on, and remains on until released. 
Therefore, the control system proceeds from the step S3 to a step S4. At 
the step S4, the control system sends the interrogation signal to the card 
21 and receives the cipher code signal from the card 21. At a step S5, the 
control system determines whether the card 21 exists in a predetermined 
key operating area, which is, for example, an area located at and near the 
driver's seat. If the card 21 is nonexisting in the key operating area, 
then the control system actuates the buzzer 46 at a step S7 to warn the 
driver with a buzzing sound that the card 21 is missing. After the step 
S7, the control system returns to the step S1. If the card 21 exists in 
the key operating area, then the control system proceeds from the step S5 
to a step S9. At the step S9, the control unit 29 transmits the cipher 
code signal received from the card 21, a request code for requesting the 
collation of the checking section 59 and other information, to the 
steering lock unit 49. In the steering lock unit 49, therefore, the 
checking section 59 checks the code signal of the card 21 to ascertain 
that the code signal is in complete agreement with the stored code. If the 
agreement is confirmed, the steering lock unit 49 releases a button 49b 
(shown in FIG. 4) for a limited time duration, and allows the driver to 
turn the vehicle control selector switch VCSW to start the engine. If the 
code signal sent from the card 21 is not in complete agreement with the 
stored code, then the steering lock unit 49 holds the lock button 49b 
immovable, and the vehicle control switch VCSW inoperable to protect the 
vehicle against theft. 
The key request switch KRS corresponds to the first request switch RSW1 
shown in FIG. 1; the step S3 corresponds to the first switch condition 
discriminating means SDM1; and the steps S4 and S5 corresponds to the 
first switch request examining means SREM1. 
(C) When the vehicle control main switch VCSW is in the ACC position or the 
ON position (the vehicle unlock state): 
When the ignition switch IGS is in the on state for switching on the 
ignition system, the control system proceeds from the step S1 to a step 
S53 to determine whether the electric accessory system is in the on state. 
When the answer of the step S53 is affirmative, the control system checks 
the state of the key request switch KRS at a step S55. If the key request 
switch KRS is in the off state, the control system proceeds to a step S57 
to check the state of the door request switch DRS. 
When the vehicle control main selector switch VCSW is in the ACC position 
for turning off the ignition switch IGS and turning on the accessory 
system, the control system reaches a step S87 through the steps S1 and S2. 
At the step S87, the control system determines whether the driver's door 
is in the open state or not. If the door is in the closed state, the 
control system proceeds directly to a step S91 to check the state of the 
key request switch KRS. When the key request switch KRS is in the off 
state, the control system proceeds to the step S57. 
From the step S57, the control system proceeds to a step S59 if the door 
request switch DRS is in the off state. At the step S59, the control 
system determines whether a monitored door of the vehicle is moved from 
the open state to the closed state. In this example, the answer of the 
step S59 becomes affirmative when the monitored door is in the closed 
state in the current execution of the step S59 although the monitored door 
was in the open state in the last execution of the step S59. It is 
convenient to use for the step S59 a flag (or condition code) indicating 
the open and closed states of the monitored door. In this example, the 
control system monitors the positions of all the doors of the vehicle, and 
makes an affirmative answer to the step S59 if any one or more of all the 
doors of the vehicle is moved from the open state to the closed state. The 
control system returns to the step S1 when the answer of the step S59 is 
negative, and proceeds to a step S61 when the answer of the step S59 is 
affirmative. At the step S61, the control unit 29 performs radio 
communication with the card 21. At a next step S63, the control system 
determines whether the card 21 exists in a predetermined safe area. For 
example, the control system determines whether the card 21 exists in the 
passenger compartment of the vehicle. If the card 21 is absent in the safe 
area, the control system proceeds from the step S63 to a step S65. At the 
step S65, the control system actuates the buzzer 46 to produce a card 
warning signal indicating the absence of the card 21. After the step S65, 
the control system returns to the step S1. In this way, this control 
system can prevent the card 21 from being taken away by a passenger, by 
producing the card warning signal. As shown in FIG. 3A, the step 59 is 
reached only when at least one of the steps S1 and S2 provides an 
affirmative answer. When the driver leaves the vehicle, the ignition 
switch IGS is normally turned off, and, therefore, the control system does 
not reach the step S65. 
The step S59 corresponds to the first door condition discriminating means 
DDM1, and the steps S61 and S63 correspond to the automatic request 
examining means AREM. 
(D) The control system prevents the driver from leaving the vehicle without 
locking the steering system. 
If the driver opens the driver's door while the vehicle control main 
selector switch VCSW is in the ACC position, the control system proceeds 
from the step S2 to a step S87 to determine whether the driver door is in 
the open state or not. If the door is open, the control system proceeds to 
a step S89. At the step S89, the control system actuates the buzzer 46 to 
produce a steering lock warning signal to warn that the steering lock is 
forgotton. The step S87 may be so designed that the answer of the step S87 
is affirmative when either or both of the left and right front doors is in 
the open state. It is optional to employ a warning device which is used 
only for the steering lock warning of the step S89. From the step S89 or 
the step S87, the control system proceeds to a step S91 to determine 
whether the key request switch KRS is in the on state or not. If the key 
request switch KRS is in the off state, the control system proceeds to the 
step S57, at which the control system determines whether the door request 
switch DRS is in the on state or not. If the door request switch DRS is in 
the on state, then the control system proceeds to a step S67 shown in FIG. 
3C, through a connector point C. At the step S67, the control system 
determines whether any one or more of the vehicle doors is in the open 
state If all the doors are in the closed state, then the control system 
proceeds from the step S67 to a step 75. At the step S75, the control 
system determines whether the driver's door is in the locked state or not. 
If the driver's door is not in the locked state, then the control system 
returns from the step S75 to the step S1 through the connector point X. 
Therefore, the control system of this embodiment prevents the keyless lock 
operation when the steering system is not locked, and by so doing makes 
the driver aware of the steering lock. 
If any one or more of the doors is in the open state, the control system 
proceeds from the step S67 to a step S69 to perform radio communication 
with the card 21. At a step S71 following the step S69, the control system 
determines whether the card 21 exists in the predetermined door operating 
area. If the card 21 exists in the door operating area, then the control 
system produces a door warning signal at a step S73 to warn that at least 
one door is not securely closed. 
If the driver's door is locked, and accordingly the answer of the step S75 
is affirmative, then the control system proceeds from the step S75 to a 
step S77. At the step S77, the control system determines whether the radio 
receiving mode is in the low sensitivity mode or not. If it is, the 
control system restores the sensitivity to the normal level at a step S78, 
and then proceeds to a step S79. If the answer of the step S77 is 
negative, then the control system proceeds directly to the step S79. The 
control unit 29 performs radio communication with the card 21 at the step 
S79, and determines, at a step S81, whether the card 21 exists in the door 
operating area. If the card 21 is detected in the door operating area, 
then the control system unlocks the driver's door by producing a door 
unlock command signal at a step S83. 
The step S87 corresponds to the second door condition discriminating means 
DDM2, and the step S57 corresponds to the third switch condition 
discriminating means SDM3. 
(E) The driver can stop the engine as follows: 
The driver can stop the engine by turning the vehicle control main selector 
switch VCSW from the ON position to the ACC position. In this case, the 
control system proceeds to the step S87 through the step S2. If the 
driver's door remains in the closed state, then the control system 
proceeds to the step S91 to determine whether the key request switch KRS 
is in the on state. When the key request switch KRS is in the on state, 
then the control system proceeds from the step S91 to a step S93 to 
determine whether at least one of the door request switch DRS and the 
trunk request switch TRS is in the on state. If both of the request 
switches DRS and TRS are in the off state, the control system proceeds 
from the step S93 to a step S95 to perform radio communication with the 
card 21. Then, the control system determines, at a step S97, whether the 
card 21 exists in the predetermined key operating area which is, for 
example, an interior area at and near the driver's seat. If the card 21 
exists in the key operating area, then the control system determines, at a 
step S101, the current value of the vehicle speed V of the vehicle sensed 
by the vehicle speed sensor VSS, and determines, at a step S103 whether 
the vehicle is in motion or at rest. If the vehicle is moving, then the 
control system returns to the step S1 through the connector point X. In 
this way, the control system improves the safety of the vehicle by making 
it impossible to lock the steering system while the vehicle is moving. 
When the vehicle is not moving, the control system proceeds from the step 
S103 to a step S105 to determine whether the automatic transmission is in 
the parking range. In this example, it is determined whether the driver's 
shift lever is in the parking position or not. If the automatic 
transmission is not in the parking range, then the control system returns 
to the step S1. In this way, the control system can improve the safety of 
the vehicle by inhibiting the steering lock while the shift lever is out 
of the parking position. 
If the automatic transmission is in the parking range, the control system 
proceeds from the step S105 to a step S107. At the step S107, the control 
unit 29 transmits the cipher code signal of the card 21, the request code 
for requesting the collation of the checking section 59 and other 
information, to the steering lock unit 49. Therefore, the steering lock 
unit 49 releases the button 49b and allows the driver to turn the selector 
switch VCSW from the ACC position to the LOCK position to lock the 
steering system if the cipher code signal of the card 21 is in complete 
agreement with the stored code. 
If the card is not detected in the key operating area, then the control 
system proceeds from the step S97 to a step S99 to actuate the buzzer 46 
to warn that the card 21 is missing. 
The step S91 corresponds to a first lock request signal producing means of 
the first switch condition o discriminating means SDM1, and the steps S95, 
S97, S101, S103 and S105 correspond to a first lock command signal 
producing means of the first switch request examining means SREM1. On the 
other hand, the step S3 corresponds to a first unlock request signal 
producing means of the first switch condition discrminating means SDM1, 
and the steps S4 and S5 correspond to a first unlock command signal 
producing means of the first switch request examining means SREM1. 
(F) The driver can get off the vehicle as follows: 
When the vehicle control main selector switch VCSW is turned to the LOCK 
position, the control system reaches the step S11 through the steps S1, S2 
and S3. When the door request switch DRS is in the on state, the control 
system proceeds to the step S13. Therefore, the control system performs 
radio communication with the card 21 at the step S13, determines, at the 
step S15, whether the card 21 exists in the predetermined door operating 
area, and determines, at the step S17, whether all the doors are in the 
closed state. If all the doors are securely closed, then the control 
system determines, at the step S21, whether the driver's door is in the 
locked state or not. If the driver door is not locked, then the control 
system locks all the doors by producing a door lock command signal at a 
step S29. 
Then, the control system detects the position of the card 21 at a step S31, 
and determines, at a step S33, whether the card 21 is left behind in the 
passenger compartment. If the card 21 is not in the passenger compartment, 
then the control system returns from the S33 to the step S1. If the card 
21 is forgotten in the passenger compartment, the control system proceeds 
to a step S35, and changes the radio receiving mode to the low sensitivity 
mode by lowering the sensitivity to a low level. Therefore, if an 
unauthorized person pushes the door request switch DRS, the control system 
prevents the door from being unlocked by preventing radio communication 
between the control unit 29 and the card 21 left behind in the passenger 
compartment. 
(G) The driver can open the trunk lid as follows: 
When the key request switch KRS and the door request switch DRS are both in 
the off state, then the control system reaches a step S37 through the 
steps S3 and S11. The control system determines, at the step S37, whether 
the trunk request switch TRS is in the on state or not, and proceeds to a 
step S39 if the trunk request switch TRS is in the off state. At the step 
S39, the control system determines whether at least one door is in the 
unlocked state. If all the doors are in the locked state, the control 
system determines, at a step S41, whether at least one door is changed 
from the unlocked state to the locked state. If at least one door is in 
the locked state in the current execution of the step S41 although that 
door was in the unlocked state in the previous execution, then the control 
system proceeds from the step S41 to the step S31. If the answer of the 
step S41 is negative, then the control system returns from the step S41 to 
the step S1. If at least one door is in the unlocked state, then the 
control system proceeds from the step S39 to a step S43 to restore the 
sensitivity of the control unit 29. From the step S43, the control system 
returns to the step S1. 
When the trunk request switch TRS is in the on state, the control system 
proceeds from the step S37 to a step S45, at which the control unit 29 
performs radio communication with the card 21. Then, the control system 
determines, at a step S47, whether the card 21 exists in a predetermined 
trunk operating area near the trunk lid of the vehicle. If the card 21 is 
missing, then the control system directly returns to the step S1. If the 
card 21 is present in the trunk operating area, then the control system 
opens the trunk lid by producing a trunk open command signal at a step 
S49. From the step S49, the control system returns to the step S1. 
FIG. 4 illustrates operations of the steering lock unit 49. The steering 
lock unit 49 has a selector member 49a and a button 49b. The selector 
member 49a is rotatable from the LOCK position, through the ACC position 
and the ON position, to the ST (Start) position. Between the LOCK position 
and the ON position, there is only the ACC position, and there is no OFF 
position. The selector member 49a is movable between the LOCK position and 
the ACC position only while the button 49b is pushed. The selector member 
49a is a movable component of the vehicle control main selector switch 
VCSW, and simultaneously a component of the ignition switch IGS. 
Furthermore, the selector member 49a is a component of the key request 
switch KRS. The key request switch KRS is switched on when the selector 
member 49a is pushed. The ignition switch IGS is operated by turning the 
selector member 49a. 
At a step S201, the radio communication is performed when the driver pushes 
the selector member 49a to turn on the key request switch KRS. If the 
driver carries the card 21, the control system releases the button 49b. 
Therefore, the driver can turn the selector member 49a from the LOCK 
position to the ACC position by pushing the button 49b, as shown in a step 
S207. The steering lock unit 49 is resistant to being tampered by a child, 
as shown in a step S203, because it is necessary to push the selector 
member 49a and the button 49b in order to turn the selector 49a. If the 
driver does not have the card 21, the control system holds the button 49b 
immovable, and produces the card warning signal, as shown in a step S205. 
Therefore, the driver cannot push the button 49b, and cannot turn the 
selector member 49a. 
The selector member 49a is freely movable between the ACC position and the 
ST position. Therefore, the driver can start the engine of the vehicle by 
turning the selector member 49a from the ACC position to the ST position, 
as shown in a step S209. The select member 49a automatically returns to 
the ON position, as shown in a step S211, after the engine starting 
operation. 
At a step S213, the control system ascertains the existence of the card 21 
in the predetermined safe area each time any one of the doors is brought 
from the open state to the closed state. If the driver does not have the 
card 21 in the vehicle, then the control system produces the card warning 
signal to warn that the card 21 is missing, as shown in a step S215. 
The driver can stop the engine by turning the selector member 49a from the 
ON position to the ACC position, as shown in a step S217. The selector 
member 49a is freely movable between the ST position and the ACC position. 
If the driver's door is opened while the selector member 49a is in the ACC 
position, then the control system produces the steering lock warning 
signal to warn the steering lock is forgotten, as shown in a step S219. 
In order to turn the selector member 49a from the ACC position to the LOCK 
position to lock the steering system, the driver must push the selector 
member 49a in the ACC position and further push the button 49b, as shown 
in steps S221 and S229. If the card 21 is missing in the key operating 
area, the button 49b remains incapable of being pushed, so that the 
selector member 49a is incapable of being turned to the LOCK position, and 
the card warning signal is produced, as shown in a step S223. When the 
shift lever of the automatic transmission is out of the parking position, 
or the vehicle speed is greater than zero, then the button 49b is not 
released, as shown in a step S225 and S227. Therefore, the driver can turn 
the selector member 49a to the LOCK position only when the card 21 exists 
in the predetermed area, and the vehicle is at rest. When the vehicle is 
equipped with a manual transmission, it is necessary to omit the step S225 
from FIG. 4, and the step S105 from FIG. 3A, and to employ only the 
vehicle speed check shown in the step S103 and S227. In the case of the 
automatic transmission, it is optional to employ only one of the vehicle 
speed check of the step S103 and the parking range check of the step S105. 
The vehicle control main selector switch VCSW of this example has only the 
LOCK position for locking the steering system, the ACC position for 
turning on the elecric accessories such as an air conditioning system and 
a sound system, the ON position for the normal vehicle operation, and the 
ST position for starting the engine. Unlike the conventional ignition 
switch, the vehicle control main selector switch VCSW of this example has 
no OFF position. Therefore, when the vehicle control selector switch VCSW 
is out of the LOCK position, the accessories are always operative, so that 
the driver can readily notice the selector switch VCS being out of the 
LOCK position. 
A second embodiment of the present invention is shown in FIGS. 5-8C. A 
keyless lock control system of the second embodiment is designed to 
calculate a distance between a keyless entry card 21 and an antenna by 
using a propagation time of radio waves. 
As shown in FIG. 5, the keyless lock control system of the second 
embodiment is almost the same as the keyless lock control system of the 
first embodiment, but different in the following points. 
The keyless lock control system of the second embodiment has only two 
antennas, a center antenna 24 and a trunk control antenna 25. The trunk 
antenna 25 is provided in the rear bumper, as in the first embodiment. The 
center antenna 24 is disposed at a central portion 13 of the vehicle shown 
in FIG. 6. The keyless lock control system of the second embodiment 
employs a microwave system utilizing microwaves, and the card 21 is 
capable of transmitting microwaves. 
The control section 39 of the control unit 29 is designed to measure a 
propagation time (or propagation delay) of microwaves received by the 
center antenna 24, to calculate a distance between the card 21 and the 
center antenna 24 by using the propagation time, and to determine the 
position of the card 21. The control section 39 serves as a measuring 
means for measuring the propagation time, and as a calculating means for 
calculating the distance between the card 21 and the center antenna 24. 
The control section 39 comprises a comparing means for comparing the 
calculated distance between the card 21 and the center antenna 24, with a 
predetermined first value. The control section 39 judges the card 21 to be 
present in a predetermined inside area AB shown in FIG. 6 if the 
calculated distance is equal to or smaller than the predetermined first 
value. If the calculated distance is greater than the predetermined first 
value, the control section 39 judges the card 21 to be present in a 
predetermined outside area AA shown in FIG. 6. It is possible to further 
provide a second comparing means for comparing the calculated distance 
with a predetermined second value which is greater than the first value. 
In this case, the control section 39 judges the card 21 to exist in the 
outside area when the calculated distance is greater than the first value, 
and smaller than the second value. The control section 39 sends a signal 
indicative of the judgement to the steering lock unit 49. 
FIG. 7 illustrates operations of the keyless lock control system of the 
second embodiment. 
When the vehicle control main selector switch VCSW is in the ACC position: 
In this case, the control system of the second embodiment allows a keyless 
unlock operation of a controlled door only when the controlled door is in 
the locked state, and the card 21 is present in the outside area AA. If 
the door is in the unlocked state, then the door lock control is 
inoperative irrespective of the position of the card 21. The control 
system allows a keyless steering unlock operation only when the card 21 is 
present in the inside area AB. 
When the vehicle control main selector switch VCSW is in the LOCK position 
(or in the OFF position), that is when the ignition system and the 
accessory system are both in the off state: In this case, the control 
system allows a keyless door unlock operation only when the door is in the 
locked state and the card 21 is present in the outside area AA. Therefore, 
an unauthorized person cannot enter the vehicle even if the card 21 is 
left in the passenger compartment. The control system allows the keyless 
door lock operation only when the door is unlocked and the card 21 is 
present in the outside area AA. Furthermore, the control system allows the 
keyless steering unlock operation only when the card 21 is present in the 
inside area AB. 
The control procedure of the second embodiment shown in FIGS. 8A, 8B and 8C 
is almost the same as the control procedure of the first embodiment shown 
in FIGS. 3A, 3B and 3C. In the second embodiment, the steps S61, S63, S69, 
S71, S79, S81, S95, S97, S4, S5, S13 and S15 are modified, and the steps 
S23, S25, S31, S33, S35, S39, S41 and S43 are omitted. 
At the step S61, the control system of the second embodiment performs 
microwave communication, and calculates the distance between the card 21 
and the center antenna 24 by using the propagation time of the microwave 
signal transmitted from the card 21. At the step S63, the control system 
of the second embodiment determines whether the card 21 exists in the 
inside area AB, or not. If the card 21 is present in the inside area AB, 
then the control system returns to the step S1 through the connector point 
X. If the card 21 is absent in the inside area AB, then the control system 
proceeds to the step S65 to produce the card warning signal. 
At each of the steps S69, S79, S95, S4 and S13, the control system of the 
second embodiment performs microwave communication with the card 21 and 
calculates the distance between the card 21 and the center antenna 24, as 
in the step S61. 
At the step S71 shown in FIG. 8C, the control system determines, by using 
the distance obtained at the step S69, whether the card 21 exists in the 
outside area AA, or not. Then, the control system proceeds from the step 
S71 to the step S73 to produce the door warning signal only when the card 
21 is present in the outside area AA. 
At the step S81, the control system determines, by using the distance 
obtained at the step S79, whether the card 21 exists in the outside area 
AA, or not. Then, the control system proceeds from the step S81 to the 
step S83 to unlock the door only when the card 21 is present in the 
outside area AA. 
At the step S5 shown in FIG. 8B, the control system determines, by using 
the distance obtained at the step S4, whether the card 21 exists in the 
inside area AB, or not. Then, the control system produces the card warning 
signal at the step S7 if the card 21 is not present in the inside area AB, 
and proceeds to the step S9 if the card 21 is present in the inside area 
AB. 
At the step S15, the control system determines, by using the distance 
obtained at the step S13, whether the card 21 exists in the outside area 
AA. Then, the control system returns to the step S1 if the card 21 is not 
present in the ouside area AA, and proceeds to the step S17 if the card 21 
exists in the outside area AA. 
At the step S97 shown in FIG. 8A, the control system determines, by using 
the distance obtained at the step S95, whether the card 21 exists in the 
inside area AB, or not. Then, the control system produces the card warning 
signal at the step S99 if the card 21 is not present in the inside area, 
and proceeds to the step S101 if the card 21 is present in the inside area 
AB. 
The keyless lock system of the second embodiment employs only the center 
antenna 24 instead of the door control antenna 23 and the ignition control 
antenna 27. Therefore, the system of the second embodiment is advantageous 
in cost reduction. However, it is optional to provide two center antennas 
at appropriate positions in the vehicle in order to further improve the 
accuracy in detecting the position of the card 21. 
The keyless lock control system of the second embodiment can detect the 
position of the card 21 in a speedy and accurate manner, as compared with 
the conventional system which is arranged to detect the position of the 
card by monitoring the variation of the signal level of the signal 
received from the card. The conventional system is susceptible to noises 
of electromagnetic waves, and slow in detecting the position of the card.