Note: Descriptions are shown in the official language in which they were submitted.
WO 94/28301 ~16 4 313 PCT/AU94/00293
VEHICLE SECURITY ~:;Y~
Technical Field
This invention relates to a security system and
particularly to a system for reducing the incidence of
5 theft of apparatus powered by internal combustion engines.
Backqround Art
Theft of vehicles is a common occurrence and many
systems and products have been used in the past aimed at
reducing such occurrences. Such systems and products have
10 ranged from burglar alarms installed in the vehicle which
are actuated when an attempt is made to break into the
vehicle, to physical restraints on moving the vehicle such
as steering wheel lock~, gear lever locks or systems which
activ~ate the brakes of a vehicle. In most of the systems
15 and products available, however, the vehicle can still be
stolen if the theft prevention devices are circumvented.
This can occur often because the thief, being experienced
can "hot wire" the ignition circuit 80 that the engine may
still be started and driven away.
A further security risk which has arisen with
motor vehicles is that known as "car jacking". This occurs
when a vehicle which is driven by an authorised user is
entered, for example through one of the passenger doors by
an unauthori~ed user when, say the vehicle is stopped at
25 traffic light6. In such instances the authorised user may
be exposed to violence and pos~ible theft of the vehicle.
Summary of the Invention
The present invention aims to overcome or
alleviate the above disadvantages by providing a security
30 syste]n applicable primarily to vehicles having internal
combustion engines which simply and effectively disables
such engines and prevents their unauthorised starting. The
present invention aims in a preferred aspect to provide a
system which prevents unauthorised starting of an engine by
"hot wiring". The present invention is particularly
suitable for use with motor vehicles, however it may
readily be applied to boats, motor cycles or other
equipment powered by an internal combustion engine and thus
W094/~01 ~ PCT/AU94/00293
the term "vehicle" used throughout the specification
includes the aforementioned. The present invention also
aims in a further preferred aspect to provide a security
system which incorporates means to prevent or minimise the
5 risks of "car-jacking". Other objects and advantages of
the invention will become apparent hereunder.
The present invention thus provides in one aspect
a security system for use with a vehicle of the type having
an internal combustion engine and a management system for
10 controlling the operation of said engine, said security
system including control circuit means having first and
second states, said control circuit means in said first
state inhibiting operation of said management system 80 as
to prevent operation of said engine, control means for
15 causing said control circuit means to be placed from said
first state into said second state, said control circuit
means in said second state enabling operation of said
management sy3tem thereby allowing operation of said
engine.
The management system of the engine normally
includes a number of data lines which receive data from
various sensors around the engine such as sensors
associated with the harmonic h~lAncer and which supply data
for control of various engine components including an
25 igniter for providing ignition pulses to the vehicle spark
plugs and in the case of a fuel injected vehicle, to fuel
injectors for supplying fuel at desired intervals through
the injectors. The security system of the invention
operates on the data lines to either prevent signals being
30 received by the management system, such as timing signals
from the harmonic balancer or prevent signals being
transmitted to the igniter or fuel injectors.
The control circuit means includes first switch
means which is connected, preferably by DC isolating
35 circuit to one or more of the data lines. The switch means
when the ignition switch is OFF is normally open but is
closed by the control circuit means when the ignition
switch is turned ON. This connects the data lines to the
W094/2~01 ~l 6 ~ 313 PCT/AU94/00293
main supply via a DC isolating circuit to suppress the data
signals ~y effectively sending back an equal and opposite
signal to cancel the data signals.
The control circuit means also has a third
5 inoperative state, when the engine is not in operation and
the ignition switch is OFF, the control circuit means being
J placed from its third state into its first state upon
switching of the ignition switch to an ON position which
supplies current to the control circuit means.
The internal combustion engine includes a starter
solenoid and the control circuit means in its third and
first states suitably maintains the circuit between the
ignition switch and starter solenoid open, the control
circuit means closing the circuit between the ignition
switch and the solenoid in its second state. For this
purpose the control circuit means may include a second
switch means in series between the starter solenoid and
ignition switch, the ~econd switch means being normally
open but being clo~ed when the control circuit means is in
20 its second state.
Preferably, an anti-hotwiring circuit is
associated with the security system for preventing starting
of the engine by hot wiring. Suitably, the anti-hotwiring
circuit comprises capacitance means associated with the
25 control circuit means for inhibiting operation of the
management system by preventing or corrupting data input
thereto or data output therefrom when the circuit means is
in its first state.
The anti-hot wiring circuit may include the first
switch means which is connected to one or more of the data
input or data output lines of the management system 80 as
to prevent data being supplied to the management system, or
transmitted from the management system. Preferably, the
capacitance means of the anti-hot wiring circuit is in
series with the first switch means and connected to the
ignition switch or a supply line supplied by the ignition
switch. Thus, if the ignition switch terminals are bridged
to suLpply current to the ignition system, the first switch
WO94/~01 2 ~ 6 4 3 ~ ~ PCT/AU94100293
will close connecting the data lines through the
capacitance means to the supply effectively providing an AC
short to suppress the data signals.
The switch means may comprise mech~n;~l switches
5 but preferably the switch means are semiconductor switches
such as MOSFET switches.
In one particularly preferred form, the control
means comprises touch responsive switch means. In a
further form, the control means comprises remote actuating
l0 means. The remote actuating means may include infra-red
control means.
Preferably the control circuit means includes
timing circuit means which requires the touch pad to be
touched for a predetermined period of time before the
15 control circuit means operates to switch the respective
switches and enable the ignition circuit. This thereby
prevents operation in the event that the touch pad is
inadvertently touched.
The security system of the invention also
20 suitably includes a circuit which may be actuated to
prevent continued engine operation where unauthorised entry
to the vehicle has occurred during normal vehicle
operation. For this purpose, the control circuit means is
connected to one or more of the door switches to sense
25 opening thereof. A timing circuit is provided ~o as to
cause the control circuit means to be placed in its first
state a predetermined time after sensing of opening of the
door. This then prevents engine operation.
In yet a further aspect the present invention
30 provides a security system for use with a vehicle of the
type having an internal combustion engine and a management
system for controlling the operation of said engine, said
management system having a plurality of data lines, said
security system including control circuit means connectable
35 to at least one of said data lines, said control circuit
means in a first state suppressing or corrupting
information on said at least one of said data lines to
prevent operation of said engine, touch sensitive circuit
W094/~01 ~ 313 PCT/AU94/00293
means operable to cause said control circuit means to be
placed from said first state into a second state, said
control circuit means in said second state permitting data
to flow along aid data line to thereby permit operation of
5 said engine.
In yet a further aspect the present invention
Jprovide~ a security system for use with a vehicle of the
type having an internal combustion engine and a management
system for controlling the operation of said engine, said
lO security system including control circuit means having
first and second states, said control circuit means in said
first state i nh; h; ting operation of said management system
80 as to prevent operation of said engine, said circuit
means in said second state enabling operation of said
15 management system thereby allowing operation of said
engine, and means for sensing opening of a door of said
vehic:Le to cau3e said control circuit means to be placed in
said Eirst state to ~Le~ellt operation of said engine.
Brief DescriPtion of the drawing
In order that the invention may be more readily
under~tood and put into practical effect, reference will
now be made to the accompanying drawing which is a block
diagram of a management controlled vehicle engine provided
with 3ecurity means according to a preferred embodiment of
25 the present invention.
Detailed Description of the Preferred Embodiment
Referring to the drawings there is illustrated
schematically a vehicle engine 10 having an associated
management system 11 incorporates a computer or
30 microprocessor and which includes a number of data lines
compr:ising input lines 12 which are connected to various
sensors and receptors around the engine 10, including for
examp:Le a sensor connected to a harmonic balancer to
provide timing signals. The management system 11 also
35 includes data output lines 14 which are connected say to an
igniter 15 which generates pulses for application to the
engine spark plugs. The management system 11 may also be
connected through the output data lines 14 to electronic
W094/~01 ~ 4 6 PCT/AU94/00293
fuel injectors 16 of the engine 10 to control operation
thereo~. Other sensors and receptors around the vehicle
engine 10 provide various signals by which the management
system 11 controls vehicle operation. As is conventional a
starter motor 17 is provided for the starting of the engine
10, the starter motor 17 being controlled by a starter
solenoid 18. A battery 19 is provided for supplying current
to the starter ~olenoid 18 and motor 17 and other
electrical componentR of the engine, application of current
from the battery 19 being controlled by a ignition switch
20 which suitably is key operated.
The security system 21 of the invention is also
adapted to receive supply through the ignition switch 20
and is based around a control circuit 22 which in this
15 embodiment includes a software programmed microprocessor
23. The microprocessor 23 however, may comprise a hardware
wired circuit. The control circuit 22 includes a first
normally opened switch 24 which is arranged to be connected
in series between the ignition switch 20 and starter
solenoid 18. The system additionally includes a further
normally open switch 25 which is co~nected to a DC
isolating circuit 26 which may include a capacitor and
which may be connected through line 27 to one of the data
lines 12 or 14, to or from the management system 11. A
25 capacitor 28 is provided between the ignition ~witch 20 or
a supply line connected to the ignition switch 20, and
switch 25.
The switches 24 and 25 are preferably semi
conductor switches, such as MOSFETS, whose switching is
30 controlled by the microproce~sor 23, the microprocessor 23
to cause switching of the MOSFET switches applying pulse~
to their gates. The microprocessor 23 is also supplied
through the ignition switch 24.
Connected to the microprocessor 23 is a touch
sensitive switch circuit 29 which includes a touch pad
or terminal 30. Also connected to the microprocessor 23 is
a door switch circuit 31 which is connected to one or more
door switches 32 of the vehicle, the door switches 32
2~ ~ 13 t 3
W094/~01 PCT/AU94/00293
comprising the normal courtesy or interior light switches
moun1:ed on the door pillar.
In use and if one attempts to start the vehicle
engine 10 by normal switching on the ignition switch 20, no
5 current will be applied to the starter solenoid 18 becau~e
the circuit is broken by the normally open switch 24.
J Turning the ignition switch 20 to its ON state will,
however, supply current to the control circuit 22 of the
system 21 and place same in an active mode. Supply to the
10 control circuit 22 will also cause the normally open switch
25 to close. If the touch pad 30 is touched during the
time that current is supplied to the circuit 22 of the
system 21 in its active mode, 80 as to complete, through
the skin of the user, a circuit to earth, a triggering
15 signal will be generated to cause the switch 24 to close
and the switch 25 to open. A time delay provided by the
micrc~proce~or 23 however, will require the pad 30 to be
touched, say for two seconds before the switching pulses
are sent to the switches 24 and 25. When the ignition
20 switc:h 20 is then turned to its ignition state, current
will flow to the starter solenoid 18 through the closed
switc:h 24 and at the same time the switch 25 being opened
will disconnect the data lines 12 or 14 from the control
circuit 22 80 as to permit data to be received by or
25 tran~mitted to the management system 11. The engine 10 may
thus be started. If, however, the ignition switch 20 is
turned OFF, power will be removed from the circuit 22 80
that the circuit 22 is deactivated causing the switches 24
and 25 to return to their non-operative attitude with the
30 switches 21 and 22 open. It will thus be apparent, that
the engine 10 cannot be started until and unless the above
procedure is again adopted.
If one attempts to start the engine merely using
the ignition key, nothing will happen as the ignition
35 switch 20 is isolated from the starter solenoid 18 by the
open switch 24. If one attempts to start the engine by
"hot wiring", the ignition switch 20 is usually bypassed 80
that current can be supplied to the starter solenoid 18 and
L3~
W094/~01 PCT/AU94/00293
thus the starter motor. This supply will also be available
or provided to the control circuit 22 so that the switch 25
will close. When the starter motor 17 cranks the engine
10, the sensors associated with the engine 10 will attempt
5 to send data signals to the management system 11 and the
management system 11 will attempt to send data to the fuel
injectors 16 and/or the igniter 15. The capacitor 28,
however, connected to the supply and through the closed
switch 25 and isolating circuit 26 to the data lines 12 or
14 will effectively suppress through the switch 22 the data
signals transmitted by or received from the management
system 11. The capacitor 34 thus provides an AC short to
cancel the data ~ignals. The isolating circuit 26 prevents
DC passing to the data lines 12 or 14 and thus the
15 management system 11 from the supply to which the capacitor
28 is connected.
The touch pad 30 for the touch switch circuit 29
may compri~e any metal part of the vehicle which is
insulated from earth or alternatively any metal part
20 mounted to the vehicle ~uch a~ a screw, bolt, or emblem
again in~ulated from earth and the remainder of the
vehicle. Such a touch pad 30 may be provided by any
conductive element which for example may be mounted to a
vinyl panel within the vehicle. Operation of the circuit
25 29 relies on a circuit being made from the touch pad 30 to
earth through the body. This will occur when a person is
touching the touch pad 30 at the ~ame time that he is
touching the ignition key, the ignition key completing the
circuit to earth. If the ignition key i~ covered with an
30 insulating material such as plastics it may be provided
with an exposed metal portion for contact by the user.
Such an exposed metal portion may comprise a rivet or other
fastener. Alternatively, one may touch the touch pad 30
and another earth in the vehicle such as a metal trim strip
35 and this will place the circuit 22 in an active mode 80 as
to enable the ignition switch 20 to be operated to start
the vehicle engine. In yet an alternative arrangement, an
earth point or terminal may be located adjacent to the
W094/~01 ~16 ~ 313 9 PCT/AU94/00293
touch pad 30 so that a finger of a user may span both
creat.ing the circuit between the touch pad 30 and earth.
The touch sensitive switch circuit 29 may be
provided with an override facility in the form of a switch
5 which will connect the touch pad to earth, furthermore a
pair of spaced apart touch pads or terminals 30 may be
provided in place of the single touch pad 30. A switch
also may be provided to enable selection of the pad 30
which will cause actuation of the circuit.
As ~tated above the control circuit 22
incorporates in a preferred form a microprocessor and
MOSFET switches. The microprocessor however, may be
replaced by a hardware wired control circuit with the
MOSFET switches replaced by relay operator switches.
Whilst the preferred security system 21 suitably
incorporates a touch switch circuit 29 as described and
illustrated, the system may include remote actuating means
such as an infra red or ultrasonic or radio wave remote
actuating system in place of the touch switch circuit 29 80
20 that the system can be operated remotely.
The security system 21 may additionally include a
door opening ~ensitive circuit 31 which includes the door
switches 32 as normally incorporated in a vehicle door
pillar actuated when a door is open to actuate courtesy
25 or interior lights within the vehicle. When the vehicle is
operating with the engine 10 running, and if one of the
doors i8 opened, the correspo~ing switch 32 will be
actuated. This will be sensed by the microprocessor 23 and
after a set time delay, for example thirty seconds, the
30 microprocessor 23 will cause the switch 25 to close to
thereby suppress the management system data signals. This
will immediately cause the engine 10 to stop operating.
Additionally, the engine 10 will not be able to be
restarted unless the touch pad 30 is again touched in the
35 manner described above to open the switch 25 and close the
switch 24.
The anti-car~acking circuit, could of course be
used with forms of security systems other than that
WO94/2~01 ~ PCT/AU94/00293
described above. This circuit also preferably include~ an
override switch which enables the circuit to be
disconnected or overridden which can be used at the owners
discretion.
Whilst the above has been given by way of
illustrative embodiment of the invention, all such
modifications and variations thereto as would be apparent
to persons skilled in the art are deemed to fall within the
broad scope and ambit of the invention as herein defined in
10 the appended claims.
