Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-06-04
2001-06-05
Pope, Daryl (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S438000, C340S638000, C340S870030, C340S517000
Reexamination Certificate
active
06243018
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for multiplexing between on-board units of a vehicle by using wire harnesses.
Recently, various controls in a vehicle are performed by an on-board computer and the associated electrically controlled equipments. Thus, large amounts of electric wiring are used in the vehicle. The electric wiring, such as the wire harnesses, have the potential for causing a short-circuit. Therefor, various apparatus for detecting the short-circuit of wire harnesses for power supply have been proposed in the past.
One of them is disclosed in Japanese Patent publication No. 4-17809 (1992), in which the rated consumption currents for respective loads are calculated in advance, the occurrence of an abnormality due to the short-circuit is detected by comparing the sum of the rated consumption currents with the sum of the current one in the vehicle.
However, when a wire harness is installed into a vehicle body, the harness may be jammed into the vehicle body and/or the coating of the harness may be broken due to the rubbing of the harness on metal portions of the vehicle body. Therefore, a core wire of an electric power source may short to a ground portion of the vehicle body, and thus serious accidents such as a fire in the vehicle may break out in the worst case.
In the above prior art, the apparatus is constructed such that the serious accidents can be prevented immediately by cutting off the whole current. Therefore, when such accidents occur during driving, a power source is cut off. As a result, the vehicle stops suddenly. Further, when the driver changes the load of an electric system, it is required to change the predetermined rated value. Therefore, there was a possibility that a malfunction would occur. In addition, while the short-circuit of the wire harness can be detected, the processing after the detection of the short-circuit can not be performed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus for multiplexing between on-board units of a vehicle, which apparatus can detect at an early stage the short-circuit of the wire harness.
Another object of the present invention is to provide an apparatus for multiplexing between on-board units of a vehicle, which apparatus can perform a suitable processing when the short-circuit of the wire harness is detected, thereby the serious accident can be prevented in advance.
In order to achieve the above objects, an electric conductivity layer is provided outside the electric wires, and the predetermined electric potential is provided to the electric conductivity layer. Further, the outside of the electric conductivity layer is covered with an insulator layer. As a result, a sub-wire harness is formed as a whole. The wire harness in the whole vehicle is constructed by connecting the sub-wire harnesses to each other by a connector. The multiplexing apparatus includes, besides a monitor for monitoring an electric potential of the wire harness and detecting a short-circuit to the ground, a control system for determining the short-circuit on the basis of the result of the detection by the monitor, and an alarm raising system for raising an alarm according to a command from the control system, and a circuit breaker to break the current from a power source.
According to one aspect of the present invention, the multiplexing apparatus multiplexes between processing units and a battery unit of a vehicle which are connected to one another by wire harnesses, by grouping a variety of on-board controlled objects into a plurality of neighboring controlled objects and controlling each of the groups by respective processing units. The wire harness has electric conductors of which the outer peripheral portion are covered with a first insulating layer, electric conductivity layer which covers the electric conductors, a second insulating layer which covers the peripheral portion of the electric conductivity layer, device for applying an electric potential to said electric conductivity layer, and a monitor the electric potential of said electric conductivity layer.
Preferably, the electric conductivity layer is formed by a thin mesh wire.
The multiplexing apparatus according to the present invention further may include an alarm for raising an alarm to a driver, and a control system for starting up the alarm to raise the alarm.
In addition to the alarm and the control system, the multiplexing apparatus further may include a power source circuit breaker for cutting off a current supplied from the battery unit, wherein said control system start up said power source circuit breaker to cut off the current from the battery, when said electric conductivity layer is short-circuited to the ground.
In the multiplexing apparatus according to the present invention, there may be provided a plurality of electric conductivity layers between which insulating layers are sandwiched alternately.
Preferably, the multiplexing apparatus further may include an alarm for raising an alarm to a driver, a power source circuit breaker for cutting off a current supplied from the battery unit, and a control system for starting up said alarm to raise the alarm and starting up said power source circuit breaker to cut off the current from the battery unit, when at least one of said electric conductivity layers is short-circuited to the ground.
Preferably, the multiplexing apparatus further include a device for applying an electric potential to said electric conductivity layer, a monitor the electric potential of said electric conductivity layer between respective groups, a detector for detecting the short-circuit of the wire harness to the ground on the basis of the output of said monitor, and a circuit breaker for cutting off a current passing through said electric conductor from the power source when the short-circuit of the wire harness to the ground is detected by said detector.
The above multiplexing apparatus further may include a data storage for storing the data used to estimate the damage by using at least one of the frequency of the short-circuit of the wire harness to the ground, the term of time of the short-circuit, the position of the short-circuit and the importance as parameters, and a control system for setting the condition of cut-off of the circuit breaker on the basis of the data stored in the data storage.
Preferably, the multiplexing apparatus according to the present invention further includes a device for applying an electric potential to said electric conductivity layer, a monitor for the electric potential of said electric conductivity layer between respective processing units, a detector for the short-circuit of the wire harness to the ground on the basis of the output of said monitor, and an alarm for raising the alarm to a driver when the short-circuit of the wire harness to the ground is detected by said detector.
In the multiplexing apparatus described above, the electric potential applying device preferably include a C-shaped electric conductivity body a portion of which is notched, an electric conductor connected to the electric conductivity body, for detecting an electric potential, and a pull-up resistor, and wherein said electric conductivity body is press-bonded to the electric conductor from the outside of the electric conductivity layer of the thin mesh wire.
It is desirable to provide data storage for storing the data used to estimate the damage by using at least one of the frequency of the short-circuit of the wire harness to the ground, the term of time of the short-circuit, the position of the short-circuit and the importance as parameters, and a control system for changing a alarm level of the alarm on the basis of the data stored in the data storage.
Further, the power source cut-off preferably includes a switching element.
The multiplexing apparatus according to the present invention further may include a fail-safe device which allows the processing unit in charge of the group of the area where the abnormality occurred to notify the occurrence of t
Kon'i Mitsuru
Saito Hiroyuki
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Hitachi , Ltd.
Pope Daryl
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