Interrelated power delivery controls – including engine control – Transmission control – Engine starting interlock
Reexamination Certificate
1999-08-04
2001-01-23
Wright, Dirk (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Engine starting interlock
Reexamination Certificate
active
06176810
ABSTRACT:
The invention concerns a starter interlock system for a motor vehicle with an automatic transmission in which the starting of a vehicle is prevented when a selector lever actuatable by a driver is in a position other than parking or neutral.
BACKGROUND OF THE INVENTION
Automatic transmissions are usually equipped with a starter interlock system. This serves the purpose that a vehicle can only be started when a selector lever, actuatable by the driver, is in neutral or parking position. Starting the vehicle in a driving position, e.g. R or D, is hereby prevented. Such a starter interlock system has the following units: ignition lock, starting relay, selector lever, electric position switch and an electronic transmission control system. The electric position switch coverts the position of the selector lever into electrical signals. In practice, this can be obtained by situating the position switch on a rotatable shaft and the position switch having inside several conductor tracks with sliding contacts or working without contact. The output signals of the electric position switch represents in coded form, e.g. as 4-bit code, the position of the selector lever. The signals are then passed to the electronic transmission control system. Two contacts are also integral parts of the position switch. The first contact serves to control the reverse drive headlights when the driver has introduced the position R via the selector lever. The second contact serves to control the starting operation. This contact can be designed as closing switch, i.e. when the selector lever is in position P or N, said mechanical contact is closed. In this position, a current path exists from the supply potential to the reference potential, via ignition lock, starter relay and closed position switch. The vehicle can be started.
The above described starter interlock system has been disclosed, e.g. in the book “Automatische Fahrzeuggetriebe,” H. J. Forster, Springer Verlage, 1991, pages 344 to 347. The electric design of the position switch is known from the same book, FIG. 10.48 on page 392.
A new trend of development in automatic transmissions now moves toward reducing the interfaces of the automatic transmission and moving the electronics to the interior of the transmission. This development is known by the technical expression “Elektronik vor Ort” or “Mechatronik.”
SUMMARY OF THE INVENTION
Departing from the above described prior art, the problem on which the invention is now based is further developed in the direction of “Elektronik vor Ort.”
According to the invention, the problem is solved by the fact that on the electronic transmission control system two supply voltages are applied, the first supply voltage applied permanently and the second supply voltage applied when the ignition lock is moved to the first position. The application of the second supply voltage activates the electronic transmission control system which for its part supplies the position switch and the starter switch with current. The starter switch is not activated when the signals of the position switch indicate a driving position so that with moving of the ignition lock to the second position the starter relay remains deactivated. The starter switch is located within the automatic transmission and is designed as a semiconductor switch. The transmission control system detects the state of the starter switch via an informed variable.
The solution, according to the invention, offers the advantage that both the position switch and the starter switch are an integral part of the automatic transmission. By using the semiconductor switch as starter switch, the added advantage is obtained that the latter is short-circuitproof.
It is proposed in a development of the invention that the electronic transmission control system be activated by means of the first supply voltage when the informed variable of the starter switch indicates that the ignition lock has been moved to the second position and, at the same time, a failure of the second supply voltage has been found. This development substantially contributes to the operating safety of the vehicle. It is here assumed that as consequence of a line interruption the second supply voltage is not applied to the electronic transmission control system. The electronic transmission control system is then activated via the informed variable of the starter switch. This informed variable appears when the driver moves the ignition lock to the second position, i.e. when he intends to start the vehicle. After the electronic transmission control system has been activated, the position switch and the starter switch are supplied with current. The starter switch is controlled by the position switch according to the position of the selector lever. A perfect operation of the starter interlock system, i.e. a prevention of starting in a drive position, is thus also ensured when there is no second supply voltage applied to the electronic transmission control system. By using the informed variable as a signal for activating the electronic transmission control system, the advantage obtained is that no redundant, permanent supply voltage has to be fed to the semiconductor switch.
In a development of the invention, it is proposed that the electronic transmission control system has, in addition, a function block by means of which results a self-blocking of the informed variable of the starter switch. It is also proposed that the function block has a time stage, there being proposed in one other development that after lapse of the time stage the self-blocking is terminated so that the function block is deactivated. The advantage obtained with said developments is that even when the driver changes the ignition lock directly from the second position, back to the first position, the electronic transmission control system is nevertheless activated by the self-blocking function.
REFERENCES:
patent: 5009295 (1991-04-01), Kinkade et al.
patent: 5377641 (1995-01-01), Salazar
patent: 5445575 (1995-08-01), Sundeen
Eschrich Gerhard
Horsak G{umlaut over (u)}nther
M{umlaut over (u)}ller Andreas
Davis and Bujold
Wright Dirk
ZF Friedrichshafen AG
LandOfFree
Starter interlock system for a motor vehicle with an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Starter interlock system for a motor vehicle with an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Starter interlock system for a motor vehicle with an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2464495