Interrelated power delivery controls – including engine control – Transmission control – With brake control
Reexamination Certificate
2002-01-30
2004-02-10
Lewis, Tisha D (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
With brake control
C180S271000, C074S473120
Reexamination Certificate
active
06689014
ABSTRACT:
BACKGROUND
This invention relates to mobile vehicle automatic transmissions, transmission shifters, and vehicle communication sub-systems. The communication sub-system makes use of existing industry standard or proprietary communication protocols and communication spines replacing separate hard wired circuits for ensuring that the shifter is not moved out of a park position without the application of service brakes. Such vehicles appropriate for such installation include but are not limited to light, medium, and heavy-duty trucks and buses.
PRIOR ART
Many transmission shifters have a position labeled “Park” or labeled with some abbreviation of “park” or similar word that is meant to operate some device to halt the vehicle's forward and reverse motion. The driveline of a vehicle transmits power first from the engine and eventually to the wheels and road. Some transmissions have a built in “park pawl” that locks the driveline through a ratchet-like mechanism, while other transmissions have a device that automatically actuates the vehicle's park brake. In either case, an injury could potentially occur if the transmission is shifted out of this park position to free the transmission or release the park brake without some other means of impeding the vehicle's forward or reverse progress.
One way to avoid sudden, perhaps unexpected, vehicle movement is to disallow the operator to shift the transmission out of this “park” position until the service brakes have been applied. U.S. Pat. No. 5,853,348 owned by the same assignee as this invention provided such a system. This prior art system was for selectively locking a steering-column-mounted transmission shifter in a park position that places the transmission in one of two neutral positions. An electrically operated shift lock releasably locked the shifter in park position. The shift lock was under the control of an electric circuit that contained a first and second shift lock relays having normally open contacts connected in series to the shift lock. The electric circuit operatively coupled the relays'coils with the ignition switch, a transmission neutral position-sensing switch, and a service brake-sensing switch. When the service brakes were applied and the ignition switch was on, the shift lock was operated to release the shifter, allowing the shifter to be moved to other positions. This system while effective involved complexity with the two separate relays and two sensing switches.
One issue with mobile vehicle electronics is managing communication between on-board controllers or electrical agents. At a simple level, communication between two electrical agents may be kept physically separated from communications occurring among other agents. Where two or more signals do not use the same physical space, there is no need to separate the signals in time or in carrier wave frequency. Such a communications regime is sometimes termed as physical division multiplexing although the term multiplexing is usually reserved to techniques for applying multiple signals to a single medium or physical space. So-called physical division multiplexing describes how motor vehicles have been traditionally wired. The use of separate dedicated wires to connect each switch and lamp is a type of physical division multiplexing. Obviously, physical division multiplexing, while simple in concept, results in the use of many wires (the classical motor vehicle electrical harness), which are difficult to install during manufacturing and problematic to maintain in the field.
Arrangements allowing a number of agents to communicate over a common physical layer or medium offer much greater physical simplicity. Intelligible communication between two or more devices among a greater plurality of devices, all over a common medium, depends upon the communicating devices being able to distinguish, and understand, messages directed to them from other messages which they receive, but which are not intended for them. The process of distinguishing messages depends upon the transmitter of the message applying some attribute to the message that identifies it to the intended recipient. In human conversation, most people readily distinguish speech directed to them from interfering cross talk in a crowd by the distinctive aspects of the voice of the person addressing them. Where the members of the group are electrical components, the problem still involves identification of a distinguishing attribute of the signal. Appropriate attributes for signals take a number of forms.
A line communicating a signal from a remote switch to a lamp to turn on or off (by having a second switch, local to the lamp, change states to control connection of the lamp between a power bus and ground) cycles only rarely. In a typical trip such a change in state occurs only once or twice, if at all. Where such a line is not intended to provide power to the lamp, and simply indicates changes in state for the local switch controlling the lamp, the line will have the capacity to handle far more data than the occasional indications to turn a lamp on and off. The objective of maintaining simplicity in manufacturing and maintenance are preferably met by allowing communication among a number of components to occur in a single medium, or at least as few communication lines as possible. The line used to connect switch and lamp could interconnect a number of components, carrying messages between any groupings of elements connected to the line when not required to carry an instruction to a lamp to turn on. One way of achieving this objective is a communications regime that divides time into slots during which particular combinations of components have use of a signaling line. Such methods are well known in the art and are examples of time division multiplexing (TDM). In motor vehicles, time division and related multiplexing techniques offer substantial simplification in physical layer required to support the control of vehicle vocations.
Rigid time division multiplexed communications appear to interleave data signals into a single serial signal over a single physical medium. Multiplexed communication systems also provide the reverse function (de-multiplexing) of dividing the single signal into multiple, non-synchronous digital signals. Where demands on the capacity of the data transmission medium are not especially heavy, any unit may be allowed to claim the medium provided collision detection is provided for and other indicia, such as address headers, indicate the signal's destination.
As applied to motor vehicles, multiplexed communications over serial data paths are an effective technique for reducing the number of dedicated communication paths between the numerous switches, sensors, devices and gauges installed on the vehicles. With each increase in the number and variety of accessories and functions installed on each vehicle, the benefits of using a single, multiplexed communication serial link for passing instructions to and receiving information from vehicle devices as diverse as running lights and rear axle temperature sensors becomes greater. Multiplexing the signals to and from local controllers and switches for vehicle systems promises greater physical simplicity through displacing much of the vehicle wiring harness, reducing manufacturing costs, facilitating vehicle electrical load management, and enhancing system reliability.
The specific manner of implementing multiplexed communications is outside the scope of the present invention, which applies a defined protocol such as the SAE J1939 protocol. Additionally, proprietary protocols may be used although over a network similar to as described here. The development by the Society of Automotive Engineers of the J1939 series of standards for multiplexed communications testifies to the progress in the application of multiplexed communications to vehicles. Standards have been or are being developed relating the communication path, transmission collision detection, diagnostic ports and data protocols, among other topics. The J1939 protoc
Downes Trevor T.
Fleming William R.
Lahr Jeremy A.
Lindsey Aaron D.
Calfa Jeffrey P.
International Truck Intellectual Property Company, LLC
Lewis Tisha D
Lukasik Susan L.
Sullivan Dennis Kelly
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