Electronic controller for automatic transmissions

• US 4,892,014 A
• Filed: 02/01/1988
• Issued: 01/09/1990
• Est. Priority Date: 02/01/1988
• Status: Expired due to Fees

• Current Assignee: Sparton Engineered Products, Inc.
• Original Assignee: Sparton Corporation (Elbit Systems Limited)
• Inventors: Morell, Thomas H., Schonfeld, Frederick A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/150,985
• Time in Patent Office: 708 Days
• Field of Search: 74/866, 74/856, 74/861, 192/4 A, 192/4 C, 192/1.33, 180/272, 180/273, 364/424.1
• US Class Current: 477/92
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: F16H 2059/746 Engine running state, e.g. on-off of ignition switch
• CPC Class Codes: F16H 59/08 Range selector apparatus
• CPC Class Codes: F16H 59/50 Inputs being a function of the status of the machine, e.g. position of doors or safety belts
• CPC Class Codes: F16H 59/54 dependent on signals from the brakes, e.g. parking brakes
• CPC Class Codes: F16H 61/0251 Elements specially adapted for electric control units, e.g. valves for converting electrical signals to fluid signals
• CPC Class Codes: F16H 61/0286 Manual valves
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18
• CPC Class Codes: F16H 61/32 Electric motors actuators or related electrical control means therefor
• CPC Class Codes: F16H 63/483 Circuits for controlling engagement of parking locks or brakes

Abstract

A microprocessor controlled automatic transmission range shift selector positions the range shift valve in accordance with a shift request by an electric motor. A feedback transducer provides valve position information for motor control purposes. Vehicle conditions transducers including a door switch, a seat switch, vehicle speed and RPM sensors, ignition circuit status and key presence detectors, a parking brake sensor and a foot brake switch provide inputs to the microprocessor which is programmed to determine appropriate shifts to prevent requested range shifts in some cases and automatically initiating shifts into park in other cases. An automatic parking brake actuator and door lock actuators are also controlled by the microprocessor system.

Claims

1. In an automotive vehicle, an electronic transmission controller for an automatic transmission having neutral, reverse, forward and park ranges and subject to range selection by electrical signals from the controller, the controller comprising;

speed sensors for sensing vehicle speed and engine speed,

ignition sensors for sensing whether the ignition is on and whether the key is in the ignition switch,

means for controlling the transmission park range in response to preset values of sensed vehicle conditions including programmable electronic means coupled to the sensors for producing electrical signals for range selection, the electronic means being programmed to limit the transmission to park range on the basis of prescribed sensor conditions,

said vehicle being equipped with a power operated parking brake and wherein the electronic means produced a brake signal, and

actuator means responsive to the brake signal for applying the parking brake when the transmission is shifted to its park range.

2. The invention as defined in claim 1 wherein the electronic means is programmed to issue a release brake signal when the transmission is shifted out of its park range, causing the actuator means to release the brake.