DIGITAL SHIFT CONTROL FOR VEHICULAR TRANSMISSION

• US 3,732,755 A
• Filed: 03/18/1971
• Issued: 05/15/1973
• Est. Priority Date: 03/19/1970
• Status: Expired due to Term

• Current Assignee: Herbert Seibold, Willi Beig, Willi Kuhnle
• Original Assignee: Herbert Seibold, Willi Beig, Willi Kuhnle
• Inventors: Beig, Willi, Kuhnle, Willi, Seibold, Herbert
• Primary Examiner(s): Husar, C. J.
• Application Number:
  US05/125,633
• Time in Patent Office: 789 Days
• Field of Search: 74/866,365,336,752A,752D
• US Class Current: 477/131
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: Y10S 477/90 Control signal is vehicle weight
• CPC Class Codes: Y10S 477/901 Control signal is slope
• CPC Class Codes: Y10T 74/1926 Speed responsive
• CPC Class Codes: Y10T 74/19437 Electrically operated

Abstract

To change the speed ratio of an automatically shiftable power train by which the torque of an engine is transmitted to the traction wheels of a vehicle, a logic circuit emits commands to respective solenoid valves in response to a combination of operating parameters such as vehicle speed, engine temperature, accelerator position and road gradient. Speed is measured by a pulse generator, coupled with the output shaft of the transmission, whose pulses are counted by an accumulator that is periodically reset by a timing circuit and whose count between resettings is fed to the logic circuit together with signals indicating the position of a manual speed selector. The remaining parameters are used to modify the rhythm of the timer or the operation of a decoder inserted between the accumulator and the logic circuit.

Claims

1. In an automotive vehicle having an engine, a driven shaft, a transmission of variable speed ratio coupling said engine to said driven shaft, fuel-control means for said engine and shift means for varying said speed ratio, the combination therewith of:

electric pulse-generating means coupled with said driven shaft for emitting a train of rate pulses at a cadence proportional to the speed of said shaft;

sensing means responsive to an operating parameter affecting the optimum operating point of said shift means;

signal-generating means controlled by said sensing means to produce an output related to said operating parameter;

a processor having an input stage connected to said signalgenerating means;

accumulator means in said processor coupled to said pulsegenerating means for counting said rate pulses;

timing means in said processor connected to said accumulator means for resetting same at the end of a recurrent counting period;

actuating means for said shift means controlled by said processor in response to a predetermined count of said rate pulses indicative of shaft speed; and

modifying circuitry in said timing means responsive to said output for altering the duration of said counting period, thereby varying the shaft speed corresponding to said predetermined count.

2. The combination defined in claim 1 wherein said timing means comprises a first clock controlled by said modifying circuitry for generating a succession of framing cycles of variable length, defining said counting period, and a second clock measuring a series of invariable gating intervals substantially longer than said framing cycles, said processor including a second accumulator for registering the number of framing cycles per gating interval, said actuating means being jointly controlled by said accumulators to operate said shift means at an instant codetermined by said count and said number.

3. The combination defined in claim 2 wherein said timing means comprises a source of clock pulses and frequency-dividing means connected to said source for deriving from said clock pulses a succession of lower-cadence framing pulses of a length defining said counting period.

4. The combination defined in claim 4 wherein said modifying circuitry is connected to said frequency-dividing means for varying the step-down ratio thereof.

5. The combination defined in claim 1, further comprising a manual speed-ratio selector with a plurality of operating positioNs and circuit means extending from said selector to said processor for blocking the response of said actuating means to said count in certain of said operating positions.

6. The combination defined in claim 1 wherein said pulse-generating means comprises a ferromagnetic pinwheel on said driven shaft and inductive pickup means adjacent said pinwheel.

7. The combination defined in claim 1 wherein said modifying circuitry comprises a logic network.