Gear shifting engagement shock control system
AssigneeRobert Bosch GmbH
InventorsFriedrich Rabus, Ferdinand Grob
Life of this patent
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Abstract
To control shifting shock upon starting of a stopped vehicle with an automatic transmission and when shifting from neutral into a drive gear (first, or reverse), a signal representative of transmission input speed (therefore equally representative of engine output speed) is used, twice differentiated, to control a shift-shock control system when shifting between neutral and a drive gear. When the vehicle is moving above a predetermined speed, e.g. 7 km/h, the automatic shock control system is controlled by a twice differentiated signal derived from the output of the transmission and when shifting is to be commanded between first and second, and second and third (or other gears), respectively.
Claims12
Gear shifting engagement shock control system for vehicles having an automatic multi-gear transmission having
- engine speed transducer means (1) providing an engine speed signal;
- transmission output speed transducer means (5) providing a transmission output speed signal;
- a gear change shock or jolt control stage (11);
- a gear selector stage (10);
- and clutch means (12) controlled by said shock control stage (11) establishing a driving connection between the engine and the vehicle drive wheels
- wherein
- the gear selector stage (10) comprises a first portion (101) controlling change of gears between disengaged or neutral position and an operating gear (R, D), and a second portion (102) controlling change of gears between gear ranges commanding movement of the vehicle (1/2, 2/3;
- 3/2, 2/1);
- engine speed second derivative (rate-of-acceleration/deceleration) signal transforming means (3, 4) are provided connected to and controlled by said engine transducer means (1) and providing a second derived engine speed signal representative of the second derivative of the engine speed signal, whereby said derived engine speed signal will be representative of the rate of change of acceleration/deceleration of the engine,
- said engine speed second derivative signal transforming means being connected to and controlling said first portion (101) of the gear selector stage (10);
- transmission output second (rate of acceleration/deceleration) derivative signal transforming means (7, 8) are provided, connected to and controlled by said transmission output transducer means (5) and providing a second derived transmission output signal representative of the second derivative of the transmission output speed signal, whereby said second derived transmission output speed signal will be representative of the rate of change of acceleration/deceleration of the output speed of the transmission, said derived signal being applied to the second portion (102) of the gear selector stage (10);
- and selective connection means (104) controlled by the transmission output speed signal selectively connecting the output from the first portion, or the second portion, respectively of the gear selector stage to the shock control stage (11) in dependence on sensed speed of the output from the transmission.
Gear shifting engagement shock control system for vehicles having an automatic multi-gear transmission having
- engine speed transducer means (1) providing an engine speed signal;
- transmission output speed transducer means (5) providing a transmission output speed signal;
- a gear change shock or jolt control stage (11) and clutch means (12) controlled by said shock control stage establishing a driving connection between the engine and the vehicle wheels;
- and means to reduce the gear shifting engagement shock upon changing the transmission between disengaged or neutral position (N) and an operating gear (R, D) position comprising derivative signal transforming means connected to and controlled by said engine transducer means (1) and providing a second derived (rate of acceleration/deceleration) signal representative of the second derivative--with respect to time--of the engine speed signal, whereby said second derived engine speed signal will be representative of the rate of change of acceleration/deceleration of the engine;
- and controlled switch means (104) selectively connecting said second derivative derived engine speed signal to said gear change shock or jolt controlled stage (11) under control of an output signal from said transmission output speed transducer means if said transmission output speed transducer means provides an output signal indicative of operation of the vehicle below a predetermined, low speed value.
Method to reduce starting jolt or shock upon change of a gear selector lever in an automatic transmission between neutral and an operating range (N/D, N/R) comprising sensing engine output speed and deriving a speed signal representative of said engine output speed;
- twice differentiating said speed signal to derive a signal representative of the second derivative of speed and hence of the rate of deceleration of the engine upon placement of a sudden load on the engine;
- and controlling a transmission shock control train (11, 12) as a function of said second derivative of the engine output speed signal.
Dependencies are inferred from the claim text.