Patent GB-1250790-A (GB)
IPC: B60K5/08
Filed: 1968-12-09
Abstract: 1,250,790. Change speed control. ROBERT BOSCH G.m.b.H. 9 Dec., 1968 [7 Dec., 1967; 22 Dec., 1967], No. 58441/68. Heading F2D. In a change-speed control for two or more gear units G 1 , G 2  driven by separate engines, M 1 , M 2  having a common fuel supply control pedal P, automatically or manually selected ratio shifts are established in one gear unit G 1  prior to the same ratio being established in the other gear unit G 2  whereby traction effort is maintained through one gear unit whilst ratio shift is effected in the other. Manual control (Fig. 4a and 4b).-A control lever 104 actuates switches 103, 107 to preselect the same ratio in both gear units. Establishment of the selected ratio in the first gear unit G 1  is initiated by momentary depression of a main clutch pedal 111 which disengages the main clutch C 1  and actuates a pulse generator 113 (see also Fig. 6, not shown) providing a pulse through lines 115, 116, 117, a hold relay 128, and line GAL 1  to an electro-pneumatic gear shift unit GA 1  which conditions the gear unit G 1  for neutral. During neutral a gear detection and indicator unit A 1  (see also Fig. 10, not shown) provides an output L 1  through lines 127, 116 to an electro-pneumatically operated servo device SP 1  (see also Fig. 8, not shown) which disconnects the engine fuel control lever 137 from the control pedal P and thereafter automatically adjusts engine speed until synchronism in the gear is achieved. A polarized relay synchronism detector V 1  having two windings respectively energized by an input driven generator DM 1  through one of a series of resistors 103 corresponding to the gear ratios and by an output driven generator DG 1  produces an output, on balanced energization of its windings, through a line 106 and switch 107 to the gear shift unit GA 1  to establish the selected ratio in the first gear unit G 1 . Thereupon the gear detection and indicator unit A 1  indicates the ratio engaged, cuts off the output L 1  to the servo SP 1  to restore engine fuel control to the pedal P and produces an output E 1  which triggers a pulse generator 119 supplying a pulse through a holding relay 121 (see also Fig. 7, not shown) to an electro-pneumatically operated servo 133 which momentarily disengages the main clutch C 2  of the second gear unit G 2 . The pulse is also supplied through lines 123, 124, 125, a holding relay 131 and line GAL 2  to the electro-pneumatically operated gear shift unit GA 2  which conditions the second gear unit G 2  for neutral. Thereafter ratio shift in the second gear unit is established in a manner similar to that described for the first gear unit. For simultaneous ratio shift in both gear units a switch 157 is changed over so that momentary depression of the clutch pedal 111 supplies a pulse initiating ratio establishment to the second gear unit in addition to that supplied to the first gear unit. The first gear unit may be used alone by opening a switch 154 (see also Fig. 9, not shown) to prevent establishment of a ratio in the second gear unit and by closing a switch 155 which produces neutral in the second gear unit. In Fig. 5 (not shown) the pulse from the generator 119 is only supplied to the clutch operating servo 133 and the pulse for operating the gear shift unit GA 2  is provided by an additional pulse generator activated by the clutch linkage. Automatic control (Fig. 2).-Ratio shifts are selected and established in response to input and output speeds detected by input and output speed responsive generators DM 1 , DG 1 . The input generator DM 1  supplies a signal generator Z 1  (see also Fig. 3, not shown) which produces no signal when the input speed is between first and second predetermined values corresponding to the optimum operational range of the engine, produces a signal on a line 11<SP>1</SP> when the input speed is below the first predetermined speed and produces a signal on a line 13<SP>1</SP> when the input speed is above the second predetermined speed. The signal generator Z 1  supplies an additional signal on a line 14<SP>1</SP> when either of the other two signals are present. The output generator DG 1  is in series with a battery 18 to provide a control voltage on a line 17 which is maximum when the vehicle is stationary and is zero at maximum vehicle speed. Relays 19 ... 23 are initially energized by the voltage on the line 17 and are sequentially de-energized as the output speed rises. Variable resistors 19e ... 23e permit adjustment of the output speed at which the relays are de-energized. Contact sets of the relays 19 ... 23 selectively energize secondary relays 27 ... 31 which close contacts 27b ... 31b through which gear shift signals A ... E are supplied. The gear shift signals are supplied from the line 14 through a hold relay 39 and a switch 37 which is closed at synchronism by a polarized differential relay 24 having its windings 25, 26 respectively fed from the input generator DM 1  and the output generator DG 1 . Resistors 32 ... 36 corresponding to the gear ratios are selectively inserted between the output generator DG 1  and the relay winding 26 by relay contacts 27a ... 31a. The control system for each gear unit may be identical with staggered shifts obtained by adjustment of the resistors 19e ... 23e. Operation.-Assuming the gear to be in second ratio with the relay 19 de-energized and the relays 20 ... 23 energized and the engine working in its optimum speed range, an increase in output speed de-energizes the relay 20 and thereafter when the input speed exceeds the second predetermined value a signal on the line 13<SP>1</SP> is conducted through contacts 19a, 20a, 21b to energize the relay 29 and close its contacts 29a, 29b. Simultaneously the signal on the line 14<SP>1</SP> disengages the previous ratio. On synchronism detected by the differential relay 24 the switch 37 closes to provide a signal C which established third ratio in the gear. Downshift is initiated when the engine speed falls below the first predetermined speed by a signal on the line 11<SP>1</SP> which is conducted through one or more of the contacts 21c ... 23c and one of the contacts 20d ... 22d to energize one of the relays 27 ... 29 for establishment of a ratio two lower than the ratio previously engaged.