Patent GB-1311771-A (GB)
Title: Automatic transmission control systems for automobiles
IPC: F16H61/08
Filed: 1970-05-04
Abstract: 1311771 Change-speed control NIPPON-DENSO KK 4 May 1970 [9 May 1969] 21355/70 Heading F2D An automatic electronic control, for a fluidcoupling-driven four-speed and one reverse transmission on a motor-vehicle, comprises ratio-establishing solenoid valves in a unit 40, energized, to supply compressed air to the ratio-establishing devices, under control of a valve drive circuit 180, Figs. 1 and 7, which includes timer circuits 1810 ... 1840, which de-energize all the valve solenoids to neutralize the transmission for a predetermined time period every time a shift signal is received at the valve drive circuit, the time period being appropriate to the particular shift. Shift parameters are vehicle speed and engine throttle setting. Speed is sensed by a generator 10, driven through a cable or arranged inside the transmission, and providing a current frequency proportional to output speed, which is converted at 110 to a D.C. voltage 112. The throttle pedal operates, in three stages, switch contacts controlling resistors, Fig. 4 (not shown), to provide three throttle responsive D.C. voltage steps 124. Speed and throttle voltages are compared in signal generating circuits 130, 140, 150, comprising comparison, feed-back and phaseinverter circuits, not described, controlling respectively shifts between ratios 1 and 2; 2 and 3; and 3 and 4, each having two outputs as follows. Taking the 1-2 signal generator as an example, a 1-2 upshift is signalled when one output 134 has an imposed voltage, and the other, 133, has no voltage, a 2-1 downshift being signalled when the reverse is the case. The shift signals 133 &c. feed a logic circuit 160 (not described) which passes shift signals through lines 161<SP>1</SP> ... 164<SP>1</SP> direct to the valve drive circuit 180 and also thereto through a memory circuit 170 (not described), which memorizes the vehicle speed. Thus, release of the accelerator to idle, which causes the throttle signal to disappear, also cancels a signal 179 to the memory circuit 170, which then retains the signal state which it had before accelerator release. In the memory circuit 170 each ratio is represented by a single input voltage signal and three zeros in the four input lines 171 ... 174; and by two output signal voltages and two zeros in the four output lines 175 ... 178. Thus, for example, first ratio has input signal voltage at 171, zero at 172, 173 and 174; and output signal voltages at 176, 178, zeros at 175, 177. Different combinations represent the other three ratios. The valve drive unit 180 has four inputs 181 ... 184 from the memory circuit 170; four 181<SP>1</SP> ... 184<SP>1</SP> from the logic circuit 160, and one 189 from a manual selector switch 30 in automatic setting. Other settings of the manual switch 30 feed directly the solenoid shift-valve unit 40 for the first three ratios and reverse. Four outputs 185 ... 188, from the valve drive unit 180 to the solenoid-valve unit 40, control ratios in automatic phase. The valve drive circuit 180, Fig. 7, comprises four power transistors 1806 ... 1809 fed from the automatic lead 189 from the manual selector valve 30, and having outputs 185 ... 188 connected to the respective solenoids of the shift valve unit 40. The power transistors 1806 &c. are triggered by four transistors 1800 ... 1803, receiving shift signals at 181 ... 184 from the memory circuit 170, Fig. 1, which are themselves triggered by a common transistor 1804, triggered by timing circuits 1810 ... 1840 controlled by signals 181<SP>1</SP> ... 184<SP>1</SP> from the logic circuit 160, Fig. 1, the timing circuits 1820, 1830, 1840 controlling 1-2, 2-3 and 3-4 upshifts, whilst 1830, 1820, 1810 control 4-3, 3-2 and 2-1 downshifts, respectively. For initial first ratio the memory circuit 170 provides voltage signals at 182, 184 and zero at 181, 183, which triggers the transistor 1800, which in turn triggers the power transistor 1806, energizing the lead 185 of the first ratio solenoid valve. For 1-2 upshift the logic circuit 160 produces a voltage signal at 182<SP>1</SP>, and the memory circuit 170 voltage signals at 181, 184 zero at 182, 183. For a predetermined time interval the logic signal 182<SP>1</SP> renders the timing circuit 1820 conducting, which cuts off the common transistor 1804, thus de-energizing any solenoid lead 185 ... 188, and neutralizing the transmission. At the end of the interval the circuit 1820 ceases to conduct, the common transistor 1804 again conducts and triggers transistors 1802, 1807 to energize the second ratio solenoid-valve lead 186, completing the shift. Furthr upshifts and downshifts are similar, using the appropriate timing circuits as above described.