| 摘要 |
1,188,174. Change speed control; valves. FORD MOTOR CO. Ltd. 11 July, 1967 [1 Aug., 1966], No. 31815/67. Headings F2D and F2V. In a fluid pressure control system, for a motor vehicle automatic change speed epicyclic gear, comprising automatic (vehicle speed and engine load demand responsive) 1-2, 2-3 Shift valves 180, 218, a Downshift valve 252 is rightwardly shiftable by TV pressure from an inlet manifold pressure responsive TV valve 266, only when said TV pressure reaches a maximum value with manifold pressure usually only slightly less than atmospheric) corresponding to a wide-open through-detent ("kickdown") accelerator pedal position, to direct said maximum value TV pressure to said shift valves for forced downshifting (at differing vehicle speeds for 1-2 and 2-3 shifts). To ensure that forced downshift only occurs when the accelerator pedal reaches its throughdetent position, an inlet manifold pressure responsive valve 336 isolates the manifold 334 from the TV valve 266, and traps a residual vacuum in the line 300 to the TV valve, when manifold vacuum reduces to a predetermined value, say less than 4 inches Mercury, and a valve 364 in parallel with the valve 336 and actuable by a lever 366 connected to the accelerator pedal re-connects the manifold to the TV valve when the pedal reaches its throughdetent position. The valve 366 (Fig. 6, not shown) comprises a ball (354) closed against a seat (356) by a spring (344) in opposition to manifold vacuum acting on a diaphragm (340). The valve 364 comprises a flexible tube 368 which is connected between the manifold and the TV valve, surrounds and normally closes on a ball 370, and, when acted on by the accelerator pedal-connected lever 366, is deformed, as shown, to provide passage past the ball. The Gear arrangement and Friction Clutches and Brakes are as described in Specification. 1,123,081. The Fluid System Components are similar to those in Specification 1,123,081, the principal described exceptions including the Cut-Back valve 216 which directs TV pressure direct to the Main Regulator valve 120, and the Coasting Boost valve 272 which directs, at High coasting speeds, Main line pressure to the Main Regulator Valve. |
