Abstract A fluid power control system for a vehicle having forward, reverse and speed range clutches, and the vehicle being driven from a source of power, such as an internal combustion engine, through a torque converter, which is controlled by a fluid actuated and modulated main clutch. The control system (FIG. 4) includes cross-over valve means connected with the direction clutches and the speed change clutches so that when a shift from one clutch to the other is called for by the action of the operator, the clutch which had been engaged is held in engagement until the newly selected clutch is at least partially engaged, and then the clutch which had been engaged is released. The system eliminates heat generation which is otherwise caused by slow shifting which in turn permits the vehicle power source to build up inertia energy in the power input parts, such as the flywheels, main clutch and torque converter.
A vehicle having a gear speed shift mechanism including a pair of fluid actuated gear shift clutches, and also having fluid pressure circuit means for actuating said clutches, said circuit means including a fluid pressure operated shiftable control valve having a shiftable portion for each of said gear shift clutches, said shiftable control valves each having a first operating pilot at one end and a larger operating pilot at the other end for shifting their respective shiftable portions, a high hold pressure line connected to each of said shiftable control valves and communicable with said portion, an apply pressure line connected to each shiftable control valve and communicable with said portion, a pair of cross-over fluid circuits each connected between said first operating pilot of one of said shiftable control valves and the larger operating pilot of the other control valve, each of said cross-over fluid circuits also communicable with said shiftable portion of a control valve and one of said clutches, a check valve between each apply line of one control valve and that cross-over circuit which is connected to the larger operating pilot of said other control valve, and control means for selectively applying fluid pressure to each of said apply pressure lines.
Claim 2
Dependent Claim
205 words
A vehicle having a gear speed shift mechanism including a pair of fluid actuated gear shift clutches, and also having fluid pressure circuit means for actuating said clutches, said circuit means including a fluid pressure operated shiftable control valve having a shiftable portion for each of said gear shift clutches, said shiftable control valves each having a first operating pilot at one end and a larger operating pilot at the other end for shifting their respective shiftable portions, a high hold pressure line connected to each of said shiftable control valves and communicable with said portion, an apply pressure line connected to each shiftable control valve and communicable with said portion, a pair of cross-over fluid circuits each connected between said first operating pilot of one of said shiftable control valves and the larger operating pilot of the other control valve, each of said cross-over fluid circuits also communicable with said shiftable portion of a control valve and one of said clutches, a check valve between each apply line of one control valve and that cross-over circuit which is connected to the larger operating pilot of said other control valve, and control means for selectively applying fluid pressure to each of said apply pressure lines.