Clutch actuating apparatus controlled by accelerator

In an automotive vehicle including a vacuum source, a transmission gear shift lever and an accelerator pedal, an apparatus for actuating an automatically operated clutch forming part of the driveline of the vehicle and continuously operable between a disengaged condition and a fully engaged condition through a partial torque transmission range, comprising (a) a vacuum chamber in communication with said vacuum source, (b) an air chamber communicable with the open air through each of first and second restricted-flow air inlet ports, (c) a valve chamber alternately communicable with said vacuum chamber and said air chamber, (d) first valve means having a first position isolating said vacuum chamber from said valve chamber and establishing communication between said air chamber and said valve chamber and a second position blocking the communication between the air and valve chambers and establishing communication between the vacuum and valve chambers, (e) second valve means having a first position allowing said first air inlet port to open and a second position closing the first air inlet port, (f) third valve means continuously movable between a first position closing said second air inlet port and a second position allowing the second air inlet port to fully open, (g) first valve actuating means for moving said first valve means in response to predetermined conditions of the transmission gear shift lever and the accelerator pedal, said first valve actuating means being operative to move said first valve means into said first position thereof in response to at least one of the condition in which the transmission gear shift lever is free from a manipulative effort and the condition in which the accelerator pedal is at least partially depressed from the released position and being operative to move said first valve means into said second position thereof in response to the conditions in which the transmission gear shift lever is being manipulated and simultaneously the displacement of the accelerator pedal from the realeased position is smaller than a predetermined value, (h) second valve actuating means responsive to vehicle speed for moving said second valve means into said first position thereof in response to a vehicle speed higher than a predetermined level and into said second position thereof in response to a vehicle speed lower than said predetermined level, (i) third valve actuating means responsive to movement of the accelerator pedal for continuously moving said third valve means between said first and second positions thereof as the accelerator pedal is moved between the released position and the fully depressed position so that the flow of air through said second air inlet port is varied substantially proportionate to the depth to which the accelerator pedal is depressed from the released position thereof, (j) a differential-pressure assembly including a variable-volume chamber defined in part by a flexible diaphragm which is at least partially movable between positions respectively providing minimum and maximum volume conditions of said variable-volume chamber, and biasing means for urging said diaphragm toward the position providing the maximum volume condition in said variable-volume chamber, said variable-volume chamber being in constant communication with said valve chamber so that said diaphragm is moved toward the position providing the minimum volume condition of the variable-volume chamber in the presence of intake manifold vacuum in said valve chamber and toward the position providing the maximum volume condition of the presence of atmospheric air in the valve chamber, and (k) a mechanical linkage operatively interconnecting said diaphragm and said clutch for driving the clutch toward the disengaged and fully engaged conditions thereof as the diaghragm is moved toward the positions providing the minimum and maximum conditions, respectively, of said variable-volume chamber.