How does governor pressure work in a transmission?
How does governor pressure work in a transmission?
Shift Valves: Shift valves control hydraulic pressure flow to the reactionary devices (clutches and bands) that drive and hold members of the planetary gearset. Transmissions change gears by moving shift valves. Governor pressure works on one end of the valve, and a spring assisted by throttle pressure works on the other.
When does throttle pressure overcome the governor pressure?
When throttle pressure overcomes governor pressure, the transmission downshifts. When a driver accelerates to pass another vehicle, there’s an increase in throttle pressure, causing a downshift. These two pressures control shift valve movement.
How does the Governor affect the shift timing?
Governor pressure increases with vehicle speed. Older transmissions had mechanical governors that consisted of springs, centrifugal weights, and a spool valve to control this pressure. Governor pressure causes a transmission to upshift, and throttle pressure causes it to downshift. Today’s transmissions use solenoids for the shift timing.
What happens when the governor pressure goes up?
Now you take your foot off the break but don’t hit the gas. The car will slowly speed up and the governor pressure will go up. When the governor pressure is high enough it will overcome the spring and slide the spool valve over turning off first gear and turning on second gear.
How does the Governor of a transmission work?
Governor pressure increases with vehicle speed. Older transmissions had mechanical governors that consisted of springs, centrifugal weights, and a spool valve to control this pressure. Electronic transmissions use the vehicle speed sensor signal for vehicle speed.
How is governor pressure similar to throttle pressure?
Governor pressure is similar to throttle pressure in that it is a derivative of line pressure but it is generated relative to the speed of the vehicle. Normally the governor is in or near the tail shaft of the transmission. The governor has a set of fly weights (like centripetal advance in a distributor).
How does governor pressure affect the shift valve?
Shift Valves: Transmissions change gears by moving shift valves. Governor pressure works on one end of the valve and throttle pressure aided by a spring works on the other. When a vehicle first accelerates from a stop, throttle pressure is higher than governor pressure, so the vehicle stays in first gear.
Now you take your foot off the break but don’t hit the gas. The car will slowly speed up and the governor pressure will go up. When the governor pressure is high enough it will overcome the spring and slide the spool valve over turning off first gear and turning on second gear.
How is the mainline pressure of an automatic transmission controlled?
Mainline pressure is controlled by the pressure regulator valve. Mainline pressure is the source pressure for the torque converter, valve body, and the clutches and bands in an automatic transmission.
Why does governor pressure increase with vehicle speed?
Governor pressure increases with vehicle speed. Older transmissions had mechanical governors that consisted of springs, centrifugal weights, and a spool valve to control this pressure. Governor pressure causes a transmission to upshift, and throttle pressure causes it to downshift.
Governor pressure increases with vehicle speed. Older transmissions had mechanical governors that consisted of springs, centrifugal weights, and a spool valve to control this pressure. Governor pressure causes a transmission to upshift, and throttle pressure causes it to downshift. Today’s transmissions use solenoids for the shift timing.
Mainline pressure is controlled by the pressure regulator valve. Mainline pressure is the source pressure for the torque converter, valve body, and the clutches and bands in an automatic transmission.
