How does engine acceleration cause a compressor stall?
A compressor stall occurs when there is an imbalance between the air flow supply and the airflow demand; in other words, a pressure ratio that is incompatible with the engine RPM. Compressor stalls cause the air flowing through the compressor to slow down or stagnate and sometimes result in reverse flow.
What’s the difference between acceleration and stall time?
The time necessary to achieve cooling is related to speed; longer dwell required at standstill than at speed. The rated stall time is the time the motor may operate with a locked rotor, whereas the acceleration time would be the time the loaded motor takes to reach its rated speed from startup.
Why does my car stall at highway speeds?
The engine may start and idle fine, but run out of power or even stall at highway speeds. If the engine starts right back up after stalling, the likely cause is low fuel volume delivery because of a weak pump. If the engine is running normally one minute, but suddenly quits, loss of ignition may be the problem.
What is the allowable stall time for an electric motor?
The motor manufacturer can furnish the allowable locked-rotor time only after the motor design is completed. This is given as time at rated lockedrotor current starting from either rated ambient temperature or rated operating temperature also referred to as cold stall time or hot stall time.
Why are stall times given at 1.0 Pu?
The reason two times are given (9 sec at 1.0 pu, 15 sec at 0.8 pu volt) is that the high inrush current (at least 6x rated) will cause line voltage to dip (to roughly 0.8 pu). This means the real acceleration torque profile is somewhere between the 0.8 and 1.0 pu values. Safe Stall Times are ALWAYS given with a speed rating.
The engine may start and idle fine, but run out of power or even stall at highway speeds. If the engine starts right back up after stalling, the likely cause is low fuel volume delivery because of a weak pump. If the engine is running normally one minute, but suddenly quits, loss of ignition may be the problem.
Can a stalling engine be intermittent driveability?
Intermittent driveability problems of any kind are always a challenge to diagnose. When a customer brings you a vehicle and complains of a stalling problem, you may not have much to go on other than their description of what’s happening and when it happens.
What should I do if my engine is stalling?
Cleaning the idle air bypass circuit in the throttle body with aerosol throttle cleaner; will often remove the gunk and solve your stalling problem. If a good soaking with cleaner fails to fix the stalling problem; check the wiring connector. It might be loose or corroded.
What causes an engine to stall at idle?
If the ISC valve is gummed up with fuel varnish or dirt, it may stick, preventing the engine from maintaining the proper idle speed when the throttle closes. A faulty idle speed control circuit may also allow the engine to stall when idling if it fails to compensate for idle loads placed on the engine by the charging system or A/C compressor.