SYSTEM / Control System Auto-Warming Up Control Purpose: To warm up the engine in response to the hydraulic oil temperature automatically. Operation: Actual Engine Speed 1. At start of the engine, if the hydraulic oil tem- perature is 0°C (32°F) or below, MC transmits the signal that the engine slow idle speed is set at 1100 min -1 to ECM. Fast Idle Auto-Warming Up Speed 2. ECM increases the engine slow idle speed to 1100 min -1 . Speed Increase 3. When the engine coolant temperature or hydrau- lic oil temperature is 40°C (104°F) or above, or when 10 minutes have passed, MC stops the signals and ECM decreases the engine slow idle speed to the idling speed.
Slow Idle Slow Idle Fast Idle Target Engine Speed NOTE: At start of the engine, if the hydraulic oil temperature is 1°C (34°F) or above, auto-warming up control is not made. NOTE: In case the hydraulic oil temperature sen- sor becomes abnormal, auto-warming up control is not made. NOTE: When the parking brake switch is turned OFF, auto-warming up control is released. NOTE: In case auto-warming up control is re- leased by Dr. ZX, retrieve the auto-warming up control effective by Dr. ZX the moment releasing becomes unneces- sary. (Retrieving is impossible by just turn- ing the key switch OFF.) T2-1-10