Hitachi ZW180, Technical Manual

Page: 52 / 374

SYSTEM / Control System
T2-1-10
Auto-Warming Up Control
Purpose: To warm up the engine in response to the
hydraulic oil temperature automatically.
Operation:
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.
2. ECM increases the engine slow idle speed to
1100 min
-1
.
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.
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.)
Slow Idle
Slow Idle
Fast Idle
Actual
Engine
Speed
Speed
Increase
Auto-Warming
Up Speed
Target Engine
Speed
Fast Idle