Kubota D1803-CR-E4 User Manual

(1) Bearing unit
(2) Pump body
(3)
Mechanical seal
(4) Impeller
7.5.3 Function of water pump
The water pump is driven by the crankshaft via the fan
belt, fan pulley
, and fan drive pulley
.
Coolant is suctioned into the impeller rotating at high
speed, pressurized by the centrifugal force, and fed to
the crankcase water jacket.
The mechanical seal provided between the bearing and
pump chamber prevents leaking of the coolant.
7.6 Thermostat
7.6.1 Outline of thermostat
The thermostat opens and closes the coolant path
based on the engine coolant temperature.
The thermostat
maintains coolant at a suitable
temperature.
7.6.2 Structure of thermostat
The thermostat is made up of a pellet, bypass valve,
and spring and the like.
(1) Valve
(2) Spring
(3)
Pellet
(4) Bypass valve
(5) Jiggle valve
7.6.3 Function of thermostat
(A) When coolant temperature is
low (valve is closed)
(B) When coolant temperature is
high (valve is open)
The thermostat opens and closes the coolant path
based on
the engine coolant temperature to maintain
suitable temperature.
(A) When coolant temperature is low (valve is
closed)
The wax inside the pellet is solidified so that the valve
of the thermostat is closed by the spring.
Also, the bypass part is opened by the bypass valve.
(B) When coolant temperature is high (valve is
open)
The wax inside the pellet liquefies and expands
pushing down the valve and opening the thermostat.
Here, the bypass valve closes the bypass part.
The jiggle valve is a valve to prevent build up of air
inside the thermostat.
(A) Coolant temperature
(B)
T
ime (min)
(C) Overshoot
7.6.4 Specification of thermostat
Coolant suitable temperature
85 to 95 ℃
185 to 203 ℉
4. ENGINE
MECHANISM
7. Cooling system
4-62
D1803-CR-E4,D1803-CR-TE4,D1803-CR-TIE4,V2403-CR-E4,V2403-CR-TE4,V2403-CR-TE4BG,V2403-CR-TIE4
KiSC issued 12, 2018 A

Kubota D1803-CR-E4 Specifications

General

Brand	Kubota
Model	D1803-CR-E4
Category	Engine
Language	English