1-11
GEN
INFO
E
INTERNATIONAL SYSTEM OF UNITS [SI]
The unit system currently applied in our daily life is called gravitational system of units. Both
gravitational system of units and International System of Units belong to the metric system of
measurement, and basically the same units are used in both systems, i.e.
“
meter
”
to indicate
length,
“
second
”
to indicate time, and
“
kilogram
”
to indicate mass.
Essential difference found in International System of Units in comparison with the gravita-
tional system is the clear distinction between the unit of
“
mass
”
and the unit of
“
force
”
.
In addition, the different units of
“
force
”
applied in the SI system results in the different units
of
“
amount
”
(e.g. amount of energy) related to the force.
The abbreviation
“
SI
”
stands for the French expression of International System of Units (Le
System International d
’
Unites ).
Description of “SI” Units in This Service Manual
Both SI units and gravitational system of units are indicated in this service manual.
e.g.) Tightening torque 98 N
·
m (10 kgf
·
m, 71 lbf
·
ft)
Examples for major units
INTERNATIONAL SYSTEM OF UNITS [SI]
ITEM
Force
Torque
Pressure
Rotational
speed
Output power
Specific fuel
consumption
SI UNIT
N
N
·
m
Pa
r/min
min
–
1
W
W
·
h
g/W
·
h
OLD
UNIT
kgf
kgf
·
cm
kgf/cm
2
mmHg
rpm
PS
cal
g/PS
·
h
EQUIVALENT
(1 [FORMER UNIT] = X
[SI UNIT])
1 kgf = 9.80665 N
1kgf
·
cm = 0.0980665 N
·
m
1 kgf/cm
2
= 98.0665 kPa
= 0.0980665 MPa
1 mmHg = 0.133322 kPa
1 rpm = 1 r/min
1 rpm = 1 min
–
1
1 PS = 0.735499 kW
1 kcal = 1.16279 W
·
h
1 g/PS
·
h = 1.3596 g/W
·
h
REMARKS
10 kgf/cm
2
= 980 kPa,
0.98 Mpa
100kgf/cm
2
= 9.8 MPa
1 HP = 0.745 kW
1 HP = 1.01387 PS
