PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IC-G-D-30-001e
D
March 2014
FUEL SPECIFICATIONS FOR GAS ENGINES. GENERAL
1/5
1.
AIM
This product datasheet defines the conditions a gas must comply with in order for it to be used as a fuel in
Kohler
gas engines.
Every parameter or component out of this specification should be consulted to and
authorized by Kohler, else Kohler won't take any malfunctioning responsibilities.
2.
GASES USED AS ENGINE FUELS
The gaseous fuels used in internal combustion engines are available in a large variety of compositions
and conditions of supply, which will affect the configuration, design, life expectancy and performance of the
engine to a greater or lesser extent,. The gaseous fuels used in
Kohler
engines may range from "dry"
natural gas to different kinds of synthesis gases resulting from thermochemical processes or the anaerobic
digestion of organic matters.
In all cases, the gas is a mixture of major constituents, some combustible and others inert, and a number of
minor or low-concentration components which may however play an important role for the correct operation
of the engine, since they could be very harmful in quantities exceeding the manufacturer-specified limits.
As a consequence, it is necessary to assess the fitness of a given type of gas for its use in internal
combustion engines. Where appropriate, the gas must be cleaned or filtered, to make it match the
specifications required for its use in IC engines, by limiting its contents of corrosive and abrasive
components, in order to guarantee a reasonable service life of the engine.
Depending on the type of constituents to be completely or partly eliminated from the gas so as to adjust
their concentration to the specifications, one of several filtering techniques may be used.
Kohler
does not
wish to make any recommendation with respect to any of them, provided that the limit values specified in this
document are complied with. However,
Kohler
has experience in this
field and may be consulted for advice by the customer, on the understanding that
Kohler
will not assume
any responsibility for the effectiveness or performance of the recommended equipment or systems. Any such
responsibility being directly incumbent upon the system's supplier.
2.1. BASIC PARAMETERS OF GASEOUS FUELS
There are several basic parameters to bear in mind when specifying or selecting a gas-fueled engine.
Those parameters, which are listed below, can be calculated with reference to the chemical analysis of the fuel
mixture:
-
LHV (Lower Heat Value):
This indicates the amount of energy available per unit volume or mass of gas. Its SI
units are kJ/m
n
3
or kJ/kg.
-
Methane number:
Is an indicator of a gas mixture's pro-knock tendency. The higher the methane number, the
smaller the pro-knock tendency. This is a dimensionless number.
-
Density:
This is the mass per unit volume of combustible gas. It depends on pressure and temperature. So,
for its measurement, standardized values of pressure and temperature are normally used, namely 101325 Pa
(1 atm) and 0ºC. The SI unit of density is kg/m
n
3
.
-
Stoichiometric A/F ratio:
Indicates the minimum amount of air necessary for a complete combustion of the
fuel gas mixture. It is a dimensionless number representing the ratio of air volumes or masses per unit of fuel
gas.
4.1.13
O&M_2.002211.810_A_10_2016
