Diesel engine
generators the best choice for your generator needs for longevity & efficiency.
Why is
diesel a better choice for your generator application?
We recommend
diesels due to their:
a) Longevity
- Think of all the18 wheeler trucks capable of 1,000,000 miles of operation
before major service. Most trucks are diesel powered.
b) Lower
fuel costs - Diesel uses less fuel consumption per kilowatt (kW) produced).
c) Lower
maintenance costs - diesel have fewer parts. no spark system, more rugged
and more reliable engine.
Today’s
modern diesels are quiet and normally require less maintenance than comparably
sized gas (natural gas or propane) units. Overall operating costs are
typically thirty to fifty percent less than gasoline units.
Diesel
engines running at 1800 RPM and water cooled operate on average for 12,000
to 30,000 hours before major maintenance is required. Gasoline engines
running at 1800 RPM and water cooled gas units normally operate on
average for 6,000 to10,000 hours because they are built using lighter
duty gasoline engine blocks.
Gasoline
engines running at 3600 rpm and air cooled are normally replaced
– not overhauled at 500 to 1500 hours.
Gasoline
units run hotter due to the higher BTU rating of the fuel, you will therefore
see significantly shorter gasoline engine life. Diesels run cooler and last
longer.
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DIFFERENCES
BETWEEN GASOLINE AND DIESEL ENGINES |
|
Fuel |
Gasoline |
Diesel |
|
Ignition |
Takes a mixture of gas
and air, compresses it and ignites the mixture with a spark. |
Takes in just air, compresses
it and then injects fuel into the compressed air. The heat of the
compressed air lights the fuel spontaneously. |
|
Compression |
Compresses at a ratio
of 8:1 to 12:1 |
Compresses at a ratio
of 14:1 to as high as 25:1. The higher compression ratio of the
diesel engine leads to better efficiency. |
|
Fuel Provision |
Uses either
carburetion,
in which the air and fuel is mixed long before the air enters the
cylinder, or port
fuel
injection, in which the fuel is injected
just prior to the intake stroke (outside the cylinder). |
Uses direct fuel injection
-- the diesel fuel is injected directly into the cylinder.
The diesel engine has no spark plug, that it intakes air and compresses
it and that it then injects the fuel directly into the combustion
chamber (direct injection). It is the heat of the compressed air
that lights the fuel in a diesel engine. |
|
Injection Process |
Most car engines use port injection or
a carburetor rather than direct injection. In a car engine, therefore,
all of the fuel is loaded into the cylinder during the intake stroke
and then compressed. The compression of the fuel/air mixture limits
the compression ratio of the engine -- if it compresses the air
too much, the fuel/air mixture spontaneously ignites and causes
knocking. |
Diesels compress only air, so the compression
ratio can be much higher. The higher the compression ratio, the
more power is generated. |
|
Injector Engineering |
Fuel injected gasoline
engines is more refined and less problematic then diesel engines
because the fuel is easier to ignite. |
The injector on a diesel engine is its
most complex component and has been the subject of a great deal
of experimentation -- in any particular engine it may be located
in a variety of places. The injector has to be able to withstand
the temperature and pressure inside the cylinder and still deliver
the fuel in a fine mist. Getting the mist circulated in the cylinder
so that it is evenly distributed is also a problem, so some diesel
engines employ special induction valves, pre-combustion chambers
or other devices to swirl the air in the combustion chamber or otherwise
improve the ignition and combustion process. |
|
Starting Process |
Smaller engines and engines that do not have
such advanced
computer
controls use glow plugs to solve
the cold-starting problem |
When a diesel engine is cold, the compression
process may not raise the air to a high enough temperature to ignite
the fuel. The glow plug is an electrically heated wire (think of
the hot wires you see in a
toaster)
that helps ignite the fuel when the engine is cold so that the engine
can start. |
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In
today's world, where fuel prices are increasing as a consequence
of spiraling demand and diminishing supply, you need to choose a
cost effective fuel to meet your needs. Thanks to the invention
of Rudolph Diesel, the diesel engine has proved to be extremely
efficient and cost effective. Diesel fuel is priced moderately
higher than gasoline but diesel has a higher energy density,
i.e. more energy can be extracted from diesel as compared with
the same volume of gasoline. Diesel engines in automobiles
provide higher mileage, making it an obvious choice for
heavy-duty transportation and equipment. Diesel is heavier and
oilier compared with gasoline, and has a boiling point higher
than that of water. Diesel engines are attracting
greater attention due to higher efficiency and cost
effectiveness.
How Does a Diesel Engine Work?
The distinction lies in the type
of ignition. While gasoline engines operate on spark ignition,
diesel engines employ compression - ignition for igniting the
fuel. In the latter, air is drawn into the engine and subjected
to high compression that heats it up. This results in a very
high temperature in the engine, much higher than the temperature
attained in a gasoline engine. At peak temperature and pressure,
diesel that is let into the engine ignites on account of the
extreme temperature.
In a
diesel engine air and the fuel are infused into the engine at
different stages, as opposed to a gas engine where a mixture of
air and gas are introduced. Fuel is injected into the diesel
engine using an injector whereas in a gasoline engine, a
carburetor is used for this purpose. In a gasoline engine, fuel
and air are sent into the engine together, and then compressed.
The air and fuel mixture limits fuel compression, and hence the
overall efficiency. A diesel engine compresses only air, and the
ratio can be much higher. A diesel engine compresses at the
ratio of 14:1 up to 25:1, whereas in a gasoline engine the
compression ratio is between 8:1 and 12:1. After combustion, the
combustion by-products are removed from the engine through the
exhaust. For starting during cold months extra heat is provided
through 'glow plugs'.
Diesel engines can either be two cycle or four cycle and are
chosen depending on mode of operation. Air-cooled and
liquid-cooled engines are the variants to be chosen
appropriately. It is preferable to use a liquid-cooled generator
as it is quiet in operation and has evenly controlled
temperature.
Advantages of a Diesel Engine
The diesel engine is much more
efficient and preferable as compared with gasoline engine due to
the following reasons:
-
Modern
diesel engines have overcome disadvantages of earlier
models of higher noise and maintenance costs. They are
now quiet and require less maintenance as compared with
gas engines of similar size.
-
They are
more rugged and reliable.
-
There is no
sparking as the fuel auto-ignites. The absence of spark
plugs or spark wires lowers maintenance costs.
-
Fuel cost
per Kilo Watt (kW) produced is thirty to fifty percent
lower than that of gas engines.
-
An 1800 rpm
water cooled diesel unit operates for 12,000 to 30,000
hours before any major maintenance is necessary. An 1800
rpm water cooled gasoline unit usually operates for
6000-10,000 hours before it needs servicing.
-
Gas units
burn hotter than diesel units, and hence they have a
significantly shorter life compared with diesel units.
Applications & Uses for Diesel Engines
Diesel engines are commonly used as mechanical engines, power
generators and in mobile drives. They find wide spread use in
locomotives, construction equipment, automobiles, and countless
industrial applications. Their realm extends to almost all
industries and can be observed on a daily basis if you were to
look under the hood of everything you pass by. Industrial diesel
engines and diesel powered generators have construction, marine,
mining, hospital, forestry, telecommunications, underground, and
agricultural applications, just to name a few. Power generation
for prime or standby backup power is the major application of
today's diesel generators. Check out our article on the various types of engines and generators and
their common applications for
more examples.
Power Generators
Diesel powered generators, or
electrical generator sets, are used in countless industrial and
commercial establishments. The generators can be used for small
loads, such as in homes, as well as for larger loads like
industrial plants, hospitals, and commercial buildings. They can
either be prime power sources or standby/back-up power sources.
They are available in various specifications and sizes. Diesel
generator sets rating 5-30KW are typically used in simple home
and personal applications like recreational vehicles. Industrial applications cover a wider spectrum of power ratings
(from 30 kW to 6 Megawatts) and are used in numerous
industries throughout the globe. For home use, single-phase
power generators are sufficient. Three-phase power generators
are primarily used for industrial purposes. |
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