16-07-2014, 04:47 PM
DTSI Revolution of Twin Spark in I.C. Engine
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Abstract
It is very interesting to know about complete combustion in automobile
engineering, because in actual practice, perfect combustion is not at all
possible due to various losses in the combustion chamber as well as
design of the internal combustion engine. Moreover the process of
burning of the fuel is also not instantaneous. However an alternate
solution to it is by making the combustion of fuel as fast as possible.
This can be done by using two spark plugs which spark alternatively at
a certain time interval so as increase the diameter of the flame & burn
the fuel instantaneously. This system is called DTSI (Digital
Spark Ignition system). In this system, due to twin sparks,
combustion will be complete.
This paper represents the working of digital twin spark ignition system,
how twin sparks are produced at 20,000 Volts, their timings, efficiency,
advantages & disadvantages, diameter of the flame, how complete
combustion is possible & how to decrease smoke & exhausts from the
exhaust pipe of the bike using Twin Spark System
Introduction
A conventional 4 Stroke engine has a Single Spark Plug located at one
end of the combustion chamber and hence the combustion is inefficient
leading to sub optimal mileage and sub optimal performance & can
even have problems with oil flow. Hence forth there was a requirement
to change engines' design, fuelling, ignition, production and quality to
achieve the following objectives. Uniform power delivery in all
operating conditions:-
A high degree of drivability
First rate standards of reliability
Long service life.
With a view to overcome the above limitations a new patent was
introduced that is known as DTS-I technology & its use is increasing
day by days
Engine construction
The engine used on the Alfa 164 T. Spark is a four-in-line cylinder unit
whose weight has been considerably reduced with all aluminium-alloy
engine block, cylinder head, oil sump and tappet covers.
Eight counterweights ensure optimal balancing of the high strength
nitride steel crankshaft.
The pressed-in cast iron cylinder liners feature wet mounting for more
effective heat dissipation.
Valve drive
The twin overhead cams, driven by a double chain, act directly on the
valves set in a tight Vee configuration (46o
).
The timing of the valve train is not fixed as in most present day
engines, but can be adjusted by a patented device conceived and
produced by Alfa Romeo,
the timing variation.
This is an electro-hydraulic
actuator keyed onto the gear
that drives the camshaft
acting on the intake valves.
This actuator enables the
camshaft to be shifted into
two different angular
positions and to modify the
intake valve opening durations. Its operation is controlled by the
electronic control box of the integrated
ignition and fuel injection system.
Fuel feed
The Alfa 164 T. Spark power plant is equipped with the ML 4.1 Bosch
Motronic multi-point injection system, controlled by the same
microprocessor which governs the twin spark ignition and variable
valve timing Systems.
The excellent volumetric efficiency of the Twin Spark engine is also
enhanced by the special straight section individual intake man folding
that cuts down losses and fully exploits intake resonance for better
mid-range torque.
Having all thermodynamic cycle components under the wings of a
single electronic control unit means that the power plant used on the
Alfa 1 64 T. Spark can guarantee-in addition to outstanding torque and
power figures-regular, smooth running at all speeds regardless of
load. Moreover, this engine features particularly attractive specific fuel
economy compared with rival naturally aspirated units in the same
displacement class (with savings of up to 20- 25%).
Ignition with a Digital C.D.I.
A Digital CDI with an 8 bit microprocessor chip handles the
spark delivery. The programmed chip’s memory contains an optimum
Ignition timing for any given engine rpm, thereby obtaining the best
performance characteristics from the combustion chamber. Working
together with the TRICSIII system, it delivers Optimum Ignition
Timing for varying load conditions.
Ignition
The ignition system on the Twin spark is a digital system with static
spark advance and no moving parts subject to wear. It is mapped by the
integrated digital electronic control box which also handles fuel
injection and valve timing. It features two plugs per cylinder.
This innovative solution, also entailing a special configuration of
the hemispherical combustion chambers and piston heads, ensures a
fast, wide flame front when the air-fuel mixture is ignited, and
therefore less ignition advance, enabling, moreover, relatively lean
mixtures to be used. As a result, the adoption of twin spark ignition
yields:
Conclusion
Hence it can be concluded that the application of these technologies in
the present day automobiles will give the present generation what they
want i.e. power bikes with fuel efficiency. Since these technologies
also minimize the fuel consumption and harmful emission levels, they
can also be considered as one of the solutions for increasing fuel costs
and increasing effect of global warming.
From this paper I have concluded that perfect Combustion in
Internal Combustion engine is not possible. So for the instantaneous
burning of fuels in I.C. engine twin spark system can be used which
producing twin sparks at regular interval can help to complete the
combustion.