Twin Spark Technology 732f2t

What is twin spark ? • Twin Spark name usually refers to the engines installed in Alfa Romeo

cars. Initially appearing in Alfa Romeo 75 model and then used in Alfa Romeo 164, 155, 145, 146, 156, 147, 166 models.

• The Twin Spark name comes from the fact that there are two spark plugs per cylinder. • The two sparks fire at the same time per cylinder or at some time interval and this makes the fuel mixture burn faster than single plug ignition because it is fired from 2 different places simultaneously. So less ignition advance could be used and also leaner mixtures could be burned.

Brief history of twin spark engines and their applications

1914- ALFA ROMEO GRAND PRIX 1960 - ALFA ROMEO RACING CARD

1980- ON THE ROADS

THERMODYNAMICS CYCLES ON WHICH ENGINE WORKS  CONSTANT VOLUME CYCLE OR OTTO CYCLE - This cycle is so named as it was conceived by a scientist named “OTTO”. This cycle is mainly used in petrol engine. The P-V and T-S diagram of otto cycle are as follows-

•Used in diesel engines •Only air is compressed

In this process, some part of heat is added to air at constant volume and remainder at constant pressure

The WORKING of TWIN SPARK engines  In contrast to diesel engines during the compression cycle the combustion of the compressed fuel-air mixture is triggered by an electrical spark which is produced by the spark plug.  This is created via a correspondingly high voltage generated by the ignition coil or ignition transformer.  At a precisely predefined point the spark leaps between the central and earth electrodes. A flame emanating from the spark fills the entire combustion chamber until the mixture has been burned.  The heat released increases the temperature, there is a rapid build-up of pressure in the cylinder and the piston is forced downwards. The movement is transferred via the connecting rod to the crankshaft; this drives the vehicle via the gears and the axles.

Labelled diagram of spark plug

If the electrode gap is too small this may cause misfiring, noisy action and poor exhaust levels.

Electrode gap

❚ If the electrode gap is too large then a higher ignition voltage is required to enable the spark to jump the gap: this may lead to misfiring.

Defects in spark plug Excessive lead Cause: Lead additives in the fuel cause deposits. Effect: At increased load the coating becomes electrically conducting, leading to misfiring. Possible damage to the catalytic converter. Solution: Change fuel; replace spark plugs since these cannot be effectively cleaned Deposit Cause: Incorrect mixture setting. Mixture too rich. Air filter blocked, defective cold start system (injection). High proportion of short journey use. Thermal value of plug too high. Effect: Due to leakage currents, cold starting behaviour is poor and misfiring occurs. Solution: Correction of mixture and cold start system. Check air filter

Oiled-up Cause: Too much oil in combustion chamber. Oil level too high, heavily worn piston rings, cylinders and valve guides. Effect: Misfiring or even shorting of the spark plug, complete failure. Solution: Overhaul engine, correct fuel-oil mixture, fit new, original Beru spark plugs Extreme overheating Cause: Thermal overload due to “glow ignition“, e.g. through ignition timing set to early, combustible residue in chamber (choked-up), defective valves, damaged distributor, too weak a fuel mixture, spark plugs incorrectly tightened. Effect: Prior to engine failure, efficiency (output) will drop. Solution: Check engine, ignition and mixture; check tightening torque of the spark plugs. Fit new, original Beru spark plugs.

DIGITAL TWIN SPARK ignition engine • two Spark plugs located at opposite ends of the combustion chamber • fast and efficient combustion obtained. • better fuel efficiency and lower emissions. • delivers exhilarating performance or exceptional mileage.

DTS - I

DTS – SI Digital twin spark swivel ignition

DTS – FI Digital twin spark fuel ignition

DTS-Si Engine Like DTS-i (which is the mother technology) the engine has 2 spark plugs but, instead of conventionally positioned straight ports, the offset positioning of the ports generate high swirl and turbulence of the air fuel mixture in the combustion chamber. This results in highly efficient combustion that further results in exceptional mileage.

DTS-Fi stands for "Digital Twin Spark Fuel Injection".  In fuel injection the conventional carburettor has been replaced by injector  injects fuel in to the engine in a spray form  based on the instructions of the Engine Control Unit (ECU) which processes information sent by various sensors and instantly determines optimum fueling and spark timing for various engine operating conditions.

ADVANTAGES OF TWIN SPARK TECHNOLOGY • Twin Plugging makes your engine less prone to detonation. • Makes your car less prone to Bad Gasoline related pinging. • Given Identical Engines, you can retard the timing on the twin plugged engine relative to the non twin plugged engine to make the same power. • Enhanced Driveability and a more smooth running engine. • minuscule torque gains.

• For the most part, increasing the spark insures that the combustion will be optimized thus insuring the best chance or decreasing the chances of improper firing.And, if any, minimal horsepower gains could be expected.

Comparision between single & twin spark technology Sl no

Single spark technology

Twin spark technology

1

One spark plug used

Two spark plugs used

2

Slower & incomplete combustion of fuel

Faster & complete combustion of fuel

3

Increased rate of emission

Emission reduced considerably

4

Engine design is simple

Engine design is complex

5

Less rise in pressure and hence less torque generated

More rise in pressure and hence more torque generated

6

Less efficient

More efficient

(a )

(b)

Flame radius at crank angle interval of 10 degree starting from the initiation of spark. The pictures are in the top to bottom sequence. (a) with single spark plug (b) with twin spark plug

The future of spark plug

 Spark technology giving way to laser spark plug

 6th generation plasma iridium

Challenges of twin spark technology • Experts unsure of hype on twin-spark technology • conflict over the patent right in india • laser spark technology is at the doorway

Twin spark technology has brought about a revolutionary change in thE automobile industry. with its help the efficiency has improved considerably. A better mileage is on the cards now. Though the design of the engine is bit complicated ,this technology is praiseworthy. The temperature is going up, and so are the noise levels, as two motorcycle manufacturers get ready to duke it out.

REFERENCES

 ENGINEERING THERMODYNAMICS  THERMAL ENGINEERING

BY

 AUTOMOBILE ENGINEERING

BY P.K.NAG

R.K.RAJPUT BY

Dr. KRIPAL SINGH

 WIKIPEDIA  WWW.GOOGLE.COM  WWW.ALFAROMEO/TECHNOLOGY.COM  WWW.BAJAJAUTO.COM  WWW.AMAZON.COM