CHAPTER 7.1_ DIS & Direct Ignition

8/6/2019 CHAPTER 7.1_ DIS & Direct Ignition

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Chapter 7.1 :Chapter 7.1 : DistributorlessDistributorless

Ignition System (DIS) & DirectIgnition System (DIS) & DirectIgnitionIgnition


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y DISTRIBUTORLESS IGNITION SYSTEM (from 1980's to today)

y Figure shows an ignition system for a four-cylinder engine.y There are two ignition coils, one for cylinders 1 and 4, and another for

cylinders 2 and 3.

y A spark is produced each time a pair of cylinders.

y This means that a spark occurs on the compression stroke and exhauststroke as well

y For this reason, this type of ignition system is sometimes known as the waste spark' system.

IntroductionIntroduction


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The advantages of no distributor:1. No timing adjustments

2. No distributor cap and rotor3. No moving parts to wear out4. Timing is very precise5. Requires less maintenance

y T he major components of a distributor less ignition are:1. ECU or Engine Control Unit2. ICU or Ignition Control Unit3. Magnetic Triggering Device such as the Crankshaft Position

Sensor and the Camshaft

4. Position Sensor5. Coil Packs6. Spark plugs

DIS TR IBU TORLE SS IGNI T I O NDIS TR IBU TORLE SS IGNI T I O N


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DIS TR IBU TORLE SS IGNI T I O NDIS TR IBU TORLE SS IGNI T I O NSYS TEM (DIS)SYS TEM (DIS)


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DIS TR IBU TORLE SS IGNI T I O NDIS TR IBU TORLE SS IGNI T I O NSYS TEMSYS TEM


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y Timing for the distributorless ignition system is controlled byan electronic control unit or ECU.

y The ECU makes its decision on the best time to fire the sparkplugs based on information received from sensors such as:MAP sensor, the throttle position sensor, cam angle sensor,crank angle sensor, engine speed sensor and coolanttemperature sensor.

y The main sensors required to produce correct timing of thespark are the cranks position sensors .

y Identification of each pair of cylinders and a signal for theirtriggering is provided by a dual crank sensor fixed to theengine timing cover. This contains two Hall effect switches.

DIS T imingDIS T iming


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DIS Coil PacksDIS Coil Packs


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y Direct Ignition system is just an extension of the distributorless ignition system.

y This system utilizes one induction coil for eachcylinder.

y These coils are mounted directly on the sparkplugs.

y An individual coil for each spark plug makessure that the rise time for the low inductanceprimary winding is very fast.

Direct Ignition systemDirect Ignition system


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Direct Ignition E ngineDirect Ignition E ngine


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y The each coils ensures that avery high

voltage, high energy spark isproduced.

y This voltage, which can be inexcess of 40kV, providesefficient initiation of the

combustion process under coldstarting conditions and withweak mixtures.

Direct ignitionDirect ignition


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THE E NDTHE E ND

Any question?


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Discussion

State four (4) the advantages of DirectIgnition compared to the DistributorlessIgnition system?


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y A nswer

y 1) No waste sparky 2) No use of HT cablesy 3) Small coil on plugy 4)Shorter wires carrying higher currents.y 5) Less radio wave interference

CHAPTER 7.1_ DIS & Direct Ignition

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