KDM2

FORM 6285Copyright 1999 All rights reservedWaukesha EngineDresser, Inc.Waukesha, Wisconsin 53188Printed in U.S.A. 7/99

This document contains proprietary and trade secret information andis given to the receiver in confidence. The receiver by reception andretention of the document accepts the document in confidence andagrees that, except as with the prior expressed written permission ofWaukesha Engine, Dresser, Inc., it will; (1) not use the document orany copy thereof or the confidential or trade secret informationtherein; (2) not copy or reproduce the document in whole, or in partwithout the prior written approval of Waukesha Engine, Dresser, Inc.;and (3) not disclose to others either the document or the confidential ortrade secret information contained therein.

All sales and information herein supplied subject to Standard Terms ofSale, including limitation of liability.

First Edition

Custom Engine ControlKnock Detection ModuleInstallation, Operation &

KDM�

Maintenance

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t

FORM 6285 First Edition 1.00 -- 1

SECTION 1.00

SAFETY

SAFETY INTRODUCTION

The following safety precautions are published for yourinformation. Waukesha Engine Division, Dresser Equip-ment Group, Inc., does not, by the publication of theseprecautions, imply or in any way represent that they arethe sum of all dangers present near industrial engines orfuel rating test units. If you are installing, operating orservicing a Waukesha product, it is your responsibility toensure full compliance with all applicable safety codesand requirements. All requirements of the FederalOccupational Safety and Health Act must be met whenWaukesha products are operated in areas that areunder the jurisdiction of the United States of America.Waukesha products operated in other countries must beinstalled, operated and serviced in compliance with anyand all applicable safety requirements of that country.

For details on safety rules and regulations in the UnitedStates, contact your local office of the OccupationalSafety and Health Administration (OSHA).

The words “danger,” “warning,” “caution” and “note” areused throughout this manual to highlight importantinformation. Be certain that the meanings of these alertsare known to all who work on or near the equipment.

NOTE: This symbol identifies information which isNECESSARY TO THE PROPER OPERATION, MAIN-TENANCE OR REPAIR OF THE EQUIPMENT.

This symbol identifies in-formation about hazards

or unsafe practices. Disregarding this informationcould result in PRODUCT DAMAGE AND/OR PER-SONAL INJURY.

This symbol identifies information about hazards orunsafe practices. Disregarding this informationcould result in SEVERE PERSONAL INJURY ORDEATH.

This symbol identifies information about immediatehazards. Disregarding this information will result inSEVERE PERSONAL INJURY OR DEATH.

SAFETY TAGS AND DECALS

To avoid severe personal injury or death, all warningtags and decals must be visible and legible to theoperator while the equipment is operating.

EQUIPMENT REPAIR AND SERVICE

Proper maintenance, service and repair are important tothe safe, reliable operation of the unit and relatedequipment. Do not use any procedure not recom-mended in the Waukesha Engine manuals for thisequipment.

To prevent severe personal injury or death, alwaysstop the unit before cleaning, servicing or repairingthe unit or any driven equipment.

Place all controls in the OFF position and disconnect orlock out starters to prevent accidental restarting. Ifpossible, lock all controls in the OFF position and takethe key. Put a sign on the control panel warning that theunit is being serviced.

Close all manual control valves, disconnect and lock outall energy sources to the unit, including all fuel, electric,hydraulic, and pneumatic connections.

Disconnect or lock out driven equipment to prevent thepossibility of the driven equipment rotating the disabledengine.

SAFETY

FORM 6285 First Edition1.00 -- 2

To avoid severe personal injury or death, ensurethat all tools and other objects are removed from theunit and any driven equipment before restarting theunit.

Allow the engine to cool to room temperature beforecleaning, servicing or repairing the unit. Hot compo-nents or fluids can cause severe personal injury ordeath.

Some engine components and fluids are extremely hoteven after the engine has been shut down. Allowsufficient time for all engine components and fluids tocool to room temperature before attempting any serviceprocedure.

ACIDS

Comply with the acid manufacturer’s recommenda-tions for proper use and handling of acids. Improperhandling or misuse could result in severe personalinjury or death.

BATTERIES

Comply with the battery manufacturer’s recommen-dations for procedures concerning proper batteryuse and maintenance. Improper maintenance ormisuse could result in severe personal injury ordeath.

BODY PROTECTION

Always wear OSHA approved body, sight, hearingand respiratory system protection. Never wearloose clothing, jewelry or long hair around anengine. The use of improper attire or failure to useprotective equipment may result in severe personalinjury or death.

CHEMICALS

GENERAL

Always read and comply with safety labels on allcontainers. Do not remove or deface the containerlabels. Improper handling or misuse could result insevere personal injury or death.

CLEANING SOLVENTS

Comply with the solvent manufacturer’s recom-mendations for proper use and handling of sol-vents. Improper handling or misuse could result insevere personal injury or death. Do not use gaso-line, paint thinners or other highly volatile fluids forcleaning.

LIQUID NITROGEN/DRY ICE

Comply with the liquid nitrogen/dry ice manufactur-er’s recommendations for proper use and handlingof liquid nitrogen/dry ice. Improper handling or usecould result in severe personal injury or death.

COMPONENTS

HEATED OR FROZEN

Always wear protective equipment when installingor removing heated or frozen components. Somecomponents are heated or cooled to extremetemperatures for proper installation or removal.Direct contact with these parts could cause severepersonal injury or death.

INTERFERENCE FIT

Always wear protective equipment when installingor removing components with an interference fit.Installation or removal of interference componentsmay cause flying debris. Failure to use protectiveequipment may result in severe personal injury ordeath.

SAFETY


COOLING SYSTEM

Always wear protective clothing when venting,flushing or blowing down the cooling system.Operational coolant temperatures can range from180� -- 250� F (82� -- 121�C). Contact with hot coolantor coolant vapor can cause severe personal injuryor death.

Do not service the cooling system while the engineis operating or when the coolant is hot. Operationalcoolant temperatures can range from 180� -- 250� F(82� -- 121� C). Contact with hot coolant or vapor cancause severe personal injury or death.

ELECTRICAL

GENERAL

Do not install, set up, maintain or operate anyelectrical components unless you are a technicallyqualified individual who is familiar with the electri-cal elements involved. Electrical shock can causesevere personal injury or death.

Disconnect all electrical power supplies beforemaking any connections or servicing any part of theelectrical system. Electrical shock can cause se-vere personal injury or death.

IGNITION

Avoid contact with ignition units and wiring. Ignitionsystem components can store electrical energy andif contacted can cause electrical shocks. Electricalshock can cause severe personal injury or death.

Properly discharge any electrical component thathas the capability to store electrical energy beforeconnecting or servicing that component. Electricalshock can cause severe personal injury or death.

EXHAUST

Do not inhale engine exhaust gases. Exhaust gasesare highly toxic and could cause severe personalinjury or death.

Ensure exhaust systems are leak free and that allexhaust gases are properly vented.

Do not touch or service any heated exhaust compo-nents. Allow sufficient time for exhaust compo-nents to cool to room temperature beforeattempting any service procedure. Contact with hotexhaust system components can cause severepersonal injury or death.

FIRE PROTECTION

Refer to local and federal fire regulations forguidelines for proper site fire protection. Fires cancause severe personal injury or death.

SAFETY


FUELS

GENERAL

Ensure that there are no leaks in the fuel supply.Engine fuels are highly combustible and can igniteor explode causing severe personal injury or death.

GASEOUS

Do not inhale gaseous fuels. Some components offuel gas are odorless, tasteless, and highly toxic.Inhalation of gaseous fuels can cause severepersonal injury or death.

Shut off the fuel supply if a gaseous engine hasbeen cranked excessively without starting. Crankthe engine to purge the cylinders and exhaustsystem of accumulated unburned fuel. Failure topurge accumulated unburned fuel in the engine andexhaust system can result in an explosion resultingin severe personal injury or death.

LIQUID

Do not ingest liquid fuels or breathe in their vapors.Liquid fuels may be highly toxic and can result insevere personal injury or death.

Use protective equipment when working with liquidfuels and related components. Liquid fuel can beabsorbed into the body resulting in severe personalinjury or death.

INTOXICANTS AND NARCOTICS

Do not allow anyone under the influence of intoxi-cants and/or narcotics to work on or aroundindustrial engines. Workers under the influence ofintoxicants and/or narcotics are a hazard both tothemselves and other employees and can causesevere personal injury or death to themselves orothers.

PRESSURIZED FLUIDS/GAS/AIR

Never use pressurized fluids/gas/air to clean cloth-ing or body parts. Never use body parts to check forleaks or flow rates. Pressurized fluids/gas/air in-jected into the body can cause severe personalinjury or death.

Observe all applicable local and federal regulationsrelating to pressurized fluid/gas/air.

PROTECTIVE GUARDS

Provide guarding to protect persons or structuresfrom rotating or heated parts. Contact with rotatingor heated parts can result in severe personal injuryor death.

It is the responsibility of the engine owner to specifyand provide guarding.

SPRINGS

Use appropriate equipment and protective gearwhen servicing or using products that containsprings. Springs, under tension or compression,can eject if improper equipment or procedures areused. Failure to take adequate precautions canresult in serious personal injury or death.

SAFETY


TOOLS

ELECTRICAL

Do not install, set up, maintain or operate anyelectrical tools unless you are a technically quali-fied individual who is familiar with them. Electricaltools use electricity and if used improperly couldcause severe personal injury or death.

HYDRAULIC

Do not install, set up, maintain or operate anyhydraulic tools unless you are a technically quali-fied individual who is familiar with them. Hydraulictools use extremely high hydraulic pressure and ifused improperly could cause severe personal injuryor death.

Always follow recom-mended procedures

when using hydraulic tensioning devices. Improperuse of hydraulic tensioning tools can cause severeengine damage.

PNEUMATIC

Do not install, set up, maintain or operate anypneumatic tools unless you are a technically quali-fied individual who is familiar with them. Pneumatictools use pressurized air and if used improperlycould cause severe personal injury or death.

MANOMETER

Do not use measuringtools that contain mercu-

ry. Use a digital manometer capable of measuringinches of mercury in place of a mercury manometer.Mercury manometers contain mercury, a hazardousmaterial. Improper handling or misuse of mercurycould result in personal injury.

WEIGHT

Always consider the weight of the item being liftedand use only properly rated lifting equipment andapproved lifting methods. Failure to take adequateprecautions can result in serious personal injury ordeath.

Never walk or stand under an engine or componentwhile it is suspended. Failure to adhere to this couldresult in severe personal injury or death.

WELDING

GENERAL

Comply with the welder manufacturer’s recommen-dations for procedures concerning proper use ofthe welder. Improper welder use can result in severepersonal injury or death.

ON ENGINE

Ensure that the welder isproperly grounded be-

fore attempting to weld on or near an engine. Failureto properly ground the welder could result in severeengine damage.

Disconnect the ignitionharness before welding

on or near an engine to eliminate charging of anignition system capacitor. Failure to disconnect theignition harness could result in severe enginedamage.


SECTION 1.05

GENERAL INFORMATION

Table 1.05-1. English To Metric Formula Conversion Table

CONVERSION FORMULA EXAMPLE

Inches to Millimeters Inches and any fraction in decimal equivalentmultiplied by 25.4 equals millimeters. 2-5/8 in. = 2.625 x 25.4 = 66.7 mm

Cubic Inches to Litres Cubic inches multiplied by 0.01639 equals litres. 9388 cu. in. = 9388 x 0.01639 = 153.9 L

Ounces to Grams Ounces multiplied by 28.35 equals grams. 21 oz. = 21 x 28.35 = 595 g

Pounds to Kilograms Pounds multiplied by 0.4536 equals kilograms. 22,550 lb. = 22,550 x 0.4536 = 10,229 kg

Inch Pounds to Newton--meters Inch pounds multiplied by 0.113 equalsNewton--meters. 360 in-lb = 360 x 0.113 = 40.7 N�m

Foot Pounds to Newton--meters Foot pounds multiplied by 1.3558 equalsNewton--meters. 145 ft-lb = 145 x 1.3558 = 197 N�m

Pounds per Square Inch to Bars Pounds per square inch multiplied by 0.0690equals bars. 9933 psi = 9933 x 0.0690 = 685 Bar

Pounds per Square Inch toKilograms per Square Centimeter

Pounds per square inch multiplied by 0.0703equals kilograms per square centimeter. 45 psi = 45 x 0.0703 = 3.2 kg/cm2

Pounds per Square Inch toKilopascals

Pounds per square inch multiplied by 6.8947equals kilopascals. 45 psi = 45 x 6.8947 = 310 kPa

Fluid Ounces to Cubic Centimeters Fluid ounces multiplied by 29.57 equalscubic centimeters. 8 oz. = 8 x 29.57 = 237 cc

Gallons to Litres Gallons multiplied by 3.7853 equals litres. 148 gal. = 148 x 3.7853 = 560 L

Degrees Fahrenheit to DegreesCentigrade

Degrees Fahrenheit minus 32 divided by 1.8equals degrees Centigrade. 212� F -- 32 � 1.8 = 100� C

Table 1.05-2. Metric To English Formula Conversion Table

CONVERSION FORMULA EXAMPLE

Millimeters to Inches Millimeters multiplied by 0.03937 equals inches. 67 mm = 67 x 0.03937 = 2.6 in.

Litres to Cubic Inches Litres multiplied by 61.02 equals cubic inches. 153.8 L = 153.8 x 61.02 = 9385 cu. in.

Grams to Ounces Grams multiplied by 0.03527 equals ounces. 595 g = 595 x 0.03527 = 21.0 oz.

Kilograms to Pounds Kilograms multiplied by 2.205 equals pounds. 10,228 kg = 10,228 x 2.205 = 22,553 lb.

Newton--meters to Inch Pounds Newton--meters multiplied by 8.85 equalsinch pounds. 40.7 N�m = 40.7 x 8.85 = 360 in-lb

Newton--meters to Foot Pounds Newton--meters multiplied by 0.7375 equalsfoot pounds. 197 N�m = 197 x 0.7375 = 145 ft-lb

Bars to Pounds per Square Inch Bars multiplied by 14.5 equals pounds persquare inch. 685 Bar = 685 x 14.5 = 9933 psi

Kilograms per Square Centimeterto Pounds per Square Inch (psi)

Kilograms per square centimeter multiplied by14.22 equals pounds per square inch. 3.2 kg/cm2 = 3.2 x 14.22 = 46 psi

Kilopascals to Pounds per Square Inch(psi)

Kilopascals multiplied by 0.145 equals poundsper square inch. 310 kPa = 310 x 0.145 = 45.0 psi

Cubic Centimeters to Fluid Ounces Cubic centimeters multiplied by 0.0338 equalsfluid ounces. 236 cc = 236 x 0.0338 = 7.98 oz.

Litres to Gallons Litres multiplied by 0.264 equals gallons. 560 L = 560 x 0.264 = 148 gal.

Degrees Centigrade to DegreesFahrenheit

Degrees Centigrade multiplied by 1.8 plus 32equals degrees Fahrenheit. 100� C = 100 x 1.8 + 32 = 212� F

GENERAL INFORMATION


WIRING REQUIREMENTSAll electrical equipment and wiring shall comply withapplicable local codes. This Waukesha� standarddefines additional requirements for Waukesha engines.

Do not install, set up, maintain, or operate anyelectrical components unless you are a technicallyqualified individual who is familiar with the electri-cal elements involved. Electrical shock can causesevere personal injury or death.

Disconnect all electrical power supplies beforemaking any connections or servicing any part of theelectrical system. Electrical shock can cause se-vere personal injury or death.

1. Whenever two or more wires run together, theyshould be fastened together at no more than four (4) tosix (6) inch intervals, closer where necessary, with tape.

2. All wires should be mounted off hot areas of theengine with insulated clips, at intervals of no more thantwelve (12) inches, closer where necessary. Wires mustnever be run closer than six (6) inches to exhaustmanifolds, turbochargers, or exhaust pipes.

3. In cases where wires do not run over the engine, theyshould be fastened to rigid, non--moving bodies withinsulated clips when possible or tie wraps. Fastenersshould be spaced at no more than twelve (12) inchintervals.

4. When wires run through holes, rubber grommetsshould be installed in holes to protect the wires. Wiresshould never be run over rough surfaces or sharp edgeswithout protection (see Item 11).

Do not use non--electri-cal grade RTVs. Non--

electrical RTVs can emit corrosive gases that candamage electrical connectors.

5. An electrical grade RTV should be applied aroundthe wires entering all electrical devices such as MurphyJunction Boxes and gas valves, Syncro Start speedswitches, microswitch boxes used in conjunction withsafety equipment, solenoids, etc. An electrical gradeRTV is to be applied immediately after wire installationand prior to the engine entering the test room.

6. A small “drip loop” should be formed in all wiresbefore entering the electrical devices. This drip loopwill reduce the amount of moisture entering electricaldevice via the wires if an electrical grade RTV does notseal completely.

7. The following procedures should be followed forwires entering engine junction boxes:

� Bottom entrance best and side entrance secondbest.

� Insert grommet in opening to protect wires.

� Wires to contain “drip loop” before entering box,except where using bottom entrance.

� When installing flexible conduit, use straight connec-tor for side entrance. If top entrance is required, useelbow connector.

8. If wire harness has a covering, clamp harness soopenings of covering are downward.

9. The routing of wires should be determined forreliability and appearance and not by shortest distance.

10. Installation connection wire must be coiled andsecured to provide protection during shipment.

11. Each end of flexible metal conduit must have aninsulating sleeve to protect wires from chafing.

Always label “HIGH VOLTAGE” on engine mountedequipment over 24 volts. Failure to adhere to thiswarning could result in personal injury or death.

12. All engine mounted electrical equipment over24 volts shall have “HIGH VOLTAGE” warning decal.Decal to be attached to all the equipment and junctionboxes on visible surface (vertical surface wheneverpossible).

13. Wiring that is routed in rigid or flexible conduit shallhave all wire splices made only in junction boxes, outletboxes, or equipment boxes. Wire splices shall not belocated in the run of any conduit.

GENERAL INFORMATION


POWER REQUIREMENTS FOR CUSTOMENGINE CONTROL� PRODUCTSTable 1.05-3 provides you with the power requirementsfor Waukesha’s Custom Engine Control� (CEC) prod-ucts. An oscilloscope must be used to verify ripplelimitations. All power connections must be in accor-dance with the applicable electrical codes.

NOTE: To power the CEC Ignition Module, a nominalsupply of 24 VDC with less than a 2 volt peak--to--peakripple is recommended for compatibility with other CECproducts.

CAPACITIVE DISCHARGE ANDGROUNDINGA Capacitive Discharge (CD) ignition system, such asthe CEC Ignition Module, requires an external powersource and special wiring requirements.

This ignition system contains several large energystorage capacitors. When firing a spark plug, the energystored in one of these capacitors is rapidly dischargedinto an ignition coil which converts it to the high tensionignition voltage. Having been discharged, the energystorage capacitor must then be recharged to be ready tofire again. The storage capacitor is typically recharged

by drawing energy from the power supply as quickly aspossible, resulting in a high current flow (typically30 amps or more) in the power supply wiring for a shortperiod of time.

The average ignition system current remains low(1 or 2 amps depending on the number of cylinders,engine speed, and supply voltage) since the highcurrent only flows for the short period of time andvirtually no current flows the rest of the time. However,the wiring must be sized for the high instantaneouscurrents. In addition, the grounding, particularly wherethe ground is “referenced,” becomes more critical whenelectronic controls are used on engines having this typeof CD ignition system.

With ignition power supply currents of approximately30 amps, the resistive voltage drop of the wiring caneasily reach a volt or two. As a result, it is necessary toreference all of the grounds to the same point. Sincemany electronic sensors are internally grounded, theengine crankcase has been chosen as THE GROUNDreference to minimize problems with sensor signals. Byfollowing the recommended wiring and groundingprocedures, the concerns associated with the ignitionpower supply wiring voltage drops can be greatlyreduced or eliminated.

Table 1.05-3. Power Requirements For Waukesha Custom Engine Control� Products

CEC PRODUCTNOMINALVOLTAGE(volts DC)

OPERATINGRANGE

(volts DC)

PEAK--TO--PEAK

RIPPLE(volts AC)

OPERATING CURRENT (amps)

Ignition Module (IM) 24* 10.0 -- 32.0** less than 2** 2 (typical)

Detonation Sensing Module(DSM) System 24* 21.6 -- 30.0 less than 2 1.5

Air/Fuel Module (AFM) System 24* 21.6 -- 30.0 less than 2 2.5(all rich burn applications)

18.0(lean burn applications on VHP 6 cylinder and all

VGF engines)

32.0(lean burn applications on all ATGL and VHP 12 &

16 cylinder engines)

Turbocharger ControlModule (TCM) I and II System 24* 21.6 -- 30.0 less than 2 1.5

Knock Detection Module(KDM) System 24* 12.0 -- 36.0 less than 2 0.2

NOTE: *The voltage specifications provided in this table apply to the power that is to be supplied to the CEC modules. The CEC modules willsupply the correct voltage specification(s) to other system components if required, such as oxygen sensors used in the AFM system.**For compatibility with other CEC products, a nominal supply of 24 VDC with less than a 2 volt peak--to--peak ripple is recommendedto power the IM and the KDM.


SECTION 1.10

DESCRIPTION OF OPERATION

CUSTOM ENGINE CONTROL�

KNOCK DETECTION MODULE SYSTEM

SYSTEM DESCRIPTION

Detonation is the autoignition of the unconsumed endgas after the spark plug has fired during a normalflame--front reaction in an engine’s combustion cham-ber. When this happens, two pressure waves, createdby the two flame--fronts, slam together creating a highpressure pulse which causes an audible “ping” or“knock” known as detonation. Avoiding detonationconditions is critical since detonation is typicallydestructive to engine components.Detonation is caused by site conditions and/or enginemisadjustment, not the engine. The conditions thatpromote detonation are extremely complex. See“Detonation Theory” in this section for a definition ofdetonation and examples of detonation promoters andreducers.In order to detect detonation or knock, WaukeshaEngine has developed an electronic Custom EngineControl� (CEC) Knock Detection Module (KDM) systemfor VGF F18/H24 GL, GLD, and GSID engines (seeFigure 1.10-1). The KDM system protects WaukeshaVGF spark ignited gas engines from catastrophicdamage due to detonation.

NOTE: For maximum engine protection, the KDMsystem must be connected to a safety shutdown.

The KDM was introduced to offer a simple and costeffective knock protection option for VGF F18/H24 GL,GLD and GSID engines, since the DSM is available forATGL, VHP, and VGF L36/P48 engines only.The KDM, using a terminal in the junction box, providesa sinking circuit (connection to ground) which becomesdisconnected when detonation occurs. The sinkingcircuit can be used to control a fuel solenoid valve,activate lights or alarms, or trigger PLC (ProgrammableLogic Controller) functions such as engine load reduc-tion or alternate timing. The DSM, on the other hand,controls the timing of an engine by advancing andretarding the timing of individual cylinders, optimizingengine performance. The KDM does not controltiming.

NOTE: The circuit sinks a maximum of 3 amps, 36 VDC.

Figure 1.10-1. CEC Knock Detection Module

COMPONENTS

The KDM system includes the KDM module, two knocksensors, and harnesses that may vary depending on theapplication.

ENGINES SERVED

The KDM system is designed to function with sparkignited Waukesha VGF F18/H24 GL, GLD, and GSIDgaseous fueled engines.

IGNITION SYSTEMS SERVED

The KDM was designed to operate with the CEC IgnitionModule or Altronic� III. The KDM uses the G--lead andthe positive lead of #1 coil of these systems to determinethe number of cylinders and engine speed.

Since the KDM uses the #1 primary coil to detect enginespeed, multi--spark ignition systems, which fire severaltimes each engine cycle, will cause the KDM to readunacceptable engine speeds. This may cause the LEDto turn off.



CANADIAN STANDARDS ASSOCIATION (CSA)

The KDM system meets Canadian Standards Association(CSA) Class I, Group D, Division 2, T4 HazardousLocation requirements. Under this classification, theKDM system can operate safely in locations wheregases are contained within closed containers and canonly escape with an accidental rupture.

Never substitute anycomponents of the CSA

certified KDM system. Substitution of componentsmay impair suitability for Class I, Group D,Division 2, T4 Hazardous Location requirements.Disregarding this information could result inproduct damage and/or personal injury.

OPERATOR INTERFACE

The KDM is equipped with a light (LED) on the frontpanel that informs site personnel of system status (seeFigure 1.10-2). The light is on when the KDM ispowered and functioning properly with the knocksensors connected. The light is off when there is a faultor there is no power to the KDM.

For maximum engine protection, the KDM systemmust be connected to a safety shutdown. The KDMis considered an engine protection device and, assuch, must be connected to shut down the engine ifthe engine goes into detonation. Disregarding thisinformation could result in SEVERE PERSONALINJURY OR DEATH.

NOTE: Refer to Section 2.10 KDM System Power,Ground, And Alarm Connections for installation.

Figure 1.10-2. KDM Status LED

STATUS LED

THEORY OF OPERATIONThe KDM is a stand alone system for detectingdetonation in Waukesha� six and eight cylinder VGFgaseous fueled engines. Once connected, the KDMuses the G--lead and the #1 primary coil of the CECIgnition Module or Altronic� III to detect the number ofcylinders and engine speed.

NOTE: All of the functions and detection parameters ofthe KDM are programmed by the manufacturer and arenot user adjustable.

The KDM system senses detonation with a techniquecalled “windowing.” This technique allows the KDMsystem to look for detonation only during that portion ofthe combustion cycle in which detonation is most likelyto occur.

The “window” opens shortly after the spark plug fires toeliminate the effects of ignition noise. This noise iscaused by the firing of the spark plug and subsequent“ring--out” of coils. The “end of sample window” is closednear the end of the combustion event. This is apredetermined angle after top dead center (ATDC) incrankshaft degrees at which the “window” is closed (seeFigure 1.10-3).

Figure 1.10-3. Windowing Chart -- Example Values

PRESSURE, PSIA

DETONATIONSTART OFCOMBUSTION

IGNITIONSPARK

TDC30�

1 2 3 4

TIME, DEGREES OF CRANKSHAFT ROTATION

30� 60�

OPEN SAMPLEWINDOW

END OF SAMPLEWINDOW

When detonation occurs, a unique vibration is pro-duced at a known frequency (knock frequency). Thisfrequency is just one of many created by the engine’sdifferent vibrations. The knock sensors convert thesevibrations into electrical signals which are filtered bythe KDM. When the signal, filtered for the knockfrequency, exceeds a predetermined limit (detonationthreshold), the KDM provides a signal which can beused to shut down the engine.



When connected and powered, the KDM moduleprovides a CLOSED circuit (connection to ground) whichcan be used to control a shutdown device or triggerremote devices such as alarms or lights. This “sinkingcircuit” can also be used to signal a customer’sProgrammable Logic Controller (PLC) to off--load theengine or switch to alternate timing. If the KDM is notpowered, the sinking circuit will be OPEN (ungrounded).

When detonation occurs often enough to exceed theshutdown threshold (a predetermined number of deto-nations within a given number of cylinder firings), thesinking circuit will become OPEN. The shutdownthreshold prevents the engine from being shut downunnecessarily if intermittent detonation is detected (seeFigure 1.10-4). The shutdown threshold does notrepresent the severity of knock that occurs, but ratherthe number of times which knock has been detected. Anengine with all cylinders in detonation will exceed theshutdown threshold more rapidly than an engine with asingle cylinder in detonation. Once the sinking circuitbecomes OPEN, it will remain OPEN until one of thefollowing conditions is satisfied at which time the KDMautomatically resets:

� The detection of knock ceases and the engine speeddrops below 5 rpm for 5 seconds.

� The detection of knock ceases and the engine speedstays above 600 rpm for 20 seconds.

NOTE: All of the functions and detection parameters ofthe KDM are programmed by the manufacturer and arenot user adjustable.

DETONATION THEORYDetonation has been a known adversary of engineoperation for many years. Avoiding detonation conditionsis critical since detonation is typically destructive to enginecomponents. Severe detonation often damages pistons,cylinder heads, valves, and piston rings. Damage fromdetonation will eventually lead to complete failure ofthe affected part. Detonation is preventable; however,the conditions which promote detonation are extremelycomplex and many variables can promote detonationat any one time. This section defines detonation andgives examples of detonation promoters and reducers.

In normal combustion, the forward boundary of theburning fuel is called the “flame--front.” Research hasshown that combustion in a gaseous air/fuel homoge-neous mixture ignited by a spark is characterized by themore or less rapid development of a flame that startsfrom the ignition point and spreads continually outward inthe manner of a grass fire. When this spread continues tothe end of the chamber without abrupt change in itsspeed or shape, combustion is called “normal.” Whenanalyzing detonation, however, combustion is nevernormal.

Figure 1.10-4. Shutdown Threshold

N + 6

INTERMIT-TENTKNOCK

INA

CT

IVE

SH

UT

DO

WN

SIG

NA

L

KN

OC

KO

CC

UR

RE

NC

ES

SHUTDOWN THRESHOLD

AC

TIV

ES

HU

TD

OW

NS

IGN

AL

NOKNOCK KNOCK

NOKNOCK KNOCK

N + 12 N + 18 N + 24 N + 30 N + 36 N + 42 N + 48N

CYLINDERS FIRED



Detonation is due to the autoignition of the end gas afterspark ignition has occurred which is that part of theair/fuel charge which has not yet been consumed in thenormal flame--front reaction. When detonation occurs, itis because compression of the end gas by expansion ofthe burned part of the charge raises its temperature andpressure to the point where the end gas autoignites. Ifthe reaction of autoignition is sufficiently rapid and asufficient amount of end gas is involved, the twoflame--fronts will collide with sufficient force to be heard.This is referred to as audible “ping” or “knock.”

The tendency to detonate will depend chiefly on thetemperature and pressure of the end gas in thecombustion chamber. Any change in engine operatingcharacteristics which affects end gas temperature willdetermine whether combustion will result with or withoutdetonation. The greater the end gas pressure andtemperature and the time to which the end gas isexposed to this severe stress, the greater will be thetendency for the fuel to detonate.

Detonation is an extremely complex subject whendealing with internal combustion engines. The number ofunpredictable variables in actual field running enginescan be enormous. Table 1.10-1 lists the promoters andreducers of detonation.

Table 1.10-1. Detonation Promoters And Reducers

PROMOTERS REDUCERS

Higher Cylinder Temperature Lower Cylinder Temperatures

Lower Octane Fuels Higher Octane Fuels

More Advanced Spark Timing Less Advanced Spark Timing

Higher Compression Ratios Lower Compression Ratios

Higher Air Inlet Pressure Lower Air Inlet Pressure

Higher Coolant Temperatures Lower Coolant Temperatures

Lower Engine Speeds Higher Engine Speeds

Lower Atmospheric Humidity Higher Atmospheric Humidity

Higher Engine Load Lighter Engine Load

Stoichiometric Air/Fuel Ratio(Rich Burn Engine)

Lean or Rich Air/Fuel Ratios(Without Engine Overload)

Rich Air/Fuel Ratio(Lean Burn Engine) Lean Air/Fuel Ratios

Higher Intake Manifold AirTemperatures

Lower Intake Manifold AirTemperatures

DEFINITIONSDetonation: Detonation occurs when part of the air/fuelcharge cannot wait for the normal flame--front, whichwas started by the spark plug, to pass completelythrough the combustion chamber. The advancingflame--front heats and squeezes the unburned mixtureuntil it explodes or autoignites. A good comparison is agrass fire. Normal combustion is similar to a grass fire. Itbegins at one end of a field, and the flame--frontprogresses in an orderly manner through the field.When all of the grass is burned, the combustion stops.

During “grass--detonation,” the grass would beginburning normally, but before the flames could sweepthrough the length of the field, some portion of theunburned grass would burst into flames. When thishappens in the combustion chamber of an engine, twopressure waves, associated with the two flame--fronts,slam together and cause the audible “ping” or “knock.”Detonation Threshold: Voltage comparison that aknock sensor signal must exceed before the engine isconsidered to be in detonation (not user programmable).End of Sample Window: This is a predetermined angleafter top dead center (ATDC) in crankshaft degrees atwhich the window is closed. The window is used so thatdetonation is only looked for during the combustionevent (not user programmable).Free Wheeling Diode: A diode added across the coilsof a relay or solenoid to suppress the high inducedvoltages that may occur when equipment is turned off.Incendive Circuit: A circuit in which a spark or thermaleffect that may occur is capable of causing an ignition ofa test gas mixture.Knock Frequency: The unique vibration or frequencythat an engine exhibits while in detonation. The userselects the knock frequency that the KDM will detectbased on application.Knock: Engine detonation.Knock Sensor: Converts engine vibration to anelectrical signal to be used by the KDM to isolate the“knock” frequency.LED: Light Emitting Diode. A semiconductor that emitslight (not a light bulb) and is used as status indicator,located on the front of the KDM.Non--incendive Circuit: A circuit in which any spark orthermal effect that may occur in normal use is incapableof causing an ignition of a test gas mixture.Shutdown Signal: The KDM output that indicateswhether or not the engine is in detonation. The KDMdefaults to an inactive shutdown signal. The signalbecomes active when the engine goes into detonationor the KDM loses power (see sinking circuit).Shutdown Threshold: The number of occurrences ofknock that must occur before the shutdown signalswitches to active (not user programmable).Sinking Circuit: An electronic switching circuit with asingle output terminal used to provide a path to ground.This mechanism can be used as a trigger to driveremote devices such as alarms, lights, and relays. Thecircuit is designed to handle a maximum current ratingof 3 amps and a maximum voltage rating of 36 VDC(no AC voltages are allowed)(see shutdown).Windowing: A technique which allows the KDM systemto look for detonation only during the combustion timewhen detonation could be present.


SECTION 2.00

MOUNTING KDM SYSTEM COMPONENTS

SYSTEM COMPONENTSThe KDM system includes the KDM module, two knocksensors, and harnesses that may vary depending on theapplication.

This chapter, Chapter 2 Knock Detection ModuleSystem Installation, explains how to mount the compo-nents of the KDM system (Section 2.00), make wireharness connections (Section 2.05), make powerconnections to the KDM (Section 2.10), and makeshutdown/alarm connections (Section 2.10). Wiringdiagrams are included in Section 2.10.

For maximum engine protection, the KDM systemmust be connected to a safety shutdown. The KDMis considered an engine protection device and, assuch, must be connected to shut down the engine ifthe engine goes into detonation. Disregarding thisinformation could result in SEVERE PERSONALINJURY OR DEATH.

Figure 2.00-1. Drill/Tap Fixture Kit

MOUNTING KNOCK SENSORSThe following items are needed for field installation ofthe knock sensors on an engine crankcase withoutpredrilled knock sensor mounting holes:

� Drill/tap fixture kit (P/N 472073) (see Figure 2.00-1)

� 1/4 inch drill bit (not included in kit)

� 7/16 inch drill bit (not included in kit)

KNOCK SENSOR MOUNTING STEPS

Two knock sensors are installed on each VGF inlineengine. For six cylinder VGF engines the knocksensors are installed between cylinders #2--#3 and#4--#5 (see Figure 2.00-9), and between cylinders#2--#3 and #6--#7 for eight cylinder VGF engines (seeFigure 2.00-9). As of December 1, 1998, all six and eightcylinder VGF crankcases are drilled at the factory toaccommodate the installation of the knock sensors. If theknock sensor holes are predrilled, remove plug fromhole and continue with Step 17. If the knock sensorholes are not predrilled, continue with Step 1.

1. Remove the upper right and upper left capscrews ofthe two adjacent camshaft access covers. Secure anybrackets, tubing, or wiring that may be connected tothese capscrews (see Figure 2.00-2).

NOTE: On VGF F18 engines, it will be necessary toremove the auxiliary rocker shaft locknut and lockscrew,between cylinders #2 and #3, in order for the drill fixtureto seat properly (see Figure 2.00-2).

NOTE: On VGF F18 engines, remove the right most(rear) oil filter to gain access to the knock sensor drill/taplocation. Cover oil filter base to keep debris from fallinginto engine.

KDM2

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