Traditional multi-cylinder exhaust gas and cylinder headtemperature systems that force the pilot to switch or scanan indicator from cylinder to cylinder in search of criticalengine data, are long obsolete. Using the latest computertechnology, the G3 presents a clear, concise, graphicpicture of all engine temperatures simultaneously forinterpretation at a glance.Never before has so much engine diagnostic information beenavailable to the pilot and never before, has the pilot beenable to control mixture with such ease and precision forpeak fuel efficiency.Insight's latest G3 automatically records flight temperatureand will also interface with other data sources and reportinformation to other instruments like MFD’s. The data-logfiles stored on the SD card can be easily retrieved by thepilot, in-flight or post-flight, for instant viewing orpermanent record-keeping.The G3 is a sophisticated tool for engine management.
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Itsmicroprocessor performs many tasks that used to be handledby the pilot. One of the basic functions performed by the G3is monitoring exhaust gas temperatures for all cylinderswith one degree resolution. What is important is the exhaustgas temperature of a particular cylinder in relation to itspeak. But peak EGT is not a constant; it changes withatmospheric conditions, altitude, power setting and enginecondition and for this reason absolute exhaust gastemperatures in degrees Fahrenheit are quite meaningless.The real objective of mixture management is finding amixture setting which represents the correct position on theEGT/Fuel Flow Curve. As we will see later, this abstracttask is easily accomplished by the G3's microprocessor whichsamples EGT's for all cylinders many times a second andsubjects this data to a complex mathematical analysis canidentify peak. This capability allows the pilot to operatehis or her aircraft engine at the most economical mixturesettings.It is generally known that EGT can be a valuable source ofinformation for engine diagnosis and troubleshooting, butthere is a great deal of confusion when it comes tointerpreting this data.
One of the basic principles of EGTengine analysis is that engine temperatures (EGT and CHT)achieve equilibrium in an engine operating at a constantpower and mixture setting. What is often overlooked is thatthis equilibrium cannot be defined as a single point butrather a range of temperatures.The Graphic Engine Monitor (G3) is ready to operate themoment electrical power is applied.
This package contains the firmware upgrade for HPE P2000 G3 MSA storage arrays which includes array controller firmware and approved companion versions of drive enclosure firmware. When installing array controller firmware, the process will also update firmware on attached drive enclosures. (software RAID) on top of hardware RAID, there are.
Within seconds afterstarting the engine, the white EGT bar graph columns willbegin to appear on the G3 display. Each column correspondsto the Exhaust Gas Temperature (EGT) of a cylinder. Thelowest exhaust gas temperature that can be displayed by theG3 is 800° F. In some engines, the throttle will have to beopened to the fast idle range to get an EGT indication forall cylinders. As the cylinder heads begin to warm up, thedisplay will indicate Cylinder Head Temperature (CHT) forall cylinders as a smaller green bar in each EGT column.
Ahorizontal red line across each column represents themaximum allowable CHT. Digital numbers below each bar graphcolumn indicates the exact EGT and CHT for each cylinder.G4 Twin Buss VoltageThe G4 Buss Voltage attempts to display the buss voltage ingreen when it’s normal and red when it’s outside of normal.In an aircraft with a 12V electrical system the Buss Voltagewill be annunciated in green so long as the voltage is 12.0Vto 14.9V (inclusive).In an aircraft with a 24V electricalsystem the Buss Voltage will be annunciated in green so longas the voltage is 24.2V to 28.7V (inclusive). Below thisrange the alternator isn’t charging the battery and abovethat it’s overcharging, and the Buss Voltage will beannunciated in red. The instrument must be connected to themain voltage buss (not in series with something else, on alighting buss, etc.) and must have a good low-resistanceground connection, otherwise the voltage measurement itselfwill be in error causing the Buss Voltage to indicate in rederroneously.Controlling the G3 instrumentThe instrument has twocontrol knobs that operate combination rotary and pushbutton switches. The top knob in general controls screenselection while the bottom knob controls items within thegiven screen. Each screen assigns its own functional needsto the controls that may change depending on context. Ascreen may also label the controls with guidance informationlike “Push to exit”.The Bar-Graph Display ScreenThe Exhaust GasTemperature is displayed in white bar graph form and isinterpreted much like a conventional mercury thermometer.The higher the bar, the higher the temperature.The cylinder head temperature is displayed in green singlebar format.
During normal operation it shows as a greenilluminated bar in the lower half of the bar column. SinceEGT is normally higher than CHT, the green bar whichrepresents CHT is on top of the white illuminated EGT barand stands out clearly. However, when the engine isshutdown, the EGT quickly drops to zero and the cylindersremain warm for sometime.The G3 provides a reliable indication of cylinder headtemperature even with the engine shut down.
Should an EGTprobe fail, the entire EGT column for that cylinder will goblank, and the numeric indication will show - that isdashes, but the CHT bar will still remain green. The failureof one probe will not affect the display of any other probe.An Easy UpgradeA key requirement of the G3 design was compatibility withprevious GEM’s. We strive to never leave our loyal customersbehind.
Packing all the functionality of the G3 in packagehalf the size of the original GEM took us to the limit ofour patience many times but it was worth it. Fortunately itsamazingly compact circuits will be built by robotic machinesbecause most of the parts are too small to handle and toodifficult to be seen by eye. Products like the modern cellphone have driven the electronic assembly technology we usea long way.AVWeb Insider -By Rick LindstromInsight the originator of the Graphic Engine Monitor surprisedeveryone by unveiling a new third generation GEM called G3 atSun n Fun. By no means a luke warm sequel the G3 isa breakthrough product.Featuring a bright full color display it offers numerous screensof new functionality previously unavailable anywhere.While the original lean screen is gone a vastly improved screenreplaces it with special functionality for lean of peakoperation.G3 logs data to readily available SD digital camera cards. A lowcost card will store decades of flight data.The new G3 writesPC compatible files and directories so no special software isrequired to process or transfer data. Its extensive data logfiles include flight data from Insight’s TAS-1000 air datasystem and nav info from your GPS.Despite its enormous capabilities the new G3 isa compact size and plug-compatible replacement for all previousGEMs.
Insight offers a generous GEM trade-in to make upgradeseasy.Restarting The Leaning ProcessRestart the leaningprocess and resetting the peak indications on G1 by short pushof bottom button.Restart the leaning process and resettingthe peak indications on G2/3/4 single by a short push of the SELbutton.Holding the SEL knob for about 3 seconds on G4 twinwill take you back to twin-engine screen.Probe ScreenTheNeed for better Diagnostic ToolsEven the first GEM could detect an open probe and blank itsindication. Over the years by helping owners and their mechanicstrouble shoot instrument problems I developed a newunderstanding and sympathy for the challenge they faced.Troubleshooting avionics is an expensive and time-consumingprocess. Often times the procedure requires access to theinstrument connector for continuity measurements. This mighttake hours of instrument panel disassembly just to touch theconnector. We needed something better, easier to use, less timeconsuming and therefore less expensive.Why not have the instrument diagnose itself?
Then you don’t haveto disassemble the airplane or even touch the wiring. This isnot as easy as it might seem. Adding resistance measurementhardware for each and every probe wire would more than doublethe complexity of the measurement system. I considered thiscarefully during the development of the GEM-610 secondgeneration instrument. It would at least add a second PC boardto the instrument and have even greater adverse impact on theGEMINI twin version. Even if we endured these problems to getthe information we had no practical way to display it on anorange bar display.So I abandoned it then, but revisited again this time. The newcolor display was certainly adept at displaying the information,eliminating that problem, but the resistance data was still hardto get.So this time I was able to invent a new way of measuringresistance.
The simple idea worked beautifully without adverseimpact on the design. It was so simple in fact even I wasskeptical at first.Without this simple breakthrough we’d still be diagnosing thingsthe hard way. So what does the diagnostic system do?The probe diagnosis page indications are ingreen for normal readings and red for readingsthat fail the criteria set at the bottom of thescreen.Each temperature probe consists of two wires, apositive lead and a negative lead. The twonumbers next to each identifier show theresistance in Ohms of each lead.For example, the line EGT1 8 3 means thepositive lead of the EGT1 probe has 8 Ohmsresistance, and the negative lead has 3 Ohmsresistance.When the probe is new, it will have relativelylow resistance.As the probe ages, it’s resistance will slowlygo up. Eventually, the probe will measureoutside the pas/fail criteria you set at thebottom of the screen, and change from green tored, indicating that the probe should bereplaced before it fails and leaves you with notemperature reading at all.One other point to consider is that the longerthe wiring to the probes, the higher itsresistance.Every foot of EGT wire adds 1.7 Ohms/ft for the+ lead and 0.8 Ohms/ft for the - lead.
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Everyfoot of CHT wire adds 0.8 Ohms/ft for the + leadand 1.2 Ohms/ft for the - lead.A 24 ft harness will fail the criteria that an 8ft harness will pass with. That is why we allowthe user to modify the pass/fail criteria on thebottom of the screen.The meaning of thepass/fail criteria is as follows:R MAX sets the maximum resistance (in Ohms) thatany single lead may have. If the R MAX is set to20 Ohms a probe with either the positive ornegative leads measuring greater than 20 Ohmswill be annunciated in RED, otherwise itsdisplayed in GREEN.R DIF sets the maximum resistance (in Ohms) thatthe positive lead may differ from the negativelead. If R DIF is set to 10 Ohms, the positiveand negative leads need to measure within 10Ohms of each other to be annunciated in GREEN,otherwise its REDEGT Variation Screen -Thisis a new form of engine analysis.Some valve related engine faults produce a slow periodicvariation in EGT.The oscillation rate is on the order of one cycle every minuteor two. This is just too slow to be identified by occasionalobservation of the temperatures alone. Yet it is very importantto discover this phenomenon because it may lead to acatastrophic engine failure. It readily appears in a slowsampled spectrum analysis.Temperature samples are collected once per second for eachcylinder and analyzed each second.
The entire sample interval isabout 8 minutes. A normal indication will be a flat line with alittle noise, while a trouble indication will show as an obviousspectral peak.Vibration ScreenNew Capabilities for the Next Generation G3 GEMIf you take a step back from the EGT/CHT idea to explore enginemonitoring in general, you discover that at least half theengine monitoring solution is missing. EGT analysis revealscombustion phenomenon but simply ignores mechanical problems.By the time a mechanical problem shows up in EGT, if it everdoes, the damage is done and it is far too late to do anythingabout it.Vibration analysis is the key to pre-emptive detection ofmechanical problems.Following the update of the G3 Graphic EngineMonitor to V1.78 or higher, the Vibration Analysis screen willnow appear among the supplementary screens when the PG knob isturned. In order for the vibration analysis to function your G3must be equipped with a vibration sensor and a connection to themagneto for RPM measurement. Ifyour instrument was purchased prior to September 2011, Insightwill be sending you a vibration sensor shortly. Instrumentspurchased after this date will ship with the sensor includedwith the main kit.After the electrical connections to thesensor are made, then sensor may be tested simply by powering upthe G3 and vibration sensor.
It is not necessary to start theengine to perform this test. The sensor LED should flash brieflyand rapidly when power is first applied until communication isestablished with the G3, at which time the LED blinks moreslowly (approximately once per second). When the LED indicatescommunications with the G3 has been established select theVibration Analysis screen by turning the PG knob. Whileobserving the vibration graph disregard the “RPM Required”message and rap lightly on the vibration sensor with the handleof a screw driver. The graph should register the impacts.The sensor should then be firmly mounteddirectly to the engine case, preferably oriented in such amanner as to match the small airplane symbol engraved on thesensor body. In some rare cases it may not be possible to mountit in this manner, and the installer will have to fabricate anappropriate bracket or else be prepared to compensate for thechange in orientation when viewing the vibration data.
Arepresentative installation is shown in the following figure:Using the Vibration Analysis Screen on theG3:The sensor detects vibration in all 3 axis(fore-aft labeled x, up-down labeled z, and left-right labeledy) which are presented on different sub-screens. The vibrationanalysis only functions when the engine is running and a validrpm signal is detected.In regards to the vibration graph, thevertical axis represents the amount of vibration energy and thehorizontal axis represents the frequency spectrum expressed asmultiples of crankshaft rpm. When the engine is running, thescreen will come alive with a waveform that represents theengine motion, presented in a spectral format with thecrankshaft energies appearing at the 1x mark on the bottomscale. Propeller vibration will likewise be synchronous with thecrankshaft vibration. Other sources of vibration will tend toproduce energies at other frequencies.For example, camshaft vibration tends toaccumulate at the.5x mark, since the cam turns at 1/2 the rateof the crankshaft.
Magneto vibration will appear at 1.5x mark ina 6-cylinder engine. Alternator vibration may appear somewherearound 3x or 4x, depending on the ratio it is driven at.A gear-driven alternator may appear in adifferent axis than the crankshaft does ifit is mounted at 90deg to the engine, although ANY source ofvibration will show some energy in all three axis. Complexvibration as generated by reciprocating machinery will alsoproduce a great number of harmonic spikes, which at first glancemay seem confusing. The user should experiment with running theengine at different power settings under different conditions toget a feel for what is a 'normal' spectrum for their particularengine. Asimplified case of vibration is shown in the following figure:In the example shown above the main source ofenergy is at the 1x mark, and represents the crankshaft rpm. Thesmaller spikes at the 0.5x mark and the 1.5x point are probablycreated by the camshaft and the magneto, respectively. The usershould be aware that a multi-cylinder reciprocating engineproduces energies at a multitude of frequencies and directions,which reinforce and subtract from each other to create a verycomplex waveform.
It is the responsibility of the user to gainfamiliarity with a waveform that is typical of their particularengine, so that unusual readings can be detected andinterpreted.The user may examine the various sub-screensby pushing the top button (PG). There are presently six screensto examine, each of the primary axis (X,Y and Z) and an averagedversion of each (denoted Ax, Ay, and Az). The averaged versionwill be much 'cleaner' and contain less noise than the rawmeasurement and is the preferred screen to examine for eachaxis. The bottom knob (SEL) controls a cursor which will 'snap'to nearby vibration spikes to make it easy to examine themcloser. The bottom knob can also be pushed to enter a zoom mode.When in zoom mode, turning the bottom knob will allow you toscroll through the waveform. Continue to press the bottom knobto set progressively higher zoom modes.
A further press when atmaximum zoom will return you to the overall view.Pressing and holding the PG button willtrigger the G3 to save the present vibration waveform for futurereference. The waveform will be stored as a series ofhexadecimal bytes in the current log file. Insight can provide atool for examining this waveform using Excel or a similarspreadsheet. The tool is presently in the earliest functionalstages of development, and will be improved over time.It is expected that the vibration functionswill be used as a 'condition-monitoring tool'. Since everyengine and accessory combination is different, everyone'svibration spectrum will look unique and it would be impossibleto generalize the interpretation of the spectrum. The user willcome to recognize what a 'normal' spectrum looks like for theirengine and by periodically scanning the vibration screen canrecognize when potential trouble is developing. When a new spikeappears or an existing spike begins to show signs of higher thannormal amplitude further investigation is warranted.
The sourceof the spike can be interpreted by noting its primary axis andits frequency relative to crankshaft RPM as discussed above.