View source for Engineering:Exhaust gas temperature gauge

An '''exhaust gas temperature gauge''' ('''EGT gauge''' or '''EGT sensor''') is a [[Engineering:Measuring instrument|meter]] used to monitor the exhaust gas temperature of an [[Earth:Internal combustion engine|internal combustion engine]] in conjunction with a [[Physics:Thermocouple|thermocouple]]-type [[Physics:Pyrometer|pyrometer]].  EGT gauges are found in certain cars and aeroplanes. By monitoring EGT, the driver or pilot can get an idea of the vehicle's air-fuel ratio (AFR).

At a [[Chemistry:Stoichiometry|stoichiometric]] air-fuel ratio, the exhaust gas temperature is different from that in a lean or rich air-fuel ratio. At rich air-fuel ratio, the exhaust gas temperature either increases or decreases depending on the fuel. High temperatures (typically above {{convert|1600|F|C|disp=or|sigfig=1}}) can be an indicator of dangerous conditions that can lead to catastrophic engine failure.

==Applications==
*Most light piston aircraft still have manual mixture controls, and pilots use an EGT gauge to set the optimal fuel-air mixture for their current density altitude and power. The hottest cylinder-head temperatures (CHT) and highest internal cylinder pressures occur around 50 °F (28 °C) rich of peak EGT, and risk predetonation, making it essential to avoid that range, and operate either lean of peak EGT or richer than 100 °F (56 °C) rich of peak EGT. Leaner mixtures result in significant fuel savings, but may result in rough operation of some carbureted or poorly-tuned [[Engineering:Fuel injection|fuel-injected]] engines. Jet aircraft used EGT gauges which were monitored by the [[Engineering:Flight engineer|flight engineer]] during engine startup and throughout the whole flight. EGT gauges were then implemented into the interfaces of [[Engineering:Engine-indicating and crew-alerting system|EICAS]] and [[Engineering:Electronic centralised aircraft monitor|ECAM]] in [[Engineering:Glass cockpit|glass cockpits]].<ref>{{cite web|url=https://www.savvyanalysis.com/articles/egt-myths-debunked|title=EGT Myths Debunked|author=Mike Busch|access-date=2019-05-19}}</ref>
*EGT meters are used for tuning turbo-equipped cars. If the sensor is installed at the manifold collector before the turbo, the turbine inlet temperature can be monitored. If the sensor is installed after the turbo, the exhaust temperature can be monitored. Because EGT typically drops 200–300 °F (111–167 °C) across the turbine, installers try to put the thermocouple as close to the [[Engineering:Cylinder head|cylinder head]] as possible to give a true reading, and a reading that will react faster to the engine's condition compared to an installation after the turbo.
* [[Engineering:Air-cooled engine|Air-cooled engine]]s, like used in [[Company:Volkswagen|Volkswagen]], [[Company:Porsche|Porsche]] and other cars can be damaged by [[Physics:Internal combustion engine cooling#Air-cooling|over heating]]. An exhaust gas temperature gauge can be used to prevent damage.<ref>{{cite web|url=https://uh.edu/engines/epi2558.htm|title=No. 2558: Cooled by Air or Water|website=uh.edu|access-date=30 April 2018|url-status=live|archive-url=https://web.archive.org/web/20170809234658/http://www.uh.edu/engines/epi2558.htm|archive-date=9 August 2017}}</ref>
* Air-cooled [[Engineering:Motorcycle|motorcycle]] engines also can  be damaged by over heating.

==Oxygen sensor==
Using an EGT meter alone is considered an older technique for getting the most out of petrol and diesel engines,{{according to whom?|date=December 2020}} as gauge-type wideband digital [[Chemistry:Oxygen sensor|oxygen sensor]]s are similarly priced.{{where?|date=December 2020}} However, some advanced racers{{such as?|date=December 2020}} will use EGT gauges in combination with a wideband oxygen sensor to lean the fuel ratio a bit to safely raise the temperature for more power.{{Citation needed|date=December 2020}}

==Advanced tuning==
Though by tuning primarily by EGT and air fuel ratio values, EGT is still to this day a used data output for engine tuning. When fine tuning an engine, if possible with the ECU manipulation with the cylinder's timing can be made. By adjusting the timing, the resultant cylinder temperature can be used to improve cylinder efficiency. Though this is still widely done,{{timeframe?|date=December 2020}} EGT values should be used as a safe guard sensor measure and as a tuning guide.{{Citation needed|date=December 2020}}

==References==
<references/>

== External links ==
* {{webarchive |url=https://web.archive.org/web/20110903190448/http://www.apexspeedtech.com/benefits-of-individual-cylinder-tuning |date=3 September 2011 |title=Benefits of individual cylinder tuning}}

{{Automotive engine}}
[[Category:Engine technology]]



{{Sourceattribution|Exhaust gas temperature gauge}}