Engine Monitoring Systems: Are they all the Same?

we're going to start this puppy up clear prop [Music] and welcome back to tip of the week today we're going to discuss an important design detail you should be aware of when selecting an engine monitoring system for your home built aircrafts panel nowadays many builders are opting for an electronic version of the traditional steam gauges whether you prefer the analog traditional gauges or the more modern electronic displays we need to monitor critical engine parameters like rpm head and oil temperatures oil and fuel pressures and don't forget electrical things like voltages and current draws if you are shopping for an electronic engine monitoring system or EMS as they are sometimes called you should be aware that not all popular brands of these devices are created equal we're going to focus on one such design detail that makes a difference to be considered while building your aircraft some designs of these instrument displays combine engine monitoring with efis or electronic flight instrument systems efis instruments monitor flight parameters like air speed altitude attitude compass heading etc this plane has a separate display for each engine monitoring on the left and Aoife s-- information on the right this large display in this aircraft combines both into one large panel whether you prefer separate or combine panels that's merely a cosmetic choice for the details we are discussing now one of the biggest challenges for installing an engine management system in your home built is going to involve the wiring think of the number of engine sensors that are required to supply the data for display on the panel depending on your engine you may have rpm oil pressure oil temperature cylinder head temperature how many cylinders egt temps how many cylinders fuel pressure fuel flow maybe coolant temperature because of water-cooled voltage current draws in your electrical system I'm sure I've left a couple additional measuring points off all of those sensors need wires to be fed up to the panel display that's a lot of wires and some of the temperature sensors will use that special thermocouple wire how these wires are fed up to the display panel is where you will find a difference between the manufacturers of the engine management systems you can purchase let's look at two design strategies that are currently being used by engine monitoring system vendors as an example I will use the popular dining system to demonstrate one of these strategies in order to get all of those wires from all of the engine sensors we just mentioned to the display panel Dinan uses an EMS module that sits between your sensors and the display panel it's job is to provide an interface and termination point for all of those physical sensor wires it must be mounted on the panel side of the firewall not the engine on one side are two multi pin connectors that can accommodate specially made cables running from the engine sensors on the other side is a much smaller connector that feeds the data to the display on the panel now here's my question to you do you feel comfortable making a pair of computer type cables with all of those tiny pins and wire in them to each of your sensors now some of you will say yes that is not a problem in which case this method of installing your engine management system is quite acceptable however many of us are just not skilled in the assembly of such cables and we can purchase these for a considerable cost from specialty shops that are in business to make them keep in mind these cables are somewhat custom made as every engine you might choose to mount your aircraft is going to need a specific collection of sensors that are appropriate and hence the cable needs to have the right wires made for those sensors in other words you need to tell the cable maker exactly what set of sensors you're going to use based on the engine you chose for your aircraft so the positive side of this strategy is that someone else is going to make your custom plug-in cables based on the engine and sensor information you provide them the downside is that unless you are making the cables yourself this is gonna cost you some point and you have to be careful about specifying exactly what sensors you're going to be using it may be somewhat challenging to rewire the cable if there are changes or modifications in the future let's contrast this with a different strategy for wiring up your engine management system for this example we're going to show the MGL avionics brand of engine monitoring system MGL takes a slightly different approach for connecting the sensor wires to its display screen like Dinan they also use an interface box but their's is called an hour deck looking at the RDoc you see lots of small screw terminals these are used instead of a computer type cable and connector with all those tiny pins you don't build or buy a custom cable rather you wire each sensor directly to the appropriate screw terminal on the our DAC box the our deck box is placed on the engine side of the firewall this means that all of those sensor wires do not pass through the firewall this allows the builder to route each sensor wire only as far as the our DAC box which you mount in a convenient location the benefits of this system start to be evident when you consider that the sensors can be changed or added as desired by simply connecting them yourself to these screw terminals the our deck box communicates with the display on your panel with a simple twisted pair cable this is the only penetration to the firewall for all of those engine sensors modifications to your sensor wiring adding removing or changing them in the future does not involve getting under your panel for wiring changes this strategy of using screw terminal connections will probably appeal to those builders that want the greatest flexibility for managing their sensor wiring and no expensive or challenging cables need to be built for this system and there you have it now you know one important design difference to look for when selecting an engine management system you can decide which is the best for your home built aircraft and there's no time like now to get back to building you

Channel: HomebuiltHELP

Views: 20,500

Rating: 4.9618139 out of 5

Keywords: homebuilthelp, experimental aircraft, homebuilt aircraft, tip of the week, EFIS, EMS, Dynon, MGL, glass panel, engine monitoring, avionics panel, engine sensor, light sport aircraft, RV12, Zenith CH750

Id: WW0KA0D3aMM

Length: 8min 55sec (535 seconds)

Published: Fri Oct 19 2018