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E-TEC: Simple Engine: Complex Computer
|Author||Topic: E-TEC: Simple Engine: Complex Computer|
posted 11-10-2004 02:13 PM ET (US)
As part of their recently revised website, Evinrude makes this statement about their E-TEC outboard engines:
"...an E-TEC has been described as a very simple engine controlled by an extremely powerful computer."
This is really a very important observation. The engine is very simple mechanically. There are no multiple valves, multiple cam shafts, no multiple cam lobes, no superchargers, no belts, no pulleys, no idlers, no tensioners,--in short none of the stuff bolted onto the power heads of other low-emission outboard motors. All of this missing mechanical equipment saves weight, complexity, and cost. And the absence of it all should cause an increase in reliability, and a decrease in maintenance.
As the power of the microprocessor was increasing while at the same time its cost was decreasing, it was observed that in the future the product with the most transistors (i.e., the most powerful microprocessor) would tend to dominimate over other similar products. Failure to take advantage of the full power and low cost of microprocessors would be a critical mistake for any product which could benefit from their inclusion.
Extraordinarily complex and sophisticated microprocessors are now a part of everyday life. And in well designed products they have proven to be astonishingly reliable. In most workplaces there are now thousands of microprocessors involved in critical functions, yet I have never heard of an actual failure of the microprocessor itself.
Also, by asserting so much control over the engine management with the microprocessor, Evinrude has made it possible to easily incorporate upgrades to the engine in the form of software changes.
posted 11-10-2004 07:01 PM ET (US)
>>>Also, by asserting so much control over the engine management with the microprocessor, Evinrude has made it possible to easily incorporate upgrades to the engine in the form of software changes.<<<<<<<
Evinrude has been able to do this since the 1996 introduction of the first FICHT. Each subsequent year the processing power has increased. The FICHT Ram that came out in 2000, put the regulator/rectifier inside the "computer box" along with everything else. They change the name of it from ECU (electronic control unit) to EMM (engine management module)
The E-TEC simplified the electronics to a single microprocessor instead of several chips used on the FICHTS. The E-TEC EMM also changes the stator winding from series to parallel depending on the requirements of the engine. There are 3 banks of 4 pole windings under the flywheel.
E-TEC uses a 55 volt electrical system that uses pulse width modulation to deliver 12 volts to the charging system and the electric fuel pump. It also has a completely independent charging system for a 2nd battery ( V6 models). All this is also directed by the EMM.
posted 11-10-2004 08:29 PM ET (US)
Here is the quotation I was thinking of:
"Over the last 30 years, we've seen transistors (or switching power) move from being expensive, crafted vacuum tubes to being virtually free. So today, the prime rule of thrift in business is "waste transistors." We "waste" them to correct our spelling, to play solitaire, to do anything. As a matter of fact, you've got to waste transistors in order to succeed in business these days."
posted 11-10-2004 09:27 PM ET (US)
The nasty part so far is the lack of good interfaces into these processors to diagnose problems. There is a strong tendency to only interface with very expensive specialized computers. Effectively locking folks into taking that engine back to the dealer for service forever. The processor run engine may be more reliable and so on, but it's a expensive thing to repair compared to the mechanical engines. The end result may very well be more expensive total lifetime repair cost.
posted 11-10-2004 11:29 PM ET (US)
The more transistors in the microprocessor, the better the interface can be. With simple processors, maybe all they can provide is a few binary bits coming out of a serial port in reply to cryptic commands received. Get more transistors in there and you can build a little web server into the engine and an ethernet port. Pretty soon you can use a web browser to check on your engine!
This is not really all that far-fetched. There are plenty of electronic gadgets with built-in web servers providing a web-brower interface to their controls. I think outboard motors won't be far behind.
I can browse into network printers and see all kinds of information about their status: how much cyan toner is left, how many cycles on the transfer unit before it needs replacement, how many two-sided copies the sales department ran this week. All of this comes with using powerful electronics in conjunction with the mechanics.
This is another area where Evinrude seems to be in the lead: they are already providing an interface to a Palm OS based reader for their engines. No expensive diagnostic tool needed.
posted 11-11-2004 01:18 AM ET (US)
I think that you will find that both FICHT and E-TEC can be serviced by individuals with either a laptop or a PDA. Unlike other makes that need propriatary test tools or super expensive software and cables.
Evinrude items are fairly inexpensive and easily ordered by any authorized dealer.
FICHT software in a 3.5 disk (about $35) will run on an old cheapie 286 or better laptop computer with DOS or up to Windows 98. They came out with a fancier Windows version on CD for around $200. An interface cable is about #50 or you can make your own.
Bass and Walleye Boats Magazine has had several FICHT articles on repairing them yourself.
posted 11-11-2004 07:06 AM ET (US)
One thing I forgot to add about the computer on the E-TEC. Because the motor is so quiet at idle, it is easy to think it is not running, and turn the key to START. That is a good way to break Bendix drives and nick up the flywheel teeth.
The EMM on the Evinrude E-TEC senses that the motor is running from the tach signal, and will not energize the starter solenoid when the motor is operating.
Talk about a nice way to waste transistors!!!!
posted 11-11-2004 11:57 AM ET (US)
With a console mounted Palm OS based reader for the E-TEC, you could add a GPS module, cellular capability, and wireless web interface. This would answer many questions...where are the kids? How fast are they going? Are they running the boat at WOT, the little brats? I'd better call them and tell them to add some XD100 oil. I can't believe they ran full speed in a no wake zone...better put them in SAFE mode.
|John from IL||
posted 11-11-2004 02:05 PM ET (US)
To clarify what seahorse said earlier: "E-TEC uses a 55 volt electrical system that uses pulse width modulation to deliver 12 volts to the charging system and the electric fuel pump."
The pulse width modulation only applies to the electric fuel pump on 40 thru 90 hp E-TEC models (for now anyway). The 200-250 models do not use this, they're "constant on."
And the charging system actually uses a step down converter, which functions like a transformer to drop charging system voltage from 55 to 12 volts.
As far as gadgets for the processor, the V6 model E-TEC's are compatible with NMEA 2000 CANbus (Contoller Area Network bus) such as offered by Teleflex. As I understand it, any NMEA 2000 compliant device (gps, fish finders, whatever...) can all be inter-connected. I'll bet someday you'll be able to plug you boat & motor into your cell-phone and call the factory for "real-time" diagnostics.
posted 11-11-2004 04:26 PM ET (US)
rather has an interesting point. Is there a user selectable mode to limit output? In other words, could I make my 90HP etec into a 40HP etec for use by my kids? Sadly, I really don't need a new engine but if I did, ETEC is the first choice. What's a 1992 evinrude 100XP worth anyway?
posted 11-11-2004 05:09 PM ET (US)
Laptop, cell phone, autopilot, web cam, just go boating from you computer. You will need to keep a bucket of water handy to splash a little spray in your face.
posted 11-11-2004 05:20 PM ET (US)
The option to limit HP output on an outboard motor when used by novice boaters is a really, really good idea - especially for people on this site who own 15' Sports with 70 HP motors.
Limiting the output to 40 HP would be a very attractive option if I had kids learning to operate the boat, and I am certain that there would be a strong market for this type of option if it were exploited and promoted by the marketing folks.
posted 11-12-2004 02:48 AM ET (US)
Yeah, but the kids would get the "crack" code at the same websites where they get the game cheats and copy-protection cracks. :-D
posted 11-12-2004 07:37 AM ET (US)
Ya, I don't know, I like to have everything out in front of me where I can see it. Have you ever had your computer start working funny and not be able to figure out what is wrong? For example the computer we use for the Internet, is now much slower to boot up than before, other little glitches always develope over time. Granted, who knows what our machine is exposed to from the Net. Our policy here at the office is once they go bad, toss them and get a new one, cheaper than calling the IT repairman. Even Rob (Ratherwhalering) mentioned a while back that after plugging in an upgrade, his motor ran different for some unforeseen reason. I may be a little old fashioned, but until the EMM becomes truly plug and play, meaning that you can pull and toss one and plug in a new one in a few minutes, like a printer cartridge or a bad spark plug in order to restore original settings, I will always be a bit sceptical. I doubt the production cost of an EMM is that much anyway.
posted 11-12-2004 01:25 PM ET (US)
My 03 Bombarier Seadoo GTX 4 stroke has 2 tether's. One let's the watercraft go full out, and the other is called a "Learning Key" (I think). It holds the machine to less than 30 mph. So no doubt it is possible for Bombardier to govern the outboards.
posted 11-12-2004 09:03 PM ET (US)
With the hacks now out for bluetooth, you could extend the 'tooth range up to a mile. No need for cellular!
posted 11-13-2004 06:38 AM ET (US)
Getting back to the original focus of this thread, by wasting even more transistors there is another unique thing of which the E-TEC "computer" is capable.
The EMM keeps track of the number of pulses each injector "fires" during its lifetime. The EMM stores into memory, every 250,000 pulses of a single injector as a count of one. As that number adds up, the computer is programmed to slightly change the parameters of the injector pulse to compensate for the internal wear that might occur.
That way the motor stays in "spec" for emissions and proper combustion as it ages. Unlike 4-strokes that increase hydrocarbon emissions as they "age" due to ring, cylinder, and valve seal wear and leakage, the E-TEC "self-heals" itself and keeps the already low emissions at the same level as it was certified.
posted 11-13-2004 11:17 AM ET (US)
Very cool stuff.
I read that the BPR engineers figured out how to reduce the noise of the E-TEC injectors by modifying the waveform applied to them. The were able to soften the landing of the injector on the return stroke, making the "click" a bit quieter. This is just another example of how a sophisticated software control mechanism can be used to improve the performance of a mechanical device. Instead of re-tooling the mechanics of the injector, they tweaked them in software. Brilliant!
posted 11-13-2004 12:31 PM ET (US)
Mind you, I'm not a two-stroke expert, and this is my understanding of how they work. If it's wrong, feel free to correct it.
The fuel injector pulse of a direct-injected two-stroke has nothing to do with oil, so changing that characteristic cannot compensate for oil getting into the combustion chamber, past worn cylinders and piston rings.
The oil is injected into the air below the piston, just as it was in carbureted and EFI two-strokes... with one BIG difference... there's no gas to dilute it so it has a harder time getting into tight clearanced places and past the bottom ring to lubricate the top ring. That has been addressed with new design components.
Yes, the computer controls the oil injector, and can reduce the amount of thinner synthetic oil injected. But if that computer cuts back on injected oil to compensate for oil getting into the combustion chamber past the rings, there will be less injected oil to lubricate the cylinder and rings, not to mention the crankshaft.
So, IMHO, this "self-healing" by injector pulse characteristic is questionable, at best. Reducing lubrication as the engine wears would sure guarantee you'd be back for a replacement earlier, wouldn't it?
The problem of valve stem seal wear is also exaggerated. It's less of a problem on a vertically mounted engine than a horizontal one, where oil draining down from the stem and valve springs pools around the seal, rather than drains away from it.
There's no doubt the direct-injected engines are a vast improvement over older technology two-strokes, and that they're comparable to four-strokes in many ways (including weight). But there's also a lot of marketing exaggeration surrounding them that's pro-two-stroke and anti-four-stroke.
posted 11-13-2004 07:56 PM ET (US)
Re: the evolving waveform applied to the E-TEC injector:
Compare the waveform shown in Figure 6 of U.S. Patent 6,398,511 with the waveform shown in the website animation.
posted 11-13-2004 08:33 PM ET (US)
Some atomized oil gets to lubricate the upper ring as oil is injected into the crankcase air is also pre compressed in the crankcase and gets to the intake ports as they open. The great difference between legacy two strokes is that only fuel is injected only when all the ports are closed.
Also these are lean burn motors at low revolutions per minute and that makes them more fuel efficient than legacy two strokes.
I prefer two strokes for marine application as they are mechanically simpler, as there is no valve train to adjust valve lobe gap between and there is no oil in the crankcase where it could get directly into the water.
In modern two strokes the little oil that might get into the water is so thin that it is rapidly absorbed by nature.
posted 11-14-2004 12:43 AM ET (US)
As I understand it, one of the innovations of the FICHT engine was a lower piston ring that let thicker oil, not diluted by gas, to bypass it in order to lubricate the upper piston ring. Apparently, this thicker oil in suspension in the intake air was insufficient to lubricate the top ring from the chamber side.
posted 11-14-2004 10:46 AM ET (US)
As I understand the system, there is no atomized oil in the air. All the oil, straight, undiluted, is pumped to the the upper main bearing, center main(s), lower main, connecting rod(s), wrist pin(s), and piston skirt(s).This is done at a very low rate. In the EPA tests all oil is accounted for in the burned residue. Roller or needle bearings don't need the pressure that a four stroke needs to keep the babbats operating. Evidently this is a very efficient method, in keeping with keeping it simple.
posted 11-14-2004 12:49 PM ET (US)
That's why I put the caveat about not being a two-stroke guy at the beginning of my message... I was wondering if two-strokes would get a pressurized lubrication system.
You need to keep in mind that not all four-strokes have plain main bearings. Harleys have roller bearing mains and use a low pressure, dry sump system. The pump has both a feed AND scavenge side, which returns the oil to the reservoir.
My question to you would be, if the oil isn't eventually atomized into the intake air, how is all oil accounted for as burned?
posted 11-14-2004 02:46 PM ET (US)
As it is mostly a one way system,there is a bleeder system that recirculates excess oil from the lowermain to the upper main, and low spots in the cylinder back into the system. It is a 100% net loss over a period of time.At some point the oil does enter the intake air stream and into the combustion chamber. What makes the difference is that running time- say per quart-is about equal+- to service interval on a four stroke oil change. Depending on usage, you may need to add oil to the tank once or twice a year.
We need to hear from some of the folks putting the 225's and 250's on for some on the water reports.
posted 11-14-2004 06:02 PM ET (US)
The oil in a four-stroke and the oil in a two-stroke eventually end up in the same place--the environment--it is just a matter of when and where the transition from the engine to the environment takes place.
posted 10-24-2014 12:02 AM ET (US)
[Revived this thread after ten years in order to change the topic. Please, do not revive ten-year-old threads, and particularly do not revive them in order to change their topic, and, please, in particular, do not revive any thread in order to change the topic to a non-boating topic. I deleted your comments and am closing this thread.--jimh]
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