Speaking of ECMs . . .

[JustJason]

Re: Speaking of ECMs . . .

Just curious.... what do you do for a living? I'm guessing some kind of electronic engineer?

 

[SuzukiChopper]

Re: Speaking of ECMs . . .

Went to school for Computer Engineering, which is why I'm a little edgy with the 'not a computer' comments, sorry. It's basically the same course material and study as Electronics but instead of learning RF and circuit repair, we learn about microcontrollers and control systems (one of which being ECMs).

 

[JustJason]

Re: Speaking of ECMs . . .

ECM's in boats/cars?

 

[SuzukiChopper]

Re: Speaking of ECMs . . .

Cars and Military spec

 

[QC]

Re: Speaking of ECMs . . .

FWIW, we actually buy the same box from Mototron (now Woodward) that Merc uses. We call it "Hawk" as our old box was "Eagle". We take signals from the Vehicle's Computer Area Network (CAN). Usually we are communicating via the SAE J1939 data link which is primarily driver torque, speed and/or fuel commands. We return signals that override/control the diesel injectors to our liking. We also take MAP, RPM, Crank angle (timing) etc from the vehicle. We use our box to run independent sensors for NatGas pressure, temp, knock, and we drive our NatGas injectors too. The reason I thought the Raylar claims were odd was that the stuff I describe is easy with OEM participation, really hard without

I am sure to most that it is still very confusing, but what we basically do is tell the diesel injectors to inject about 10% of their usual amount and maybe a couple of degrees later, we replace the remainder of the required fuel with NatGas.

 

[Rotorfixer]

Re: Speaking of ECMs . . .

Smartcraft Engine Gaurdian mode is not a simple "limp home" program, it will limit engine power (and show on how much power is available (%) on any smartcraft display) based on the type of fault to try to prolong it's life. The amount of power it releases is variable dependant on the condition of the fault, i.e. if the fault progressivly gets worse the engine power avalable will go down. Also engine power available will depend on the type of fault.

Peter.

 

[ron7000]

Re: Speaking of ECMs . . .

The engine measures the amount of air comming into it. Depending on what it see's for air it adds a specific amount of fuel to get the mixture right.

If you read the advertisement it's a speed density fuel injection system. Speed density only uses manifold pressure, from a MAP (manifold absolute pressure) sensor to calculate fuel requirement. It does not measure the amount of air coming in, that happens on a Mass Air Flow (MAF) system which mercruiser is not smart enough to implement.
http://www.carcraft.com/techarticles/electronic_fuel_injection/index.html

Those things make sense to me, but in a diesel truck engine the ECM would say "too much air, you're messing about with stuff you shouldn't, take this (check engine light), sorry, mess with somebody else's stuff."

do you know that diesel engines do not have a throttle blade? Diesel's are controlled entirely by the amount of fuel injected, the amount of incoming air has no relevance regarding the fuel injection system and the fueling calculation. The ECM is not going to give a CEL from seeing too much air, and the purpose of the MAF sensor that is being used on the late model diesels is for controlling EGR and other emission crap.

If you have 40 psi behind an injector and you turn it on for .25 of a second, you will get a specific amount of fuel out of it. If you have 60psi behind the injector and you turn it on for that same .25 of a second you obviously get more fuel out of the injector.

at 800 rpm one revolution of the crank (that's piston goes down then comes back up) happens in 0.075 seconds, half of that which is the intake stroke is 0.0375 seconds. Before you get technical you should double check basic math, pulling numbers out your *** to prove a point also tends to prove you don't know what you're talking about.

and then you guys try to explain what's inside the ECM

 

[JustJason]

Re: Speaking of ECMs . . .

It does not measure the amount of air coming in,

Actually, its only sorta true. The amount of air coming in was most certainly measured when the package was designed at the factory. That measurement was used as a baseline when the design/programing of the fuel/air tables went into the final product of the ECM. Do say that it does not measure is a false statement. It measures by the position of the TPS.

a Mass Air Flow (MAF) system which mercruiser is not smart enough to implement.

Okay then boy genius. Why don't you go and work for Mercruiser and show them how a MAF sensor can work (and work reliably) in a marine enviourment.
MAF sensors DO NOT work/last in a boat.period.

The ECM is not going to give a CEL from seeing too much air

Sure it will, if the engine starts to misfire because of that air.

at 800 rpm one revolution of the crank (that's piston goes down then comes back up) happens in 0.075 seconds, half of that which is the intake stroke is 0.0375 seconds. Before you get technical you should double check basic math, pulling numbers out your *** to prove a point also tends to prove you don't know what you're talking about.

Whuah? I don't know what YOUR talking about with that one. What I was talking about was how this Raylar company manipulates fuel pressures to make the factory ECM (in Raylars eyes, not in my own eyes) work.

So why don't you get crackin on making Mercruiser see the err of their ways by not using a MAF.

 

[QC]

Re: Speaking of ECMs . . .

do you know that diesel engines do not have a throttle blade?

Do you know that I have a 30 year career in diesel engines? Specializing in emission control systems for the last 10?. . . I was trying to tie it to the topic. The fact is that diesels do look at excessive boost (too much air) as an indication that something fishy is going on. Especially since there are those that inject all kinds a stuff into the intake stream. My company included.

Diesel's are controlled entirely by the amount of fuel injected, the amount of incoming air has no relevance regarding the fuel injection system and the fueling calculation.

This is false although I understand why you are confused . . . FWIW I spent two hours with the Chief Technical Officer of Navistar yesterday. We debated the efficiency of modern catalysts on methane. We also discussed the legal complexities of certifying diesel cycle, pilot ignition, natural gas engines to Euro 5 standards and the use of up to 40% EGR for EPA 2010. If we want to have a debate about who is smarter on engine tech lets start another thread. Thanks for your contributions . . .

And because this actually has become a who knows more about nothing regarding my original question/topic then I am going to insist on the last word and lock it . . .