Thread: Temptec, XMT7100 (+Auber SYL 1512) EGT Gauges, Faster

Hi ??,

Your making this all far too hard. P, I & D setting have no effect whatsoever on the temperature measurement. They effect the response of the output of the device when it's being used as a controller. You are (I presume) using the device only to display a measured temperature input.

There may be a parameter in the set-up menus to adjust the level a filtering or damping applied to the measurement input. This will after the speed of response of the display to temperature changes and would normally be set to the minimum value for EGT display. But it can never be faster than the inherent response of the EGT thermocouple itself, which will usually have a time constant of several seconds. This is OK and very much quick enough for EGT measurement.

If you can post a link to the instruction sheet, I'll see if I can spot the right parameter to look at.

Hope this helps,
Ian (aka ThermoGuard)

Found the SYL1512A2 Instruction Manual. The parameter you need to look at is "FiLt" in table 3 on page 2. The initial setting of 0 should give a quick display response.

You should not be using control modes ("outY", table 1) of 1 or 2 (the PID control modes) for an EGT system. If you wish to use one of the outputs for alarming or driving some device, use modes 0, 3, 4 or 6. Modes other than 1 and 2 will disable parameters P, I & D and SouF and make life simpler.

By all means use one of the outputs to drive an audible alarm device if you wish. (Tho' I don't think it's usually necessary in a vehicle EGT system, as you know full-well when you foot is flat to the floor and tend to check the gauge often in that situation.)

But I don't think it worth the effort to use it to 'force' a performance drop from the engine - in fact it could be downright dangerous. Imagine you're overtaking a B-double and have misjudged the room available - last thing you want is your engine to go 'flat' on you to prevent high EGT when you're stranded on the wrong side of the road!

Using a 'high EGT' output to limit fuelling could well be useful on a stationary engine such as an irrigation pump or generator to prevent expensive damage but not on a road vehicle, IMHO.

Thanks for that.
I figured that was probably the case in the end.
I still may try it to automatically reduce EGT's as I go up Cunninghams Gap a fair bit, and would rather use the relay function to reduce EGT,s , either with increased boost, or a bleed on the injector pump boost line.


I intend to run the turbo wastegate hose straight to the compressor,
so a normal or electronic boost controller can be used to adjust boost easily.


A boost gauge is running from a hose etc. to the intake manifold bolt hole at the moment,
and would likely require tapping another hole for a new line to the injector pump if running a bleed to reduce temps.


Either way It would be set up to drop the EGT temp 50degC or so to get back in the safe zone,
Not a total fuel cut or over boost. (eg wastegate hose disconnected)
The overtemp mode in a TD5 is dangerous,
I don't want anything like that.
Just a slight fuelling drop, or boost increase, till EGT's are safe,
Cheers

Thank Leo 109 for confirming P,i,d settings only effects the relay.
As a bonus I can now program an expresso machine.


That's good to know as I will most likely use it to control temp,
It is a temperature controller after all,
that will be helpful,
to get the EGT drop just right. (eventually)
That should allow the progression to be as smooth as possible.
Cheers.

Originally Posted by 99TDI

Thank Leo 109 for confirming P,i,d settings only effects the relay.
As a bonus I can now program an expresso machine.


That's good to know as I will most likely use it to control temp,
It is a temperature controller after all,
that will be helpful,
to get the EGT drop just right. (eventually)
That should allow the progression to be as smooth as possible.
Cheers.

Hi Mr. X,
Sorry but it still won't be practical to use the Auber's PID control functions to give a 'smooth progression' of fuelling or boost change.

These types of controller can be used as on-off controllers, where the output (relay contact or SSR (solid state relay), say, turns on when the input (EGT) exceeds a setpoint and turns off when the EGT later drops below the setpoint (actually, usually a few degrees below the setpoint, as set by the hysteresis or deadband setting, to avoid rapid and repeated cycling of the relay.)

For example, a stationary engine might be set to, at say 700 C, vent the boost pressure from its injection pump's manifold pressure compensator to reduce fuelling. (As mentioned, I wouldn't recommend doing this in a road vehicle.)

Now the controller can also be programmed so that the output acts in a sort-of analog or variable way. It's called pulse width modulation (PWM). Let's say it is set for a cycle time of 20 seconds. If the controller decided, due to its P, I & D settings that the output should be 10%, the output relay will turn on for 2 seconds, every 20 seconds. If the output is set to 50%, the output will be on for 10 seconds every 20, 80% - 16 secs every 20 etc.

This sort of output is fine for an application like an espresso machine where an electrical element heats a thermal block with a fair bit of heat capacity. But it wouldn't work trying to modulate boost, IMO, as the cycle time is far too slow for such a fast acting parameter.

The minimum cycle time of the Auber is 2 seconds. Factory electronic boost controllers do use PWM to modulate a solenoid valve but they have cycle times of a fraction of a second. This very fast switching actually results in the solenoid plunger 'floating' somewhere between full open and fully closed, based on the PWM output percentage.

If you want a true continuously adjustable output you'll need a controller with an analog output, such as 0 - 10 volts, 4 - 20 mA etc. and a suitable modulating valve etc.

Hi,
Thanks for that.


What I was thinking of is either increasing the boost,
or... if bleeding off air from the Injector pump,
I was going to use a bleed valve on a solenoid that only dropped the pressure by a few psi. (like when people increase boost)


2 seconds isn't so bad, as Limp Home mode on my Ford used to last 30 seconds.... and the TD5 seems to last a while too.


With the PID settings, I am fairly sure you can adjust this rate of change from 0 - 100% power.


Anyway I was just chasing an on off set up, and if used to increase boost, would just be a solenoid to a bleed valve for a couple more psi.
I have a Turbotech boost controller on its way, (not just a bleed valve),
it holds the wastegate shut till about 8 psi, basically and can also be used to increase boost once the injector pump is hooked up to manifold pressure.


Geeze maybe I should just use for a water spray on the intercooler,
or to turn on the thermos,
(which I have never used as are staying on if aircon fuse in),
or some water injection.


Would really like to use the output for something to cool down EGT's automatically eventually.
We'll see what happens...

Maybe I should explain myself a bit more.
I used to Program my Ford EF's computer myself.
Changing Air fuel ratio's, Ignition Timing, Rev Limit,
Shift Points, VE Table ,Automatic line pressure etc.
(in fact a ford ecu could likely run many other electrically controlled automatics)


So sorting this out shouldn't be too hard.
Anything is better than a total fuel cut,
or a limp home mode that hit too hard and nearly puts you through the windscreen. Yet new cars have these failsafes.
I want something that reduces egt's but doesn't drop power much if anything.


You know your stuff about these gauges that's for sure.
Cheers.