12v DC Delay Timer

If you don't mind that the pump is running all the time that your vehicle is running, the answer is rather simple. If you only want the pump to run from the time you turn the ignition off and then for a minute thereafter, it is a little more difficult, but not by a bunch.

In the first case, you use a transistor (a darlington to get the base current into the microamp range) to turn on the relay and a resistor with a large capacitor to create a one minute time delay. Run the base of the darlington to the capacitor through an appropriately sized resistor and that's all there is to it.

Let us know if you only want the pump on at the time you turn the ignition off.

Jim

Reply to
RST Engineering (jw)
Loading thread data ...

Can anyone tell me how to design a delay timer so that when I turn off the car key the timer turns on my pump?

I think I can use a relay to get the power from 12v DC up to the amps I need to run my oil pump.

I am installing a remote oil pump on my turbo car and want the pump to continue to supply the turbo with oil for a minute or two after the car's ignition is shut off. How can I create this?

Reply to
HotRod

The best solution to a problem is to eliminate the problem in the first place. Why do you want the oil pump to run? If the turbo is not turning, what good is the oil doing. Can't you achieve the same thing by turning on the oil pump for a few seconds before you START the engine? mike

--
Return address is VALID but some sites block emails
with links.  Delete this sig when replying.
 Click to see the full signature
Reply to
mike

OK after giving this a lot of thought it would also work if

1) Once the ignition is turned off I can have the engine Idle for another minute. BUT here's the tricky part there are some components that are "ON" when the ignition is "ON" but I want everything shut "OFF" except for the engine that will run for a few minutes. So basically I need a way to keep the power going to the engine "ON" switch (I'll find this wire) for another minute or two while the key is off. I can't have this switch on all the time like suggested.
Reply to
HotRod

The turbo is driven off the exhaust velocity and spins LONG after the engine shuts down. No oil to the turbine bearings and they spall rather quickly. Remember, not only is that sucker spinning at several thousand RPM, it is hotter than hell from the exhaust.

Why would you turn the oil pump on before you start the engine? Once you start the engine, you've got oil pressure from the engine driven pump AND the turbine really doesn't start to whine in the normal idle start sequence.

Jim

Reply to
RST Engineering (jw)

Sounds like a really horrible design. My mistake in assuming that it wouldn't be spinning all that fast at idle/shutdown and since it's compressing air, it shouldn't spin very long with no input power. And that maybe the oiler design would account for all that. I should stick to things I know something about ;-(

For a delay, use a big fet with a cap on the gate and a big resistor in parallel with a diode to switched +12V.

mike

--
Return address is VALID but some sites block emails
with links.  Delete this sig when replying.
 Click to see the full signature
Reply to
mike

--
It\'s helping to cool down the turbo and keep the oil moving until
the turbo can\'t burn it.  And the bearings, I think.
Reply to
John Fields

As many have already mentioned Turbo's run very fast and very hot and it is always recommended to let the engine idle for a minute or two when you stop (get home). Unfortunately this isn't practical for me to sit in the car waiting for the turbo to cool down. Despite the confusion I've caused what I need is something that will

1) Keep the engine running for 1 - 2 minutes once the key is turned off. 2) Will only supply power to motor while the accessories are shut down. If I have to I will separate all of the accessories to another switch that will still need to be turned off by the "electronic device". 3) If possible I want to add a thermal switch to the "water jacket" around the turbo so that if the switch is off (cold turbo) the engine won't bother running for another minute. This would happen when I run around town but not the HWY.

I'm going to have a look at the turbo timer and see if it might do what I need.

Reply to
HotRod

"RST Engineering (jw)" schreef in bericht news: snipped-for-privacy@corp.supernews.com...

engine

sequence.

The problem is not the turbine spinning when you turn off the engine, it stops spinning quite fast. No exhaust gases to drive it, and an (almost) shut throttle give a lot of resistance. (there is also a dumpvalve, so when you let go off the throttle the turbo won't stall by routing the compressed air back into the air intake. It's common 'tuning' to change this so it vents in to open air, giving that hiss when the throttle is released).

The problem is that heat from the exhaust soaks into the bearings, burning up the now stationary oil, so it will coal.

There are commercial 'turbo timers' that keep the engine running for a minute or two, so the turbo can cool down a bit. But of course, you can also do that yourself; what is usually recommended in the instruction manual.

Jeroen

Reply to
Jeroen

Alas.

I was on the edge of exclaiming: "way to go! - not once a 555 or PIC was mentioned!" :-)

I make it a habit of coasting to the gas pump when coming from the highway - assuming the turbo cooled down in that period. Most times I forget however. My turbo does not seem to mind @ 145KKM.

But then again - it is a leased car - and those are indestructible.

--
 - René
Reply to
René

HotRod pretended :

timer modules can be had at appliance or air conditioning parts houses.. Diaram is printed on the case... Simple.

--
This is an automatic signature of MesNews.
Site : http://www.mesnews.net
Reply to
Lawrence Oravetz

This project is typical of what you can expect of people who shy away from confronting the challenge directly. The first purpose of the accessory is to allow the pump oil to cool, so what are you doing measuring time? I am not aware that time is the basic unit of measure of temperature. What's so unique about a temperature actuated autonomous control that runs the pump? It seems like those poorly designed foreign cars have been doing that for years with the engine coolant fan.

Reply to
Fred Bloggs

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.