Query on diesel engine

[12vdc]

Warming up is not a myth but the method is.

It is not a myth that Cold engine consumes more fuel.

It is not a myth that metal expands as it warms so the sealing of pistons and efficiency of burning fuel is achieved only when it reaches normal operating temperature.

The method i do is to drive off the garage with a cold engine and maintain low rpm and shift early untill reaching the operating temp indicated on the dash, or let the cold engine dumb light estinguish before revving hard the engine.

[oj88]

The method i do is to drive off the garage with a cold engine and maintain low rpm and shift early untill reaching the operating temp indicated on the dash, or let the cold engine dumb light estinguish before revving hard the engine.

If we're going to be really technical, you shouldn't shift early. On the contrary, you'd want to delay the up-shift and stay at a relatively low gear at any given speed to let the engine run at high-idle (approx. 1-1.3k RPM). This presents the least load to the engine and promotes higher oil pressure to really get it circulating.

I've observed with my previous Honda that when the engine is cold, the ECM delays shifting up and lets the engine sit at high idle longer than usual before shifting to the next gear.

My current Innova doesn't have that intelligence so while cold, I shift the A/T to 2 then progress to D3 then finally D as the engine warms up. But most of the time, I just start off in D but being mindful on the gas pedal so the ECM doesn't shift up to 3rd.

[Lin Dan]

Recently I heard a Toyota staff said that diesel engine should be turned on and let it run for 30 minutes before the first driving every day.

Is this correct?

This is plain silly.

Just drive slowly then eventually mawawarm up na din ang engine mo.

[monty_GTV]

what a waste of precious fuel[emoji107]

the perfect reincarnation of the old comic cartoon character asiong aksaya...

Sent from my SM-G935F using Tapatalk

[granro01]

Recently I heard a Toyota staff said that diesel engine should be turned on and let it run for 30 minutes before the first driving every day.

Is this correct?

Your Toyota staff might be 60 yrs. old then as he is still using an old school method of warming engines. Diesels then are not even common rail. Sometimes thermostat are remove and even radiator fans are not working automatically and in sync. with the engine tempt.

For your peace of mind, 30 SECONDS is even more than enough to warm your engine.

Bob

[Vodka]

For your peace of mind, 30 SECONDS is even more than enough to warm your engine.

Bob

30s won't warm your engine







but you don't need to

[DiliKoAmericano]

So this is why all the idiots in our subdivision leave their engines running filling the air with fumes. Tossers, absolute tossers, and to hear that the people in charge of selling the vehicles are suggesting this is a good idea is hilarious, and disgraceful at the same time, and is typical of business ethics in this country.

Lesson one.
Startup Oil pressure is regulated by the oil pressure relief valve located in the oil pump or nearby early in the system. This is due to the high viscosity of cold oil, which is sometimes ten fold what it is deisgned to operate at. if the releif valve wastn there, oil seals at the bottom end are very likely to literally blow out of their seats. If you go the route of revving the engine early, all that will happen is this oil pressure relief valve will open, and most of the pressure will be lost back to the sump. it is not a regulator, it is a relief valve so it lets off pressure in an on and off fashion. It does not regulate to a steady pressure.
However, if you go the route of literally letting the engine idle, you are taking the longest route to getting the oil up to its operating temperature. In fact, the diesel engine will take longer than a petrol engine to reach this temp at any given load or power output, so the folowing should be taken even more as gospel for diesel engines.

Lesson two.
When oil is at correct viscosity, that is, at operating temperature, it is best able to perform its main duties, which are to lubricate the faces of bearing journals. At higher viscosities, (when cold) the oil may be too thick to have enough flow to make its way through the conrod journal holes into the conrod to be ejected out the top of the piston in the wrist pin and then onto the cylinder walls. It is so thick that it restricts flowing through the main and big end journals so it ends up just back in the sump rather than up the conrods. So driving cold, is fine for the bearings, but terrible for the piston skirts and rings.

Lesson three.
There is more lubrication of the general sump and crankcase area at higher RPM than at idle. the crankshaft is designed to create a washing machine effect inside the crankcase, by dipping in to oil and splashing it everywhere. the faster the better.

Lesson four.
Time spent rotating the engine whilst these temperatures are still low, is the biggest enemy. The quicker you can get the temperatures up, the better. There is a hazy line between these two areas.
Too much time rotating with high oil pressure is more time the pistons are running drier than they should.
Too little time means pushing the engine to the point of pistons running dry.

The answer.
Start your engine, let the combustion chamber get to the temperature at which combustion is occurring economically (the manufacturer has done this for you, notice when the RPMS first drop), then drive gently, shifting at the normal shift times,until the heat needle has reached somewhere near its mid operating range.
A gentle load is far better than no load.

[jick.cejoco]

Lesson three.
There is more lubrication of the general sump and crankcase area at higher RPM than at idle. the crankshaft is designed to create a washing machine effect inside the crankcase, by dipping in to oil and splashing it everywhere. the faster the better.





This is not true and should not happen.
If the crankshaft counterweight or the bottom of the connecting rods hits the oil at speed, it will cause the engine oil to foam resulting in noisier engine since foam does not cushion the conn rod bearings agsinst the crank pins, same is true with the main journals. If the conn rods or the crank counterweights hit the oil sump, it will cause a whole lot of vibration. It will also cause a lot of oil to be sucked into the intake through the PCV valve, make a lot of smoke at the tailpipe. If the engine uses hydraulic valve lifters, they will make tappet noises since what used to be hydraulic valve lifters are now pneudraulic lifters.


Small engines like the lawn mower briggs and stratton uses a spoon connected at the end of the conn rod since these small engines do not have oil pumps like the automotive engines with pressurized lubrication system.




A quick review of lubrication systems from the nineteenth century to present:

Drip type- used to have a glas bowl filled amd monitored by an oil man

Splash type- uses a spoon or scraper submerged in the oil sump to splash all over i side of the crank case connected to a fast moving internal engine component like the connecti g rod.

Forced/pressurized type-uses a gear type pump, or a trochoid rotor pump, or a lobe type oil pump-modern automobile engines

[dr. d]

Recently I heard a Toyota staff said that diesel engine should be turned on and let it run for 30 minutes before the first driving every day.

Is this correct?

perhaps the statement was in response to, "how do you adjust the engine?"
some engines indicate adjustments be done when the engine is already hot. i have seen stickers pasted in the engine bay or under the engine hood indicating it.
some engines indicate adjustment be done while the engine is still cold.

or maybe, he was trying to sell you the gas model.
heh heh.

[DiliKoAmericano]

Sorry, not dipping, flicking. I have personaly seen a transparent oil sump of a v6 motor at University in australia. At idle the crankcase is clear and when rpms are increased its a shitstorm of oil flying everywhere in the crankcase, including, up to the bottms of the cylinder walls for the required lubrication.
But yes very stupid of me to suggest thats because the counterweights are hitting the oil level in the sump. But my point still stands, please understand that idling at no load does not lubricate as wel as some load at somewhere over 1500 rpm. At no load, the exlosions are quite weak and warmup takes significantly longer.