Warming up an engine

[freight_dog]

Carryfast:
]

For the umpteenth time you can’t ‘improve’ the ■■■■■■■■■■ of a cold diesel engine.It’s the same whether it’s idling or under load.

Mmm, puzzling response .

So its known a diesel will operate at higher temperatures with increasing engine speeds or loads. And its proven that combustion is improved in both cases.

So you’re suggesting increasing the engine speed of a cold engine or driving away will nett the same slobbered combustion, the same combustion chamber temperatures, or the same mechanics of atomisation and mixture rate.

Intriguing. So all the papers and studies by various manufacturers, defence companies are wrong.

Just out of interest. Why do you think some manufacturers build in a reving sequence into their start programs? Why do some manuals urge to drive away after start? Don’t tell me, it’s solely for the greeenies . Perhaps it’s the engine builders want you to just chuck in more fuel willy nilly? After all, you tell us all this does is “wash the bores”

So despite, evidence to the contrary, you think there is no risk with idling a diesel and in fact, increased revs or load only exacerbate the risks of wet stacking, glazing and bore score. Ok

[grumpy_dad]

Isn’t the best performance from a cold engine? The cooler the engine the colder the air increases a better combustion, hence intercoolers, and massive radiators, obviously an engine will never run cold but isn’t performance enhanced through a reduction in temperature ?

[rjan]

Carryfast:

Rjan:
You’re on shaky ground indeed if the best you can do is post some visual anecdote about a smoky engine as proof that any appreciable use of an engine whilst cold is seriously harmful for its health.

No the perfect ground of a truck without any emissions crap hiding the truth and which shows the idiocy of the eco warriors in thinking that applying load to a cold diesel engine is supposedly cleaner/better than letting it warm up at idle.Bearing in mind that the let’s drive off when it’s cold lot don’t even seem to understand the difference between idle v load.

But the situation is complicated by the very fact that the engine is old and knackered. The smoke being emitted could be engine oil that has seeped in overnight. And is the injection system modern - when did mechanical injection become obsolete? It only raises a flurry of additional questions like these.

And I haven’t said anything either way about applying load to an engine being “cleaner”. I haven’t made any environmental argument, except many posts back when I pointed out the value of emissions control equipment in putting an end to pea-soup smog.

[freight_dog]

Grumpy Dad:
Isn’t the best performance from a cold engine? The cooler the engine the colder the air increases a better combustion, hence intercoolers, and massive radiators, obviously an engine will never run cold but isn’t performance enhanced through a reduction in temperature ?

A factor with diesels is maintaining combustion temps high enough to ensure a complete combustion. The combustion cycle requires sufficient heat on the compression stroke.

Large radiators are necessary to provide sufficient cooling over a wide envelop of operation on an engine that uses compression as it’s source of ignition. Such as pulling up a hill in 35 degree heat.

Actual cool air mass inflow on a diesel will nett improved performance provided efficient combustion is achieved at correct temperature. This is because cold air is more dense. The MAF/ECU regulate more fuel to achieve a correct mixture. Nett result is engine performs well but uses more fuel.

Intercoolers are fitted for a reason entirely at the opposite end of the spectrum. To remove excess heat created by compression and reduce mass airflow to a temperature and density conducive to good combustion.

[carryfast]

Freight Dog:

Carryfast:
]

For the umpteenth time you can’t ‘improve’ the ■■■■■■■■■■ of a cold diesel engine.It’s the same whether it’s idling or under load.

Mmm, puzzling response .

So its known a diesel will operate at higher temperatures with increasing engine speeds or loads. And its proven that combustion is improved in both cases.

So you’re suggesting increasing the engine speed of a cold engine or driving away will nett the same slobbered combustion, the same combustion chamber temperatures, or the same mechanics of atomisation and mixture rate.

Intriguing. So all the papers and studies by various manufacturers, defence companies are wrong.

Just out of interest. Why do you think some manufacturers build in a reving sequence into their start programs? Why do some manuals urge to drive away after start? Don’t tell me, it’s solely for the greeenies . Perhaps it’s the engine builders want you to just chuck in more fuel willy nilly? After all, you tell us all this does is “wash the bores”

So despite, evidence to the contrary, you think there is no risk with idling a diesel and in fact, increased revs or load only exacerbate the risks of wet stacking, glazing and bore score. Ok

What so called ‘evidence’ possibly contradicts the fact that a ‘cold’ diesel can’t burn its fuel properly and chucking more fuel into it by applying load isn’t going to change that fact it will just make it worse.

On that note it isn’t ‘operating’ at ‘higher’ temperatures because it’s bleedin ‘cold’ ‘until’ it warms up in either case.The only question then is how much fuel do you want to chuck into the engine ‘while’ it’s warming up and applying load is obviously the wrong answer at least unless you want to increase the amount of unburnt fuel in the cylinder while it’s warming up.Compared to the lesser amount of fuel involved by idling it.So yes I’ll go with silly appeasement of typical muddle headed eco warrior thinking.All based on the fact that strangling the thing with emissions crap means that the results of such stupidity are out of sight and out of mind when someone drives off from an MSA with a cold motor.

[rjan]

Grumpy Dad:
Isn’t the best performance from a cold engine? The cooler the engine the colder the air increases a better combustion, hence intercoolers, and massive radiators, obviously an engine will never run cold but isn’t performance enhanced through a reduction in temperature ?

I think that is on a completely different dimension to the issues in question here.

High performance engines have massive radiators to stop the block overheating under full load.

Intercoolers increase the density of the air going into the chamber (with the reduction in air pressure caused by cooling, offset by the pressure exerted on the hot side of the intercooler by the supercharger). Therefore, additional fuel can also be added without making it too rich.

With spark plug engines, you also have the problem of pre-ignition to deal with which limits the upper temperature of the air, whereas diesels rely on compression-induced ignition.

[freight_dog]

Carryfast:
No the perfect ground of a truck without any emissions crap hiding the truth and which shows the idiocy of the eco warriors in thinking that applying load to a cold diesel engine is supposedly cleaner/better than letting it warm up at idle.Bearing in mind that the let’s drive off when it’s cold lot don’t even seem to understand the difference between idle v load.

Don’t think anyone is discussing how green it all is. We’re talking about what’s best for the engine.

All I can see in your video is the back of what looks like an ancient lorry being given some boot with lots of smoke. Smoke both at idle and revving. A lorry for all we know that is plagued by glazed cylinders, sick piston rings, rubbish compression and a host of ailments (possibly caused by years of idling and wet stacking - wince )I drove an old MAN with a knackered injector that did that. Smoked like a train. Well, it would do wouldnt it ?

[carryfast]

Freight Dog:

Carryfast:
No the perfect ground of a truck without any emissions crap hiding the truth and which shows the idiocy of the eco warriors in thinking that applying load to a cold diesel engine is supposedly cleaner/better than letting it warm up at idle.Bearing in mind that the let’s drive off when it’s cold lot don’t even seem to understand the difference between idle v load.

Don’t think anyone is discussing how green it all is. We’re talking about what’s best for the engine.

All I can see in your video is the back of what looks like an ancient lorry being given some boot with lots of smoke. Smoke both at idle and revving. A lorry for all we know that is plagued by glazed cylinders, sick piston rings, rubbish compression and a host of ailments (possibly caused by years of idling and wet stacking - wince )I drove an old MAN with a knackered injector that did that. Smoked like a train. Well, it would do wouldnt it ?

Ironically what’s good for the Greens also being good for the engine in this case in that fuel washing oil off the bores and soot contaminating the oil isn’t good for the engine.

What I’m seeing there is more or less what I saw in the best case of firing up more or less new Rolls 265 powered Fodens in an early 1980’s winter.Or for that matter factory fresh Detroits out in the yard on a cold morning before they had even got anywhere near their first customer before that.

As for driving off up the road with a cold Gardner rather than idling it for a while to warm it up a bit first I’ll let Bewick answer that.

[bking]

Start the engine build up the air and drive the bloody thing.
It aint rocket science.The engine operates best when its hot or they would not fit thermostats would they?
So the sooner the engine is up to temp the better.Idling a cold engine is bollox as not enough heat is produced to warm the cylinders/coolant.
Dont have to drive it like a ■■■■■ moron just warm it nice and gentle.
And if you cant see the logic in this then you really should not be driving a truck.

[milodon]

Bking:
And if you cant see the logic in this then you really should not be driving a truck.

For the loudest part, they don’t

[pat_hasler]

Once again, my truck has been running non stop from Monday morning to 08.00 Friday. It has been extremely cold with lots of snow but at one point I actually had the A/C on
I did start at 05.00 Sunday really but I only took a loaded tanker from my house to Ben & Jerry’s which is only 100 miles away, I got back home by noon, dropped the empty tanker at the nearest truck stop, bob tailed home, backed on my driveway and plugged it into the mains. Monday I ran down to NYC for a 10 hour break, (Engine running all night). Got up at 04.30, loaded the tanker and ran down to Mount Crawford, Virginia which is a dam long drive. I never switched it off down there either even though it was quite hot down there, I only ran back north to the Flying J at the VA/WV line, there was commotion there with drivers trying to find a spot, I wasn’t going to stop but I saw the only empty spot that everyone seemed to miss, drove right in, parked and stopped for 10 hours, (Engine running all night) but this time it was so the A/C could keep me from cooking. Back up to NYC Wednesday and just do yard work, moving trailers etc and preloading one, 16 hours off (Engine running) and load next day for Philadelphia and then empty to Lancaster PA to drop and hook to bring a load back to NYC, hook to an empty that needed repairs, in order to take it to Albany NY and get me home for Christmas. Heading north again got stuck in miles of standing traffic, so home was not possible, again I stopped at Sloatsburgh NY for another 10 (Engine running), I actually started at 03.00 and got home for 08.00.
My engine runs 24/6 LOL.
Have a merry Christmas

[carryfast]

Bking:
Start the engine build up the air and drive the bloody thing.
It aint rocket science.The engine operates best when its hot or they would not fit thermostats would they?
So the sooner the engine is up to temp the better.Idling a cold engine is bollox as not enough heat is produced to warm the cylinders/coolant.
Dont have to drive it like a [zb] moron just warm it nice and gentle.
And if you cant see the logic in this then you really should not be driving a truck.

Really.So if it supposedly can’t be warmed at idle how do you explain the difference as to how this thing is running and the zb it’s chucking out of the stacks at 0.12-0.40 as opposed to even 1.15 - 1.52 bearing in mind that it obviously wasn’t driven anywhere between the two points in time.So you’re saying let’s drive off up the road pulling a load from 0.12.The clue is that it isn’t hot nor even warm it’s bleedin cold.

youtube.com/watch?v=kRziS6C3i1Q

IE you really need some experience with old school trucks to understand the difference between a cold diesel v a warm diesel and that idling it is the best way to warm it up without chucking loads of unnecessary zb into the cylinders.

[newmercman]

Bking:
Start the engine build up the air and drive the bloody thing.
It aint rocket science.The engine operates best when its hot or they would not fit thermostats would they?
So the sooner the engine is up to temp the better.Idling a cold engine is bollox as not enough heat is produced to warm the cylinders/coolant.
Dont have to drive it like a [zb] moron just warm it nice and gentle.
And if you cant see the logic in this then you really should not be driving a truck.

Build up the air? Really? If you’re as good as you say you are, there shouldn’t be a need to build up the air, the air system is not supposed to leak, it’s something that would fail an MOT or roadside inspection.

Same old stuff on here, agree with me or you’re wrong. Pathetic.

Sent from my SM-G930W8 using Tapatalk

[carryfast]

newmercman:
Build up the air? Really? If you’re as good as you say you are, there shouldn’t be a need to build up the air, the air system is not supposed to leak, it’s something that would fail an MOT or roadside inspection.

Same old stuff on here, agree with me or you’re wrong. Pathetic.

He’s probably just saying that because even he’s got nagging doubts that firing it up and driving it off up the road is the wrong thing to do.As opposed to letting it idle to warm up for a while.

So let’s get this right.We’re all agreed on the fact that a cold engine can’t burn diesel correctly and will result in loads of unburnt residue being left behind in the cylinders which has to go somewhere ?.

In which case why would anyone want to chuck all the extra fuel associated with load into the cylinders rather than pre warm them at idle thereby minimising the amount of fuel going in while it’s warming up ?.The whole theory of fire it up and drive off seeming to be based on confusing starting up an already hot engine v a cold one.Or possibly even in some cases confusing the less hostile conditions in a cold petrol engine,regarding combustion,v a cold diesel.In addition to the silly idea that an idling engine won’t create sufficient heat to produce the improved conditions needed for clean diesel combustion.

That’s without factoring in any other arguable beneficial effects of getting some heat into the engine before applying load.

[andrewg]

Carryfast:

newmercman:
Build up the air? Really? If you’re as good as you say you are, there shouldn’t be a need to build up the air, the air system is not supposed to leak, it’s something that would fail an MOT or roadside inspection.

Same old stuff on here, agree with me or you’re wrong. Pathetic.

He’s probably just saying that because even he’s got nagging doubts that firing it up and driving it off up the road is the wrong thing to do.As opposed to letting it idle to warm up for a while.

So let’s get this right.We’re all agreed on the fact that a cold engine can’t burn diesel correctly and will result in loads of unburnt residue being left behind in the cylinders which has to go somewhere ?.

In which case why would anyone want to chuck all the extra fuel associated with load into the cylinders rather than pre warm them at idle thereby minimising the amount of fuel going in while it’s warming up ?.The whole theory of fire it up and drive off seeming to be based on confusing starting up an already hot engine v a cold one.Or possibly even in some cases confusing the less hostile conditions in a cold petrol engine,regarding combustion,v a cold diesel.In addition to the silly idea that an idling engine won’t create sufficient heat to produce the improved conditions needed for clean diesel combustion.

That’s without factoring in any other arguable beneficial effects of getting some heat into the engine before applying load.

Its not a case of throwing in even more fuel to be left unburnt if you put it under load, with the increase in cylinder pressure from the turbo and increased fuel burn it will warm up a lot quicker than if just left to idle and overall emissions will be less…

[carryfast]

AndrewG:

Carryfast:

newmercman:
Build up the air? Really? If you’re as good as you say you are, there shouldn’t be a need to build up the air, the air system is not supposed to leak, it’s something that would fail an MOT or roadside inspection.

Same old stuff on here, agree with me or you’re wrong. Pathetic.

He’s probably just saying that because even he’s got nagging doubts that firing it up and driving it off up the road is the wrong thing to do.As opposed to letting it idle to warm up for a while.

So let’s get this right.We’re all agreed on the fact that a cold engine can’t burn diesel correctly and will result in loads of unburnt residue being left behind in the cylinders which has to go somewhere ?.

In which case why would anyone want to chuck all the extra fuel associated with load into the cylinders rather than pre warm them at idle thereby minimising the amount of fuel going in while it’s warming up ?.The whole theory of fire it up and drive off seeming to be based on confusing starting up an already hot engine v a cold one.Or possibly even in some cases confusing the less hostile conditions in a cold petrol engine,regarding combustion,v a cold diesel.In addition to the silly idea that an idling engine won’t create sufficient heat to produce the improved conditions needed for clean diesel combustion.

That’s without factoring in any other arguable beneficial effects of getting some heat into the engine before applying load.

Its not a case of throwing in even more fuel to be left unburnt if you put it under load, with the increase in cylinder pressure from the turbo and increased fuel burn it will warm up a lot quicker than if just left to idle and overall emissions will be less…

The problem being that any increased fuel burn under load is at the expense of more unburnt residue because however much air and fuel you put in you still can’t burn it all properly ‘until’ the cylinders have warmed up first.Because it’s the background cylinder temperature that’s stopping it from igniting and burning properly nothing to do with cylinder pressures.

IE you’re confusing just the possibility that it ‘might’ warm up marginally ‘quicker’ with the fact that you’re going to be chucking loads of extra fuel into the engine which still can’t be burnt properly because it’s …cold.So where does all that extra residue go.Either out of the exhaust thereby clogging up the DPF or it gets taken back into the engine by the EGR system.While a load of it just stays there regardless washing the oil off the bores or sooting up the oil.Obviously EGR adding to the latter.

[buckstones]

I worked for many years with development engineers at a turbo manufacturers: I watched various makers’ Diesel engines being run on our test beds, I also saw test bed procedures at Volvo, Scania, Perkins, ■■■■■■■ plants in the UK and at ■■■■■■■ Tech Centre in Columbus,Indiana.

For what it is worth, all of these ran engines at a high idle to warm up before starting to run torque curves and turbo matching tests.
Draw your own conclusions from that.

[juddian]

Buckstones:
I worked for many years with development engineers at a turbo manufacturers: I watched various makers’ Diesel engines being run on our test beds, I also saw test bed procedures at Volvo, Scania, Perkins, ■■■■■■■ plants in the UK and at ■■■■■■■ Tech Centre in Columbus,Indiana.

For what it is worth, all of these ran engines at a high idle to warm up before starting to run torque curves and turbo matching tests.
Draw your own conclusions from that.

Indeed, the last new Volvo i was issued, the handbook advised running the engine warm before driving.

Like others here, i shall continue to warm the engine a bit before driving off, and to allow the turbo to cool for a while before shutdown.
Just as i do with my own private vehicles , one of which has an automatic fast idle setting for cold mornings if you use the auxilliary heater which gives it roughly 1000rpm tickover.

Other people can do as they like, if a box ticker instructs me differently, i’ll agree with him (box ticked, cheerio) then carry on as usual.

[rjan]

Buckstones:
I worked for many years with development engineers at a turbo manufacturers: I watched various makers’ Diesel engines being run on our test beds, I also saw test bed procedures at Volvo, Scania, Perkins, ■■■■■■■ plants in the UK and at ■■■■■■■ Tech Centre in Columbus,Indiana.

For what it is worth, all of these ran engines at a high idle to warm up before starting to run torque curves and turbo matching tests.
Draw your own conclusions from that.

We could only draw conclusions if we understood the underpinning reasons (and the supporting test evidence) they had for warming the engines up - of which you say nothing.

We are all willing to accept that temperature affects the various properties of an engine somehow, including mechanical resistance, oil viscosity, air/fuel mixing, combustion efficiency, the list is endless.

But the only question at stake in this thread is whether it affects engine lifetime, and if that proposition is established, then to what degree is lifetime affected.

You would expect a manufacturer to be interested in that data, and thus you would expect them to perform some tests from cold precisely to quantify the effects of cold-running on reliability - since cold-running will occur sometimes in the real world whether they like it or not, and they don’t want an engine that performs well when at operating temperature but is so fragile that it breaks down after 10 cold starts, or it’s behaviour is so finely tuned to it’s normal operating temperature that it behaves like a pig when cold.

If they never performed any tests from cold and always warmed them up, you could as easily infer that they felt it was completely insignificant or irrelevant for reliability, and that the warm-up was designed to control for some other factor (such as to ensure that a fixed, computer-contolled fuelling programme corresponded exactly with a certain engine speed or torque output, or that any automatic chokes, or cold-running adjustments in the ECU, were not in operation during part of the test only to switch off mid-test and affect the results).

Merry Christmas!

[buckstones]

Buckstones:
I worked for many years with development engineers at a turbo manufacturers: I watched various makers’ Diesel engines being run on our test beds, I also saw test bed procedures at Volvo, Scania, Perkins, ■■■■■■■ plants in the UK and at ■■■■■■■ Tech Centre in Columbus,Indiana.

For what it is worth, all of these ran engines at a high idle to warm up before starting to run torque curves and turbo matching tests.
Draw your own conclusions from that.

I should perhaps point out that at production plants, engines coming off the line are usually connected up in the test cells to a hot water supply: once connected the programmed performance run then may take only 2 or 3 minutes. One of the reasons experimental tests take longer is the need to ensure dyno and measurement systems are at a steady state, also, oil doesn’t warm up as fast as coolant, so circulation above tickover is helpful.

Merry Christmas to all and hopes for 2018 to be a good year.