Diesels..

[Arnold]

Whatever happened?
I was talking to a great believer in diesels the other day..
he NOW simply tells the average person just not to buy one now.
IF you are using it/working it/running it a lot!..then he says get one.
If not don't.
He does a very good business..and is very respected and honest..but he sees a LOT :!: of very unhappy customers.
People buy them..use them as grocery getters..leave them with empty tanks..for too long a period of time..then make a trip down to the store Those kind of people that don't even blink to spend $100,000 on a diesel pickup up here near Toronto..treat them like this..then trade them in.That just filters down to whoever ends up at some point buying it.

 What was ONCE a great idea..diesel..pretty low grade cheap stuff to begin with..run a very long time..
 Diesels are now ladened with emmission controls..people want all kinds of junk on their diesel vehicles.
 Up here..diesel is often 5-10 cents MORE PER LITRE! Yikes.
 Ridiculous service costs.
 Gas engines are running a very long time..and their fuel economy is getting even better.
 Diesel engine options run  $10,000-$20,000.

  Perhaps someone will come up with some great idea for diesels.

  Maybe there is a great business opportunity of buying them here in the salt capital and dampness/cold and then fixing them(there are always a bazillion for sale here used needing work) and then sending them off fixed to retire somewhere warm and dry

[wayne petty]

there is a difference between the gasoline engines and diesels


the amount of air that passes thru the engine..

what..

in the diesel engines i know about.  the intake is either open or turbo charged.. or supercharged..   each time the piston moves down.. it gets a full load of air..

in gasoline engines .. the intake manifold is run at a partial vacuum.. 13 to 15 inches of vacuum or around half a bar..

if there is 15 inches of vacuum that means there is actually only half the atmosphere going thru the engine..   at cruising speeds. manifold vacuum on gasoline engines might be up around 18 to 20 inches of vacuum.. on a non race engine..   that's about 1/3 the volume of air..  so it takes less fuel to reach the air fuel ratio with the reduced pressure and reduced oxygen content.    if you tip into the throttle .. the manifold vacuum drops and more air and fuel is sent thru the engine to make more power..

with a diesel.. there is always close to the same amount of air going thru the engine at crusing speeds.. depending on the boost..  so its going to take more fuel to keep the cruise air fuel ratio from going too lean and melting things..  because diesels are compression ignition.. they need the large volume of air to compress each time to build enough compression heating to allow the fuel sprayed in to air that's above the combustion/flash point of the fuel..


now.. there is what is known in most circles as the dasterdly EGR valve and flow..  what happens is the exhaust gases in gasoline engines that are running properly.. contain about 14% oxygen..  instead of the 21 or 22% oxygen in the normal atmosphere.

what happens with egr flow is it dilutes the percentage of oxygen in the incoming air charge..  less percentage of oxygen requires a significant reduction in fuel injected to keep the oxygen fuel ratio within a burnable mixture..

a similar thing happens on the diesel side..   except the exhaust gas temps are a little higher.. so they run an EGR charge cooler..  

both gasoline and diesel engines also use EGR flow via oxygen percentage dilution to reduce combustion temps.  if they can keep the combustion temps below i think 2600F.. they reduce the formation of oxides of nitrogen.. that nasty stuff in smog that burns your eyes..  its fairly hard to break it down in the cats..

now... if they can raise the compression ratio of diesels.. use a turbo and a throttle blade to reduce intake pressures except under load..

with a high enough compression ratio.. there will be enough squeeze on the throttled incoming air charge to still ignite the spray from the injectors..

this could greatly increase the fuel economy of diesel engines..

somebody someplace back in the 80s or late 70s must have written a misleading SAE paper on how reduced manifold vacuum levels. HIGHER PRESSURE.. increased fuel economy.. because the engines were not creating intake vacuum..  this wiped out any possible fuel economy issues with the early electronic controlled engines..

i used to get a lot of SAE papers..  and it seems that one written by a manifold company misled the other manufacturers by stating in the SAE paper that square corners in intake manifolds worked better then gently sweeping intake  runners.

i am kinda drifting here.. i don't know if any of the above makes any sense..

just a few thoughts..

sorry if i highjacked your thread..

[Crosley.In.AZ]

I understand what you are sayin Arnold..  diesel fuel here is higher than regular gasoline.

Years ago, diesel fuel was referred to as "scum" fuel by the people in the oil industry. My brother was in that biz for 3+ decades.

Now daze the diesels require the blue chemical additive to separate tank on baord the vehicle... IF the tank runs dry, the vehicle systems limit the driveability (speed) of the vehicle.  That seems some what dangerous to me.

I've read on some diesel BBS , that if the blue tank runs low, some folks add premium gasoline to the tank to keep driving.  I have no idear how well that works.  May be dangerous too

[Glen]

In regards to trucks specifically:

I have drove a diesel truck since 2005.  The main reason is I pull a trailer frequently.  I drive a diesel for another reason.  In my job I put a lot of miles on a vehicle.  I put 80k miles on my 2011 F250 in about 3.5 years.  I can buy a ford ranger economy vehicle and get 14MPG or I can drive my F250 and get 19MPG.  I could drive an F150 and get 12-14 MPG ecobooost or 5.0.

The big factor is the retention of value in a diesel, I am much better off when I trade in my 80k mile diesel vs. a gas truck.

In regards to the DEF fluid.  The def fluid tank is around 5 gallons.  I was averaging 10k miles on my last truck per tank (7k is more of a national average).  There is a sensor that tells you when you are less than half a tank.  There is a warning that comes on and tells you that you have less than 750 miles on the tank of fluid and then the become more frequent after that. Most people cant drive 750 miles without a bathroom break and its way less if the wife is with you.  I can only go 500 miles on a tank of fuel anyway..... DEF is available everywhere now.

You should be changing the oil between 5-8k miles on the truck, dealers offer to fill the DEF during the oil change thru their bulk tank.  

The biggest benefit using DEF is we no longer spray raw fuel into the exhaust stroke to clean the cat we spray the synthetic urea which turns into ammonia inside the exhaust.

The raw fuel from years past was like a cancer, especially on ambulances and landscapers trucks that sit and idle all day.  The exhaust would get coked up with soot and then it would try to perform a regen to clean the exhaust.  The idling cars would have X amount of miles so the owner would change the oil every X miles.  The problem was the amount of fuel that went past the rings and ended up in the oil.  This was terrible on the valvetrain.  Not to mention the idling effects on the rest of the emissions systems.

Now add in the guys who chip the truck, add open exhaust, k&N air boxes, and the "smoke rollers" and the manufacturers get a bad rap.  I actually had a grown adult put over 30k miles on his 6.4 (that's the engine with the fuel regen setup) without changing the oil.  He said because it had amsoil he could go 30k miles.  The oil was like sludge and plugged the tubes to cool the turbo and burned it up.

[UGLY OLDS]

If you guys could see some of the problems we run into with diesel powered trucks you would cry .. The "shutting down" or "going into reduced power" when the Urea tank gets low enough ....It's designed to SAVE the DPF & convertor system .. Most Fords & Dodges have THREE different stages of "Warning" the driver for that system ... Ignore the first warning light ..The flashing warning light ..Lastly the Flashing warning light & VERY obnoxious warning buzzer ..Yep ..It will allow the engine to idle only ..Time to call the wrecker ..  

 Put gasoline in the Urea tank    A guaranteed fire ...

 During the "Re-Gen" process, the exhaust temp reaches approx. 1000 degrees..   Trust me ...Gasoline does NOT like being in that environment & we have seen the results ....

 Put Urea in the fuel tank on a Ford  It reacts chemically with the diesel fuel causing crystals & corrosion in the fuel system .. The solution ??
   Replace the fuel system ... The COMPLETE fuel system ...This is the only repair that Ford will approve to maintain the vehicle warranty ... It runs from $6K to $7K  ( yep.. THOUSAND    )  to properly repair the system ...  

I could go on & on with what we see ...EGR systems that plug with soot & sludge so badly that an "EGR SYSTEM SERVICE"  ( about $500/$600 ) is REQUIRED at 60K miles .. EGR coolers that leak ...Engine oil coolers that leak ...  Google "6.4 engine issues " sometime .......

    Sorry for the rant guys ...A week or so ago during the cold spell that we had ,  if I had a nickel for every time I had to ask ..." Are you using any type of  fuel conditioner ?? " after the drivers call to complain their trucks wont start I could retire tomorrow ...  

How about a COMPLETE fleet ( about 350 vehicles )  of diesel trucks that the drivers never knew they had electric overnight heaters as part of the diesel package ....Hello ??  Owners Manual  

Again ...Sorry for the rant ...... I need some "away" time ..  :oops:    


Bob.......

[jaybee]

I sure wouldn't put gasoline in the DEF tank. Diesel Emissions Fluid is actually a Urea solution. Gasoline would almost have to mess things up.

The biggest issue with diesels hasn't changed since they had a burst of popularity in the 1980s. Most of us drive short hops and they don't warm up fully often enough for their own good. We all know that's hard on engines, but it's even worse with diesels. The diesel Olds engines got a bad rap, but my Uncle put a whole bunch of trouble free miles on his. As a farmer he was very acquainted with diesels, though. He didn't even think of scrimping on air filter or oil changes and never drove the car except when he could get a full warm up. Even that is something folks in town don't always have the luxury of doing...everything is just too close to home and doesn't take that long to get to.

[58 Yeoman]

 
     How about a COMPLETE fleet ( about 350 vehicles )  of diesel trucks that the drivers never knew they had electric overnight heaters as part of the diesel package ....Hello ??  Owners Manual  

Again ...Sorry for the rant ...... I need some "away" time ..  :oops:    


Bob.......

Hey Bob...that wouldn't be a company that the name starts with an N and ends in O, would it?  I talked with a driver from that co. Friday, and he told me that they had 300 trucks that needed towing/starting.  No one plugged them in on Sunday.

[UGLY OLDS]

[

quote="58 Yeoman"]

 
     How about a COMPLETE fleet ( about 350 vehicles )  of diesel trucks that the drivers never knew they had electric overnight heaters as part of the diesel package ....Hello ??  Owners Manual  

Again ...Sorry for the rant ...... I need some "away" time ..  :oops:    


Bob.......

Hey Bob...that wouldn't be a company that the name starts with an N and ends in O, would it?  I talked with a driver from that co. Friday, and he told me that they had 300 trucks that needed towing/starting.  No one plugged them in on Sunday.

[/quote]


   No Phil ..   Not that one .. I won't divulge name as it's not really needed ...  Let me just say that these are HIGH end diesel trucks that do get EXCELLENT maintenance preformed on schedule ....  But at -18 degrees they DO need some help.......    


Anyone want to talk about using starting fluid on glow plug equipped engines ??    ( We only had one go Ka-Boom all week...  :? )

Bob.....