Warming up Diesels with minimum fuel usage in mind

[GIJOE]

I usually let mine idle until the temp gage needle starts to move (lifts off the pin stop). That ensures everything internally is well lubricated, and allows me enough time to make one last walk around before putting the machine to work.

Joe

[patrick_g]

There are pre and post luber accessories that use a pump to circulate the engine oil before starting to avoid dry starts and after shut down to let the turbo bearings cool and not fry the oil in contact with them.

Cummins literature recommends that if you go for lengthy periods between engine runs that you install a switch to disable the fuel control solenoid. This allows you to crank the engine till you see oil pressure building and then allow it to have fuel and start. This prevents dry starts, a major contribution to engine wear. (If you hide the switch it make unauthorized use of the vehicle rather difficult.)

While pre and or post lubers can serve a useful purpose, neither will substitute for warm up. As soon as the engine is running smoothly, go ahead and drive the tractor, gently, really gently if it is hydrostat and it is really cold. After you can confirm definite positive movement of the temp gauge you should be ready for light to medium tasks and HD work when more near normal operating temps.

Turbo or not, I don't personally recommend shutting down an engine immediately after working it hard. Give it a moment to cool a bit. I like to let my Cumins B5.9 cool down to an exhaust pyro (downstream of the turbo) reading of 350 degrees which can take a while on a really hot day. A post luber like I had on my '84 Ford diesel does the waiting for you. You shut the engine off but the pump circulates the oil for a user adjustable period to cool the turbo bearings.

Hybrids were mentioned as an example of starting and stopping an engine a lot. Our '04 Prius hybrid doesn't just turn the ICE off at each stop but every time you coast more than about a second. Even on cruise if you go down a hill it may shut the ICE off until speed drops as you start back uphill again. But the engine was designed for this service. It has computer controlled valve timing and clever programing.

The starting sequence is: valves open to eliminate compression, spark and fuel off, spin the engine up to speed with a BIG electric motor (which brings up the oil pressure and lubes everything) Then set valves to normal and turn on the gas and spark. The engine is running instantly. The ICE in the Prius is shut down and restarted hundreds of times in just a little in-town driving. It is designed to do this and is not sacrificing longevity to pump up mileage figures. We have 100,000 mile warranty (including the high voltage battery.) We are at 36,000 miles in almost 48 months so anticipate lots more years before getting to 100,000. I expect to make it with no service beyond the regular schedule in the manual. So far it has been totally reliable and trouble free.

The Prius has a really good "thermos bottle" under the hood where it stores hot engine water. The water will stay really hot for a couple days (if I recall correctly.) Anyway when you "boot" the Prius a little pump takes the hot water from the thermos bottle and pumps it through the intake manifold and throttle body area to heat up the fuel delivery portions of the engine. This gets your fuel vaporizatioin "jump started" so you get good economy and low emissions right away. This essentially elliminates much of the benefit of a warm up period but not going to max throttle before the lubricants are warmed just a bit when in really cold weather is a good idea.

Pat

[john_bud]

Originally Posted by patrick_g

The Prius has a really good "thermos bottle" under the hood where it stores hot engine water. The water will stay really hot for a couple days (if I recall correctly.)

Pat

Can you tap into that hot water for a morning cup of java? That would be worth while!!

jb

[patrick_g]

Originally Posted by john_bud

Can you tap into that hot water for a morning cup of java? That would be worth while!!

jb

John, I don't usually drink coffee and coffee made with engine coolant might not be a terrific idea.

Now if you had a heat exchanger and a small reservoir of potable water... Ah a Prius with a small custom samovar!

Pat

[Steve_Miller]

Just thought I'd throw this in there, quite a variance around the world in prices.

Gasoline usage and pricing - Wikipedia, the free encyclopedia

Steve

[RalphVa]

Use of a engine and transmission heaters would be more efficient than letting the tractor idle to warm up. Diesel engines are only about 21-22% efficient vs. at least about 33% for the electric generation cycle (if from fuel gas or oil, better if nuclear or water power). Use them even in warm weather if you think you have to get it fully warmed before using it.

Ralph