Go BottomLittle research on Diesel vs Gasoline
 | MichaelSnyder
Join Date: Jun 1999 Posts: 0 
|
1999-06-03 4680
The question seems to come up "Why Diesel over Gasoline"? Not knowing exactly why, I did a little research to find out what makes a Diesel a Diesel. These results may help answer our questions. Thought I would share my findings with all of you.The BTU, or British Thermal Unit, for Diesel is 130K BTU's per gallon,at a weight of 7.0 lbs./gallon. Gasoline yields 117K BTU's,6.3 lbs./gallon. This means that Diesel has the ability to produce more"energy/work" per gallon of fuel. Because Diesel only uses compressed air to ignite the fuel,a diesel engine's ("heat engine"),air to Fuel Mixture ratio varies upon load, as high as 85-100:1(unloaded/Idle) down to a miserly 25-30:1 (Loaded). Gasoline engines remain at a constant 14:1 regardless of load. The fact that diesel fuel is ignited by compressed/heated air,also explains one reason a diesel can be more difficult to start in the cold winter months. Compression Ratios for Diesels average 20-25:1, vs gasoline at 8-9:1(normal), 14:1(Max) in race form. All of these Diesel attributes add up to more miles(HOURS) per gallon of fuel. It also means that a Diesel varies its operating efficiency based upon loading. Most new Diesels are so efficient at idle, the engine manual informs you not to idle for extended periods of time. This causes your cylinder temps to drop below normal, causing unburned fuel to make its way past the rings, into your oil. Hope you found these findings helpful
Reply to |
Quote Reply |
Add PhotoLittle research on Diesel vs Gasoline
| mike
Join Date: Posts: 1
|
1999-06-03 4685
mls, you made a good point about NOT letting your diesel idle away for long periods. This is one of the worse things you can do to a diesel. Not only does it contaminate your oil it also causes a "fuel loading" problem in the cylinder thus stressing the lower end. People think that the semis do it so why not me. The semis use cold weather bras in front and have a thing called idle control do prevent fuel loading. It is now an option on the Ford Powerstroke to prevent a $7500 trashed motor. I explained this on the Kubota message board and got laughed at by the guys that think its safe to let thier tractors idle away for hours. ....
Reply to |
Quote Reply |
Add PhotoLittle research on Diesel vs Gasoline
| Alan
Join Date: Posts: 1
|
1999-06-03 4686
What is considered "idling". I let my B2710 diesel run at about 1300 RPMS for 5 minutes for warmup, and it runs about that for a few minutes when I get off for something. Is this considered "idling", or is idling lower than that? ....
Reply to |
Quote Reply |
Add PhotoLittle research on Diesel vs Gasoline
| MichaelSnyder
Join Date: Jun 1999 Posts: 0
|
1999-06-03 4690
Alan,Please don't quote me on this, I think my Dodge Cummins manual warns of allowingthe engine to idle for more than 10 minutes. Mike mentioned an important point,The big rigs use an idle control switch, which essentially holds the throttle at the RPM of choice.Your 5 minute warm-up IMHO is the best thing you could be doing for your Compact. If I need to let my Diesel tractor/truckrun for any extended length of time, I usually adjust the throttle lever to the point where theengine runs smooth as silk (900-1000 RPM I think?). Compared to the racket & vibration a Diesel generally makesat idle. ....
Reply to |
Quote Reply |
Add PhotoLittle research on Diesel vs Gasoline
| MichaelSnyder
Join Date: Jun 1999 Posts: 0
|
1999-06-03 4691
One more tid bit of info:The diesel engine was designed and patented in 1892 by Rudolf Diesel.The first engine designed by Clessie Cummins in the 1920's, was a monster at400 lbs./per horsepower produced. The 1998 "Highly Restricted" B-series 5.9 Liter 235hp Turbo Diesel is about 4 lbs./per horsepower.Highly restricted due to drivetrain reliability & emission control in pick-ups. This same engine has actual reports of producing +450 HP, using #2 Diesel Fuel.I would assume Powerstroke and others would be capable of producing the same results.Diesels have made some progress in 70 years.Compliments of: www.turbodieselregister.com ....
Reply to |
Quote Reply |
Add PhotoLittle research on Diesel vs Gasoline
| mike
Join Date: Posts: 1
|
1999-06-03 4699
Alan, I don't know the standard procedure for a Kubota warm-up but it should be a little less than half thottle about 1200 rpm for 5 min. is a good rule after start-up. Then maybe keep it below 1900 after you take off for 5 more min. Idle speed for your Kubota is the throttle lever all the way back--about 650-800 rpm maybe. But I bet the owners manuel recommends a least 1000 rpm after start for warming the motor--NOT IDLE. Because diesels generate little heat at idle so you are wasting your time to warm it up at idle speed. After working it hard its a good idea to let it idle for a couple min. to remove hot spots before shut down. ....
Reply to |
Quote Reply |
Add Photo
Go Top
Share This