oldnavy wrote:
Jeger wrote:
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?
Yes they have high idle throttle either hand or automatic. Some of the new truck stops now have islands with heat or a/c that can be attached to windows so as not to need to waste fuel with engine running while driver sleeps/eats/showers or whatever, some trucks have aux small diesels that run a/c and even keeps engine coolant warm from what I have read. The savings in fuel cost seems to have paid for the aux diesel in just a few short months and the same for the use of the rental a/c and heat at truck stops.
When I need to idle my semi, I engage the cruise control which steps up the motor to a PTO idle (approx 900 RPM). During the recent "hot" spell, that meant for up to 8 hrs. It is true that there is some carbon/soot buildup, but this is purged by 11 hrs of highway driving with 80,000 lbs. This really works the motor, especially in hill country.
The APU units that are on some trucks currently sell in the $7-8K range. They do save a considerable amount of fuel, but the break even point is not reached for over a year.
The "idle-air" setups at some truck stops are really only for a limited number of trucks. They are only located in high volume stops along the major east-west routes. They are useless for majority of trucks since most of us need to take our breaks at loading/unloading locations. Therefore, unless the truck owner decides to install the APU's, the driver is forced to idle the truck.
It does cause wear and excess fuel use, however, if done in moderation and good driving technics used, the amount of fuel and wear is not excessive. To point: I have averaged 7+ mpg over the last 11 years and put on 1.4 million miles on my last truck without an overhaul or major repair. Considering the industry mpg average is 6 or less, the amount of idling I have done has not been a serious enough issue to justify 8k for an APU. Just by getting a 1+mpg more than the industry average saves approximately $7k a year in fuel at the current price. But that is on a semi.
All being said, unless you have a real need to idle the engine, don't. It is never a good option unless absolutely necessary. I never idle unless I am in the semi and needing rest in hot/cold weather. I never idle the truck when I am out of it, even in -20 weather. That is what a block heater is for. For hot weather, crack a couple of windows and shut the vehicle off. I do the same with my CRD. The idling done with most diesel engines is unwarranted. It comes from old wives tales and such. Modern diesels do quite well starting in cold weather, even after sitting with block heater unplugged for up to 4 hrs in the most extreme cold weather. The only situation I ran into that caused me to not shut the truck off for any reason was running the interior of Alaska in the middle of winter. But that was to keep the diesel fuel warm just as much as keeping the engine warm.
Unless it is a matter of life or death, I would advise not idling your CRD for extended periods of time.
Login
Register
FAQ
Search
