Verified Alternate Fuels....NOT!

What are some other options for Contractors, other than retrofitting their equipment with devices that reduce diesel exhaust emissions required by the EPA's voluntary retrofit program? Alternate fuels can be used to power diesel engines to meet EPA's category 1 emission reduction. These fuels can be mixed directly with the existing fuel in the equipment's tank without engine modification. The combination of an DOC with the use alternative fuel will allow for even greater amount of emission reduction.  

 

There is one problem. The only EPA and CARB verified alternate fuel listed is PuriNOx. PuriNOx is produced by Lubrizol and is no longer available in North America. This leaves contractors no other options but to retrofit their equipment. Alternate fuels need to become more readily available due to the frequent use of rental equipment. Rental companies refuse to retrofit their equipment with devices because of overall demand. A solution to rental equipment exhaust dilemma is to use alternate fuels.  

 

DPF Retrofit Evaluations

 

A contractor should be able to determine without hesitance which piece of equipment will be best suited for a DPF retrofit. Even for me with 14 years of heavy and highway construction field experience I can envision which equipment will be best suited to study. The evaluation should begin by examining various pieces of equipment that will be active most times during and others which will be used sporadically. Using these types of equipment for the evaluation will take into account a wide range of possible exhaust temperatures.

 

I would recommend beginning the study with a front end loader.  A front end loader is used for multiple activities and is used frequently during the workday. It can be used to load triaxls, unload flatbed trailers or move materials and smaller equipment around the project . The evaluation should also include a piece of equipment that is used intermittently during the workday. A good example of a piece of equipment that is used intermittently is a rubber tire excavator. This type of excavator has multiple uses and is not as limited as a tracked excavator. Rubber tire excavators are a nice choice for on-road light digging or grading where damage to the pavement needs to be controlled. 

 

Both pieces must have exhaust temperature monitoring devices installed on the stacks for a period of approximately one week. All data will be tabulated and examined to determine which pieces will be best suited for a diesel particulate filter. As I said in my previous post, I believe that a front end loader will achieve the proper exhaust temperatures for a passive DPF as long as the periods of idle time are limited during the work day. The results will also show that the exhaust temperatures for the rubber tire excavator fall below the minimum required for a passive DPF. The choice of retrofit device on the excavator will be an active DPF. 

 

Even if all test results show that exhaust temperatures do not meet minimum requirements for passive filters, an active filter can be a retrofit last resort.  

Passive or Active DPF's for Construction Equipment?

 

Will the retrofitting of construction equipment with diesel particulate filters (DPF) be as easy as retrofits on school or transit buses? I seem to think that retrofitting construction equipment with DPF's will be more difficult than anyone anticipates. The exhaust temperatures are critical for DPF regeneration. If the filters become clogged, a buildup of backpressure can damage the engine. Extensive testing must be done to determine proper exhaust temperatures. The following are some issues that should be given some thought:

•  Since busses, both school and transit, run continuously without long periods of idle time, there most likely will not be a issue with exhaust temperatures. If a bus was border line, a passive catalyzed DPF could be used. A catalyzed DPF uses catalyst coated filter fibers to increase exhaust temps for proper regeneration of the filter. The catalyzed filter coverts NO to NO2 which then reacts with more trapped particulate matter.

 

•  The issue with construction equipment DPF retrofits are exhaust temperatures. My experience with the operation of construction equipment leads me to believe that passive DPF's will not be the proper device for this industry. Most equipment will have periods of intermittent heavy use and idle time. Therefore, exhaust temperatures will not be sufficient for the use of passive DPF's. Construction equipment will require the use active DPF's. Active DPF's regenerate when engine backpressures reach a minimum threshold or at the end of an eight hour workday. The regeneration can be completed in one of three ways.

1. The injection and burning of diesel fuel upstream of the filter to generate proper exhaust temperatures. A draw back of this method is additional fuel  consumption.
2. Electric regeneration through which a current is passed though conductive resistant filter material, thus creating heat which burns the particulate matter.
3. The filter can physically be removed from the housing and placed in a regeneration system which burns off the particulate matter.

Construction equipment will have to use one of the above mentioned three methods for proper filter regeneration.

Diesel Hybrids on the Beat & in the Garage

Mayor Bloomberg is truly taking a step in the right direction by converting the NYC Taxi fleet to hybrid vehicles. This in turn will lower exhaust emissions in the City and our dependency on foreign oil. I say why not take it a step further. Along with the yellow taxis we all see around the city, there are just as many police cruisers (marked and unmarked) throughout the five boroughs. 

 

Yesterday I posted a comment on the DeSmogBlog.com in regards to the idea of swapping out gas powered NYC police cruisers, over a period of time, with diesel powered cars. At best diesel engines are 50% more efficient than a same sized gas engine. The increased efficiency to due to several factors.

1. Diesel engines use compressed air to create a reaction when mixed with diesel fuel. With the compression ratios twice as high as they are in gas engines, the air gets extremely hot and combusts without the need of a spark. In simpler terms, the more compression in the cylinder the more efficient the engine will be.
2. One gallon of diesel fuel is actually heavier than one gallon of unleaded gasoline. Both fuels are comprised of carbon and hydrogen atom chains. The chains in diesel fuel are longer which makes the fuel heavier and more efficient. So, by comparison a gallon of diesel fuel is 17% more efficient than a gallon of unleaded gasoline.

My point is, over a period of time the City of New York should phase out gasoline powered NYPD police cruisers and replace them with diesel hybrid electric cruisers. The reason I suggest diesel hybrid electric cruisers again is two fold.

 

1. Diesel engines are sluggish off the line. The addition of electric motors solves the problem of acceleration in emergency situations.
2. As we all know hybrid diesel and gas engines achieve even better fuel economy on city streets. The energy created from braking is stored in a bank of batteries to power the electric motors in the future.

 

In the future, I think we'll see diesel hybrid police cruisers in all urban areas and even possibly diesel hybrids in our garages.    

Increase Profits...Stop Truck Idling

Many states recently have been considering anti-idling campaigns to generate interest and awareness of anti-idling state laws. For these campaigns to truly work the industry owners need to take a look at fuel savings and lowered maintenance costs which ultimately lead to company profits. Most often truckers will run the engines to keep cool in the summer and warm in the winter when taking mandatory rest periods in their sleeper compartments.

Here is a good example of how much money could be saved with the elimination of idling from just one truck. Approximately .8 gallons of diesel fuel are used per hour when a engine is idling. I'll use a conservative long haulers rest/idle time figure which is approximately six hours per day.

• Six hours of idle time per day multiplied by .8 gallons of fuel per hour equals 4.8 gallons of fuel used for daily idle time.
  
• Over a period of a year, assuming the truck is active 250 days out of the year and the cost of diesel fuel remains at $3.00/gal, the total savings per truck is $3600.00.
• For a large fleet the savings are substantial.

Did I forget mention that the elimination of idling also makes the air we breathe better and will cut down on global warming for future generations.

American Truck Manufactures Goin' Diesel

Finally, were beginning to see more interest in light duty truck diesel engines. In fact, I think I should also be writing about automobiles as well. But, for now there seems to be some competition in the light duty truck sector. Each player wanting to grab the consumers attention with increased fuel economy.

 

Remember the days of the VW diesel rabbit....I sure do. They were noisy, dirty and would run forever. By the way the way the fuel economy is about the same as it is today. Too bad that price of diesel fuel was much higher than regular fuel in those days. The prices of regular fuel is what made the American pubic fall in love with the gas powered automobile. 

 

There is a whole new spark, or shall I say compression, for the diesel powered automobile in the United States. Today's diesel engines are extremely quite, emit zero emissions and most of all the fuel is less costly than regular unleaded gasoline.