If you belong to the majority of people who think the diesel generator is one of those noisy, smoky engines that farmers don't seem to be able to do without, then you are going to have to think again. There is a growing surge, almost a tidal wave of new owners sweeping across the United States. These are the people who through no fault of their own seem to be forever losing their power supply. It is not until you are faced with trying to take care of your family through an extended power outage that you realise just how difficult life becomes without that magical current flowing through the lines.
It seems that storms are becoming more severe, with some badly affected areas having to go without power for between one and two weeks. On the other hand, heatwaves put so much demand on the national grid that rolling outages have to be forced on the population to keep the whole system from crashing. Then of course there are all the other things that can go wrong, such as transformers malfunctioning, but they all mean the same thing, you are left searching for candles and matches in the dark.
The diesel generator has always been regarded as belonging to industry, and indeed this is where you will find the giant units ranging from 20kW to way over 2000kW's that produce the same amount of power as a small power station. You will also find them permanently installed at hospitals, nursing homes, fire and police departments or anywhere that reliable stand-by power is required. Our transportation systems such as air traffic, sea navigation, and radio communications all rely on diesel generators in times of emergencies. In the situation of a natural disaster, it is the diesel generator that will be the heart beat of emergency services and reconstruction.
Many suburban homeowners, RV owners, tradesmen and small businesses are paying the extra, and purchasing a diesel generator in preference to a gasoline powered unit. When there are so many gas generators coming on to the market at such ridiculously low prices you can be forgiven in asking why. The consumer has finally woken up to the benefits of diesel. There are in fact four main reasons why people are turning away from the cheaper gas alternative in their droves.
1. The diesel generator likes to work, and it is very happy putt-putting away 24 hours a day, 7 days a week. It works well under load too, in fact it loves to work hard. Many of the discount and hardware store bought gas generators virtually disintegrate during prolonged use, and you are doing well if they last more than a couple of hundred hours. There are of course very good models, but they will still be more suited to intermittent use, and will need a thorough overhaul at around 1,000 hours. The diesel generator on the other hand won't need anything except regular maintenance - such as oil change, for the first 20,000 hours of its life.
2. Maintenance. No ignition system to give you trouble, no carburettor that needs rebuilding or cleaning, no distributor to go kaput, and no spark plugs to be replaced. Maintenance is simplified on a diesel generator, they are in fact a much simpler system altogether. Regular oil changes as well as replacing the oil, fuel and air filters are all that is required.
3. The diesel generator is way more fuel efficient, and the exhaust is not nearly as toxic as gasoline.
4. Diesel power is synonymous with dependability and for standby or emergency power, this is essential. The quality of the electrical output is also excellent and this means that you are bale to run your computers and electronic equipment with peace of mind.
The cost factor has been a stumbling block for many people, but at the end of the day, the diesel generator is worth every extra dollar and more. It is common for them to outlast their gasoline counterparts by anything up to ten to one. Their work ability has never been questioned, but their noisy and smelly habits have. The diesel generator has cleaned up its act and is now a much quieter and cleaner producer of commercial grade power, and it is fast becoming the preferred choice of all those people who want the best.
Friday, October 12, 2007
Your Diesel Generator Will Ensure the Lights Are On When Somebody's Home
If you're considering putting a permanent power generating system such as a Yamaha generator, in your home or office, this is definitely a job for the experts! Any wiring that is done to the transfer switch and circuit board will need to be done according to your local electrical code and you may need a plumber in to set up the hoses and connect the Yamaha generator to the home's fuel supply.
Diesel generator dealers that are licensed will generally oversee the installation process, and some companies will a secure a permit and schedule the electrical inspection as part of your purchase price. Prices will vary, but you'll find that a 12 kW generator package excluding the transfer switch to be somewhere in the vicinity of US$1,000-$7,000. A 20 kW package will run you somewhere in the vicinity of $8-$10,000. Many brand-name manufacturers are now making home power generating systems such as Generac generators, Honda generators and Kohler more affordable. Most manufacturers encourage homeowners to hire electrical contractors for installation, as these are not do-it-yourself jobs. If you decide to install a permanent diesel generator somewhere outside your home, it should usually be on a concrete pad near the utility meter. Some generators come with a built in mounting pad and you may want to consider these instead of pouring your own concrete pad. As a rule, the unit is usually run off your home fuel supply and you'll need to connect it to the propane or natural gas supply.
The transfer switch is commonly installed inside next to the distribution panel and wiring is run from the generator into the house. Once the transfer switch is connected, it monitors your home's power supply for any interruptions. Backup power from Honda generators or diesel generators is almost becoming a necessity in today's technology-driven world. There are many more electrical items to run now other than lights, heating, cooling system and appliances. Most homes have computer systems, home automation systems and security systems. Electrical regulation has caused complete power outages in many areas and is more prevalent than years gone by.
It is almost essential that when bad weather knocks out your power for days or possibly weeks on end that you have a Honda generator backup power system. A self-contained backup system will help keep your phones ringing, water running, computers running and the furnace keeping your home warm, too. Pipes freezing are also a hazard when power loss occurs, and if you live in an area where intruders could be a problem, your security system on all the time will keep them at bay, too. It's important to understand what a "watt" means if you're going to install a home power generating system. This starts with an assessment of your basic needs, and you'll want to calculate the complete wattage that your home consumes at any one time. If you're at a loss as far as to this calculation, call your electrician and have him do it for you. Such items as heating, cooling, security systems, fans, refrigeration and lighting are some of the items that you need to consider. The size of your diesel generator backup system is based on the essential wattage that you're going to need. When this calculation is done, it is important to remember that you must accommodate the peak power load that these devices will supply. You must make allowances for power surges as well as appliances that are considered to be steady-rate. A good example of a high-demand system with high startup power is your furnace. If your furnace has a low start motor, this will still tax the load a bit. Energy-efficient appliances will directly impact how much load a backup power source can support. If you're in an area that loses power often, you may be well advised to get rid of the energy hogs and replace them with more energy-efficient appliances. If you use electric heat, a gas or wood stove is a great addition. Let a reputable generator dealer in your local area assess your true wattage needs. This way you'll be more confident when you purchase your Yamaha generator system.
Diesel generator dealers that are licensed will generally oversee the installation process, and some companies will a secure a permit and schedule the electrical inspection as part of your purchase price. Prices will vary, but you'll find that a 12 kW generator package excluding the transfer switch to be somewhere in the vicinity of US$1,000-$7,000. A 20 kW package will run you somewhere in the vicinity of $8-$10,000. Many brand-name manufacturers are now making home power generating systems such as Generac generators, Honda generators and Kohler more affordable. Most manufacturers encourage homeowners to hire electrical contractors for installation, as these are not do-it-yourself jobs. If you decide to install a permanent diesel generator somewhere outside your home, it should usually be on a concrete pad near the utility meter. Some generators come with a built in mounting pad and you may want to consider these instead of pouring your own concrete pad. As a rule, the unit is usually run off your home fuel supply and you'll need to connect it to the propane or natural gas supply.
The transfer switch is commonly installed inside next to the distribution panel and wiring is run from the generator into the house. Once the transfer switch is connected, it monitors your home's power supply for any interruptions. Backup power from Honda generators or diesel generators is almost becoming a necessity in today's technology-driven world. There are many more electrical items to run now other than lights, heating, cooling system and appliances. Most homes have computer systems, home automation systems and security systems. Electrical regulation has caused complete power outages in many areas and is more prevalent than years gone by.
It is almost essential that when bad weather knocks out your power for days or possibly weeks on end that you have a Honda generator backup power system. A self-contained backup system will help keep your phones ringing, water running, computers running and the furnace keeping your home warm, too. Pipes freezing are also a hazard when power loss occurs, and if you live in an area where intruders could be a problem, your security system on all the time will keep them at bay, too. It's important to understand what a "watt" means if you're going to install a home power generating system. This starts with an assessment of your basic needs, and you'll want to calculate the complete wattage that your home consumes at any one time. If you're at a loss as far as to this calculation, call your electrician and have him do it for you. Such items as heating, cooling, security systems, fans, refrigeration and lighting are some of the items that you need to consider. The size of your diesel generator backup system is based on the essential wattage that you're going to need. When this calculation is done, it is important to remember that you must accommodate the peak power load that these devices will supply. You must make allowances for power surges as well as appliances that are considered to be steady-rate. A good example of a high-demand system with high startup power is your furnace. If your furnace has a low start motor, this will still tax the load a bit. Energy-efficient appliances will directly impact how much load a backup power source can support. If you're in an area that loses power often, you may be well advised to get rid of the energy hogs and replace them with more energy-efficient appliances. If you use electric heat, a gas or wood stove is a great addition. Let a reputable generator dealer in your local area assess your true wattage needs. This way you'll be more confident when you purchase your Yamaha generator system.
Thursday, October 11, 2007
History of the Diesel Generator
The diesel generator owes its roots to mainly two inventors. One of these is the creator of the first generator Michael Faraday and the other is the creator of the diesel engine Rudolph Diesel. The first of these two has contributed greatly to life as we know it today with all his discoveries in electricity.
Michael Faraday was of humble beginning but always had a curious nature. He was at an early age an errand boy for a bookbinding shop and here he vastly increased his knowledge as he read anything he could put his hands on. He was very interested in the concept of energy and force and this interest is one that continued throughout his life and eventually he developed into a famed chemist and physicist.
It was his discovery of electromagnetic induction in the year 1831 that led to the development of the modern generator. He used what he termed his induction ring to discover the electromagnetic induction. This was the generation or induction of electricity in a wire by the use of the electromagnetic effect of the current in another wire. This was the first transformer and followed closely with the discovery of the magneto-electric induction process which is the production of a steady electric current.
He attached two pieces of wire by the use of a sliding contact to a copper disc. He rotated the disc through the poles of a magnet and was able to generate continuous direct current. This was the first generator of time. This group of experiments led to the revolutionized generator that we know today.
The diesel generator however owes its development to the inventor Rudolph Diesel. He started off as a refrigerator engineer and eventually found himself working on many heat engine designs. He in 1892 put out a patent that dealt with the method and design of a engine where combustion would take place in the cylinder. He continued to work to this goal and was successful in the production of a diesel engine that produced an efficiency of 75%.
It is the coupling of his diesel engine with the generator that led to the diesel generator that we known today. His design was rather large and very heavy and found more use in industrial applications as a generator. They were used to power pipelines and for electric plants and water plants. Later on they found applications in the mines and in oil fields. The diesel generator is simply the coupling of the diesel engine with an electrical generator and has been use throughout history since its invention for many applications.
The diesel generator has been seen to be the choice of many of the larger companies as it is well suited for industrial use. A major discouraging factor for its use in terms of the retail market has been the fact that it can be rather noisy but this has been reduced greatly from the first diesel generators and is now almost comparable to the gasoline generators. These generators also offer other perks such as increase fuel economy and reduced maintenance costs which can explain their popularity in industrial applications.
Michael Faraday was of humble beginning but always had a curious nature. He was at an early age an errand boy for a bookbinding shop and here he vastly increased his knowledge as he read anything he could put his hands on. He was very interested in the concept of energy and force and this interest is one that continued throughout his life and eventually he developed into a famed chemist and physicist.
It was his discovery of electromagnetic induction in the year 1831 that led to the development of the modern generator. He used what he termed his induction ring to discover the electromagnetic induction. This was the generation or induction of electricity in a wire by the use of the electromagnetic effect of the current in another wire. This was the first transformer and followed closely with the discovery of the magneto-electric induction process which is the production of a steady electric current.
He attached two pieces of wire by the use of a sliding contact to a copper disc. He rotated the disc through the poles of a magnet and was able to generate continuous direct current. This was the first generator of time. This group of experiments led to the revolutionized generator that we know today.
The diesel generator however owes its development to the inventor Rudolph Diesel. He started off as a refrigerator engineer and eventually found himself working on many heat engine designs. He in 1892 put out a patent that dealt with the method and design of a engine where combustion would take place in the cylinder. He continued to work to this goal and was successful in the production of a diesel engine that produced an efficiency of 75%.
It is the coupling of his diesel engine with the generator that led to the diesel generator that we known today. His design was rather large and very heavy and found more use in industrial applications as a generator. They were used to power pipelines and for electric plants and water plants. Later on they found applications in the mines and in oil fields. The diesel generator is simply the coupling of the diesel engine with an electrical generator and has been use throughout history since its invention for many applications.
The diesel generator has been seen to be the choice of many of the larger companies as it is well suited for industrial use. A major discouraging factor for its use in terms of the retail market has been the fact that it can be rather noisy but this has been reduced greatly from the first diesel generators and is now almost comparable to the gasoline generators. These generators also offer other perks such as increase fuel economy and reduced maintenance costs which can explain their popularity in industrial applications.
Guide to purchasing a Diesel Generator
There are many grades of durability of diesel generators on the market. You will find that the larger the machine the more well built it is to withstand the pressures of use. This is the general concept when it comes to the diesel generator that the larger the generator the better it is designed.
It is essential when considering purchasing a diesel generator that you are sure of what kind of use you will be demanding. It is very common for the diesel generators that are larger to be installed on ships as backups during power failures. There are often systems on ships that use power systems that are related to weather. This is not reliable and as such a diesel generator is a good choice. It is better to opt for the larger models as these are very well designed to handle the load.
Many businesses seeking to protect their sensitive computer networks can also depend on the diesel generator. These are excellent sources of power should the power fail. This is also great for medical equipment such as those that are essential in hospitals and can provide performance that is low maintenance.
When deciding which diesel generator to choose it is important that a list is constructed of the various pieces of equipment that will be using the generator power. This will aid in the determination of the total wattage requirements and therefore determine which capacity of generator will be required.
One of the first points when comparing diesel generators is to determine the wattage requirement and compare this to the price of the particular generator. This is essential as it is important not to overload the system and this will determine the best generator to suit your needs. It is also possible for persons with intermittent generator usage to opt for the diesel generator due to all the perks such as reduced fuel costs and maintenance costs.
It is also advisable that when you purchase your generator that you install it with a transfer switch. This may require a qualified electrician. It is also essential that the generator you choose will have adequate storage as this is important in maintaining the right temperature. You may also need other features such as soundproof enclosures depending on your space limitations as the diesel generator can be quite noisy and is best installed away from homes.
Other features that will be needed for your generator include shutdown systems. There are three major shutdown systems available. These are low oil pressure automatic shutdown kits, over-speed shutdown kits and high temperature shutdown kits. These are all necessary for the protection of any diesel generator that you purchase.
Make sure that the diesel generator you choose is run at a low rpm approximately 1800 rpm to ensure long life. It is better to opt for a generator that is the best in terms of fuel efficiency and if you can opt for a brand name. They may be a bit more expensive but they will tend to have better warranties than the other generic brands on the market.
It is essential when considering purchasing a diesel generator that you are sure of what kind of use you will be demanding. It is very common for the diesel generators that are larger to be installed on ships as backups during power failures. There are often systems on ships that use power systems that are related to weather. This is not reliable and as such a diesel generator is a good choice. It is better to opt for the larger models as these are very well designed to handle the load.
Many businesses seeking to protect their sensitive computer networks can also depend on the diesel generator. These are excellent sources of power should the power fail. This is also great for medical equipment such as those that are essential in hospitals and can provide performance that is low maintenance.
When deciding which diesel generator to choose it is important that a list is constructed of the various pieces of equipment that will be using the generator power. This will aid in the determination of the total wattage requirements and therefore determine which capacity of generator will be required.
One of the first points when comparing diesel generators is to determine the wattage requirement and compare this to the price of the particular generator. This is essential as it is important not to overload the system and this will determine the best generator to suit your needs. It is also possible for persons with intermittent generator usage to opt for the diesel generator due to all the perks such as reduced fuel costs and maintenance costs.
It is also advisable that when you purchase your generator that you install it with a transfer switch. This may require a qualified electrician. It is also essential that the generator you choose will have adequate storage as this is important in maintaining the right temperature. You may also need other features such as soundproof enclosures depending on your space limitations as the diesel generator can be quite noisy and is best installed away from homes.
Other features that will be needed for your generator include shutdown systems. There are three major shutdown systems available. These are low oil pressure automatic shutdown kits, over-speed shutdown kits and high temperature shutdown kits. These are all necessary for the protection of any diesel generator that you purchase.
Make sure that the diesel generator you choose is run at a low rpm approximately 1800 rpm to ensure long life. It is better to opt for a generator that is the best in terms of fuel efficiency and if you can opt for a brand name. They may be a bit more expensive but they will tend to have better warranties than the other generic brands on the market.
Tuesday, October 09, 2007
Mobile generator
Raven Technology offers the 5 kW Blackbird generator for the underhood installation in a variety of Ford, GM and International chassis. The generator provides 110 V pure sine power through the flip of a switch to power tools, lights, computers, communications and other equipment used in emergency, utility and construction vehicles. The speed independent Blackbird system weighs in at 75 lb. and is designed to be belt- or PTO- driven from the engine and is speed independent to offer full power from idle to redline, said Raven.
New generator set filter/silencer
The Santa Fe, N.M., manufacturer said the new filter/ silencer is designed to reduce PM emissions by 85% and carbon monoxide and hydrocarbons by up to 99%. The CleanAIR Filter/Silencer has an all stainless-steel construction and is fully insulated for sound attenuation, the company said.
The concept of the CleanAIR filter/silencer combines the benefits of a silencer for sound reduction and the benefits of diesel particulate filters for emissions control into one space-saving unit.
"We designed our Permit filter/silencer specifically to fit facilities that need to reduce emissions and sound," said CleanAIR Sales Engineer, Daniel Serrano. "By combining our diesel particulate filters with a silencer, the customer no longer needs two separate units that take up a lot of space. Our Permit filter/ silencer does the job of both by eliminating emissions while at the same time providing sound reduction. It also reduces the overall cost."
Available for all stationary engine sizes, the custom-designed Permit filter/silencer is manufactured using 304 stainless steel. Utilizing CleanAIR's integrated approach, the product is designed and manufactured in-house, including: product design; flow, stress and sound modeling; filter catalyzation; and custom fabrication of the silencer shell. Each Permit filter/silencer is fully insulated to reduce heat loss and provide sound attenuation.
The concept of the CleanAIR filter/silencer combines the benefits of a silencer for sound reduction and the benefits of diesel particulate filters for emissions control into one space-saving unit.
"We designed our Permit filter/silencer specifically to fit facilities that need to reduce emissions and sound," said CleanAIR Sales Engineer, Daniel Serrano. "By combining our diesel particulate filters with a silencer, the customer no longer needs two separate units that take up a lot of space. Our Permit filter/ silencer does the job of both by eliminating emissions while at the same time providing sound reduction. It also reduces the overall cost."
Available for all stationary engine sizes, the custom-designed Permit filter/silencer is manufactured using 304 stainless steel. Utilizing CleanAIR's integrated approach, the product is designed and manufactured in-house, including: product design; flow, stress and sound modeling; filter catalyzation; and custom fabrication of the silencer shell. Each Permit filter/silencer is fully insulated to reduce heat loss and provide sound attenuation.
Monday, October 08, 2007
Generator drive power pack introduced by Perkins
Perkins Engines has introduced the 1104C-44TAG2 ElectropaK generator drive power pack. First shown at the World of Concrete show earlier this year, Perkins said the hunch of the engine is with an eye on broadening its overall product range in the power generation markets.
Power for the new power pack is Perkins 1104C diesel which is packaged with a skid-mounted cooling system. The 1104C is a four-cylinder, turbo-charged and air-to-air intercooled engine designed for 80 and 100 kW 60 Hz standby applications, as well as 50 Hz prime power needs from 80 to 100 kVA, Perkins said.
Perkins is positioning its 1100 series diesels as its premium emissions compliant platform, with the line available in three-, four- and six-cylinder configurations. For Tier 3, Perkins has increased the 1100 series per cylinder displacement to 1.1 L, and has undertaken aggressive development of the combustion system. Other engineering changes include a fundamental redesign of the cylinder block to create an advanced "open-top deck" structure that Perkins said radically reduces transmitted noise.
Further, the addition of air-to-air charge cooling on the 80 and 100 kVA models has enabled Perkins to offer what it says is six-cylinder power from a four-cylinder package.
Power for the new power pack is Perkins 1104C diesel which is packaged with a skid-mounted cooling system. The 1104C is a four-cylinder, turbo-charged and air-to-air intercooled engine designed for 80 and 100 kW 60 Hz standby applications, as well as 50 Hz prime power needs from 80 to 100 kVA, Perkins said.
Perkins is positioning its 1100 series diesels as its premium emissions compliant platform, with the line available in three-, four- and six-cylinder configurations. For Tier 3, Perkins has increased the 1100 series per cylinder displacement to 1.1 L, and has undertaken aggressive development of the combustion system. Other engineering changes include a fundamental redesign of the cylinder block to create an advanced "open-top deck" structure that Perkins said radically reduces transmitted noise.
Further, the addition of air-to-air charge cooling on the 80 and 100 kVA models has enabled Perkins to offer what it says is six-cylinder power from a four-cylinder package.
Diesel particulate filter regeneration: what Cummins is learning in field tests - Around the World of Diesel
San Diego -- Diesel particulate filters (DPFs) might work "passively" in some applications, but growing field experience shows that many DPFs will need sophisticated engine management or other schemes to avoid failures, Cummins field experience shows.
Example: In tests with 17 "passive" DPFs in a New Jersey Transit (NJT) test program, five cracked or melted, seven failed emissions requirements and seven caused excess backpressure to the engine, Cummins engineer Bruce Bunting explained to the Diesel Engine Emissions Reduction (DEER) workshop here.
Data-logging for a separate project for the U.S. Navy likewise showed that only 30% of vehicle applications would allow DPFs to regenerate passively, and a New York City Transit project with diesel-electric hybrids also showed the need for special heat-boosting measures to ensure DPF regeneration.
"Cold," low-load operations cause excessive soot loading in a DPF. If followed by high-load operation, "uncontrolled" regeneration can crack or melt a DPF.
For the Navy project -- all Thomas school buses with different engines -- data logging indicated that typical duty cycles should have allowed for passive regen, with exhaust temps at 400[degrees]C 10% of the time. Yet in its field tests, Cummins found excessive backpressure, Bunting said.
More issues: DPFs not only must be designed to be able to regenerate in any application, regardless of duty cycle, but also provide "self-monitoring" for problems or service. These systems also must be "easily applied to any application with a minimum of special mapping and test work," he said.
Among the possibilities for fail-safe regen are diesel fuel injection into an upstream catalyst (prior to DPF); injection into an upstream fuel burner to boost DPF temps; DPF electrical heater schemes; an exhaust brake scheme; and engine management (including post-main injection, timing, air/fuel ratio changes, exhaust gas recirculation) combined with an upstream pre-catalyst.
Using an upstream catalyst to oxidize NO to [NO.sub.2] (for soot oxidation) can employ both "passive" and engine management schemes in an exhaust temperature range of about 200 to 400[degrees]C, Bunting showed. By contrast, "catalytically enhanced oxidation" could work at temperatures over 300[degrees]C, while "direct oxidation" (using hydrocarbon injection) works above 450[degrees]C, he showed.
Given the advantage of wide effective temperature range, the engine management/upstream catalyst combo seems to be a logical path for future development. However, integration of combined PM/NOx reduction systems could lead to even more clever schemes, and certain diesel applications might favor special technologies.
Example: In a separate investigation, Cummins tested the Rypos electrically-regenerated soot filter for a gen-set application. This four-month operations test involved two 72kW mobile generator-sets at Edwards Air Force base, with emissions tests by University of Utah.
The Rypos system includes four uncatalyzed sintered metal fiber cartridge elements housed in a metal can. Electric heat regenerates the cartridges sequentially. Electric power for the oxidation conveniently came from the Cummins B9 185 horsepower gen-set itself, although secondary (or extra-large) alternator power could be used in a mobile application.
This first-generation system only filtered 62% of particulates smaller than 10 microns, as it suffered from gasket leaks and a failed cartridge. This has led to an improved design. An "overly aggressive regeneration strategy" also may have penalized system efficiency, he said. So, Cummins aims to test the second-generation system for PM reduction performance and energy efficiency.
Example: In tests with 17 "passive" DPFs in a New Jersey Transit (NJT) test program, five cracked or melted, seven failed emissions requirements and seven caused excess backpressure to the engine, Cummins engineer Bruce Bunting explained to the Diesel Engine Emissions Reduction (DEER) workshop here.
Data-logging for a separate project for the U.S. Navy likewise showed that only 30% of vehicle applications would allow DPFs to regenerate passively, and a New York City Transit project with diesel-electric hybrids also showed the need for special heat-boosting measures to ensure DPF regeneration.
"Cold," low-load operations cause excessive soot loading in a DPF. If followed by high-load operation, "uncontrolled" regeneration can crack or melt a DPF.
For the Navy project -- all Thomas school buses with different engines -- data logging indicated that typical duty cycles should have allowed for passive regen, with exhaust temps at 400[degrees]C 10% of the time. Yet in its field tests, Cummins found excessive backpressure, Bunting said.
More issues: DPFs not only must be designed to be able to regenerate in any application, regardless of duty cycle, but also provide "self-monitoring" for problems or service. These systems also must be "easily applied to any application with a minimum of special mapping and test work," he said.
Among the possibilities for fail-safe regen are diesel fuel injection into an upstream catalyst (prior to DPF); injection into an upstream fuel burner to boost DPF temps; DPF electrical heater schemes; an exhaust brake scheme; and engine management (including post-main injection, timing, air/fuel ratio changes, exhaust gas recirculation) combined with an upstream pre-catalyst.
Using an upstream catalyst to oxidize NO to [NO.sub.2] (for soot oxidation) can employ both "passive" and engine management schemes in an exhaust temperature range of about 200 to 400[degrees]C, Bunting showed. By contrast, "catalytically enhanced oxidation" could work at temperatures over 300[degrees]C, while "direct oxidation" (using hydrocarbon injection) works above 450[degrees]C, he showed.
Given the advantage of wide effective temperature range, the engine management/upstream catalyst combo seems to be a logical path for future development. However, integration of combined PM/NOx reduction systems could lead to even more clever schemes, and certain diesel applications might favor special technologies.
Example: In a separate investigation, Cummins tested the Rypos electrically-regenerated soot filter for a gen-set application. This four-month operations test involved two 72kW mobile generator-sets at Edwards Air Force base, with emissions tests by University of Utah.
The Rypos system includes four uncatalyzed sintered metal fiber cartridge elements housed in a metal can. Electric heat regenerates the cartridges sequentially. Electric power for the oxidation conveniently came from the Cummins B9 185 horsepower gen-set itself, although secondary (or extra-large) alternator power could be used in a mobile application.
This first-generation system only filtered 62% of particulates smaller than 10 microns, as it suffered from gasket leaks and a failed cartridge. This has led to an improved design. An "overly aggressive regeneration strategy" also may have penalized system efficiency, he said. So, Cummins aims to test the second-generation system for PM reduction performance and energy efficiency.
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