Question About De-Tuning CAT Standby Generators
 

Without going into it too much, an organization that I associate with has 4 standby emergency generators they are CAT and John Deere, I can get exact model numbers if needed all are in the 65-80 HP range. The local air pollution district wants them to spend about $10K each to install particulate traps on the exhaust. If they can be de-tuned to under 50 HP, they become exempt from the P-trap and air district permitting. These generators are diesel and all are less than five years old. I don't know generators very well, but I believe industrial generators like to run at a fixed RPM and as the load increases, they increase fuel flow and air mixture to increase HP to meet the load demand.

Can a modern fuel injected diesel generator like this be de-tuned from say 65 hp to just under 50 HP by putting some kind of fuel flow limiter in line, or some kind of stop on the how far the intake manifold is allowed to open?

Selling the generators out of the state of CA and buying new ones is not economically feasible.

Thanks for any input and suggestions.

rated under 50 hp or produce under 50 hp? I can't imagine the later.

They need to be rated under 50 at the crank.

As you realize this is what's wrong with the US today. These idiots regulate things that are not worth regulating. The key word here is 'stand-by". This, I assume, means it only runs during a power outage. Sorry for the rant. To answer your question, you wouldn't be able to cut the horsepower on a generator. As you said, a generator runs at a very precise RPM rating. Any change in horsepower would mean a drop in RPM's with a drop in voltage output and cycles.

Are you sure? I understand that it runs at a constant HP, but can't you use a governor to limit the HP so that you can only pull so many KVA?

I still think output would suffer but if Hugh can get some model and serial number data I'll be at the Cat place sometime next week and I'll run it past them. It might be possible with some of the newer style engines as they are all computer controled now. If you have engine trouble nowadays, the first thing the Cat man does when he gets to the machine is hook up a laptop. I had a D6T quit recently. When the mechanic hooked up the laptop in just a minute he said the trouble was that the injection pump was "only" putting out 20,000 PSI, it was supposed to be putting out 30,000 PSI. I was stunned, it seems like the old pumps with the mechanical governors only put out about 1200 PSI or so. You can't even reuse injector lines anymore. If removed, replace them he told me. Different world nowadays.

That would be great. I'll get the model and serial numbers and send them to you.

I think the problem is certifying them as detuned or finding a state citified dyno willing to run them, if this even exists. Maybe Cat or John Deer sells a kit (most likely smaller injectors) to de-tune them.

The primary thing would be a smaller throttle assembly to limit airflow into them. I definitely would talk to CAT about this. I bet you'd be better off selling them and buying new ones.

CARB is the Devil

Hugh, what is the cost to install the particulate traps in the exhaust system?

I'm sure someone that knows the numbers could calculate an air intake restrictor or that would limit the HP to whatever you want.

Hugh, just to throw this in the Mix, the cost for a Particulate Trap for my Ford F250, 350 hp, 4.6l Diesel is $1500, list price. I cannot imagine an 80 hp unit would cost even $1000.

the state is going to check the specs for that model, which will say what it's hp is, and that's that.

The p traps are around $12,000 each.

I was wrong, they are Cummins and John Deere.

Someone at the organization (it's a very small elementary school district) who doesn't know anything about generators asked Cummins to do something, and they offered to sell them 4 $12,000 load banks and 4 p-traps, the load banks do nothing to reduce HP, and they were an additional $12,500 each.

Larry: here is the info from the descriptions on the Air Permits:

Cummins Model No. 4BTA3.9-G5, four cyl. 99 BHP, turbocharged, after cooled No. Serial No. at this time.

Cummins MModel 4BT3 3-G2 Serial No. 68011959 82 BHP

John Deere 4 cyl tubrocharged Model No. 4045TF150 110 BHP No Serial No.

Cummins Model No. 4Bt3.9-G4 Serial No. L00185069 4 cyl turbocharged 102 BHP

I will contact Cummins, but in looking at the permits I see three of them would have to have their BHP reduced by 50% or so. That may not be obtainable. Since I don't know generators, as Larry said some of them run 30,000 PSI on the injection which to me is amazing. I just want to be able to talk to Cummins intelligently about options.

My understanding is that any modifications to get under 50 BHP must be "real, quantifiable and permanent". John Walker, you are correct in that they look at the model and what the State and local agency will require and that is generally it, unless you can demonstrate a real, permanent drop in BHP.

Let me look into it...

You would have to decrease fuel delivery from the injection pump to decrease power output. I've seen fuel delivery increased before to raise the output on road, and farm tractors, or when turbocharging is added, but not the other way around.

I would guess that the power units are certified for their respective outputs at the crankshaft by the manufacturer. Turning down the fuel rate would decrease the power, but the air quality police would likely still have to regulate based on the factory's standards for fuel rate on that power unit, and not on an altered, and non-certified fuel rate.

Have you verified that 1st hand?

Seems you can buy the generator itself for not much more.

Cummins 4BTA3.9G5 Diesel Generator - Caterpillar Diesel Generator, Used Diesel Generator

GeneratorJoe Generators: Cummins, Industrial Generator, 50 kW, (50 kVA) 60 Hz,, diesel fueled, liquid cooled, single phase, Model DGCA

Would be really insulting and piss me off to no end if true.

Don't diesel big rigs have particulate traps?

Do you have to get it from Cummins or can you source and fab something yourself?

can't u just do like nascar? install a restrictor plate.

Quote from Cummins Cal Pacific LLC is $47,179.49 for four DCL International Mine-X Sootfilters.

It's a CA requirement for standby generators within 100 meters of a K-12 school (SCAQMD Rule 1470). Since these are schools, they have to comply with the rule.

My wife is the purchasing manager for the school district and I'm trying to help them out gratis

I've given them several suggestions including selling them outside of CA and buy gasoline ones under 50 HP (exempt from permitting).

Don't know about exhaust filters on diesel trucks other than that they are requiring older ones to be phased out in CA and replaced with much cleaner ones. Going the same way with cargo ships.

Hugh-I'm sorry but I don't have any contacts at Cummins or John Deere. They are both excellent engines with great product support and no doubt in my mind would bend over backwards to help you. Good luck in your search!!!

Thanks very much Larry! I appreciate the generous offer, I was told they were CAT until I actually go my hands on the permits to operate.

I think someone is trying to screw you guys in California. That price is crazy. As I said, I checked the LIST price for one for my Truck, and International with a 4.6 liter, 350 hp (262 kW) engine. And it was $1500. I can't believe there isn't something for less money.

Seriously.

That price is outrageous.

Don't know if you can but you'd think it would be cheaper to relocate them 100 meters.

Problem is that they'd still be on school property. Yeah its crazy and the p-traps have to be State-Certified. Also what is stupid is that the State of CA over estimated the carcinogenic potential from diesel particulate by something like 400% and passed lots and lots of air regulations before they realized their mistake, but are they re-writing the regs? Hell no. In a past life, I did air pollution permitting for lots of equipment.

Ah, I misunderstood.

They need to be 100 meters from the school property line and not just the physical building.

If I come up with a simple solution can I get a reward!




Look at a dyno chart, if it makes 49.9 hp at 2,137 rpm just limit the FRICKEN RPM:cool:

Seems like a silly rule, since they would be used in an emergency, and in that case, would school be open or open for long?

Doing a search for particulate filters, it seems like a heavy duty catalyst/filter and simple to retrofit on a generator, but maybe I'm I'm just seeing small engine stuff?

Cummins Emission Solutions

http://cumminsemissionsolutions.com/pdfs/4973751%20DPF.pdf

tier_4_info_CPF_

Jim, can't limit the RPM, a generator like this spins at a constant RPM and the engine works harder as load increases.

The generators are for a few lights, computers, etc. School would not stay in session. The p-traps have to be state certified for that engine class, can't just bolt on one from Pep Boys.

what about making them mobile. I know there is a lot to do that but most MOBILE power plants are exempt from that reg. put the trailer on a pad and plug it in when needed.

Sell the engines and get smaller ones.

Diesels don't have carbs, throttle plates or any kind of air intake control. engine speed and HP is controlled by fuel delivery.

generators maintain a constant speed, usually 3600 rpm to maintain 60 cycles (hz) per second frequency output. If you could electronically limit the generator power output to equal less than 50hp that could work. Limiter would control fuel for combustion.

HA-HA this is the best answer, remove the problem from the problem

Those engines have a tag / sticker on them stating their HP from the Mfg. and if the sticker is not legible or removed it's a fine.

To my knowledge only a 2008 or newer diesel engine w/ particulate traps already on them from the factory will get you an OK from CARB. But even they will be fazed out in several more years, 15 years or so ?

Otherwise you will need to have particulatee traps installed on the 5 year old engines. You might be able to buy some time by either buying "one" new generator 2008 or newer. ie one new cleaner burning generator updates the fleet a bit buying time for the others.
And or you might not have to do all the generators at once to comply. Put a P. Trap on one a year might get you buy with CARB.


Check with CARB on what you need to do.

I won't be able to register my 2001 KW in this state in January 1st 2014.
How would you like to have that hanging over your head in a down construction economy ? I wish I could put a $15K particulate trap on it to comply but it's too old of an engine. It has to be 04 or newer to comply with an added particulate trap as the regulations keep getting stricter as time goes by.

Very Interesting. Should I remove the throttle body from my truck?

On non-high tech diesels, there is no throttle body. I searched, and can only figure yours is for emissions. I doubt it's for power or efficiency.

Are you sure it's a throttle body and controls air flow? could be a air flow sensor, or intake air heater.

f'em

burn BIO-Fuel!

Hugh,

I think you should give up on the idea of limiting power output. The generators were likely speced for a particular load. Not much point on saving a few thousand by down-rating your generators then having a pile of expensive equipment burn out when the power fails and the back-up can't handle the load.

Good luck.
Les

Thanks for all the input guys. Mobile presents an interesting solution, but they're located at schools for a power failure, and the air pollution agency won't waive the requirement if they have wheels. Bob, the rule doesn't allow for averaging of emissions between newer and older units. The power issue is a problem, but they can buy all the less than 50 HP generators that they want and non will require a permit or p-trap. Its stupid, they can have ten 45 HP generators hooked together and no permit or p-traps, but one 51 HP generator is fully regulated.