whats up everybody? I have heard alot about tier on equipments, such as komatsu , and cat and so on, and i've heard about tier 3 and tier 4. My question is whats the difference between them, I know when the companies talk about tier it is pertaining to emissions but I want to know what sets tier 3 apart from tier 4? And as well as Tier 1 and Tier 2, if there are such things
Tier 1 engines met the emissions specs by basically changing combustion chamber geometry, injector spray patterns, raising injection pressures, cam profiles, more turbo boost, etc. Basic design changes. Tier 2 was mostly a move to electronic control, some common rail, some EGR, etc. depending on make and model. Typically speaking Tier 3 was was achieved without extraordinary external measures, though common rail fuel systems, EGR and variable geometry turbos were typical measures used to achieve the specs. Tier 4i (Interim) often required a Diesel Particulate Filter (DPF) next to the muffler which takes up a lot of space and requires periodic Regeneration which creates a tremendous amount of heat to burn off carbon particles, this sometimes will require the truck or machine to stop working while the computer does it's thing. Some Tier 4i and almost all Tier 4 final also added Selective Catalytic Reduction (SCR) which is the injection of a liquid urea solution called Diesel Exhaust Fuid (DEF) into the exhaust stream as it enters a catalytic converter. Tier 4 engines are typically referred to with words that show up like this: B%^&*, D$%^, S^&*, F#%@&^, Spawn of Satan, or F*(^&%$ Obama S***. Just off the top of my head, wiser men will most likely have more lucid thoughts to add.
^ sums things up nicely. Teir 4i machines showed lots of trouble to excessive idling and light work plugging after treatment, tear 4 final machines seem to be 100 times better already. Komatsu related.
I'm curious... I have a Tier 4 Duramax in a Silverado and have not had regeneration issues. Never even had to stop and let it do it's thing. I SUSPECT it's because I'm almost always pulling 6 or 7 tons and therefore generating plenty of heat. Am I correct or just lucky so far?
ericscher, Probably your suspicion is correct. For the periodic regen, every few minutes, extra fuel injection 'events' inject fuel into the cylinders during the exhaust strokes, to send fuel into the exhaust to burn in the catalysts and the particulate filter, to burn out the carbon particles, so I've been told. Pulling six or seven tons means you have "plenty of heat".
Where I am, our county road dept has repowered old machines and added particulate filters to other machines. The road dept guys 'complain' that they have to stop working every half hour to wait for the machines to "regen"... Sometimes it is not a bug, it is a feature...
I've driven Cali's roads, how the hell do the stop working if they never start?
Tier 3 and 4i and 4 final were mainly concerned with the formation of Nox or oxides of nitrogen. Nox if formed at high combustion temperatures so engines were changed to fire at lower compression which limited the high temperatures. It also made the engine less efficient. DEF reacts with the molecules that form Nox changing it into something that is apparently benign. What this does is enable the use of high firing temperatures again which is what makes the diesel engine more efficient. All this added incredible amounts of cost to operating diesel powered equipment all through the working life of the machine. I would like to see the audible pollution coming for those of use who own, operate and repair this stuff to start drowning out some of the greenie rhetoric that forces this stuff on the public.
Also there is a difference depending on whether the engine is defined as road or non-road. Obviously the vast majority of the engines we deal with here on HEF are non-road engines. Remember also that the use of low sulphur fuel (<15ppm) was not required for EPA Tier 1 through 3 but is mandatory for Tier 4 engines. This link may answer some of your questions ....... https://www.dieselnet.com/standards/us/nonroad.php Also this one ........ http://www.ourair.org/wp-content/uploads/epatierstnds.pdf
LOL, applies to most county road depts also. They are doing a lot of interstate work, seems to take forever though
How do they measure the polution? Years ago they measured PPM which was Particles of Polution per Million particles of air. If they are still doing it that way its a joke. Add more fuel to burn with more added air to decrease the PPM but in actual added to the polution per mile. If some one knows how they measure today please advise.
No difference in spec here on the Tier ratings. The on road stuff had to be in place a couple of years earlier.
thanks everyone for your help now i know
Fuel consumption and CO2 emission regs are coming for the on road engines, I'm not sure there's a final date in place yet but they're working on it.
I don't think they are as concerned with how much fuel or polution is coming out, they are just targeti g specific things like NOX and Sulpher ash reduction. It's always been my gripe that wasting fuel doesn't help the environment either. It's not a clean process gathering and preparing the fuel but they seem to overlook that for some reason.