CAT ACERT Technology
CAT solutions for EPA requirements
Updated 9-26-07
Here is some info on CAT's ACERT systems to meet EPA requirements for 2004 and the new 2007 requirements.
See CAT's web site at -
CAT On-Highway Engines - About Us - ACERT Technologies
http://ohe.cat.com/cda/layout?m=115235&x=7
For Video explanations - see
CAT On-Highway Engines - About Us - ACERT Technologies
http://ohe.cat.com/cda/layout?m=115239&x=7
EPA Emission Controls - 2004
| Control | C7 | C9 | C13 | C15 |
|---|---|---|---|---|
| Advanced Fuel Injection | HEUI* | HEUI | MEUI** | MEUI |
| Air Mgmt System | NA | NA | Dual Turbos | Dual Turbos |
| Controlling Air Volume - Variable Valve Actuation | NA | NA | X | X |
| After Treatment - DOC muffler # | X | X | X | X |
Note * - HEUI Hydraulically Actuated, Electronically Controlled Unit (Fuel) Injection, that is, the fuel injectors are hydraulically managed by the ECM to create 'Split injection'...a small fuel injection (pilot injection), followed by the main injection. The injectors also spray fuel in special patterns to enhance combustion to reduce emissions. These fancy injectors are one reason we need to use 2 micron fuel filters!
Note ** - MEUI Mechanically Actuated, Electronically Controlled Unit (Fuel) Injection, that is, the fuel injectors are mechanically operated under ECM control to produce special injection sequences and patterns like the HEUI does for the smaller engines.
Note # - While the combustion process functions to cut oxides of nitrogen (NOx), it's only part of the story. Regulated exhaust emissions also include particulates, hydrocarbons and carbon monoxide. So a simple, effective exhaust after treatment completes the story of ACERT Technology: the Caterpillar Diesel Oxidation Catalyst (DOC). See http link above for more info.
EPA Emission Controls - 2007
| Control | C7 | C9 | C13 | C15 |
|---|---|---|---|---|
| Fuel Injection* |
CAT Common Rail Injection |
CAT Common Rail Injection | MEUI** | MEUI |
| Air Mgmt System |
VGT Variable Geometry Turbo |
VGT Variable Geometry Turbo |
Dual Turbos | Dual Turbos |
| Variable Valve Actuation - Controlling Air Volume | NA | NA | Yes | Yes |
| After Treatment - PM Filter ** | Yes | Yes | Yes | Yes |
|
DPF Regeneration System |
Yes | Yes | Yes | Yes |
| CGI - Clean Gas Induction *** | Yes | Yes | Yes | Yes |
Note * - New for the '07 emissions, CAT has gone back to a Common Rail Injection system instead of the HEUI injectors!? Probably to offset some of the increased costs of the other EPA equipment?
Note ** - The new DPF [Particulate Matter (Soot) filters] are required to clean up the allowable soot. The PM filter has a self regeneration system. The PM filter has a sensor that tells the ECM that excess soot has built up and it is time to 'clean' the filter. The regeneration system burns the soot into a fine ash by applying a small amount of fuel into the exhaust stream after the turbo and before the filter (sort of like a fighter plane's after-burner(?), only I doubt you get a huge surge of power)! This PM reduction is why we now have Ultra-Low Sulfur Diesel Fuel (=< 15ppm). The old Low Sulfur Diesel (500 ppm) has too much sulfur for these filters to work properly. This new DPF system replaces the DOC mufflers used starting in 2004.
CAT Heavy Duty Engine (C13, C15) - EPA Systems
Note *** - CGI - Clean Gas Induction is CAT's version of EGR, whereby a small amount of burned exhaust gas is routed to a new cooler, then re-introduced back into the engine. This technique has been used on cars for several years and is called Exhaust Gas Recirculation...the 'dead air' helps remove NOx emissions, but of course doesn't help your HP or MPG. It does clean up the exhaust. CAT's CGI system is different than EGR, in where the exhaust gas is sampled...CAT pulls the gas AFTER is has been cleaned by the PM filter.
Updated 9-26-07
Posted 4-08-07
