What is ACERT Technology
Important note: The new CAT engines will have the ACERT technology in order to meet the EPA 04 regulations and will be available during the 4th quarter 2007. When tougher emissions regulations went into effect in 2002, other engine makers turned to a compromise: Cooled-EGR (Exhaust Gas Recirculation) technology that recycles exhaust back through the engine in an attempt to reduce emissions. But Caterpillar engineers didn't stop there. Instead, they continued to search for a better answer-a long term solution that would provide the same kind of reliability, durability, fuel economy and resale value Cat customers have always counted on. Revolution Through Evolution
After intensive lab testing and millions of miles of real-world, on the road proof, we discovered the answer: ACERT technology, an innovative "systems solution" that derives from proven Cat components and technology. It's a "revolution through evolution" that not only meets today's clean air regulations, but also establishes the building blocks for attaining tomorrow's more stringent standards. Most importantly, ACERT technology provides Cat customers with all of the reliability, durability and fuel economy Cat engines are renowned for providing.
ACERT technology is Caterpillar's innovative, long-term solution for generating Pure Power...and pure customer value. The following pages detail how this breakthrough technology combines four existing engine systems into a single, unparalleled success... ACERT Technology is based on proven Caterpillar technology and is a systems approach to emissions reductions! This systems approach includes the following: Advanced Air Systems and Turbocharging:
In general, the smaller displacement mid-range Caterpillar engines with ACERT Technology will continue to use conventional single turbocharging. For the heavy duty engines, series turbocharging will be utilized. Series turbocharging provides more air flow and higher boost levels. Rather than putting recycled exhaust into the combustion chamber like Cooled-EGR, the air system used by ACERT Technology puts in more clean, cool air. Our turbocharger system uses proven technology that has been working in diesel engines for years. Basically, two regular turbochargers working in series are used, which puts less stress on either turbo, reducing wear and increasing component life. These turbos use proven waste-gate design to increase boost levels.There are several competitive advantages to this system. These advantages include: A reduction in Nox, improved response, and better fuel economy. Advanced Air Systems:
The new engines with ACERT Technology also use an advanced air system that is able to control the air volume required at various loads and speeds to achieve complete combustion and excellent fuel economy. Engine controls automatically adjust the air system to meet the requirements of the engine. As part of the ACERT Technology in our heavy duty engines, Caterpillar has introduced a new control system that allows the valves to be actuated, or controlled, in concert with the camshaft. The system uses engine oil at normal oil pressure to assure the valve is open, permitting the optimum air flow. Only a carefully measured amount of air is allowed to enter the cylinder for efficient and clean combustion. | |  |
Fuel Systems for Enhanced Combustion:
The advanced HEUI and MEUI fuel systems in Caterpillar's engines with ACERT Technology allow for precisely timed, multiple injections during the firing stroke -- which means peak cylinder temperatures are lowered and fuel is more completely burned. Engineers have found that by providing micro-bursts of fuel before and after the main injection, they can better control emissions. Managing these brief events requires the world's best injector technology from Caterpillar, the Mechanically Actuated Electronically Controlled Unit Injector systems or its hydraulic equivalents, HEUI and the HEUI single fluid. All three systems provide multiple injection and sophisticated rate shaping to improve combustion and allow better control of noise, vibration, and harshness. Basically, emissions are reduced at the point of combustion, eliminating the recycling of dirty exhaust gases. | |  |
Advanced Electronics:
The volume of fuel delivered in each precise injection is determined by the Electronic Control Module (ECM). Caterpillar electronics integrate all the systems to provide the logic, software, hardware, and sensors that manage the ACERT Technology. With the ADEM electronics, the engine can tie into the CAN bus and exchange information with other components. Engine operating parameters are then fine-tuned to match such things as the demands of the hydraulic system, the ambient conditions in the operating environment, and even the actions of the operator. This interactive communication not only reduces emissions, it also improves performance. While the software has been enhanced, the ECM is the same as the one in production prior to October 2002. | |  |
Aftertreatment Provides Finishing Touches:
The advanced combustion processes -- the fuel and air systems -- in the new engines with ACERT Technology provide the solution to reduce NOx and improve fuel economy. But to reduce particulates, hydrocarbons, and carbon monoxide to the level required by EPA regulations, a simple, yet effective aftertreatment system is used -- the Caterpillar Diesel Oxidation Catalyst (DOC). The DOC has a stainless steel outer shell for long life, with a skin temperature the same as today's mufflers. The system has no moving parts, requires virtually no service or cleaning, and has a projected life is as long as the engine itself. The aftertreatment consists of a substrate material core that provides the foundation for the wash coat. The wash coat is a catalyst, or a substance that is used to speed up a chemical reaction. Hydrocarbons (particulates) in the exhaust pass through the catalyst, and are chemically converted to carbon dioxide or water. This emissions reduction system is incorporated into a muffler system that is designed to each truck manufacturer's specifications. The engine and aftertreatment solutions are integrated into the chassis when the truck is built. 120,000 engines are running with this technology with virtually no reliability issues. | |  |
The Bottom Line:
With the use of additional components and proven Caterpillar Technology, ACERT Technology from Caterpillar will be ready to meet the challenges posed by Tier 4/Stage IIIb standards. Extensive experience with On-Highway applications have proven that compared to other emissions reductions technologies, ACERT Technology provides better reliability, easier servicing, and lower cost of operation. It's also worth noting that while the extensive development costs invested in ACERT technology are reflected in slightly higher engine costs, total cost of ownership is lower than with other systems. For “Pure Proof”, see our Value Calculators on this site!
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