Gulf Construction Online - Cat comes clean with emissions rating

Power Generation

Acert... revolutionary technology from caterpillar

Cat comes clean with emissions rating

01 September 2003

Caterpillar says it has developed a revolutionary emission technology called Acert (advanced combustion emissions reduction technology), which will achieve the Tier 3 emission levels required by the governments in North America and Europe.

North America and Europe have set mandatory standards for diesel engines to achieve Tier 3 emission levels by 2010.

The technology is not just advanced, when compared to similar emission control systems developed by other manufacturers, but also fuel efficient, Caterpillar says.

'Most manufacturers have elected to use EGR (exhaust gas recirculation) technology, which, in use has shown to increase fuel consumption, and there is some concern about achievement of Tier 3 emission levels,'' says a Caterpillar spokesman.

''Acert has entailed Caterpillar to commit a major investment in the development of the four core engine systems: fuel, air, electronics and after treatment. The combination and management of these improved systems has proved so successful that they already achieve the emission levels required by 2007 - without sacrificing fuel consumption.''
He continues: ''An important component of Acert is the advanced air systems and the turbo charger. Caterpillar heavy-duty products will use conventional single turbo-charging to provide more airflow and higher boost levels. This puts cleaner air into the combustion chamber, instead of recycled exhaust gas, thereby providing the needed reduction in nitrogen oxide (Nox) as well as improving on fuel economy, response and additional engine braking.

'The Cat advanced air system employs a technology called variable valve actuation, which is controlled by Cat advanced electronics, and allows just the right amount of air to be pulled into the inlet valve for clean and efficient combustion. Future engine models will incorporate a new cylinder head design which will have an inlet valve actuation, as well as an exhaust valve actuation.

''The new engines with Acert technology will feature Cat's hydraulically actuated electronically controlled unit injector (HEUI). The system allows multiple injections for low emissions with complete combustion and maximises fuel economy.

''The advanced Caterpillar ADEM electronics package used by Acert technology integrates the systems to achieve reduced emissions while achieving excellent fuel economy and performance. The electronics provide the software, hardware and sensors that manage Acert technology.

''The combustion process provides the solution to reduce Nox emissions while maximising fuel economy and performance.

While most of the development has been based on the highway truck market requirements, the technology is now also being incorporated in all future diesel engines used for power generation. The use of the Acert technology is expected to improve power density figures and therefore maximise the output from current equivalent engine size.

Gas and liquid fuel capability
At the other end of the power generation scale, Caterpillar medium speed engines have been developed for operation on gas fuels and multiple liquid fuels.
''Whilst gas engines are not yet a common feature in the Gulf, with the current gas initiatives in Saudi Arabia, the availability of gas for use by the private sector is only a matter of time,'' says the spokesman.

''Crude oil and heavy fuel oil ( HFO) on the other hand are readily available, and with significant cost savings over diesel fuel, is becoming a fuel of choice in certain private market sectors. Caterpillar's CM engines have a proven track record of safe and fuel efficient operation, with low maintenance cost on either of these fuels. A new power plant, comprising four 3.5 MW gensets is operating very successfully on Arabian Light crude in Jeddah. The selection of Cat CM engines was based on initial cost, low operating costs and the ability to utilise the fuel.

''The decision to build its own power plant rather than rely on the utility, was based on operating costs and reliability - as well as the local support provided by Zahid Tractor, the sole Caterpillar dealer for Saudi Arabia for over 50 years.

'We have a commitment to provide our customers with the world's finest equipment, backed by outstanding product support. Wherever our customers are located, a network of over 30 facilities ensures that Zahid Tractor service is never far away,'' says a Zahid official.

Caterpillar's line of diesel engines/generator sets range from 20 kVA to around 14,000 kVA (with extended models in development). Zahid Tractor supports these products with sales, application, design and project engineers. 'We have the capability to offer turnkey power plants from initial evaluation through to testing, commissioning and final handover,'' he says.