Meeting global emissions challenges: How Italian engine manufacturer Lombardini met EPA self-certification standards - Test Equipment 2002

Diesel Progress North American Edition, Feb, 2002 by Roberto Chellini

Back in 1997, Lombardini decided to enter an emission reduction program for its line of diesel engines in order to comply with European and American emission standards.

Unlike European legislation, the U.S. EPA requires engine manufacturers to self-certify the engines they want to export to the U.S. This implies that the manufacturer must set up at its facilities the necessary equipment to develop engines that comply with the required emission limits and subsequently the testing facilities to test samples of production engines from the assembly line.

The program was thus started by the Italian engine builder with an investment of about $1 million, by ordering from AVL of Graz, Austria, under a turnkey contract, two test cells purpose-designed to measure gaseous and solid emissions from diesel engines. These test facilities were subsequently completed with a third cell for testing samples of production diesel engines and two test cells for gasoline engines.

The first test cells were commissioned after a very precise calibration program to properly set all parameters and automatically transfer the gaseous emission measurements into the AVL data acquisition systems. These cells are now in full operation and work full time under two shifts.

Particulates collected by the filters are weighed by a high-precision weighing machine, capable of measuring one ten-millionth of a gram, in a conditioned room after the filter has been reconditioned to withdraw all moisture collected from the engine exhaust.

The emission reduction program was started by examining the emissions of the IDI, liquid-cooled, FOCS and CHD diesel engine families. Since these engines are modern designs, very little work was necessary to make them comply with the requested limits, the company said.

More complicated was the work on the DI air-cooled engines, which were originally designed to obtain maximum power output, with minimum weight and bulk, to meet the market's requirements when they were first introduced. Major modifications were required in the geometry and the dynamic of the fuel injection system and combustion process, which involved the redesign of the entire thermal part of the engines.

As Dr. Ing. Giuseppe Duri, technical director of Lombardini's R&D Center, explained, the EPA imposes heavy burdens on the engine manufacturer, which at Lombardini are handled by a nine-member team from the engineering department and a five-member team from the quality assurance department working full time on the emission reduction program.

Once a certain type of engine has obtained the EPA certificate, it is valid for one year and must be renewed annually (with a different code number). The approved engine type must be labeled with the EPA number on the production line, which implies the knowledge that a certain engine will be exported to the U.S. It is no longer possible to take an engine out of stock, and thus production flexibility is negatively influenced by this rule.

The quality assurance department has to declare in advance the sampling criteria for testing the engines from the assembly line (on the third test cell). One of every 'X' engines produced, this number can be freely selected by the quality assurance department and can be different for each type of engine -- but once declared to the EPA, it cannot be changed, and all the testing documentation of these engines must be kept available to EPA inspectors.

If an engine operating in the field is tested by the EPA, and it is found that the emission levels are different from those declared in the self-certification of the engine, EPA inspectors can visit the manufacturer with only two hours notice, randomly select 20 engines from the assembly line and test them on the same test cell used for the certification to ascertain that the measurements carried out in the presence of inspectors are within the limits.

Lombardini has a number of EPA certified engines and will apply for the CARB (California Air Resources Board) certificate as well this year. The emission levels required by the two American authorities are very similar, and Lombardini's present IDI, liquid-cooled engines show emission levels well under Tier 1 now in force and also comply with Tier 2 planned to start in 2004 for engines in Lombardini's power range.

American emission limits for off-road applications of interest to Lombardini (25 to 47 hp) are very similar to European limits 97/68 CE norms (25 to 50 hp). Introduction schedules are different and both American and European norms divide the engines into power classes that show some differences but are very similar, with the main difference being that the Americans take into account the sum of HC [NO.sub.x], while Europeans consider one limit for each of the pollutants.

The test program required for off-road engines in the power range of 25 to 50 hp is subdivided into eight stationary modes (ISO C1 cycle) spanning idle to maximum torque to rated power. Measurements are made for each of the eight operating modes. Lombardini uses the multifilter method, therefore the pairs of filters used to measure the particulate are changed after each mode. They are weighed before and after the test (under the same moisture conditions) and the particulate collected related to time and engine power output. The average of all eight modes will give the particulate emission value in g/kWh.