Isuzu has been known for producing commercial vehicles, particularly medium duty trucks. This is Isuzu's its primary objective along with producing diesel engines. As a matter of fact, it has produced a staggering number of this kind of engines in a year with the figure going up to 16 million units. And with joint ventures with companies like General Motors, their diesel engines have been improving year after year. These engines are being used in various vehicles and various vehicle brands all over the world.

With the diesel engine being known for its ?black soot? disease and the rise in environmental awareness, the company sure has got to be working on a plan to reduce the potentially harmful emissions of their engines. Government mandated standards for emission should be followed in order to secure certification from the EPA (Environmental Protection Agency) and CARB (California Air Resources Board).

This is just what the company has secured for their two new engines, the 4H and the 6H. Both of these engines are now being used in various Isuzu, GM, and Chevrolet cars. These engines have passed the nitrogen oxide emission and the particulate matter emission tests. These tests are being implemented by the government to cut down the increasing harmful effects of such emissions to the environment. With the new design and the inclusion of Isuzu parts, the 4H and the 6H has cut down on the harmful emissions without sacrificing the performance of the engine.

To cut down nitrogen oxide emissions, the company uses their new advanced Exhaust Gas Recirculation (EGR) system on both engines. And to cut down the level of particulate matter on exhaust gases, the company created a ceramic called the Diesel Particulate Filter (DPF). This is a honeycomb channel through which the exhaust gases are made to pass. A porous material in the system traps the particulates. These trapped particulates can then be burned so that it will not clog the system.

Burning this trapped matter can either be self regeneration or a forced one. In the self regeneration process, the particulates are burned by the heat produced by the exhaust gases. If the vehicle does not produce enough hot exhaust gases, the particulate matters can be burned through driver intervention. Once the filter is almost filled to its capacity, the driver is warned through a control light, and then all the driver has to do is to activate a dashboard switch to start the regeneration process. This process is computer aided thus the burning of the trapped particulate matter is ensured.