The overhead cam design of the 6H allows the engine designer the flexibility in engine design needed for the 21st century. The overhead cam configuration of the 6H also allows the engine designer more flexibility in configuring the engine valve ports. The traditional engine designer was often constrained in valve porting because of the need for space allocation for the push rods.

The 6H was designed with four valves per cylinder to optimize the air flow into and out of the engine. Four valves per cylinder is a highly efficient way to maximize the fuel, air, and exhaust flows for today's diesel engines.

Four-valve layout allows for the fuel injection nozzles to be located in the center of the cylinder. The central location allows for even fuel distribution in the combustion chamber. This fuel distribution contributes to reduction of NOx, black smoke and particulate matter. The customer also sees the end result of enhanced fuel economy.

The traditional engine forced the engine designer to allocate significant engine block space for the push rods and tappets. The overhead cam engine does not need to allocate this space. Instead, the space can be used to increase the rigidity of the overall engine block. Modern computer tools have been used by the engine designer to allow for precise mechanical system modeling of the overhead camshaft. The Isuzu 6H camshaft design and the valve drive operation have been intensively studied using these tools.

The elimination of the push rods also allows for symmetry in the engine design; the right and left sides of the 6H engine block have the same configuration.

The churning fluid component around the center of the air cylinder, called swirl, is drawn into the cylinder. In direct fuel injection diesel engines in particular this is an important factor in the mixing of the fuel and air; and has a major impact on fuel combustion. The modeling used during the 6H engine design has optimized this airflow.

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