Abstract: A control system for an internal combustion engine can include a fuel molecular weight sensor to determine an actual and a desired Excess Air Ratio for an air/fuel mixture supplied to the engine. To prevent engine overload, the control system limits the amount of fuel delivered to the engine based on the amount of air available to the engine. High pressure exhaust gas can drive an air compressor which pressurizes inlet air. A exhaust bypass valve controls the amount of power delivered to the compressor, and the pressure and amount of inlet air delivered to the engine. Independent control of the main fuel flow and pilot fuel flow allows the control system to maintain a desired air/fuel ratio in the main combustion chamber and in the precombustion chamber.

Abstract: A combustion system of an internal combustion engine includes a main combustion chamber and a swirl flow precombustion chamber connected by a communicating passage. The communicating passage is connected tangentially to the precombustion chamber so as to induce a consistent, repeatable swirling flow pattern of gasses in the precombustion chamber during the compression stroke of the engine cycle. The swirl pattern thoroughly mixes the air, unburned fuel and burned fuel in the precombustion chamber. An igniter such as a spark plug is disposed in the precombustion chamber in a region having a low gas velocity during swirling to allow a small flame kernel to grow every engine cycle and consistently ignite the swirling gas, thereby improving engine efficiency, toxic emissions spark plug life, and allowing the igniter to run at a cooler temperature.