Digital Twin Spark Ignition for Improved Fuel Economy and Emissions on Four Stroke Engines

The Digital Twin Spark Ignition (DTS-i) is a concept developed specifically for small bore four stroke engines with two valves. Two spark plugs placed diametrically opposite to each other in the combustion chamber fire simultaneously igniting the charge. The benefit of this concept is improved fuel economy, better drivability, and reduced engine on a emissions. The concept has been successfully launched on two products namely 150 DTS-i and 180 DTS-i engine. The DTS-i concept helps the products meet the India 2005-emission standard without the use of secondary air injection and exhaust after treatment.

The DTS-i concept allows the compression ratio of the engine to be increased from 9.65 to 9.85. At part load conditions (Indian Driving cycle) the DTS-i technology allows the engine to run leaner at a lambda of 1.2 with excellent stability. On a bore size of 57 mm (150 DTS-i) the maximum flame travel length was reduced by 18 %. The power, torque and specific output per liter were increased, while the fuel consumption and emissions were reduced due to the rapid combustion brought about by the twin spark plugs.

This paper discusses the test results of the 150 DTS-i engine. The cylinder pressure was measured at full load and part load to see the effects of the DTS-i on burn duration, cyclic variation of IMEP, and peak pressure. The engine was run on a dynamometer to simulate road load at 30, 40 and 50 km/h constant speed. The emission and fuel consumption values for the Indian Driving Cycle (IDC) of the DTS-i engine are discussed.