Turbocharger Booster System (TuBS)
Reference Number: K 08-05
Inventors: Chapman, Kirby; Wolfram, Kyle; Figge, Eric
Owner: Kansas State University Research Foundation
Standard turbocharged engine systems are being refined to increase air flow into the system with the goal of meeting PRCI 2010 emission reduction expectations. Current turbochargers extract energy from exhaust gases to power an air compressor, which compresses air into the air manifold at pressure ratios ranging from 1.25 to approximately 3.0; however, it is believed that the 2010 engine will require a pressure ratio of approximately 2.4 to 3.0 in order to achieve the target NOx level of 0.5 g/bhp-hr.
While turbochargers solve many lean burn engine problems, they too have draw backs. Changing ambient temperatures affect the performance of the entire system by changing the air mass flow rate delivered from the turbocharger compressor to the engine. Also, as the trapped equivalence ratio is decreased to achieve successively lower NOx emissions, the reduction in exhaust temperature lowers the available thermal energy to drive the turbocharger turbine.
Research conducted at K-State has found that by installing a relatively small dry low emission (DLE) burner between the exhaust manifold and the turbocharger turbine nozzle ring, we are able to increase the turbine inlet temperature and consequently, the turbocharger rotating speed. This allows for precise adjustment of the air mass flow rate and turbocharger rotating speed independent of the engine operation.
Increases net airflow to the engine, offsetting the negative effects of high ambient temperatures
Enhanced degree of control frees the turbocharger to operate independent of engine operating point and ambient conditions
Proven reduction in CO emissions without adversely affecting NOx emissions
Potentially reduces the need for air assist, especially while engine is idling
Considerably lower capital and operating costs than other available options
Large bore, multi-cylinder legacy engines in the following fields