Effect of Waste-Gate Turbocharging on the Exhaust Particulate Matter of an Off-Road Diesel Engine 2002-01-2159
The effect of turbocharger design on engine performance and exhaust emissions was studied. The test engine was a direct injection turbocharged, intercooled off-road diesel engine. Special attention was paid to the exhaust particulate matter (PM) emissions of the engine.
The engine was first equipped with a standard (Std), uncontrolled turbocharger (TC) which was then replaced by a waste-gate (WG) turbocharger. The engine was fueled with commercial diesel fuel oil.
The engine was operated at three speeds within the entire load range. Basic performance, gaseous exhaust emissions and exhaust particle quantities were recorded.
The results showed that the WG TC is advantageous at high loads at low and medium speeds, where reductions of PM emissions and smoke were observed when running the engine with this TC. At rated speed, however, the Std TC proved slightly better than the WG one.
Regarding gaseous exhaust emissions, there was no noteworthy difference between the tested turbochargers. The brake torque increased at low speeds with the WG TC, as expected.
The brake thermal efficiency improved at the lowest speed, was almost equal at the intermediate speed, and decreased slightly at rated speed when the WG TC was adopted.
In the future, effective measures must be resorted to particularly reduce exhaust emissions of nanoparticles of the test engine, since these emissions were at a high level with both TCs. Additionally, a chemical analysis of particle samples is required to provide information about the composition of each particle fraction.
Subsequent studies on further optimization of the entire injection system are also needed.