<p dir="ltr"> Diesel engines are widely used in various off-road settings, ranging from railroad locomotives and marine vessels to agricultural, construction, logging, and mining equipment. Diesel engines are favored due to their reliability, durability, high thermal efficiency, and capacity to generate significant power. However, they also emit a range of harmful pollutants, such as oxides of nitrogen (NOx), particulate matter (PM), carbon monoxide (CO), and hydrocarbons (HC). Over the past three decades, original engine manufacturers have faced increasingly stringent emission regulations. In the United States, the proposed Tier 5 emission standards aim to achieve a significant reduction in NOx emissions, targeting a reduction of up to 90%, as well as a reduction in particulate matter emissions of up to 75%. To meet these stringent regulations, original engine manufacturers are investigating new technologies.</p><p dir="ltr"> Cooled exhaust gas recirculation (EGR) is a widely used method to lower NOx emissions. The EGR flow rates are contingent on positive engine delta pressure (exhaust manifold pressure - intake manifold pressure) to drive EGR. Eaton’s Generation 3 Exhaust Gas Recirculation Pump (EGRP) eliminates the need for positive engine delta pressure and enables the application of a high-efficiency turbocharger. A high-efficiency turbocharger reduces the pumping work and thus improves fuel efficiency.</p><p dir="ltr"> Transient tests were conducted on a 13.6 L S750 John Deere Engine with both the stock hardware and the EGRP and high-efficiency turbocharger hardware, to evaluate the benefits of the new technology. The transient tests included the Constant Speed Load Acceptance Test (CSLA), the Nonroad Transient Cycle (NRTC), and the Low Load Application Cycle (LLAC). There was no aftertreatment systems in the test cell setup, so engine-out brake specific oxides of nitrogen (BSNOx) and engine-out brake specific particulate matter (BSPM) were examined. To evaluate the technology, results from the stock hardware setup were compared to the results from the EGRP and high-efficiency turbocharger setup.</p><p dir="ltr"> During the CSLA, the time response to 90% load with the EGRP-equipped engine was <a href="" target="_blank">generally slower</a> than the stock engine, with deviations ranging from 0.1s to 1.6s. This result was attributed to the EGR pump not reducing speed fast enough, resulting in insufficient fresh air to produce torque. In the NRTC, engine torque was compared between both configurations. It was discovered that the EGRP-equipped engine did not reach the desired torque setpoints. There was more EGR flow than expected and not enough fresh air. This pattern was also revealed in the LLAC.</p><h4> To ensure accurate comparisons, measured engine speed and load data from the EGRP configuration were used to establish a Modified NRTC and Modified LLAC. For the Modified NRTC, the brake specific fuel consumption (BSFC) improved by 1.3%, and the engine-out brake specific particulate matter improved by 33.1% with the EGRP and high-efficiency turbocharger. However, the engine-out BSNOx increased by 12.9%. For the Modified LLAC, the BSFC and engine-out BSNOx improved by 2.5% and 11.1%, respectively, with the EGRP setup. However, this improvement came at the expense of engine-out BSPM, which increased by 34.2%. The improvement in BSFC for both cycles could be attributed to the increased open-cycle efficiency seen in steady state data with the EGRP and high-efficiency turbocharger.</h4><p></p>