Cody M Allen’s research while affiliated with Purdue University West Lafayette and other places

This paper describes the development and experimental validation of a novel grain unloading-on-the-go automation system (automatic offloading) for agricultural combine harvesters. Unloading-on-the-go is desirable during harvest, but it requires highly-skilled and exhausting labor because the combine operator must fulfill multiple tasks simultaneously. The automatic offloading system can unburden the combine operator by automatically monitoring the grain cart fill status, determining the appropriate auger location, and controlling the relative vehicle position and auger on/of. An automation architecture is proposed and experimentally demonstrated to automate the unloading-on-the-go process. To allow for diferent operator-selected unloading scenarios, the automatic offloading controller has three fill strategies and two movement control options, “open-loop” and “closed-loop”. The automatic offloading controller was implemented on a dSPACE MicroAutoBox II and integrated into a combine harvester. In addition, a stereo-camera-based perception system was connected to the automatic offloading controller via an Ethernet cable for grain fill profile measurement during unloading. In-feld testing demonstrated that the automatic offloading system can effectively automate the unloading-on-the-go of a combine harvester to fill a grain cart to the desired level under nominal harvesting conditions.

This paper describes the development, simulation, and experimental validation of a novel grain unloading-on-the-go automation system (automatic offloading) for agricultural combine harvesters. Unloading-on-the-go is desirable during harvest, but it requires highly-skilled and exhausting labor because the combine operator must fulfill multiple tasks simultaneously. The automatic offloading system can unburden the combine operator by automatically monitoring the grain cart fill status, determining the appropriate auger location, and controlling the relative vehicle position and auger on/off. An automation architecture is proposed and experimentally demonstrated to automate the unloading-on-the-go process. To simulate the automatic offloading operation, a grain fill model and vehicle dynamics models were developed and validated with in-field testing. To allow for different operator-selected unloading scenarios, the automatic offloading controller has three fill strategies and two movement control options, “open-loop” and “closed-loop”. Simulation results demonstrated that both movement control options can achieve the fill target. The automatic offloading controller was implemented on a dSPACE MicroAutoBox II and integrated into a combine harvester. A PC-based user interface was developed for the combine operator to monitor unloading status and provide commands during the test. In addition, a stereo-camera-based perception system was connected to the automatic offloading controller via an Ethernet cable for grain fill profile measurement during unloading. In-field testing demonstrated that the automatic offloading system can effectively automate the unloading-on-the-go of a combine harvester to fill a grain cart to the desired level under nominal harvesting conditions. The achievable fill level for a 1000-bushel grain cart without spillage ranges from −0.7 m to −0.2 m for the near-edge grain height relative to the cart edge.

Diesel engine cylinder deactivation (CDA) has been demonstrated to provide significant efficiency and aftertreatment thermal management benefits, enabling fuel-efficient emissions reduction from modern diesel engines at low load engine operation. Dynamic cylinder activation (DCA), a variant of CDA where the set of deactivated cylinders varies on a cycle-by-cycle basis, has been demonstrated to enable greater control over driveline torsional vibration while maintaining the fuel efficiency and thermal management benefits shown by fixed CDA via appropriate design of firing patterns. A model-based algorithmic approach to designing firing patterns during DCA – to control driveline torsional vibration in a user-defined frequency range, given firing density, engine speed, and maximum length of firing pattern – is described in this article. The described algorithm is generalizable to any engine configuration including different piston–cylinder layouts and number of cylinders. The algorithm is extended to design firing patterns for constrained DCA operation when CDA hardware is installed on a subset of cylinders of the engine. The resulting optimal firing patterns using the algorithm, for various combinations of inputs, are presented through an experimentally-validated simulation framework and discussed. It is demonstrated that the weighted phase-angle approach can accurately predict the frequencies and relative amplitudes of the vibration content, and, if theoretically possible, the proposed algorithm determines firing patterns that meet the specified requirements. The presented algorithm can be easily extended in future work for simultaneous selection of firing density and firing pattern during online, real-time implementation during both steady-state and transient operating conditions.

Fuel-efficient aftertreatment thermal management in modern diesel engines is a difficult challenge, especially during low-load operation. This study explores the performance of cylinder deactivation in a diesel engine during low-load operation following highway cruise through experimental evaluation of two drive cycles, specifically extended idle and repeated heavy heavy-duty diesel truck creep cycles. Cylinder deactivation operations are shown to maintain comparable aftertreatment thermal management performance to conventional thermal management operation while reducing fuel up to 40% during extended idle operation. This fuel efficiency improvement coincides with engine-out emission reductions of 72% for soot and 52% for NOx. Cylinder deactivation also shows improved thermal management compared to a more fuel-efficient conventional operation.

Cylinder deactivation has been recently demonstrated to have fuel savings and aftertreatment thermal management benefits at low to moderate loads compared to conventional operation in diesel engines. This study discusses dynamic cylinder activation as an effective variant to fixed diesel engine cylinder deactivation. The set of inactive and active cylinders varies on a cycle-by-cycle basis during dynamic cylinder activation. This enables greater control over forcing frequencies of the engine, thereby allowing the engine to operate away from the drivetrain resonant frequency at all engine speeds, while maintaining similar fuel savings, thermal management, and emission characteristics as fixed cylinder deactivation. Additional benefits of dynamic cylinder activation include a reduction in the consecutive number of cycles a given cylinder is deactivated, and more even cylinder usage. Enablement of engine operation without exciting drivetrain resonant frequencies at similar fuel efficiency and emissions as fixed cylinder deactivation makes dynamic cylinder activation a strong candidate to augment the benefits already demonstrated for fixed cylinder deactivation.

Cylinder deactivation is an effective strategy to improve diesel engine fuel efficiency and aftertreatment thermal management when implemented through deactivation of both fueling and valve motion for a set of cylinders. Brake power is maintained by injecting additional fuel into the remaining activated cylinders. The initial deactivation of cylinders can be accomplished in various ways, the two most common options being to trap freshly inducted charge in the deactivated cylinders or to trap combusted gases in the deactivated cylinders. The choice of trapping strategy dictates the in-cylinder pressure characteristics of the deactivated cylinders and has potential to affect torque, oil consumption, and emissions upon reactivation. The effort described here compares these trapping strategies through examination of in-cylinder pressures following deactivation. Proponents of each trapping strategy exist; however, the results discussed here suggest no significant performance differences. As an example, the in-cylinder pressures of both trapping strategies converge as quickly as seven cycles, less than 1 s, after deactivation at curb idle conditions.

Valve train flexibility enables optimization of the cylinder-manifold gas exchange process across an engine’s torque/speed operating space. This study focuses on the diesel engine fuel economy improvements possible through delayed intake valve closure timing as a means to improve volumetric efficiency at elevated engine speeds via dynamic charging. It is experimentally and analytically demonstrated that intake valve modulation can be employed at high-speed (2200 r/min) and medium-to-high load conditions (12.7 and 7.6 bar brake mean effective pressure) to increase volumetric efficiency. The resulting increase in inducted charge enables higher exhaust gas recirculation fractions without penalizing the air-to-fuel ratio. Higher exhaust gas recirculation fractions allow efficiency improving injection advances without sacrificing NOx. Fuel savings of 1.2% and 1.9% are experimentally demonstrated at 2200 r/min for 12.7 and 7.6 bar brake mean effective pressure operating conditions via this combined strategy of delayed intake valve closure, higher exhaust gas recirculation fractions, and earlier injections.

A large fraction of diesel engine tailpipe NOx emissions are emitted before the aftertreatment components reach effective operating temperatures. As a result, it is essential to develop technologies to accelerate initial aftertreatment system warm-up. This study investigates the use of early exhaust valve opening (EEVO) and its combination with negative valve overlap to achieve internal exhaust gas recirculation (iEGR), for aftertreatment thermal management, both at steady state loaded idle operation and over a heavy-duty federal test procedure (HD-FTP) drive cycle. The results demonstrate that implementing EEVO with iEGR during steady state loaded idle conditions enables engine outlet temperatures above 400 °C, and when implemented over the HD-FTP, is expected to result in a 7.9% reduction in tailpipe-out NOx.