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The presented work describes how spark calorimeter testing was used for parametric study and secondary circuit model calibration. Tests were conducted at different pressures, sparkplug gaps and supplied primary energies. The conversion efficiency increases and the spark duration decreases when the gas pressure or the sparkplug gap size is increased. Both gas pressure and sparkplug gas size increase the positive column voltage which represents part of the electrical energy delivered to the gas. The opposite direction occurs when the supplied primary energy is increased. The testing results were then used to calibrate the secondary circuit model which consisted of the sparkplug, the sparkplug gap and the secondary wiring. A step-by-step method was used to calibrate the three constants of the model to match the calculated delivered energy with test data during arc / glow phase.

As fuel economy becomes increasingly important in all markets, complete engine system optimization is required to meet future standards. In many applications, it is difficult to realize the optimum coolant or lubricant pump without first evaluating different sets of engine hardware and iterating on the flow and pressure requirements. For this study, a Heavy Duty Diesel (HDD) engine was run in a dynamometer test cell with full variability of the production coolant and lubricant pumps. Two test stands were developed to allow the engine coolant and lubricant pumps to be fully mapped during engine operation. The pumps were removed from the engine and powered by electric motors with inline torque meters. Each fluid circuit was instrumented with volume flow meters and pressure measurements at multiple locations. After development of the pump stands, research efforts were focused on hardware changes to reduce coolant and lubricant flow requirements of the HDD engine.

The short-term future direction of the automotive transportation sector is uncertain. Many governments and environmental localities around the world are proposing internal combustion engine (ICE) bans and enacting large subsidy programs for zero-tailpipe emissions vehicles powered by batteries or fuel-cells. Such policies can be effective in driving the consumer towards specific powertrains. The reason for such aggressive change is to reduce the sector’s carbon footprint. However, it is not clear if these proposals will reduce greenhouse gas (GHG) emissions. Emissions from raw material extraction, manufacturing, and power generation are shadowed by the focus on reducing the reliance on fossil fuel use. Emissions from non-tailpipe sources should also be considered before pushing for a rapid change to powertrains. Life-cycle analysis (LCA) can assess the GHG emissions produced before, during and after the life of a vehicle in a cradle-to-grave analysis.

In this work, a novel bearing test rig was used to evaluate the impact of oil viscoelasticity on friction torque and oil film thickness in a hydrodynamic journal bearing. The test rig used an electric motor to rotate a test journal, while a hydraulic actuator applied radial load to the connecting rod bearing. Lubrication of the journal bearing was accomplished via a series of axial and radial drillings in the test shaft and journal, replicating oil delivery in a conventional engine crankshaft. Journal bearing inserts from a commercial, medium duty diesel engine (Cummins ISB) were used. Oil film thickness was measured using high precision eddy current sensors. Oil film thickness measurements were taken at two locations, allowing for calculation of minimum oil film thickness. A high-precision, in-line torque meter was used to measure friction torque. Four test oils were prepared and evaluated.

The influence of nozzle geometry on spray and combustion of diesel continues to be a topic of great research interest. One area of promise, injector nozzles with micro-holes (i.e. down to 30 μm), still need further investigation. Reduction of nozzle orifice diameter and increased fuel injection pressure typically promotes air entrainment near-nozzle during start of injection. This leads to better premixing and consequently leaner combustion, hence lowering the formation of soot. Advances in numerical simulation have made it possible to study the effect of different nozzle diameters on the spray and combustion in great detail. In this study, a baseline model was developed for investigating the spray and combustion of diesel fuel at the Spray A condition (nozzle diameter of 90 μm) from the Engine Combustion Network (ECN) community.

In this work, a dynamically loaded hydrodynamic journal bearing test rig is developed and introduced. The rig is a novel design, using a hydraulic actuator with fast acting spool valves to apply load to a connecting rod. This force is transmitted through the connecting rod to the large end bearing which is mounted on a spinning shaft. The hydraulic actuator allows for fully variable control and can be used to apply either static load in compression or tension, or dynamic loading to simulate engine operation. A variable speed electric motor controls shaft speed and is synchronized to the hydraulic actuator to accurately simulate loading to represent all four engine strokes. A high precision torque meter enables direct measurements of friction torque, while shaft position is measured via a high precision encoder.

There are numerous off-road diesel engine applications. In some applications there is more focus on metrics such as initial cost, packaging and transient response and less emphasis on fuel economy. In this paper a combustion concept is presented that may be well suited to these applications. The novel combustion concept operates in two distinct operation modes: lean operation at light engine loads and stoichiometric operation at intermediate and high engine loads. One advantage to the two mode approach is the ability to simplify the aftertreatment and reduce cost. The simplified aftertreatment system utilizes a non-catalyzed diesel particulate filter (DPF) and a relatively small lean NOx trap (LNT). Under stoichiometric operation the LNT has the ability to act as a three way catalyst (TWC) for excellent control of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx).

Dedicated EGR (D-EGR) is an EGR strategy that uses in-cylinder reformation to improve fuel economy and reduce emissions. The entire exhaust of a sub-group of power cylinders (dedicated cylinders) is routed directly into the intake. These cylinders are run fuel-rich, producing H2 and CO (reformate), with the potential to improve combustion stability, knock tolerance and burn duration. A 2.0 L turbocharged D-EGR engine was packaged into a 2012 Buick Regal and evaluated on drive cycle performance. City and highway fuel consumption were reduced by 13% and 9%, respectively. NOx + NMOG were 31 mg/mile, well below the Tier 2 Bin 5 limit and just outside the Tier 3 Bin 30 limit (30 mg/mile).

Four high-efficiency alternative combustion modes were modeled to determine the potential brake thermal efficiency (BTE) relative to a traditional lean burn compression ignition diesel engine with selective catalytic reduction (SCR) aftertreatment. The four combustion modes include stoichiometric pilot-ignited gasoline with EGR dilution (SwRI HEDGE technology), dual fuel premixed compression ignition (University of Wisconsin), gasoline partially premixed combustion (Lund University), and homogenous charge compression ignition (HCCI) (SwRI Clean Diesel IV). For each of the alternative combustion modes, zero-D simulation of the peak torque condition was used to show the expected BTE. For all alternative combustion modes, simulation showed that the BTE was very dependent on dilution levels, whether air or EGR. While the gross indicated thermal efficiency (ITE) could be shown to improve as the dilution was increased, the required pumping work decreased the BTE at EGR rates above 40%.

Southwest Research Institute (SwRI) converted a 2012 Buick Regal GS to use an engine with Dedicated EGR™ (D-EGR™). D-EGR is an engine concept that uses fuel reforming and high levels of recirculated exhaust gas (EGR) to achieve very high levels of thermal efficiency [1]. To accomplish reformation of the gasoline in a cost-effective, energy efficient manner, a dedicated cylinder is used for both the production of EGR and reformate. By operating the engine in this manner, many of the sources of losses from traditional reforming technology are eliminated and the engine can take full advantage of the benefits of reformate. The engine in the vehicle was modified to add the following components: the dedicated EGR loop, an additional injector for delivering extra fuel for reformation, a modified boost system that included a supercharger, high energy dual coil offset (DCO) ignition and other actuators used to enable the control of D-EGR combustion.