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Building on two decades of expertise, a fourth generation fleet test protocol is presented for assessing the response of engine performance to gasoline additive treatment. In this case, the ability of additives to remove pre-existing deposit from the intake systems of port fuel injected vehicles has been examined. The protocol is capable of identifying real benefits under realistic market conditions, isolating fuel performance from other effects thereby allowing a direct comparison between different fuels. It is cost efficient and robust to unplanned incidents. The new protocol has been applied to the development of a candidate fuel additive package for the North American market. A vehicle fleet of 5 quadruplets (5 sets of 4 matched vehicles, each set of a different model) was tested twice, assessing the intake valve clean-up performance of 3 test fuels relative to a control fuel.

Conventional diesel fuel has been in the market for decades and used successfully to run diesel engines of all sizes in many applications. In order to reduce emissions and to foster energy source diversity, new fuels such as alternative and renewable, as well as new fuel formulations have entered the market. These include biodiesel, gas-to-liquid, and alternative formulations by states such as California. Performance variations in fuel economy, emissions, and compatibility for these fuels have been evaluated and debated. In some cases contradictory views have surfaced. “Sustainable”, “Renewable”, and “Clean” designations have been interchanged. Adding to the confusion, results from one fuel in one type of engine such as an older heavy-duty engine, is at times compared to that of another type such as a modern light-duty. This study was an attempt to compare the performance of several fuels in an identical environment, using the same engine, for direct comparison.

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up.

This paper presents the fuel consumption results of engine and vehicle simulation modeling for a wide variety of individual technologies and technology packages applied to a long haul heavy duty vehicle. Based on the simulation modeling, up to 11% in fuel savings is possible using commercially available and emerging technologies applied to a 15L DD15 engine alone. The predicted fuel savings are up to 17% in a Kenworth T700 tractor-trailer unit equipped with a range of vehicle technologies, but using the baseline DD15 diesel engine. A combination of the most aggressive engine and vehicle technologies can provide savings of up to 29%, averaged over a range of drive cycles. Over 30% fuel savings were found with the most aggressive combination on a simulated long haul duty cycle. Note that not all of these technologies may prove to be cost-effective. The fuel savings benefits for individual technologies vary widely depending on the drive cycles and payload.

Medium- and Heavy Duty Truck fuel consumption and the resulting greenhouse gas (GHG) emissions are significant contributors to overall U.S. GHG emissions. Forecasts of medium- and heavy-duty vehicle activity and fuel use predict increased use of freight transport will result in greatly increased GHG emissions in the coming decades. As a result, the National Highway Traffic Administration (NHTSA) and the United States Environmental Protection Agency (EPA) finalized a regulation requiring reductions in medium and heavy truck fuel consumption and GHGs beginning in 2014. The agencies are now proposing new regulations that will extend into the next decade, requiring additional fuel consumption and GHG emissions reductions. To support the development of future regulations, a research project was sponsored by NHTSA to look at technologies that could be used for compliance with future regulations.

This paper presents the results of engine and vehicle simulation modeling for a wide variety of individual technologies and technology packages applied to two medium-duty vocational vehicles. Simulation modeling was first conducted on one diesel and two gasoline medium-duty engines. Engine technologies were then applied to the baseline engines. The resulting fuel consumption maps were run over a range of vehicle duty cycles and payloads in the vehicle simulation model. Results were reported for both individual engine technologies and combinations or packages of technologies. Two vehicles, a Kenworth T270 box delivery truck and a Ford F-650 tow truck were evaluated. Once the baseline vehicle models were developed, vehicle technologies were added. As with the medium-duty engines, vehicle simulation results were reported for both individual technologies and for combinations. Vehicle technologies were evaluated only with the baseline 2019 diesel medium-duty engine.

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).

The Dedicated EGR (D-EGR®) engine has shown improved efficiency and emissions while minimizing the challenges of traditional cooled EGR. The concept combines the benefits of cooled EGR with additional improvements resulting from in-cylinder fuel reformation. The fuel reformation takes place in the dedicated cylinder, which is also responsible for producing the diluents for the engine (EGR). The D-EGR system does present its own set of challenges. Because only one out of four cylinders is providing all of the dilution and reformate for the engine, there are three “missing” EGR pulses and problems with EGR distribution to all 4 cylinders exist. In testing, distribution problems were realized which led to poor engine operation. To address these spatial and temporal mixing challenges, a distribution mixer was developed and tested which improved cylinder-to-cylinder and cycle-to-cycle variation of EGR rate through improved EGR distribution.

Octane appetite of modern engines has changed as engine designs have evolved to meet performance, emissions, fuel economy and other demands. The octane appetite of seven modern vehicles was studied in accordance with the octane index equation OI=RON-KS, where K is an operating condition specific constant and S is the fuel sensitivity (RONMON). Engines with a displacement of 2.0L and below and different combinations of boosting, fuel injection, and compression ratios were tested using a decorrelated RONMON matrix of eight fuels. Power and acceleration performance were used to determine the K values for corresponding operating points. Previous studies have shown that vehicles manufactured up to 20 years ago mostly exhibited negative K values and the fuels with higher RON and higher sensitivity tended to perform better.

Gasoline Direct Injection (GDI) engines have been widely adopted by manufacturers in the light-duty market due to their fuel economy benefits. However, several studies have shown that GDI engines generate higher levels of particulate matter (PM) emissions relative to port fuel injected (PFI) engines and diesel engines equipped with optimally functioning diesel particulate filters (DPF). With stringent particle number (PN) regulations being implemented in both, the European Union and China, gasoline particulate filters (GPF) are expected to be widely utilized to control particulate emissions. Currently, evaluating GPF technologies on a vehicle can be challenging due to a limited number of commercially available vehicles that are calibrated for a GPF in the United States as well as the costs associated with vehicle procurement and evaluations utilizing a chassis dynamometer facility.

A two-phase study was performed to establish a standard diesel exhaust composition which could be used in the future development of light-duty diesel exhaust aftertreatment. In the first phase, a literature review created a database of diesel engine-out emissions. The database consisted chiefly of data from heavy-duty diesel engines; therefore, the need for an emission testing program for light- and medium-duty engines was identified. A second phase was conducted to provide additional light-duty vehicle emissions data from current technology vehicles. Engine-out diesel exhaust from four 2004 model light-duty vehicles with a variety of engine displacements was collected and analyzed. Each vehicle was evaluated using five steady-state engine operating conditions and two transient test cycles (the Federal Test Procedure and the US06). Regulated emissions were measured along with speciation of both volatile and semi-volatile components of the hydrocarbons.

In-cylinder emission controls were the focus for diesel engines for many decades before the emergence of diesel aftertreatment. Even with modern aftertreatment, control of in-cylinder processes remains a key issue for developing diesel vehicles with low tailpipe emissions. A reduction in in-cylinder emissions makes aftertreatment more effective at lower cost with superior fuel economy. This paper describes a study focused on an in-cylinder combustion control approach using a Delphi E3 flexible fuel system to achieve low engine-out NOx and PM emissions. A 2003 model year Detroit Diesel Corporation Series 60 14L heady-duty diesel engine, modified to accept the Delphi E3 unit injectors, and ultra low sulfur fuel were used throughout this study. The process of achieving premixed low temperature combustion within the limited range of parameters of the stock ECU was investigated.

Historically, heavy-duty diesel (HDD) engine designs have evolved along the path of increased power output, improved fuel efficiency and reduced exhaust gas emissions, driven both by regulatory and market requirements. The various technologies employed to achieve this evolution have resulted in ever-increasing engine operating cylinder pressures, higher than for any other class of internal combustion engine. Traditional HDD engine design architecture limits peak cylinder pressure (PCP) to about 200 bar (2900 psi). HDD PCP had steadily increased from the early 1970's until the mid 2000's, at which point the structural limit was reached using traditional methods and materials. Specific power output reversed its historical trend and fell at this time as a result of technologies employed to satisfy new emissions requirements, most notably exhaust gas recirculation (EGR).

A 13 L HD diesel engine was converted to run as a flame propagation engine using the HEDGE™ Dual-Fuel concept. This concept consists of pre-mixed gasoline ignited by a small amount of diesel fuel - i.e., a diesel micropilot. Due to the large bore size and relatively high compression ratio for a pre-mixed combustion engine, high levels of cooled EGR were used to suppress knock and reduce the engine-out emissions of the oxides of nitrogen and particulates. Previous work had indicated that the boosting of high dilution engines challenges most modern turbocharging systems, so phase I of the project consisted of extensive simulation efforts to identify an EGR configuration that would allow for high levels of EGR flow along the lug curve while minimizing pumping losses and combustion instabilities from excessive backpressure. A potential solution that provided adequate BTE potential was consisted of dual loop EGR systems to simultaneously flow high pressure and low pressure loop EGR.

This paper describes advances in variable speed supercharging, including benefits for both fuel economy and low speed torque improvement. This work is an extension of the work described in SAE Paper 2012-01-0704 [8]. Using test stand data and state-of-the-art vehicle simulation software, a NuVinci continuously variable planetary (CVP) transmission driving an Eaton R410 supercharger on a 2.2 liter diesel was compared to the same base engine/vehicle with a turbocharger to calculate vehicle fuel economy. The diesel engine was tuned for Tier 2 Bin 5 emissions. Results are presented using several standard drive cycles. A Ford Mustang equipped with a 4.6 liter SI engine and prototype variable speed supercharger has also been constructed and tested, showing low speed torque increases of up to 30%. Dynamometer test results from this effort are presented. The combined results illustrate the promise of variable speed supercharging as a viable option for the next generation of engines.

Antilock brake systems for air braked vehicles have been growing in popularity in Great Britain and Europe and appear to be candidates for extensive use in the United States as well. Previous mandated use in the United States during the 1970's was not successful, in part because of reliability problems, and the National Highway Traffic Safety Administration (NHTSA) has decided that a thorough evaluation of air brake antilock systems is necessary prior to any decision about the appropriateness of future mandatory use in the United States. This paper describes the electronic data collection equipment and processing techniques which are being used in the NHTSA 200 truck evaluation project. Detailed maintenance histories for each truck are being recorded manually as a separate segment of the project. An average of 6 to 7 megabytes of data per week is being collected in the various cities in which fleets are operating test vehicles.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

The Scuderi engine is a split cycle design that divides the four strokes of a conventional combustion cycle over two paired cylinders, one intake/compression cylinder and one power/exhaust cylinder, connected by a crossover port. This configuration provides potential benefits to the combustion process, as well as presenting some challenges. It also creates the possibility for pneumatic hybridization of the engine. This paper reviews the first Scuderi split cycle research engine, giving an overview of its architecture and operation. It describes how the splitting of gas compression and combustion into two separate cylinders has been simulated and how the results were used to drive the engine architecture together with the design of the main engine systems for air handling, fuel injection, mixing and ignition. A prototype engine was designed, manufactured, and installed in a test cell. The engine was heavily instrumented and initial performance results are presented.

Increasingly stringent fuel economy and emissions regulations around the world have forced the further optimization of nearly all vehicle systems. Many technologies exist to improve fuel economy; however, only a smaller sub-set are commercially feasible due to the cost of implementation. One system that can provide a small but significant improvement in fuel economy is the lubrication system of an internal combustion engine. Benefits in fuel economy may be realized by the reduction of engine oil viscosity and the addition of friction modifying additives. In both cases, advanced engine oils allow for a reduction of engine friction. Because of differences in engine design and architecture, some engines respond more to changes in oil viscosity or friction modification than others. For example, an engine that is designed for an SAE 0W-16 oil may experience an increase in fuel economy if an SAE 0W-8 is used.

Commercial vehicles are moving in the direction of improving brake thermal efficiency while also meeting future diesel emission requirements. This study is focused on improving efficiency by replacing the variable geometry turbine (VGT) turbocharger with a high-efficiency fixed geometry turbocharger. Engine-out (EO) NOX emissions are maintained by providing the required amount of exhaust gas recirculation (EGR) using a 48 V motor driven EGR pump downstream of the EGR cooler. This engine is also equipped with cylinder deactivation (CDA) hardware such that the engine can be optimized at low load operation using the combination of the high-efficiency turbocharger, EGR pump and CDA. The exhaust aftertreatment system has been shown to meet 2027 emissions using the baseline engine hardware as it includes a close coupled light-off SCR followed by a downstream SCR system.