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Tremendous amount of useful information can be extracted from the cylinder pressure signal for engine combustion control. However, the physical cylinder pressure sensors are undesirably expensive and their health need to be monitored for fault diagnostic purpose as well. This paper presents the results of the development of a virtual cylinder pressure sensor (VCPS) with individual variable-oriented independent estimators. Two neural network-based independent cylinder pressure related variable estimators were developed and verified at steady state. The results show that these models can predict the variables correctly compared with the extracted variables from the measured physical cylinder pressure sensor signal. Good generalization capabilities of the developed models are observed in the sense that the models work well not only for the training data set but also for the new inputs that they have never been exposed to before.

Reactivity Controlled Compression Ignition (RCCI) natural gas/diesel dual-fuel combustion has been shown to achieve high thermal efficiency with low NOX and PM emissions, but has traditionally been limited to low to medium loads. High BMEP operation typically requires high substitution rates (i.e., >90% NG), which can lead to high cylinder pressure, pressure rise rates, knock, and combustion loss. In previous studies, compression ratio was decreased to achieve higher load operation, but thermal efficiency was sacrificed. For this study, a multi-cylinder heavy-duty engine that has been modified for dual-fuel operation (diesel direct-injection and natural gas (NG) fumigated into the intake stream) was used to explore RCCI and other dual-fuel combustion modes at high compression ratio, while maintaining stock lug curve capability (i.e., extending dual-fuel operation to high loads where conventional diesel combustion traditionally had to be used).

The Exhaust Composition Transient Operation LaboratoryTM (ECTO-LabTM) is a burner system developed at Southwest Research Institute (SwRI) for simulation of IC engine exhaust. The current system design requires metering and combustion of nitromethane in conjunction with the primary fuel source as the means of NOX generation. While this method affords highly tunable NOX concentrations even over transient cycles, no method is currently in place for dictating the speciation of nitric oxide (NO) and nitrogen dioxide (NO2) that constitute the NOX mixture. NOX generated through combustion of nitromethane is dominated by NO, and generally results in an NO2:NOX ratio of < 5 %. Generation of any appreciable quantities of NO2 is therefore dependent on an oxidation catalyst to oxidize a fraction of the NO to NO2.

With the rapid expansion of the automotive market in China, air quality in the major cities has become a severe concern. Great efforts have been made in introducing new emission regulations; however, fuel and lubricant qualities, emissions aftertreatment system durability and in-use compliance to the emissions regulations still require significant improvement. China follows the European Union (EU) emission regulations in general, but different levels of standards exist. This paper gives a comprehensive overview of the current and near-future heavy-duty diesel emission regulations, as well as fuel and lubricant specifications.

Regulated and unregulated exhaust emissions (individual hydrocarbons, aldehydes and ketones, polynuclear aromatic hydrocarbons (PAH), and nitro-polynuclear aromatic hydrocarbons (NPAH)) were characterized for the following alternate diesel combustion modes: premixed charge compression ignition (PCCI), and low-temperature combustion (LTC). PCCI and LTC were studied on a PSA light-duty high-speed diesel engine. Engine-out emissions of carbonyl compounds were significantly increased for all LTC modes and for PCCI-Lean conditions as compared to diesel operation; however, PCCI-Rich produced much lower carbonyl emissions than diesel operations. For PAH compounds, emissions were found to be substantially increased over baseline diesel operation for LTC-Lean, LTC-Rich, and PCCI-Lean conditions. PCCI-Rich operation, however, gave PAH emission rates comparable to baseline diesel operation.

Beginning June 1, 2006, 80% of the highway diesel fuel produced in the United States had to contain 15 ppm sulfur or less. To account for sulfur test method variability, the United States Environmental Protection Agency (US EPA) allowed a 2 ppm compliance margin, meaning that in an EPA enforcement action fuel measuring 17 ppm or less would still be deemed compliant since the true sulfur level could still be 15 ppm. Concern was voiced over the appropriateness of the 2 ppm compliance margin, citing recent American Society for Testing and Materials (ASTM) round-robin and crosscheck test program results that showed sulfur test lab-to-lab variability (reproducibility) on the order of 4 to 5 ppm depending on test method.

Results from work focusing on the development of an ultra low emissions, high efficiency, natural gas-fueled heavy- duty engine are discussed in this paper. The engine under development was based on a John Deere 8.1L engine; this engine was significantly modified from its production configuration during the course of an engine optimization program funded by the National Renewable Energy Laboratory. Previous steady-state testing indicated that the modified engine would provide simultaneous reductions in nonmethane hydrocarbon emissions and fuel consumption while maintaining equivalent or lower NOx levels. Federal Test Procedure transient tests confirmed these expectations. Very low NOx emissions, averaging 1.0 g/bhp-hr over hot-start cycles, were attained; at these conditions, reductions in engine-out nonmethane hydro-carbons emissions (NMHC) were approximately 30 percent, and fuel consumption over the cycle was also reduced relative to the baseline.

The goal of this project was to demonstrate a low emissions, high efficiency heavy-duty on-highway natural gas engine. The emissions targets for this project are to demonstrate US 2010 emissions standards on the 13-mode steady state test. To meet this goal, a chemically correct combustion (stoichiometric) natural gas engine with exhaust gas recirculation (EGR) and a three way catalyst (TWC) was developed. In addition, a Sturman Industries, Inc. camless Hydraulic Valve Actuation (HVA) system was used to improve efficiency. A Volvo 11 liter diesel engine was converted to operate as a stoichiometric natural gas engine. Operating a natural gas engine with stoichiometric combustion allows for the effective use of a TWC, which can simultaneously oxidize hydrocarbons and carbon monoxide and reduce NOx. High conversion efficiencies are possible through proper control of air-fuel ratio.

Comparative emission measurements were made in two dynamometer-based diesel engines using protocol specified by the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). A single JP-8 fuel with a sulfur level of 0.06 weight percent (wt%) was adjusted to sulfur levels of 0.11 and 0.26 wt%. The emission characteristics of the three fuels were compared to the 1994 EPA certification low-sulfur diesel fuel (sulfur level equal to 0.035 wt%) in the Detroit Diesel Corporation (DDC) 1991 prototype Series 60 diesel engine and in the General Motors (GM) 6.2L diesel engine. Comparisons were made using the hot-start transient portion of the heavy-duty diesel engine Federal Test Procedure. Results from the Army study show that the gaseous emissions for the DDC Series 60 engine using kerosene-based JP-8 fuel are equivalent to values obtained with the 0.035 wt% sulfur EPA certification diesel fuel.

Southwest Research Institute (SwRI) has successfully demonstrated the cooled EGR concept via the High Efficiency Dilute Gasoline Engine (HEDGE) consortium. Dilution of intake charge provides three significant benefits - (1) Better Cycle Efficiency (2) Knock Resistance and (3) Lower NOx/PM Emissions. But EGR dilution also poses challenges in terms of combustion stability, condensation and power density. The Dedicated EGR (D-EGR) concept brings back some of the stability lost due to EGR dilution by introducing reformates such as CO and H2 into the intake charge. Control of air, EGR, fuel, and ignition remains a challenge to realizing the aforementioned benefits without sacrificing performance and drivability. This paper addresses the DEGR solution from a controls standpoint. SwRI has been developing a unified framework for controlling a generic combustion engine (gasoline, diesel, dual-fuel natural gas etc.).

Injuries produced by standard three point restraint systems with retractors will be compared between cadavers in laboratory simulated collisions at 30 mph barrier equivalent speed and lap and shoulder belted front seat occupants in real world frontal collisions of '73-'75 full sized cars. Tests conducted at SwRI with belted, unembalmed, fresh cadavers have resulted in extremely severe thoracic and cervical injuries, including multiple rib fractures, fractures of the sternum, clavicle and cervical vertebrae. On the other hand, injury data from a national accident investigation study to evaluate the effectiveness of restraints in late model passenger cars indicates that such injuries in real world crashes of equivalent severity are not always observed. The reasons possible for these differences are discussed. Both programs at SwRI are funded by the National Highway Traffic Safety Administration.

Radioactive tracer technology is an important tool for measuring component wear on a real-time basis and is especially useful in measuring engine wear as it is affected by combustion system operation and lubricant performance. Combustion system operation including the use of early and/or late fuel injection and EGR for emissions control can have a profound effect on aftertreatment contamination and engine reliability due to wear. Liner wear caused by localized fuel impingement can lead to excessive oil consumption and fuel dilution can cause excessive wear of rings and bearings. To facilitate typical wear measurement, the engine's compression rings and connecting rod bearings are initially exposed to thermal neutrons in a nuclear reactor to produce artificial radioisotopes that are separately characteristic of the ring and bearing wear surfaces.

A unique and attractive variator mechanism has been developed by Turbo Trac, Inc. and Southwest Research Institute (SwRI) for initial use in a heavy duty diesel truck application. High efficiency levels have been predicted with analytical models and confirmed with actual test data. Further, this variator incorporates a very stable and simple control system and has extremely high torque capacity. The prototype of the variator mechanism has also been configured with a modified Allison 650 series transmission for use as a series application in a Peterbilt truck, the final configuration will be a split power design. The setup includes a preliminary control system that allows for highway driving. It is emphasized, however, that Allison did not contribute to this design or any of the content of this paper.

The objective was to demonstrate the feasibility of operating a natural gas two-stroke engine using glow plug ignition with very lean mixtures. Based on the results obtained, the term SCGI (stratified charge glow plug ignition) was coined to describe the engine. An JLO two-stroke diesel engine was converted first to a natural gas fueled spark-ignited engine for the baseline tests, and then to an SCGI engine. The SCGI engine used a gas operated valve in the cylinder head to admit the natural gas fuel, and a glow plug was used as a means to initiate the combustion. The engine was successfully run, but was found to be sensitive to various conditions such as the glow plug temperature. The engine would run very lean, to an overall equivalence ratio of 0.33, offering the potential of good fuel economy and low NOx emissions.

The Port Fuel Injector (PFI) Deposit Test is a performance-based test procedure developed by the Coordinating Research Council and adopted by state and federal regulatory agencies for fuel qualification in the United States. To date, Southwest Research Institute (SwRI) has performed over 375 PFI tests between 1991 and 1998 for various clients. This paper details the analyses of these tests. Of the 375 tests, 199 were performed as keep-clean tests and 176 were performed as clean-up tests. The following areas of interest are discussed in this paper: Keep-clean versus clean-up test procedures Linearity of deposit formation Injector position effects as related to fouling Dirtyup / cleanup phenomena Seasonal effects This paper draws the conclusion that it is easier to keep new injectors from forming deposits than it is to clean up previously formed deposits. It was found that injector deposit formation is generally non-linear.

The new Beijing Automotive Industry Corporation (BAIC) engine, an evolution of the 2.3L 4-cylinder turbocharged gasoline engine from Saab, was designed, built, and tested with close collaboration between BAIC Motor Powertrain Co., Ltd. and Southwest Research Institute (SwRI®). The upgraded engine was intended to achieve low fuel consumption and a good balance of high performance and compliance with Euro 6 emissions regulations. Low fuel consumption was achieved primarily through utilizing cooled low pressure loop exhaust gas recirculation (LPL-EGR) and dual independent cam phasers. Cooled LPL-EGR helped suppress engine knock and consequently allowed for increased compression ratio and improved thermal efficiency of the new engine. Dual independent cam phasers reduced engine pumping losses and helped increase low-speed torque. Additionally, the intake and exhaust systems were improved along with optimization of the combustion chamber design.

Experiments were performed on a 2.4L boosted, MPI gasoline engine, equipped with a low-pressure loop (LPL) cooled EGR system and an advanced ignition system, using fuels with varying anti-knock indices. The fuels were blends of 87, 93 and 105 Anti-Knock Index (AKI) gasoline. Ignition timing and EGR sweeps were performed at various loads to determine the tradeoff between EGR level and fuel octane rating. The resulting engine data was analyzed to establish the relationship between the octane requirement and the level of cooled EGR used in a given application. In addition, the combustion difference between fuels was examined to determine the effect that fuel reactivity, in the form of anti-knock index (AKI), has on EGR tolerance and burn rate. The results indicate that the improvement in effective AKI of the fuel from using EGR is constant across commercial grade gasolines at about 0.5 ON per % EGR.

Experiments were performed on a small displacement (< 2 L), high compression ratio, 4 cylinder, port injected gasoline engine equipped with Dedicated EGR® (D-EGR®) technology using fuels with varying anti-knock properties. Gasolines with anti-knock indices of 84, 89 and 93 anti-knock index (AKI) were tested. The engine was operated at a constant nominal EGR rate of ∼25% while varying the reformation ratio in the dedicated cylinder from a ϕD-EGR = 1.0 - 1.4. Testing was conducted at selected engine speeds and constant torque while operating at knock limited spark advance on the three fuels. The change in combustion phasing as a function of the level of overfuelling in the dedicated cylinder was documented for all three fuels to determine the tradeoff between the reformation ratio required to achieve a certain knock resistance and the fuel octane rating.

Dedicated EGR has shown promise for achieving high efficiency with low emissions [1]. For the present study, a 4-cylinder turbocharged GDI engine which was modified to a D-EGR configuration was used to investigate the impact of valve phasing and different injection strategies on the reformate production in the dedicated cylinder. Various levels of positive valve overlap were used in conjunction with different approaches for dedicated cylinder over fueling using PFI and DI fuel systems. Three speed-load combinations were studied, 2000 rpm 4 bar IMEPg, 2000 rpm 12 bar IMEPg, and 4000 rpm 12 bar IMEPg. The primary investigation was conducted to map out the dedicated cylinders' performance at the operating limits of intake and exhaust cam phasing. In this case, the limits were defined as conditions that yielded either no reformate benefit or led to instability in the dedicated cylinder.

The use of cooled EGR as a knock suppression tool is gaining more acceptance worldwide. As cooled EGR become more prevalent, some challenges are presented for engine designers. In this study, the impact of cooled EGR on peak cylinder pressure was evaluated. A 1.6 L, 4-cylinder engine was operated with and without cooled EGR at several operating conditions. The impact of adding cooled EGR to the engine on peak cylinder pressure was then evaluated with an attempt to separate the effect due to advanced combustion phasing from the effect of increased manifold pressure. The results show that cooled EGR's impact on peak cylinder pressure is primarily due to the knock suppression effect, with the result that an EGR rate of 25% leads to an almost 50% increase in peak cylinder pressure at a mid-load condition if the combustion phasing is advanced to Knock Limited Spark Advance (KLSA). When combustion phasing was held constant, increasing the EGR rate had almost no effect on PCP.