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This study extends a previous study on the effects of intake throttling and post-injection on light-duty Diesel engine exhaust temperatures and emissions, and includes the effects of EGR, in-cylinder swirl air motion, and cylinder deactivation. The baseline injection strategy was adapted from a 2014 Chevrolet Cruze having an engine similar to the light-duty GM engine used for this study. While the engine was fixed to a motoring engine dynamometer, the dynamometer was not active for the study, as the engine was operated under idle conditions. The desired idle speed was controlled using a feedback loop in the control algorithm to vary the duration of the main injection event. Three methods were investigated. In the first method, the engine was operated fully warmed up, firing all four cylinders.

Especially in crowded urban areas, light-duty vehicles often spend a great deal of time operating under idle conditions for which exhaust temperatures may be too low to maintain exhaust catalyst activity. This study investigated two methods of increasing Diesel exhaust temperature of a light-duty Diesel engine under idle conditions: post injection of fuel after TDC and intake throttling. For this particular study, EGR was not used. The engine operating parameters considered included three idle speeds of 800, 1100 and 1200 rpm, with the engine fully warmed up. Two rail pressures of 500 and 800 bar were studied with the injection strategy being the primary variable. The parameters measured included exhaust temperature, exhaust concentrations of NOx and HCs, as well as fuel consumption, IMEP and COV of IMEP. For the baseline idle conditions, manifold-out exhaust temperature was approximately 100 °C-105 °C.

Laminar flow elements (LFEs) are commonly used to measure the flow rate of gases in various flow streams. Since LFEs operate on the principle of fully developed laminar pipe flow, the viscosity of the gas must be known. In many cases, the flowing gas is air of varying humidity, inlet temperature, and inlet pressure. While the viscosity of humid air has been studied extensively over the past 60+ years, the effects of humidity have not been consistently accounted for in the literature and industry documentation pertaining to LFE operation, and this can lead to errors. Additionally, the available LFE operational documentation is not presented in equation form; rather it is provided in tables and graphs which do not facilitate automation of the flow calculations during data acquisition. This paper provides a brief review of the available data and correlations for the viscosity of humid air and its application to the calculation of air flow rate using a laminar flow element.

The performance of an organic Rankine cycle (ORC) that recovers heat from the exhaust of a heavy-duty diesel engine was simulated. The work was an extension of a prior study that simulated the performance of an experimental ORC system developed and tested at Oak Ridge National laboratory (ORNL). The experimental data were used to set model parameters and validate the results of that simulation. For the current study the model was adapted to consider a 15 liter turbocharged engine versus the original 1.9 liter light-duty automotive turbodiesel studied by ORNL. Exhaust flow rate and temperature data for the heavy-duty engine were obtained from Southwest Research Institute (SwRI) for a range of steady-state engine speeds and loads without EGR. Because of the considerably higher exhaust gas flow rates of the heavy-duty engine, relative to the engine tested by ORNL, a different heat exchanger type was considered in order to keep exhaust pressure drop within practical bounds.

The performance of an organic Rankine cycle (ORC) used to recover waste heat from the exhaust of a diesel and a spark ignition engine for electric power generation was modeled. The design elements of the ORC incorporated into the thermodynamic model were based on an experimental study performed at Oak Ridge National Laboratory in which a regenerative organic Rankine cycle system was designed, assembled and integrated into the exhaust of a 1.9 liter 4-cylinder automotive turbo-diesel. This engine was operated at a single fixed-load point at which Rankine cycle state point temperatures as well as the electrical power output of an electric generator coupled to a turbine that expanded R245fa refrigerant were measured. These data were used for model calibration.

The first commercially available Plug-In Hybrid Electric Vehicle (PHEV), the General Motors (GM) Volt, was introduced into the market in December 2010. The Volt's powertrain architecture provides four modes of operation, including two that are unique and maximize the Volt's efficiency and performance. The electric transaxle has been specially designed to enable patented operating modes both to improve the electric driving range when operating as a battery electric vehicle and to reduce fuel consumption when extending the range by operating with an internal combustion engine (ICE). However, details on the vehicle control strategy are not widely available because the supervisory control algorithm is proprietary. Since it is not possible to analyze the control without vehicle test data obtained from a well-designed Design-of-Experiment (DoE), a highly instrumented GM Volt, including thermal sensors, was tested at Argonne National Laboratory's Advanced Powertrain Research Facility (APRF).

Previous studies and on-road driving by consumers have shown that Hybrid Electric Vehicle fuel economy is very dependent on driver demand in both vehicle speed and vehicle acceleration [1]. The emerging technology of Plug-In Hybrid Vehicles (PHEV) may prove to also be more sensitivity to aggressive driver demand as compared to conventional internal combustion engine vehicles. This is due to the exceptional ability of the PHEV to minimize fuel consumption at mid to low power levels by the significant use of electric propulsion which enables engine downsizing. As vehicle speed and acceleration increase so does the power demand on the powertrain. The fuel consumption is directly affected by this increase in power demand level. To examine the fuel consumption impact of changing driver characteristics on PHEV’s, testing is conducted on two vehicles (parallel PHEV and power-split PHEV) on a four wheel chassis dynamometer at Argonne’s Advanced Powertrain Research Facility.

An electronic particulate matter sensor (EPMS) developed at the University of Texas was used to characterize exhaust gases from a single-cylinder diesel engine and a light-duty diesel vehicle. Measurements were made during transient tip-in events with multiple sensor configurations in the single-cylinder engine. The sensor was operated in two modes: one with the electric field energized, and the other with no electric field present. In each mode, different characteristic signals were produced in response to a tip-in event, highlighting the two primary mechanisms of sensor operation. The sensor responded to both the natural charge of the particulate matter (PM) emitted from the engine, and was also found to create a signal by charging neutral particles. The characteristics of the two mechanisms of operation are discussed as well as their implications on the placement and operation of the sensor.

Trucks operating in inter-modal (drayage) operation in and around port and rail terminals, are responsible for a large proportion of the emissions of NOX, which are problematic for the air quality of the Houston and Dallas/Ft. Worth metro areas. A standard test cycle, called the Texas Dray Truck Cycle, was developed to represent the operation of heavy-duty diesel trucks in dray operations. The test cycle reflects the substantial time spent at idle (~45%) and the high intensity of the on-road portions. This test cycle was then used in the SAE J1321 test protocol to evaluate the effect on fuel consumption and NOX emissions of retrofitting dray trucks with light-weight, low-rolling resistance wide-single tires. In on-track testing, a reduction in fuel consumption of 8.7% was seen, and NOX emissions were reduced by 3.8% with the wide single tires compared to the conventional tires.

This paper presents the latest developments in the design and performance of an electronic particulate matter (PM) sensor developed at The University of Texas at Austin (UT) and suitable, with further development, for applications in active engine control of PM emissions. The sensor detects the carbonaceous mass component of PM in the exhaust and has a time-resolution less than 20 (ms), allowing PM levels to be quantified for engine transients. Sample measurements made with the sensor in the exhaust of a single-cylinder light duty diesel engine are presented for both steady-state and transient operations: a steady-state correlation with gravimetric filter measurements is presented, and the sensor response to rapid increases in PM emission during engine transients is shown for several different tip-in (momentary increases in fuel delivery) conditions.

A new electronic sensor has been developed to measure the time-resolved concentration of carbonaceous particulate matter (PM) emitted in engine exhaust. The sensor is approximately the size of a standard automotive spark-plug or lambda sensor and can be mounted directly in the engine exhaust. It consists of a pair of closely spaced electrically isolated electrodes that protrude into the exhaust flow. One electrode is given a voltage bias of 1000 V while the other is the signal electrode. The sensor is capable of providing cycle-resolved feedback on the carbonaceous PM concentration in the exhaust to the engine control unit (ECU), thereby enabling real-time control of engine operating parameters to lower PM emissions. This paper reports the results of an experimental study of various parameters that affect the performance of the electronic sensor.

A piezoelectric sensor to measure the mass of fuel that impacts the piston top during injection in a direct injection spark ignition (DISI) engine was developed. The sensor used a 3.18 cm (1.25-inch) long, 0.318 cm (0.125-inch) wide piezo bending motor. The principle of operation is based on the change in natural vibration frequency that occurs to the cantilever piezo beam due to a change in its mass caused by the presence of liquid fuel on its surface. An electrical impulse is used to set the piezo element in vibration after which the natural vibrational frequency is measured using a FFT analyzer. The concept was evaluated outside the engine and calibrated for the frequency shift as a function of the weight of liquid on the bending element. The change in the frequency was found to be approximately proportional to the liquid mass on the sensor. The piston top of the engine was modified to accommodate the sensor on its surface.

Vehicle emissions and fuel economy testing applications rely on accurate sensors to track power flow and measure component efficiencies. A non-intrusive in-vehicle torque sensor has been implemented in a hybrid powertrain to directly measure engine torque. Previously used off-the-shelf torque sensors required additional mechanical space, and so chassis modifications were needed to accommodate the sensor, which potentially limited the vehicle to only dynamometer testing. The challenges in implementing this type of sensor in automotive environments are described in detail, as are sensor capabilities and test results.

The 2001 FutureTruck competition involved 15 universities from across North America that were invited to apply a wide range of advanced technologies to improve energy efficiency and reduce greenhouse gas impact while producing near-zero regulated exhaust emissions in a 2000 Chevrolet Suburban. The modified vehicles designated as FutureTrucks demonstrated improvements in greenhouse gas emissions, tailpipe emissions, and over-the-road fuel economy compared with the stock vehicle on which they were based. The technologies represented in the vehicles included ICE-engines and fuel cell hybrid electric vehicle propulsion systems, a range of conventional and alternative fuels, advanced exhaust emissions controls, and light weighting technologies.

A fiber optic infrared spectroscopic sensor was developed to measure the crank angle resolved residual fraction of burned gas retained in the cylinder of a four-stroke SI engine. The sensor detected the attenuation of infrared radiation in the 4.3 μm infrared vibrational-rotational absorption band of CO2. The residual fraction remaining in the cylinder is proportional to the CO2 concentration. The sensor was tested in a single-cylinder CFR spark ignition engine fired on propane at a speed of 700 rpm. The sensor was located in one of two spark plug holes of the CFR engine. A pressure-transducer-type spark plug was used to record the cylinder pressure and initiate the spark. The temporal resolution of the measurements was 540 μs (equivalent to 2.3 crank angle degrees) and the spatial resolution was 6 mm. Measurements were made during the intake and compression stroke for several intake manifold pressures. The compression ratio of the engine was varied from 6.3 to 9.5.

Two limited-production hybrid electric vehicles (HEVs) - a 1988 Japanese model Toyota Prius and a 2000 Honda Insight - were tested at Argonne National Laboratory to collect data from vehicle component and systems operation. The test data are used to analyze operation and efficiency and to help validate computer simulation models. Both HEVs have FTP fuel economy greater than 45 miles per gallon and also have attributes very similar to those of conventional gasoline vehicles, even though each HEV has a unique powertrain configuration and operation control strategy. The designs and characteristics of these vehicles are of interest because they represent production technology with all the compromises for production included. This paper will explore both designs, their control strategies, and under what conditions high fuel economy was achieved.

A fiber optic infrared spectroscopic sensor has been developed to measure the time-resolved concentration of exhaust gas recirculated (EGR) into the intake manifold of an internal combustion engine. The sensor detects the attenuation of infrared radiation in the 4.3 μm infrared vibrational-rotational absorption band of CO2. The EGR mass fraction in the intake manifold is proportional to the CO2 concentration. The sensor was tested in a single-cylinder spark ignition engine fired on propane at a speed of 700 rpm. The sensor was located 10 cm upstream of the intake valve. The temporal resolution of the measurements was 700 μs (equivalent to 2.5 crank angle degrees) allowing the local EGR concentration throughout the cycle to be measured. Measurements were made with both real and simulated EGR. The EGR flows were introduced at various locations upstream of the probe.

The Prius is a major achievement by Toyota: it is the first mass-produced HEV with the first available HEV-optimized engine. Argonne National Laboratory's Advanced Powertrain Test Facility has been testing the Prius for model validation and technology performance and assessment. A significant part of the Prius test program is focused on testing and mapping the engine. A short-length torque sensor was installed in the powertrain in-situ. The torque sensor data allow insight into vehicle operational strategy, engine utilization, engine efficiency, and specific emissions. This paper describes the design and process necessary to install a torque sensor in a vehicle and shows the high-fidelity data measured during chassis dynamometer testing. The engine was found to have a maximum thermodynamic efficiency of 36.4%. Emissions and catalyst efficiency maps were also produced.

An infrared fiber optic instrumented spark plug probe has been used to measure the fuel concentration in the vicinity of the spark gap in a port injected gasoline fueled SI engine. The probe measured the fuel concentration spatially averaged over a distance of 6.3 mm near the spark plug for consecutive firing cycles. The crank angle resolution of the measurements was 2.5 degrees, for a temporal resolution of between 0.9 and 0.3 ms depending on the engine speed. Quantitative measurements of the fuel concentration in the pre-ignition regions of the engine cycle were obtained. Qualitative results are reported for unburned hydrocarbons in the post-combustion regions. The measurements were made in a single cylinder research engine over a range of speed, load, and stoichiometric conditions. Strong mixture inhomogeneities were measured during the intake stroke and the inhomogeneities decreased through the compression stroke.

The mixture preparation process was investigated in a direct-injected, 4-valve, SI engine under motored conditions. The interaction between the high-pressure fuel jet and the intake air-flow was observed. Laser-sheet droplet imaging was used to visualize the in-cylinder droplet distributions, and a single-component LDV system was used to measure in-cylinder velocities. The fuel spray was visualized with the engine motored at 1500 and 750 rpm, and with the engine stopped. It was observed that the shape of the fuel spray was distorted by the in-cylinder air motion generated by the intake air flow, and that this effect became more pronounced with increasing engine speed. Velocity measurements were made at five locations on the symmetry plane of the cylinder, with the engine motored at 750 rpm. Comparison of these measurements with, and without, injection revealed that the in-cylinder charge motion was significantly altered by the injection event.