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Every time we measure the terrain profiles we would get a different set of data due to the measuring errors and due to the fact that the linear tracks on which the measuring vehicle travels can not be exactly the same every time. However the data collected at different times from the same terrain should share the similar intrinsic properties. Hence it is natural to consider statistical modeling of the terrain profiles. In this paper we shall use the time series models with time being the distance from the starting point. We receive data from the Belgian Block and the Perryman3 testing tracks. The Belgian Block data are shown to behave like a uniformly modulated process([7]), i.e. it is the product of a deterministic function and a stationary process. The modeling of the profiles can be done by estimating the deterministic function and fit the stationary process with a well-known ARMA model. The Perryman3 data are more irregular.

A detailed description of a numerical method for computing unsteady flows in engine intake and exhaust systems is given. The calculations include the effects of heat transfer and friction. The inclusion of such calculations in a mathematically simulated engine cycle is discussed and results shown for several systems. In particular, the effects of bell-mouth versus plain pipe terminations and the effects of a finite surge tank are calculated. Experimental data on the effect of heat transfer from the back of the intake valve on wave damping are given and show the effect to be negligible. Experimental data on wave damping during the valve closed period and on the temperature rise of the air near the valve are also given.

The ratio of two temperature gradients across the combustion-chamber wall in a diesel engine is used to provide a heat flow ratio showing the radiant heat transfer as a per cent of local total heat transfer. The temperature gradients were obtained with a thermocouple junction on each side of the combustion-chamber wall. The first temperature gradient was obtained by covering the thermocouple at the cylinder gas-wall interface with a thin sapphire window, while the second was obtained without the window. Results show that the time-average radiant heat transfer is of significant magnitude in a diesel engine, and is probably even more significant in heat transfer during combustion and expansion.

Many metrics have been used in an attempt to predict the effects of secondary tasks on driving behavior. Such metrics often give rise to seemingly paradoxical results, with one metric suggesting increased demand and another metric suggesting decreased demand for the same task. For example, for some tasks, drivers maintain their lane well yet detect events relatively poorly. For other tasks, drivers maintain their lane relatively poorly yet detect events relatively well. These seeming paradoxes are not time-accuracy trade-offs or experimental artifacts, because for other tasks, drivers do both well. The paradoxes are resolved if driver demand is modeled in two orthogonal dimensions rather than a single “driver workload” dimension. Principal components analysis (PCA) was applied to the published data from four simulator, track, and open road studies of visual-manual secondary task effects on driving.

Misfiring or partial combustion during diesel engine operation results in the production of partial oxidation products such as ethylene (C₂H₄), carbon monoxide and aldehydes, in particular formaldehyde (HCHO). These compounds remain in the cylinder as residual gases to participate in the following engine cycle. Carbon monoxide and formaldehyde have been shown to exhibit a dual nature, retarding ignition in one temperature regime, yet decreasing ignition delay periods of hydrocarbon mixtures as temperatures exceed 1000°K. Largely unknown is the synergistic effects of such species. In this work, varying amounts of C₂H₄ and HCHO are added to the intake air of a naturally aspirated optical diesel engine and their combined effect on autoignition and subsequent combustion is examined. To observe the effect of these dopants on the low-temperature heat release (LTHR), ultraviolet chemiluminescent images are recorded using intensified CCD cameras.

At the collision moment, a driver’s lower extremity will be in different foot position, which leads to the different posture of the lower extremity with various muscle activations. These will affect the driver’s injury during collision, so it is necessary to investigate further. A simulated collision scene was constructed, and 20 participants (10 male and 10 female) were recruited for the test in a driving simulator. The braking posture and muscle activation of eight major muscles of driver’s lower extremity (both legs) were measured. The muscle activations in different postures were then analyzed. At the collision moment, the right leg was possible to be on the brake (male, 40%; female, 45%), in the air (male, 27.5%; female, 37.5%) or even on the accelerator (male, 25%; female, 12.5%). The left leg was on the floor all along.

The evolution of high power microwave (HPM) sources into practical systems requires the development of compact pulsed power that can be integrated into mobile platforms. One approach to pursuing this objective, developed by researchers at Sandia National Laboratories (Sandia) [1], is to utilize parallel-stacked Blumlein transmission lines energized with a compact Marx generator. Such a configuration would be capable of driving low impedance HPM sources with a long pulse waveform. One of the limitations of this approach is field enhancement-induced breakdown at the edges of the line. Another limitation is percolation of, and subsequent breakdown of the liquid dielectric that is used in the system. This paper describes a research program that, both computationally and experimentally, is studying electrical breakdown in such transmission line configurations for a variety of dielectric materials and substrate geometries.

Late-injection low-temperature diesel combustion is found to further reduce NOx and soot simultaneously. The combustion phenomena and detail chemical kinetics are studied with high speed spray/combustion images and time-resolved spectroscopy analysis in a rapid compression machine (RCM) with a small bowl combustion chamber. High swirl and high EGR condition can be achieved in the RCM; variable injection pressure and injection timing is supplied by the high-pressure common-rail fuel injection system. Effect of small amount of premix hydrogen gas on diesel combustion is also studied in the RCM. A hydrogen injector is located in the upstream of air inlet for delivery small amount and premixed hydrogen gas into cylinder just before the compression stroke. The ignition delay is studied both from the pressure curves and the chemiluminescence images.

A detailed mathematical model of the thermodynamic events of a crankcase scavenged, two-stroke, SI engine is described. The engine is divided into three thermodynamic systems: the cylinder gases, the crankcase gases, and the inlet system gases. Energy balances, mass continuity equations, the ideal gas law, and thermodynamic property relationships are combined to give a set of coupled ordinary differential equations which describe the thermodynamic states encountered by the systems of the engine during one cycle of operation. A computer program is used to integrate the equations, starting with estimated initial thermodynamic conditions and estimated metal surface temperatures. The program iterates the cycle, adjusting the initial estimates, until the final conditions agree with the beginning conditions, that is, until a cycle results.

The non-uniform character of the torque produced by a reciprocating I.C. engine is reflected in the cyclic variation of the crankshaft's speed. Because the crankshaft is an elastic structure, its response to the different harmonic components of the torque is different and changes with engine speed. The lowest harmonic components of the engine torque do not excite torsional vibrations and correlate fairly well with the corresponding harmonic orders of the crankshaft's speed. Based on a random vector model of the harmonic components of the gas-pressure torque, a statistical correlation is obtained between amplitudes and phases of the same harmonic component of the gas-pressure torque and of the crankshaft's speed. The lowest major harmonic order determines the average IMEP of the engine and the half-order detects if a cylinder is a lesser contributor to the total engine output and identifies the deficient cylinder.

The central performance requirement for electrochemical energy storage systems for the full power-assist hybrid electric vehicle (HEV) is pulse power capability, typically 25-40 kW pulse power capability for 10 seconds duration. Standard test procedures utilize constant current pulses. However, in the HEV application, the power transient for acceleration is a ramped power transient and the power transient for regenerative braking power is a descending power ramp. This paper compares the usable power capability of batteries and supercapacitors under constant current, constant power, and ramped power transients. Although the usable battery discharge power is relatively insensitive to the transient type applied, 10-40% higher regenerative braking charge capability is observed with ramped power transients. With supercapacitors, the discharge and charge capability is much more strongly dependent on the type of power transient.

Increasingly sophisticated vehicle automation can perform steering and speed control, allowing the driver to disengage from driving. However, vehicle automation may not be capable of handling all roadway situations and driver intervention may be required in such situations. The typical approach is to indicate vehicle capability through displays and warnings, but control algorithms can also signal capability. Psychophysical methods can be used to link perceptual experiences to physical stimuli. In this situation, trust is an important perceptual experience related to automation capability that is revealed by the physical stimuli produced by different control algorithms. For instance, precisely centering the vehicle in the lane may indicate a highly capable system, whereas simply keeping the vehicle within lane boundaries may signal diminished capability.

Highly time resolved measurements of cylinder pressure acquired simultaneously from three transducers were used to investigate the nature of knocking combustion and to identify biases that the pressure measurements induce. It was shown by investigating the magnitude squared coherence (MSC) between the transducer signals that frequency content above approximately 40 kHz does not originate from a common source, i.e., it originates from noise sources. The major source of noise at higher frequency is the natural frequency of the transducer that is excited by the impulsive knock event; even if the natural frequency is above the sampling frequency it can affect the measurements by aliasing. The MSC analysis suggests that 40 kHz is the appropriate cutoff frequency for low-pass filtering the pressure signal. Knowing this, one can isolate the knock event from noise more accurately.

The aim of this study is to develop a pathway towards Hydrogen combustoin on an opposed-piston four stroke engine (OP4S) by using 1D simulation code from Gamma Technologies. By its configuration, the OP4S engine has significant thermal efficiency benefits versus conventional ICE. The benefit of the OP4S is reduced heat losses due to elimination of the cylinder head, which increase the brake thermal efficiency. A hydrogen-fueled (H2) opposed-piston four stroke (OP4S) engine was modeled using GTPower to determine the potential on performance, thermal efficiency and emissions targets. The 1D model was first validated on E10 gasoline using experimental data and was used to explore changes to fuel type in NG and H2, fueling location (TPI and DI), fuel mixture strength (stoichiometric and lean), for an optimized plenum volume and turbocharger selection.

This study evaluates the performance of an indirect injection (IDI) diesel engine fueled with cotton seed biodiesel while assessing the engine's multi-fuel capability. Millions of tons of cotton seeds are available in the south of the US every year and approximately 10% of oil contained in the seeds can be extracted and transesterified. An investigation of combustion, emissions, and efficiency was performed using mass ratios of 20-50% cotton seed biodiesel (CS20 and CS50) in ultra-low sulfur diesel #2 (ULSD#2). Each investigation was run at 2400 rpm with loads of 4.2 - 6.3 IMEP and compared to the reference fuel ULDS#2. The ignition delay ranged in a narrow interval of 0.8-0.97ms across the blends and the heat release rate showed comparable values and trends for all fuel blends. The maximum volume averaged cylinder temperature increased by approximately 100K with each increase in 1 bar IMEP load but the maximum remained constants across the blends.

Recent legislation entitled “The Single Fuel Forward Policy” mandates that all vehicles deployed by the US military be operable with aviation fuel (JP-8). Therefore, the authors are conducting an investigation into the influence of JP-8 on a diesel engine's performance. The injection, combustion, and performance of JP-8, 20-50% by weight in ULSD (diesel no.2) mixtures (J20-J50) produced at room temperature, were investigated in a small indirect injection, high compression ratio (24.5), 77mm separate combustion chamber diesel engine. The effectiveness of JP8 for application in an auxiliary power unit (APU) at continuous operation (100% load) of 4.78bar bmep/2400rpm was investigated. The blends had an ignition delay of approximately 1.02ms that increased slightly in relation to the amount of JP-8 introduced. J50 and diesel no.2 exhibited similar characteristics of heat release, the premixed phase being combined with the diffusion combustion.

The Wayne State University (WSU) EcoCAR2 student team designed, modeled, Model-In-the-Loop (MIL) tested, Software-In-the-Loop (SIL) simulation tested, and Hardware-In-the-Loop (HIL) simulation tested the team's conversion design for taking a 2013 Chevrolet Malibu and converting it into a Parallel-Through-The-Road (PTTR) plug-in hybrid. The 2013 Malibu is a conventional Front Wheel Drive (FWD) vehicle and the team's conversion design keeps the conventional FWD and adds a Rear Wheel Drive (RWD) powertrain consisting of an electric motor, a single speed reduction gearbox and a differential to drive the rear wheels -where none of these previously existed on the rear wheels. The RWD addition creates the PTTR hybrid powertrain architecture of two driven axles where the mechanical torque path connection between the two powertrains is through the road, rather than a mechanical torque path through gears, chains, or shafts.

There is a general interest in the reduction of cooling loads in military vehicles. To that end thermal barrier coatings (TBCs) are being studied for their potential as insulators, particularly for military engines. The effectiveness of TBCs is largely dependent on their thermal properties, however insulating effects can also be modified by applying different coating thickness. Convection from in-cylinder surfaces can also be affected by manipulation of surface structure. Although most prior studies have examined TBCs as a means of increasing efficiency, military vehicle design is primarily concerned with the reduction of cylinder heat transfer to allow downsizing of cooling systems. A 1-D transient conjugate heat transfer model was developed to provide insight into the effects of different TBC designs and material selection on cooling loads. Results identify low thermal conductivity and low thermal capacitance as key parameters in achieving optimal heat loss reduction.

This paper details the vehicle testing activities performed during the Year 4 of the EcoCAR 3 competition by the Wayne State University team on a Pre-Transmission Parallel PHEV. The paper focuses on two main testing platforms: the chassis dynamometer and the closed-course track (on-road). The focus of the former is to evaluate the emissions and energy consumption associated with different driving scenarios, while the latter has been used to assess the vehicle performance and their impact on the consumer appeal. The paper presents the objectives of each test, the setup accomplished for the different vehicle testing platforms, the results obtained and the comparison with the values expected from simulations. In addition, the impact of the results on the refinement of the control strategies and on the validation of the simulation models are discussed.

This paper details the development of a test-bench simulation to characterize the behavior of an electro-hydraulic actuated dry clutch used in a pre-transmission parallel hybrid powertrain architecture of Wayne State University EcoCAR 3. Engage and disengage systems play a crucial role in a pre-transmission parallel hybrid architecture. The most common device used to meet the purpose of physically connecting internal combustion engine and electric powertrains is a dry clutch. Its own characteristics and capabilities allow its usage for this application. The transition between the pure electric and hybrid modes is dictated by the main control strategy. Therefore, the engaging system will be widely used when switching from charge depleting to charge sustaining mode, and vice versa. In addition, when torque is required from both sources for higher performance, the clutch will be responsible for mechanically connecting both torque sources.