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A multi-chamber silencer is designed by a computational approach to suppress the turbocharger whoosh noise downstream of a compressor in an engine intake system. Due to the significant levels and the broadband nature of the source spanning over 1.5 – 3.5 kHz, three Helmholtz resonators are implemented in series. Each resonator consists of a chamber and a number of slots, which can be modeled as a cavity and neck, respectively. Their target resonance frequencies are tuned using Boundary Element Method to achieve an effective noise reduction over the entire frequency range of interest. The predicted transmission loss of the silencer is then compared with the experimental results from a prototype in an impedance tube setup. In view of the presence of rapid grazing flow, these silencers may be susceptible to whistle-noise generation. Hence, the prototype is also examined on a flow bench at varying flow rates to assess such flow-acoustic coupling.

Shaped elastomeric joints such as engine mounts or suspension bushings undergo broadband, multi-axis loading; however, in practice, the elastomeric joint properties are often measured at stepped single frequencies (non-resonant test method). This article helps provide insight into multi-axis properties with new benchmark experiments that are designed to permit direct comparison between system resonant and non-resonant identification methods of the dynamic stiffness matrices of elastomeric joints, including multi-axis (non-diagonal) terms. The joints are constructed with combinations of inclined elastomeric cylinders to control non-diagonal terms in the stiffness matrix. The resonant experiment consists of an elastic metal beam end-supported by elastomeric joints coupling the in-plane transverse and longitudinal beam motion.

The engine start-up process introduces speed-dependent transient vibration problems in ground vehicle drivelines as the torsional system passes through the critical speeds during the acceleration process. Accordingly, a numerical study is proposed to gain more insights about this transient vibration issue, and the focus is on nonlinear analysis. First, a new nonlinear model of a multi-staged clutch damper is developed and validated by a transient experiment. Second, a simplified nonlinear torsional oscillator model with the multi-staged clutch damper, representing the low frequency dynamics of a typical vehicle driveline, is developed. The flywheel velocity measured during the typical engine start-up process is utilized as an excitation. The envelope function of the speed-dependent response amplification is estimated via the Hilbert transform technique. Finally, the envelope function is effectively utilized to examine the effect of multi-staged clutch damper properties.

The acoustic and performance characteristics of an automotive centrifugal compressor are studied on a steady-flow turbocharger test bench, with the goal of advancing the current understanding of compression system instabilities at the low-flow range. Two different ducting configurations were utilized downstream of the compressor, one with a well-defined plenum (large volume) and the other with minimized (small) volume of compressed air. The present study measured time-resolved oscillations of in-duct and external pressure, along with rotational speed. An orifice flow meter was incorporated to obtain time-averaged mass flow rate. In addition, fast-response thermocouples captured temperature fluctuations in the compressor inlet and exit ducts along with a location near the inducer tips.

This research was to model a 6×4 tractor-trailer rig using TruckSim and simulate severe braking maneuvers with hardware in the loop and software in the loop simulations. For the hardware in the loop simulation (HIL), the tractor model was integrated with a 4s4m anti-lock braking system (ABS) and straight line braking tests were conducted. In developing the model, over 100 vehicle parameters were acquired from a real production tractor and entered into TruckSim. For the HIL simulation, the hardware consisted of a 4s4m ABS braking system with six brake chambers, four modulators, a treadle and an electronic control unit (ECU). A dSPACE simulator was used as the “interface” between the TruckSim computer model and the hardware.

The (Vehicle Inertia Parameter Evaluation Rig) VIPER II is a full vehicle mass and inertia parameter measurement machine. The VIPER II expands upon the capabilities of its predecessor and is capable of measuring vehicles with a mass of up to 45,360 kg (100,000 lb), an increase in capacity of 18,100 kg (40,000 lb). The VIPER II also exceeds its predecessor in both the length and width of vehicles it can measure. The VIPER II's maximum vehicle width is 381 cm (150 in) an increase of 76 cm (30 in) and maximum distance from the vehicle CG to the outer most axle is 648 cm (255 in) an additional 152 cm (60 in) The VIPER II is capable of performing measurements including vehicle CG height, pitch, roll, and yaw moments of inertia and the roll/yaw cross product of inertia. While being able to measure both heavier and larger vehicles, the VIPER II is designed to maintain a maximum error of 3% for all inertia measurements and 1% for CG height.

There are many methods developed over the past decade to solve the problem of energy management control for hybrid electric vehicles. A novel method is introduced in this paper to address the same problem which reduces the problem to a set of physical equations and maps. In simple terms, this method directly calculates the actual cost or savings in fuel energy from the generation or usage of electric energy. It also calculates the local optimum electric power that yields higher electric fuel savings (EFS) or lower electric fuel cost (EFC) in the fuel energy that is spent for driving the vehicle (which in general does not take the system to the lowest engine Brake Specific Fuel Consumption (BSFC)). Based on this approach, a control algorithm is developed which attempts to approach the global optimum over a drive cycle.

Cooled LPL EGR is a proven means of improving the efficiency of a Gasoline Turbocharged Direct-Injection engine. One of the most significant hurdles to overcome in implementing a LPL EGR system is dealing with condensation of water near the entrance of the turbocharger's compressor wheel. A gasoline engine, and to a greater extent a spark ignition engine running on Natural Gas, will encounter enough water condensation at some steady-state conditions to damage the compressor wheel due to the high-speed collision between the compressor blades and the water droplets. As an alternative to not utilizing beneficial EGR at the condensing conditions, the team at BorgWarner have developed a LPL EGR mixer that is effective at condensing and collecting the water droplets and routing the water around the compressor wheel. The new Condensing EGR mixer was developed from the known concept of utilizing a mild venturi section to enhance EGR delivery and mixing.

This paper presents the transient power optimization of an organic Rankine cycle waste heat recovery (ORC-WHR) system operating on a heavy-duty diesel (HDD). The optimization process is carried on an experimentally validated, physics-based, high fidelity ORC-WHR model, which consists of parallel tail pipe and EGR evaporators, a high pressure working fluid pump, a turbine expander, etc. Three different ORC-WHR mixed vapor temperature (MVT) operational strategies are evaluated to optimize the ORC system net power: (i) constant MVT; (ii) constant superheat temperature; (iii) fuzzy logic superheat temperature based on waste power level. Transient engine conditions are considered in the optimization. Optimization results reveal that adaptation of the vapor temperature setpoint based on evaporation pressure strategy (ii) provides 1.1% mean net power (MNP) improvement relative to a fixed setpoint strategy (i).

Roll forming assemblies are generally neat and robust, but there are structural integrity risks involved too if the forming procedures and design features do not complement each other. Specifically, in solenoid valves, an imprecised roller crimping (or forming) adversely affect the desired magnetic performance of the valves. Furthermore, in-depth evaluations of the formed shape using hardware and lab testing are extremely challenging cost wise and time consuming as well. However, utilizing simulation technique such as finite element analysis (FEA) to understand the in-sights of roller formed assemblies of a solenoid valve (or other products) could be an effective way to minimize overall cost and time involved in the product development. Therefore, a three-dimensional non-linear FEA model of roller crimping simulation was established in ANSYS Workbench Mechanical, and the predicted results were correlated with real hardware data to prove the technique & process adopted.

This paper gives a thorough review of the HC/CO emissions challenge and discusses the effects of different diesel oxidation catalyst designs in a pre turbine and post turbine position on steady state and transient turbo charger performance as well as on HC and CO tailpipe emissions, fuel economy and performance of modern Diesel engines. Results from engine dynamometer testing are presented. Both classical diffusive and advanced premixed Diesel combustion modes are investigated to understand the various effects of possible future engine calibration strategies.

In this study, an adaptive control mechanism is proposed to design a silencer applying variable volume resonator concept. Transfer matrix method is used to calculate the transmission loss and evaluate acoustic performance of the proposed mechanism. Effects of damping factor, area ratio of expansion chambers are examined first for a fixed double chamber resonator. Then a two-dimensional search scheme is developed to find optimal piston position that achieves maximum transmission loss with minimal effort. This study shows that the proposed adaptive silencer can efficiently attenuate noise when comparing with a conventional fixed resonator.

This paper describes the design and implementation of the SEA, Ltd. Brake and Throttle Robot (BTR). Presented are the criteria used in the initial design and the development and testing of the BTR, as well as some test results achieved with the device. The BTR is designed for use in automobiles and light trucks. It is based on a servomotor driven ballscrew, which in turn operates either the brake or accelerator. It is easily portable from one vehicle to another and compact enough to fit even smaller vehicles. The BTR is light enough so as to have minimal effect on the measurement of vehicle parameters. The BTR is designed for use as a stand-alone unit or as part of a larger control system such as the Automated Test Driver (ATD) yet allows for the use of a test driver for safety, as well as test selection, initiation, and monitoring. Installation in a vehicle will be described, as well as electronic components that support the BTR.

Trying to improve the modern diesel engine's NOx/soot tradeoff without giving up fuel economy continues to be a core target for the engine development community. One of the options not yet fully investigated for the diesel is applying variable valve events to the engine breathing process. Already used in some heavy-duty applications, late intake valve closing has long been regarded as a possible strategy for small diesel engines. Single-cylinder tests applying fully variable valve events have demonstrated potential but also raised doubts about VVA benefits on automotive size diesel engines. Full engine testing using realistic valve train technology is seen as key to judging its true performance because it covers not only combustion benefits but also influences like engine pumping on emissions and CO₂. Different to past publications, this paper focuses on testing a production feasible variable valve train technology on a fully instrumented modern Common Rail diesel engine.

In our introductory paper on the VEMB system (SAE 2010-01-1222) we discussed the concept of a divided exhaust period turbocharging system controlled by a concentric cam system, and we presented several fixed speed/load point sets of results that demonstrated the expected BSFC benefits. The BSFC reductions (2.5% to 4%) correlated to reduction in pumping work and to improvement in combustion phasing at knock-limited points from substantial reductions in Residual Gas Fraction compared to the conventionally-boosted baseline engine. In this paper we present additional results from engine tests in the areas of full-load performance and emissions with and without Scavenge-sourced EGR. To demonstrate the WOT performance potential of a VEMB engine, we show the effect of turbocharger matching steps, with results that exceed the baseline engine output across the engine speed range.

Using a 3 liter, 4 valves per cylinder, V6 Diesel engine model, this study investigates late intake valve closing (LIVC) time in an effort to reduce the fuel consumption of the engine. Two different intake cam duration technologies for diesel engines are evaluated using a 1-D engine simulation software code. The first method utilized for duration control delays the effective closing of the intake valve by moving one intake cam lobe with respect to the other baseline intake cam lobe. In the second method, the closing of both intake valves is delayed by the introduction of an adjustable dwell period during the closing portion of the valve motion. During this mid-lift dwell period, the lift is held at a constant value until it goes into the closing phase. The systems are evaluated and compared at 4 operating points of varying engine speed and load. At each operating point, while engine load is held constant, intake valve closing time is varied.

A dynamometer test methodology was developed for evaluation of HMMWV axle efficiency with hypoid gearsets, comparing those having various degrees of superfinish versus new production axles as well as used axles removed at depot maintenance. To ensure real-world applicability, a HMMWV variant vehicle model was created and simulated over a peacetime vehicle duty cycle, which was developed to represent a mission scenario. In addition, tractive effort calculations were then used to determine the maximum input torques. The drive cycle developed above was modified into two different profiles having varying degrees of torque variability to determine if the degree of variability would have a significant influence on efficiency in the transient dynamometer tests. Additionally, steady state efficiency performance is measured at four input pinion speeds from 700-2500 rpm, five input torques from 50 - 400 N⋅m, and two sump temperatures, 80°C and 110°C.

The tractor trailer models discussed in this paper were for a real-time hardware-in-the-loop (HIL) simulation to test heavy truck electronic stability control (ESC) systems [1]. The accuracy of the simulation results relies on the fidelity and accuracy of the vehicle parameters used. However in this case where hardware components are part of the simulation, their accuracy also affects the proper working of the simulation and ESC unit. Hence both the software and hardware components have to be validated. The validation process discussed in this paper is divided into two sections. The first section deals with the validation of the TruckSim vehicle model, where experimental data is compared with simulation results from TruckSim. Once the vehicle models are validated, they are incorporated in the HIL simulation and the second section discusses the validation of the whole HIL system with ESC.

This paper describes the mechanical design of a Suspension Parameter Identification Device and Evaluation Rig (SPIDER) for wheeled military vehicles. This is a facility used to measure quasi-static suspension and steering system properties as well as tire vertical static stiffness. The machine operates by holding the vehicle body nominally fixed while hydraulic cylinders move an “axle frame” in bounce or roll under each axle being tested. The axle frame holds wheel pads (representing the ground plane) for each wheel. Specific design considerations are presented on the wheel pads and the measurement system used to measure wheel center motion. The constraints on the axle frames are in the form of a simple mechanism that allows roll and bounce motion while constraining all other motions. An overview of the design is presented along with typical results.

A GT-suite commercial code was used to develop a fully integrated model of a light duty commercial vehicle with a V6 diesel engine, to study the use of a BorgWarner dual mode coolant pump (DMCP) in active thermal management of the vehicle. An Urban Dynamometer Driving Schedule (UDDS) was used to validate the simulation results with the experimental data. The conventional mechanical pump from the validated model was then replaced with the dual mode coolant pump. The control algorithm for the pump was based on controlling the coolant temperature with pump speed. Maximum electrical speed of the pump and the efficiency of the pump were used to determine whether the pump should run in mechanical or electrical mode. The model with the dual mode coolant pump was simulated for the UDDS cycle to demonstrate the effectiveness of control strategy.