Search Results

This paper will cover the development of a high-performance snowmobile variable speed belt from concept to successful implementation. The paper includes the definition of the extraordinary demands of this extremely high-performance application, formation and membership of the development team (including the dynamic membership of the team as the development phases were achieved), modeling of the drive geometry and discussion of the vast number of design variables which had to be balanced to achieve both superior drive functionality and belt durability. The end product is described in detail to illustrate the technology employed to address the severe conditions to which the belt is exposed. Finally, the paper details the test methods (both field and laboratory) and development of a unique, application specific, test dynamometer to evaluate the various belt attributes.

An analysis method for characterizing fuel behavior during spark-ignition engine starting has been developed and applied to several sets of start-up data. The data sets were acquired from modern production vehicles during room temperature engine start-up. Two different engines, two control schemes, and two engine temperatures (cold and hot) were investigated. A cycle-by-cycle mass balance for the fuel was used to compare the amount of fuel injected with the amount burned or exhausted as unburned hydrocarbons. The difference was measured as “fuel unaccounted for”. The calculation for the amount of fuel burned used an energy release analysis of the cylinder pressure data. The results include an overview of starting behavior and a fuel accounting for each data set Overall, starting occurred quickly with combustion quality, manifold pressure, and engine speed beginning to stabilize by the seventh cycle, on average.

A by-pass zeolite adsorber system consisting of a first catalyst, a by-pass loop containing the zeolite adsorbers followed by a downstream second catalyst was FTP tested using a U.S. vehicle equipped with a 3.8 L, V6 engine. The system exhibited ULEV emissions performance with hydrocarbon adsorption and regeneration (desorption and oxidation) within the FTP cycle and required only a single diversion valve within the exhaust line. Adsorption takes place during the initial 70 seconds of the FTP cycle. The adsorbers were regenerated with the exhaust gas plus injected air.

This paper reports a 2010 study undertaken to determine generic acceleration pulses for testing and evaluating advanced batteries for application in electric passenger vehicles. These were based on characterizing vehicle acceleration time histories from standard laboratory vehicle crash tests. Crash tested passenger vehicles in the United States vehicle fleet of the model years 2005-2009 were used. The crash test data were gathered from the following test modes and sources: 1 Frontal rigid flat barrier test at 35 mph (NHTSA NCAP) 2 Frontal 40% offset deformable barrier test at 40 mph (IIHS) 3 Side moving deformable barrier test at 38 mph (NHTSA side NCAP) 4 Side oblique pole test at 20 mph (US FMVSS 214/NHTSA side NCAP) 5 Rear 70% offset moving deformable barrier impact at 50 mph (US FMVSS 301). The accelerometers used were from locations in the vehicle where deformation is minor or non-existent, so that the acceleration represents the “rigid-body” motion of the vehicle.

A novel approach to control the output voltage of the generator on a hybrid electric vehicle is proposed in this paper. In addition to the voltage control, for safety reason, it is desirable to control the current of the generator when the machine is running. In order to control the current, the reference voltage is translated to reference current by an estimator. Then current convergence is ensured by controlling the excitation voltage. Thus the over-current is prevented in the system. The rate of convergence of the voltage tracking is discussed. Robustness of the control algorithm against parameter variation is also analyzed and compared with conventional approach. Simulation results show that the safety objective is achieved without sacrificing output performance of the generator.

The mass ratio of air to fuel (air-fuel ratio) of an operating internal combustion engine is a very important metric for pollution control. Typically the air-fuel ratio is not directly measured, but instead the excess air factor Lambda (λ) is used. Lambda is the ratio of actual air-fuel ratio to the stoichiometric air-fuel ratio. Commonly switching type sensors are used. Those can detect 3 states: λ =1, λ >1 and λ < 1, and are used under low and medium load conditions to keep λ in the optimum operating range for a catalytic converter. Wideband O2 sensors are exhaust analysis devices that are used to measure air-fuel mixtures over a very large range up to air. These sensors are used in more and more engines today for closed loop fueling control under all operation conditions. They are especially important for new lean-burn technologies, clean diesel applications and for alternative fuel engines.

Automotive crankshafts are subjected to fluctuating torques due to periodic explosions in the cylinders. Accurate three dimensional finite element modeling is often time consuming. The present research aims to reduce the pre-processing efforts by developing parametric software. A three-dimensional parametric finite element model of crankshaft is developed using brick and wedge elements. Crankshaft main journal bearings are modeled as linear springs and dashpots. The piston and reciprocating masses are lumped at the ends of the crank pins. Viscous damper as well as shaft material damping has been modeled. Results from the three-dimensional analysis have been compared with those obtained using beam element models to assess the capabilities and limitations of such simplified models. It has been demonstrated that the simplified beam element models result in significant errors and 3-dimensional finite element analysis is essential for accurate predictions.

The first-ever application of a hydrogen-free diamond-like carbon (H free DLC) coating to a mass-production gasoline engine reduces friction between the cylinder bore and piston by 18%. It is explained the reducing friction effect of H free DLC by oil film thickness of piston ring. When H-free DLC is applied to top ring, friction is over 10% reduced. Because low friction coating is effective in a thin oil film at a large area near top dead center (TDC). It is also found that the friction reduction effect is enhanced when low viscosity engine oil is used. DLC as a low friction coating is more effective in a thinner oil film. In this study, the adhesion strength of H-free DLC coating on piston rings is improved because of providing a smooth substrate, the new washing process and the optimized coating characteristics. Adhesion strength is verified by test results using actual parts considered to contribute to piston ring load.

In this paper, the effect of welded joints on the crashworthiness response of a hybrid system is presented. This hybrid system consists of a steel enclosure filled with different core materials: carbon-fiber reinforced polymer, glass-fiber reinforced polyamide, polyethylene terephthalate foam and natural cork conglomerate. The metallic enclosure is a cold-formed tube which has to be spot-welded to assemble the final design. The focus is set on the assessment of the effect of the pattern and the number of spot welds on the crashworthiness results in terms of absorbed energy. Results show that variations in the number or the geometric distribution of the spot welds have a direct and noticeable effect on the final amount of energy that the part can dissipate. This is due to the crushing mechanism of the metallic column which is highly sensitive to the way that cold-formed sections are joined.

Conventionally, the automotive outer panels, giving vehicle its shape, have been manufactured from steel sheets. The outer panels are subjected to loads due to wind loading, palm-prints, person leaning on the vehicle, cart hits, and hail stones for example. Consumer awareness about these two panel characteristics: Oilcanning and Dent resistance is increased, which has been observed in recent marketing studies. Apart from perceptive quality, another factor depending on the dent performance is insurance and respective cost implications. Dents can occur due to several reasons such as object hits, parking misjudgement, hail stones etc. Phenomenon can be divided into two types, static and dynamic denting. Static dent case covers scenario wherein interaction with outer panel is mostly quasi-static. Hail stones present dynamic case where object hits a panel with certain kinetic energy. Automotive companies usually perform static dent assessment to cover all the cases.

Approximately ninety percent of automotive wind tunnels in the world have incorporated or been built with a Moving Ground Plane (MGP). However, very little research has been published in the literature on the interaction of the MGP and the vehicle. The goal of this paper is to characterize the flow structures and unsteady motion of the isolated wheel wake and its interaction with a 5-belt MGP using numerical simulations. This paper is divided into three parts. In the first part, a Computational Fluid Dynamics (CFD) study is carried out on the Mears (2004) wheel using IDDES model where the CFD process to be used later is validated against the experimental data. In the second part, a simulation is carried out for a 5-belt MGP system and the verification is carried out using the Von Karman integral formula for the boundary layer development over the belts.

Controllability of ignition timing and combustion phase by means of dual-fuel direct injection strategy in jet-controlled compression ignition mode were investigated in a light-duty prototype diesel engine. Blended fuel with lower reactivity was delivered in the early period of compression stroke to form the premixed charge, while diesel fuel which has higher reactivity was injected near TDC to trigger the ignition. The effects of several important injection parameters including pre-injection timing, jet-injection timing, pre- injection pressure and ratio of pre-injection in the total heat value of injected fuel were discussed. Numerical Simulation by using CFD software was also conducted under similar operating conditions. The experimental results indicate that the jet-injection timing shows robust controllability on the start of combustion under all the engine load conditions.

In this paper a test bench for measuring the Static Transmission Error of two mating gears is presented and a comparison with the results obtained with the commercial software GeDy TrAss is shown. Static Transmission Error is considered as the main source of overloads and Noise, Vibration and Harshness issues in mechanical transmissions. It is defined as the difference between the theoretical angular position of two gears under load in quasi-static conditions and the real one. This parameter strictly depends on the applied torque and the tooth macro and micro-geometry. The test bench illustrated in this work is designed to evaluate the actual Static Transmission Error of two gears under load in quasi-static conditions. In particular, this testbed can be divided in two macro elements: the first one is the mechanism composed by weights and pulleys that generates a driving and a braking torque up to 500 Nm.

With the passage of the Kigali Amendment to the Montreal Protocol, HFC-134a refrigerant will be phased down in all markets worldwide, including those where automotive companies have been slow to embrace HFO-1234yf. Engineers are currently being challenged to design MAC systems using alternate low GWP refrigerants that are allowed by regulations, and are simultaneously cost-effective to manufacture, energy efficient, safe, reliable, affordable for consumers, and also suitable in electrified vehicles.

Historically, crash development component testing has been conducted using gravity-based vertical drop towers. The drop tower carriage is loaded to a specified weight, raised to a specific height to achieve an energy target, and dropped onto the part. This long-used approach has significant limitations with respect to achievable speed and energy, part orientation, impact angle, useable impact surface, component size, etc. With the wide variance in simulating today’s global crash scenarios, a better approach is being developed using an impact sled. The most significant advantage of this system is that there is a much higher achievable speed and energy which can be controlled with precise accuracy. This paper will provide an overview of the impact sled test system, as well as the methodology used to conduct the testing. The overview will include the challenges faced during the development of the impact sled, as well as the need for accurate and precise component fixturing methods.

Thermal management of vehicle battery pack is crucial in determining the life/ageing of the battery pack, in establishing the range of the vehicle on a day to day basis and in determining the safety of the vehicle and occupants. An effective design of a thermal management system cannot be established solely through experimentation as it is time consuming and costly. Accurate computational models are required to aid in the design process. This study describes the development and validation of 3D computational model for simulating electrical and thermal characteristics of a vehicle-ready battery module. The modeling process starts with the full 3D CAD geometry of the module including the coolant channels and cold plate. As part of the study, an experimental test case was setup. This included a climate chamber for the initial soak of the module and to control ambient temperature. Coolant was pumped through channels underneath the cold plate atop which the cells sat in blocks.

Since the Extended range electric vehicle (EREV) powertrain structure is based on different power sources, a key vehicle design activity is related to development of an optimal control strategy for achieving a high fuel economy potential. The central role in developing an optimized energy management strategy is related to availability of computationally-efficient, high-fidelity EREV powertrain model. This paper proposes a method for developing an extended quasi-static backward-looking EREV powertrain model, which when compared to traditional backward model accounts for powertrain transient effects through additional fuel and battery state-of-charge consumptions. The effects of powertrain transients are characterized by means of extensive simulations of dynamic forward-looking EREV powertrain model covering a wide array of possible powertrain transient scenarios.

There has been growing demand for increased fuel efficiency, reduced emissions and improved power performance while maintaining reliability and durability of mechanical and structural systems in many different industries. The structural engineering components often experience long loading histories, typically ten million cycles or greater, i.e. high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regimes. HCF in the range of 106-108 cycles and VHCF in the range of 108-1010 cycles are key design criteria for aerospace, automotive, military, transportation and many other industries. However, fatigue characterization of metal alloys in the HCF and VHCF regimes is hindered by limitations of traditional fatigue testing machines due to time and cost constraints. The development of high power piezoceramic actuators enables efficient and reliable fatigue tests in the HCF and VHCF regimes within a very short time frame on the basis of ultrasonic fatigue testing approaches.

Automotive powertrain mounting system (PMS) plays a key role in the vibration isolation and the comfort improvement in vehicle. So far, most of powertrain is modeled as a rigid body in 6 Degrees of Freedom (DOF) in research. Few comprehensive and overall optimization are considered which addresses the excitation of the powertrain, the vibration and noise inside the body and the transmission path of vibration together. In this paper, a 13-DOF model including automotive powertrain mounting system and the full vehicle is developed in order to achieve comprehensive and overall optimization for PMS. The minimum of vertical vibration at seat track and the noise at driver ear on the right side, the maximum of system's vibration isolation rate and the energy decoupling rate, the reasonable allocation of system natural frequencies are considered as the optimization targets. Genetic algorithm is used to solve the multi-objective optimization problem.