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In this study, single cylinder engines with different tumble ratio were made to show the effects of tumble motion on engine performance and flame propagation. Particle tracking velocimetry technique by using chopper was adopted to examine the in-cylinder flow field for the full understanding of tumble motion. And equivalent angular speed of tumble vortex was obtained from each crank angle and compared with tumble ratio derived from the steady state flow rig test. Flame propagation speed were obtained with the gasket ionization probe and the piston ionization probe. And the combustion pressure in cylinder was measured to analyze the combustion characteristics. In case of high tumble engine, BSFC and BSHC were decreased and BSNOx was increased at part load test, BMEP and combustion peak pressure was increased at full load test. Also, flame propagation characteristics could be understood by use of piston ionization probe.

The acoustic phenomena which take place inside an intake system greatly influence the volumetric efficiency of an engine. This paper deals with the problem of improving the volumetric efficiency of a single cylinder engine for a wide range of frequencies. The proposed solution is the addition of tunable resonators to the intake system. The variation of resonator tuning makes it possible to exploit the acoustic vibrations for a wide range of piston frequencies in the best way. Several intake systems equipped with resonators are studied using analytical methods. The best results are obtained when an in-series resonator with a variable volume is placed near the cylinder and when a side-branch resonator with a variable cross section is connected to a constant volume resonator. Several results are presented which deal with the behavior of the intake system during the induction stroke and which show the effectiveness of tunable resonators.

REEV (Range-Extended Electric Vehicle) can avoid the mileage anxiety of BEV (Battery Electric Vehicle). Nevertheless, RE (Range Extender) for passenger cars prefers to use ICE (Internal Combustion Engine) with smaller displacement and lower cylinder number, which is usually with a worse vibration performance at low speeds. As RE only outputs electricity, it provides the possibility to optimize NVH (Noise, Vibration, and Harshness) of the engine by PMSM (Permanent Magnet Synchronous Motor). By real-time control, the electromagnetic torque of PMSM can track the shaft torque fluctuation during engine strokes, especially the combustion stroke. When the instability and rolling torque of RE could be suppressed, NVH performance of RE can be improved. This paper presents simulation research on speed fluctuation suppression for RE engine based on dynamic torque compensation by controlling a PMSM.

A turbulent entrainment model is considered to be reasonable for the combustion in a spark-ignition engine. For this kind of model, it is important to estimate the turbulence characteristics, turbulent burning velocity, flame surface area and several empirical constants. Nevertheless, the examination of these values have not been examined sufficiently. In this study, a combustion model was proposed, and initiation of flame propagation, burning process of an eddy, scale of turbulence and turbulent burning velocity were discussed in detail. This model was examined under various conditions of engine speed (600-1200rpm), compression ratio (3.2-4.8) and ignition timing. The calculation results of mass fraction burned, burn rate and burn duration were in good agreement with the experimental ones. It was found that the concept of such a turbulent entrainment model was valid for predicting the combustion in a spark-ignition engine.

The influence of turbulence on automotive aerodynamics requires further investigation. This paper provides evidence that turbulence directly affects average and peak forces on the front door of a sedan automobile. Wind tunnel and several on-road test conditions were investigated. The results include instantaneous peak and average force coefficients, together with experimental pressure contour plots for a sedan front door. The pressure distribution over the front door of an automobile is important for efficient structural and door seal design. Door pressure distributions vary with flow turbulence characteristics. The results presented in this paper show that turbulent properties of the flow are of importance when investigating flow over the front door of a sedan automobile.

A cylindrical combustion bomb with dynamic charging system and electro-hydraulic sampling valve is used to study the effects of turbulence on hydrocarbon (HC) emissions from a quench layer and from artificial crevices. The turbulence level is varied by changing the delay time between induction of combustible charge and ignition. Propane-air mixtures were studied over an initial pressure range of 150 to 500 kPa and equivalence ratios of 0.7 to 1.4. Sampling valve experiments show that quench-layer fuel hydrocarbons are extensively oxidized within 5 ms of flame arrival under laminar conditions and that turbulence further reduces the already low level. Upper limit estimates of the residual wall layer HC concentration show that residual quench layer hydrocarbons are only a small fraction of the exhaust HC emission.

This article first analyzes the driving characteristics of vehicles in Intelligent Vehicle Infrastructure Cooperative Systems, summarizing and proposing four characteristics, including a wider field of view, easier lane-changing conditions, less speed loss, and more flexible cooperation among vehicles than in the traditional lane-changing situation. Analysis and comparison of the update sequence in cellular automata based on the four characteristics, namely, synchronous update and asynchronous update, longitudinal vehicle sequence update and random update, horizontal express vehicle priority, and random priority. Three kinds of cooperative lane changes unique to the vehicle-road collaborative environment were discovered, which are dangerous lane change, slow car giving way, and space redistribution. The three kinds of coordinated lane change were simulated and compared with the basic diagram of the improved model and the traditional model.

It is the purpose of this paper to make clear the effect of typical torsional viscous-friction damper on the reduction of the axial, torsional and two directions of lateral vibrations from the analytical and experimental points of view. At first, a typical type of the torsional viscous-friction damper is fitted to a high-speed diesel engine and the axial, torsional and two directions of lateral vibration displacements at the pulley end are measured in order to investigate the effect of the damper on the reduction of these vibrations in the three dimensional space of the engine shaftings from the experimental point of view. Next, the characteristics of the axial, torsional and two directions of lateral vibrations of the engine shaftings are investigated by three dimensional analysis of forced vibration by the transfer matrix method, which has been developed by the authors.

This paper investigates the response of the wheel slip to brake torque perturbations during a braking manoeuvre as the wheel slip state and the vehicle speed change. Its purpose is to better understand and model the wheel slip response characteristics during braking and to inform the development process of an antiskid wheel slip controller. The developed controller is implemented in the Simulink environment on a half-car vehicle model using a nonlinear electromechanical brake (EMB) model. A linearised analysis of the wheel slip response to brake torque perturbations about a nominal “trim” condition is first performed, based on a quarter-car vehicle model. It is shown that the inclusion of first-order tyre dynamics (characterised by the so-called “relaxation length”) has a significant effect on the dynamics of the “plant” seen by the slip controller and these dynamics vary significantly with the trim value of the slip and the vehicle speed.

A carburetor for a 1968 six-cylinder Ford engine was modified to meter gasoline into the engine through an ultrasonic horn. The engine, mounted on a test stand, was loaded by a water dynamometer. The tests were performed with the horn alternately activated and deactivated for two different tip configurations. Engine operating data were taken at five throttle positions and thermal efficiency and specific fuel consumption were determined for each of these positions. Marked improvement (5-10%) in these parameters was obtained at an ultrasonic power input of 20 watts.

A major trend in current automotive research is hybridization of the power supply. This combination of electrical machine and combustion engine results, in some hybridization topologies, in a total decoupling of the combustion engine from the transmission. When the engine is decoupled from the transmission a new degree of freedom arises in engine design. The piston movement does not have to follow an evenly rotating shaft any more. It can be altered by the generator to achieve a movement found to be better from the point of efficiency or environmental concerns. Modelling work showed a potential of lowered NO emissions if the expansion could be delayed. The experimental study, conducted in a two piston Alvar engine, showed that the state of the art electrical machine (EM) propelling one of the crankshafts was too weak to change the crankshaft speed in an extent to give the fast volume changes required to change the emissions of the internal combustion engine (ICE).

In order to explore approaches for improving object detection accuracy in intelligent vehicle system, we exploit super-resolution techniques. A novel method is proposed to confirm the conjecture whether some popular super-resolution networks used for environmental perception of intelligent vehicles and robots can indeed improve the detection accuracy. COCO dataset which contains images from complex ordinary environment is utilized for the verification experiment, due to it can adequately verify the generalization of each algorithm and the consistency of experimental results. Using two representative object detection networks to produce the detection results, namely Faster R-CNN and YOLOv3, we devise to reduce the impact of resizing operation. The two networks allow us to compare the performance of object detection between using original and super-resolved images. We quantify the effect of each super-resolution techniques as well.

Three cars have been operated for approximately 8000 miles on each of four unleaded gasolines. These gasolines encompassed varied levels of C6-C8 aromatics and varied polynuclear aromatic (PNA) content. Exhaust PNA emissions and lube oil PNA content were measured periodically during the course of mileage accumulation. Results of this study show that increases in both light C6-C8 fuel aromatics and fuel-contained PNAs can result in significantly increased exhaust PNAs. Vehicles meeting increasingly stringent hydrocarbon (HC) and carbon monoxide (CO) emissions standards emit greatly reduced quantities of exhaust PNAs, though the rate of lube oil PNA accumulation appears to be unaffected by emissions control systems. Accumulated lubricating oil mileage was found to correlate with increased PNA emissions with a high level of statistical significance. This may be the result of an observed increase in lube oil PNA content with mileage accumulation.

The knock behavior of two groups of unleaded gasolines, each of which includes three fuels with different chemical compositions but comparable standard octane numbers, has been analyzed using a mass-produced engine. The aim of the work was to point out possible inconsistencies between the standard octane numbers of the fuels and their knock behavior in mass-produced engines. The fuels of the first group had R.O.N.s and M.O.N.s very close to the minimum values required by European Community regulations (95 and 85, respectively), whereas the fuels of the second group had higher R.O.N.s and M.O.N.s (about 100 and 87.5, respectively). One of the tested fuels in the first group was a typical European unleaded gasoline, the other gasolines had higher olefin or aromatic contents. An increase of the aromatic content has not shown appreciable differences between the expected knock behavior of the fuel from its standard octane numbers, and its performance on the mass-produced engine.

Automotive engineers use the wind tunnel to improve a vehicle’s aerodynamic properties on the road. However, a car driving on the road does not experience the steady-state, uniform flow characteristic of the wind tunnel. Wind, terrain and traffic all cause the flow experienced by the vehicle to be highly transient. Therefore, it is imperative to understand the effects of forces acting on the vehicle resulting from unsteady flow. To this end, the FKFS swing® installed in the University of Stuttgart’s model scale wind tunnel was used to create 36 different incident flow signals with time-resolved yaw angles. The cD values of five different 25% vehicle models, each with a notchback and a squareback configuration, were measured while under the influence of the aforementioned signals. The vehicle models were chosen to ensure a variety of different geometries, but at the same time also to enable isolated comparison of specific geometric properties.

In the ECE 127 Regulation on pedestrian leg protection, as well as in the Euro NCAP test protocol, a legform impactor hits the vehicle at the speed of 40 kph. In these tests, the knee is fully extended and the leg is not coupled to the upper body. However, the typical configuration of a pedestrian impact differs since the knee is flexed during most of the gait cycle and the hip joint applies an unknown force to the femur. This study aimed at investigating the influence of the inertia of the upper body (modelled using an upper body mass fixed at the proximal end of the femur) and the initial knee flexion angle on the lower limb injury outcome. In total, 18 tests were conducted on 18 legs from 9 Post Mortem Human Subjects (PMHS). The principle of these tests was to impact the leg at 40 kph using a sled equipped with 3 crushing steel tubes, the stiffness of which were representative of the front face of a European sedan (bonnet leading edge, bumper and spoiler).

As open-wheeled racing cars frequently race in close proximity, a limiting factor on the ability to overtake is the aerodynamic performance of the vehicle while operating in a leading car's wake. Whilst various studies have examined the effectiveness of wings operating in turbulent flow, there has been limited research undertaken on the aerodynamic effect of such conditions on wheels. This study describes the influence of upstream turbulence on the wake flow features of an isolated wheel, since the flow field of a wheel will generally be turbulent (due to the wakes of upstream cars and/or bodywork). Pressure distributions and velocity vector plots are examined, which were obtained using a four-hole pressure-sensitive Cobra probe on a traverse 2.5 diameters downstream of the wheel axle line, in smooth and turbulent flow.

Currently, a majority of the ‘gasoline’ sold at the pumps in the United States is a nominal blend of 90% gasoline and 10% ethanol. This mixture is commonly referred to as E10. This paper reports on a study conducted to determine the effects of E10 on the fuel system performance of vintage automobiles. The study focused on the potential degradation in performance of the carburetors and fuel pumps due to exposure to E10. Six fuel systems were selected for study including the 1948 Flathead Ford, 1958 Volkswagen Beetle, 1962 Ford Falcon, 1969 Chevrolet Bel Air and 1970 Chrysler New Yorker. The components tested were either rebuilt original equipment or new aftermarket replacement parts, depending on availability. Although the components tested were not all original equipment parts, they represent a reasonable sample of the types of parts likely to be found in vintage vehicles currently on the road. The fuel system components were tested under both dynamic and static conditions.

This work was conducted to evaluate the effects resulting from the use of various VI improvers in multigrade engine oils on automobile oil economy. The test oils were formulated to be of similar viscosity in the SAE 5W-40 viscosity grade. The VI improvers tested covered a range of permanent shear stability, temporary shear stability and thickening characteristics. Engine oil volatility was the only variable which could be identified as having a significant effect on automobile oil economy. The oils containing the styrene/diene VI improver were less volatile than all other oils tested and provided statistically significant improvements in oil economy. Permanent shear stability, high temperature/high shear viscosity, and in-use (used-oil) viscosity could not be identified as having a significant effect on automobile oil economy of the SAE 5W-40 oils studied.

A number of Variable Valve Actuators (VVA) has been recently proposed to improve the performances and the part load efficiency of spark ignition engines. Due to their peculiarity, these systems work with different strategies (late or early inlet valve closing, reduced lift etc.). The shape and the timing of the valve lift affect not only the pumping losses, but also air motion inside the cylinder. That influences mixture formation and combustion evolution of Direct Injection Spark Ignition (DISI) engines. The present paper compares the performances of different VVA systems with the aid of a 1D code for the simulation of the inlet and of the exhaust phases, and of a fluid-dynamic 3D code to evaluate mixing phenomena inside the cylinder.