Search Results

The weight reduction and noise refinement of powertrain has been major concern in automotive industry although they are known as self trade-off. This paper presents various methods to deal with those problems for new Hyundai 1.5 liter powertrain. It was possible to reduce the weight of powertrain by using plastic for both headcover and intake manifold, aluminum for crankshaft damper pulley and stainless steel for exhaust manifold and by reducing the general thickness of cylinder block On the other hand, the noise refinement of vibration in the powertrain was made by optimizing the engine structure and by adapting the hydraulic lash adjuster valve train system, which was proved to be effective in mechanical noise of engine.

In this paper, four different levels of finite element models of a full vehicle were developed for ride comfort and brake judder dynamics analysis. The differences between the models are how elasticity of various vehicle components is modeled. The dynamic analysis was performed considering nonlinear effects for the different levels of models. The nonlinear effects were characterized by frequency and amplitude dependent stiffness and damping values of hydraulic engine mounting, suspension lower control arm bushing, tire, shock absorber, and suspension friction. At each modeling level, simulation results were compared to those of test measurements. The differences of the analysis results of these models and the effect of nonlinear characteristics were investigated. The developed models were applied to ride comfort and brake judder dynamics analysis.

A vehicle drifts due to several reasons from its intended straight path even in the case of no steering input. The multibody dynamic analysis of vehicle drift during accelerating and braking are performed. This paper focuses on modeling and evaluating effects of suspension parameters, differential friction, engine mounting and C.G. location of the vehicle under multibody dynamic simulation environment. Asymmetry of geometry and compliance between left and right side is considered cause of drift. The sensitivities of the suspension parameters are presented for each driving condition. In case of acceleration, the interaction of differential friction and driveshaft stiffness and their influence on drift are also studied. For braking condition, suspension parameters such as initial toe variation of rear coupled torsion beam axle type suspension and kingpin inclination deviation of front suspension are studied including the braking force difference.

It has been recently reported that the crankshaft vibration provides the main exciting source in the power train vibration. This paper presents the analytical method for the vibration of crankshaft by using the finite element method. The optimization process is employed so that the beam model of the crankshaft can have the same natural frequencies as those of solid model on the free-free condition. The mode analysis of the crankshaft whirling is made in the consideration of the gyroscopic effect and the changes of the natural frequencies are also studied with the increase of the engine speed. Finally, the forced vibration of the crankshaft is solved on the time domain and the results are compared with those of the experimental measurements of bending moment by using the strain gage. This crankshft system model can be used to analyze the forced vibration of the full power train as well.

High pressure fuel injection systems, such as common rail (CR) systems and electronically-controlled unit injector (EUI) systems, have been widely applied to modern heavy duty diesel engines. They are shown to be very effective for achieving high power density with high fuel efficiency and low exhaust gas emissions. However, the increased peak combustion pressure gives additional structural stress and thermal load to engine structure. Thus, proper material selection and thermal analysis of engine components are essential in order to meet the durability requirements of heavy-duty diesel engines adopting a high pressure injection system. In this paper, thermal analysis of a 12.9 ℓ diesel engine with an EUI system was studied. Temperatures were measured on a cylinder head, a piston and a cylinder liner. A specially designed linkage system was used to measure the piston temperatures. A radio-tracer technique was also used to verify the rotation of piston rings.

There have been strong moves in recent years to introduce the metal matrix composites concept into higher volume applications, notably the automotive field where large volume production and lower material costs are required. The wettability between reinforcing materials and base material is one of important factors for the strength of composites and its manufacture. The main objective of this paper is to establish a basic understanding of wetting phenomena in SiC/liquid aluminum and aluminum alloy systems. In the present paper, results from the sessile drop method are reported for the effects on the wetting angle, θ, of free silicon in the silicon carbide substrate and of alloying additions of silicon, copper or magnesium to the aluminum drop for the temperature range 700-900 or 1400°C in the titanium-gettered vacuum (1.3 x 10-2 / 1.3 x 10-3 Pa).

For the improvement of ride quality, development of vibration damping control systems and isolating methods become more important. To define basic ride vibrational modes, the effects of vehicle velocity and wheelbase on the standard road surfaces should be investigated. The different vibrational responses depending on the measurement positions of a vehicle body are presented with the bounce and the pitch motions. A methodology for the isolation of engine mount system's resonance to the road input and periodical excitations of tire/wheel nonuniformity forces are discussed. Using the computer simulation and the experimental results, a useful ride model with respect to the vehicle velocity and the stiffness of engine mount is presented.

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 effects of tempering on carburized Cr-Mo gear steel were investigated through mechanical and fatigue tests. Specimens were carburized at 900°C for 180 minutes, and then oil quenched at 150°C for 10 minutes of holding time and cooled to room temperature. The subsequent tempering process was performed to 160°C for 90 minutes. Surface hardness and residual compressive stress were decreased by tempering treatment, whereas tensile strength, yield strength and impact energy were increased. Bending fatigue endurance limits for both tempered and untempered specimens were same as 779MPa. The strength of roller contact fatigue is also not greatly influenced by tempering treatment. Thermal distortion for carburized transfer driven gear before and after tempering exhibited a similar distribution. Microstructural changes during tempering were also discussed.

In recent years, high performance engines and the reduction in engine room due to aerodynamic styling has caused increases in engine room temperature. Because of this increasing temperature, the conventional natural rubber engine mount is now at the marginal point on its performance and durability. Several heat resistant materials have been considered for engine mount applications because of this reason. Polychloroprene rubber could be a strong candidate for engine mount application due to its balance of heat resistance, dynamic properties, and fatigue life. This paper will discuss the development of the technology, property characteristics and part performance simulations on the HYUNDAI BUSH TYPE COMPLEX ENGINE MOUNT (for 2.0L DOHC ENGINE). This type of mount requires higher creep resistance and fatigue life than those of other designs, such as block or simple shear type mounts. Early evaluations of polychloroprene mounts have shown some deficiencies in creep resistance.

Main design features and some of the development work carried out on the first new engines to be produced in-house by Hyundai Motor Co. are described. The Alpha family of multi-valve, four cylinder engines comprises 1.3 and 1.5L naturally aspirated units and a 1.5L turbocharged version. Modern features are incorporated in the engines in order to provide higher performance and good fuel economy with excellent durability at reasonable cost. Hyundai Motor Co. (HMC) was established in 1967 and, in the following year, commenced production of passenger cars for the domestic market, using CKD components supplied by Ford of Europe. In 1974 the Pony saloon car entered production; this used mainly locally produced components but most of the major items, including the power train - engine and gearbox - were manufactured under the license from Mitsubishi Motors.

In order to investigate the characteristics of top ring groove deposit formation in gasoline and diesel engine, engine test and simulation test were performed. From component analysis of used oils sampled from actual running engines, oxidation and nitration for gasoline engine and soot content for diesel engine were selected as main parameters for evaluating oil degradation. In gasoline engine, deposit formation increases linearly with oxidation and nitration, and especially, oil oxidation is a dominant factor on the deposit formation rather than nitration. And, deposit formation increases gradually in low temperature ranges below 260°C even if oils are highly oxidized, but it increases rapidly if piston top ring groove temperature is above 260°C. In diesel engine, deposit formation is highly related to soot content in lubricating oils.

As CO2 legislation tightens, the next generation of turbocharged gasoline engines must meet stricter emissions targets combined with increased fuel efficiency standards. Recent studies have shown that the following technologies offer significant improvements to the efficiency of turbocharged GDI engines: Miller Cycle via late intake valve closing (LIVC), low pressure loop cooled EGR (LPL EGR), port water injection (PWI), and cylinder deactivation (CDA). While these efficiency-improving technologies are individually well-understood, in this study we directly compare these technologies to each other on the same engine at a range of operating conditions and over a range of compression ratios (CR). The technologies tested are applied to a boosted and direct injected (DI) gasoline engine and evaluated both individually and combined.

As CO2 legislation tightens, the next generation of turbocharged gasoline engines must meet stricter emissions targets combined with increased fuel efficiency standards. Promising technologies under consideration are: Miller Cycle via late intake valve closing (LIVC), low pressure loop cooled exhaust gas recirculation (LPL EGR), port water injection (PWI), and cylinder deactivation (CDA). While these efficiency improving options are well-understood individually, in this study we directly compare them to each other on the same engine at a range of operating conditions and over a range of compression ratios (CR). For this purpose we undertake a comprehensive simulation of the above technology options using a GT-Power model of the engine with a kinetics based knock combustion sub-model to optimize the fuel efficiency, taking into account the total in-cylinder dilution effects, due to internal and external EGR, on the combustion.

Anti-vibration rubbers in vehicle play an important role in restricting vibration generated from engine and road. But, degradation occurs when rubber is exposed for a long time to heat, light, ozone and etc. These make the rubber hard and lose its initial properties. The rubber change makes N.V.H performance of vehicle the worse, and gives the discomfort to the passengers. To reduce the change of rubber properties, sulfur-donor and heat stable cross-linking co-agent vulcanization system have been introduced in the developed natural rubber compounds of the anti-vibration rubber parts. These lead to a reduction of degradation of material properties, maintenance of the initial properties and increase of the fatigue life.

An automobile's structure is generally connected by spot welding the sheets together. Sometimes more than three layers of sheets can be used in a certain location for spot welding due to the limits of design conditions. Static strength and the fatigue life characteristics can be changed according to the welding conditions, which depend on the material, the thickness, and the number of sheets. Setting the appropriate conditions of multi-layer spot welding can be determined by analyzing static strength and fatigue life. For converting multi-layer spot welding to that of twofold layer with equal strength, the converting method can be suggested from static and fatigue test results. The increasing rate of static strength is larger than that of fatigue life, so it is reasonable to use fatigue life for limit condition.

This paper describes Hyundai's research and development work on a flexible fuel vehicle (FFV). The work on FFV has been conducted to evaluate its potential as an alternative to the conventional gasoline vehicle. Hyundai FFV described here can operate on M85, gasoline, or any of their combinations, in which the methanol concentration is measured by an electrostatic type fuel sensor. For that operation, a special FFV ECU has been developed and incorporated in the FFV. The characteristics affecting FFV operation, such as FFV ECU control strategy and injector flow rate, have been investigated and optimized by experiment. Various development tests have been performed in view of engine performance, durability, cold startability, and exhaust emissions reduction. The exhaust gas aftertreatment system being consisted of manifold type catalytic converter(MCC) and secondary air injection system has shown good emission reduction performance including formaldehyde emission.

Recently, flexible fuel vehicle (FFV) has been drawn great attention because of its response for immediate use as alternative fueled one. Hyundai FFV can be operated on arbitrary fuel mixtures between gasoline and M85 with the specially programmed electronic control unit (ECU) which can determine optimized fueling quantity and ignition timing as the methanol content by the signal from electrostatic type fuel sensor. In this paper, the results of various tests including engine performance, cold startability, durability and exhaust emission reduction have been described. Full load, cold mode durability tests and field trials have been carried out with some material changes and surface treatments in the lubricating parts and fuel system. But, more work on its durability improvement is still required.

A preconverter is an essential component of the new vehicle exhaust system for the achievement of tightened emission standards. To meet those standards, the Manifold Catalytic Converter (MCC) system has been developed in the Hyundai Motor Company (HMC). Unfortunately, the conventional MCC is no longer a suitable design for the exhaust gas treatment of the newly developed high performance engine since it cannot withstand the engine's exhaust temperature, vibration, pressure pulsation, and many other severe conditions. This paper is focused on a failure-mode analysis and new packing designs for the MCC application through a series of durability tests.