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Technical Paper

Analysis of the Gear Shift Mechanisms by R-R Chart Method

2001-03-05
2001-01-1163
A new point of view in automatic transmission is proposed by R-R chart, which is a new analytic method based on the linearity of planetary gear and gear shift mechanism. The R-R chart is a visual tool to describe the whole motion of each rotational element of planetary gears in relation to the gear shift mechanism. Therefore, anyone can easily find on R-R chart not only the substance of the gear shift mechanisms in present automatic transmissions but also new gear shift mechanisms for the future automatic transmissions. This paper shows that the R-R chart is unique in 4-speed automatic transmissions with fixed compound planetary gear sets. As a result of the R-R chart application, this paper classifies the fixed compound planetary gear sets with 4 elements into 12 sets and the gear shift mechanisms into 3 types. Also, 4 R-R characteristic equations are derived as a correlation between speed ratios in 4-speed automatic transmissions.
Technical Paper

The COANDA Flow Control and Newtonian Concept Approach to Achieve Drag Reduction of Passenger Vehicle

2001-03-05
2001-01-1267
In order to reduce total drag during aerodynamic optimization process of the passenger vehicle, induced drag should be minimized and pressure drag should be decreased by means of applying streamlined body shape. The reduction of wake area could decrease pressure drag, which was generated by boundary layer separation. The induced drag caused by rear axle lift and C-pillar vortex can be reduced by the employing of trunk lid edge and kick-up or an optimized rear spoiler. When a rear spoiler or kick-up shape was installed on the rear end of a sedan vehicle, drag was reduced but the wake area became larger. This contradiction cannot be explained by simply using Bernoulli’s principle with equal transit or longer path theory. Newtonian explanation with COANDA effect is adopted to explain this phenomenon. The relationships among COANDA effect, down wash, C-pillar vortex, rear axle lift and induced drag are explained.
Technical Paper

A Study of Flow Characteristics Inside the Two Types of Exhaust Manifold and CCC Systems

1999-03-01
1999-01-0457
A study of unsteady compressible flow for two types of exhaust manifold and CCC (Close-Coupled Catalyst) systems attached to a 4-cylinder DOHC gasoline engine was carried out to investigate the flow distribution of exhaust gases and finally to make the conversion efficiency of catalyst better. An experimental study was conducted, using LDV technique, to measure the velocity distributions inside exhaust manifolds and CCC under practical engine conditions. In this study, through experiment and calculation, the effects of geometric configuration of exhaust manifold on flow maldistribution in monolith were mainly investigated to understand the exhaust flow structure in terms of flow uniformity and to improve the conversion efficiency. As a result of this fundamental study, the modified exhaust manifold (Type B) was designed and manufactured. Full load performance tests and vehicle emission tests were performed to see the effects of flow characteristics on engine performance and emission.
Technical Paper

Improvement of Fatigue Strength of Automatic Transmission Gear by Developing Controlled Rolled Alloy Steel

2000-03-06
2000-01-0614
The controlled rolling process has been introduced to increase strength and toughness of alloy steels for the application of transmission gear. Cr-Mo alloy steel containing 0.02% Nb was controlled rolled in the temperature range of 870-970°C, showed fine austenite grain size, about ASTM No.11, resulted from the effects of recrystallization and Nb(C,N) precipitation. To investigate the effects of grain refinement on mechanical properties, several tests were conducted for the newly developed controlled rolled steel and conventional Ni-Cr-Mo alloy steel after carburizing. The new steel showed 2.1 times higher pitting resistance than the conventional steel. Fatigue limits of new and conventional steels were 950 and 930 MPa respectively. Charpy impact energy of new steel was improved about 35% compared with the conventional steel. Consequently, the pinion gear from the new steel instead of conventional one showed enhanced performance, especially pitting resistance, in dynamometer test.
Technical Paper

Development Work on HMC'S Natural Gas-Fueled 1.5 L MPI DOHC Engine

1993-11-01
931869
Thii paper describes Hyundai's research and development work on the dedicated compressed natural gas (CNG) engine, A conventional light duty gasoline engine, a 1.5 liter four cylinder DOHC, has been modified to run on natural gas (NG) by a gas injection system and engine dynamometer test has been performed with emphasis on optimizations of compression ratio and intake port. Also presented are the results on the exhaust emissions characteristic and the purification performance of three-way catalytic converters developed for NG engine. Fuel composition and THC emissions are analyzed quantitatively using gas chromatography devices.
Technical Paper

A Study of Flame Propagation for Different Combustion Chamber Configurations in an SI Engine

1997-02-24
970876
High speed natural light motion picture records synchronized with head gasket ionization probe and in-cylinder pressure data have been made in the transparent engine of different combustion chamber configurations. For knocking cycles, the head gasket ionization current method simultaneously taken with pressure data was able to find the location of knocking occurrence. To investigate the effects of combustion chamber configurations, the flame propagation experiments for pent-roof combustion chamber with center ignition ( Modified Type I engine ) and modified pent-roof ( Type II engine ) combustion chamber were performed with high speed natural light photography technique. The flame propagation of Modified Type I engine represents more uniform patterns than that of Type II engine. The investigation of knocking combustion was also made possible by observing flame propagation with the measuring techniques that use head gasket ionization probe and in-cylinder pressure data.
Technical Paper

A Study on the Influence of Plastic Intake Manifold on the Performance and NVH of In-line 4 Cylinder Gasoline Engine

1998-02-01
980728
The primary purpose of using a plastic material instead of conventional aluminum cast for intake manifold is to reduce its weight and cost. Moreover, the use of plastic for intake manifold is regarded as a key for further development of so called an “intake modular system”. As a secondary effect, the engine power can be increased with the help of improved interior surface roughness and lowered air temperature. With regard to NVH, however, plastic intake manifold is considered somewhat negative since it is less rigid and less dense than aluminum one. In this paper, the mechanism that plastic intake manifold affects the performance and NVH of in-line 4 cylinder gasoline engine is presented. In connection with engine performance, air flow efficiency of not only intake manifold itself but also other components of intake system and also cylinder head is evaluated.
Technical Paper

Developing the Thermoplastic Water Pump and Power Steering Pulley for a Passenger Car

1998-02-01
980736
The thermoplastic automotive pulley has been developed and will be commercialized to high volume production that achieves cost saving and weight reduction over other automotive pulleys in the metal and thermosetting resin by Hyundai Motor Company. Design feature incorporated in this automotive pulley allow it to be manufactured and assembled onto the water pump more efficiently in consequence of design integration with the water pump and power steering pulley. However, the harsh environment and dynamic loads that the thermoplastic pulley has to withstand required extensive CAE analysis and testing of the molded parts and the standard glass reinforced PA was selected for the application to maximize cost savings. The key aspects of the plastic automotive pulley as well as its advantage are presented.
Technical Paper

A Study of the Auxiliary Belt Drive System for Actual Fuel Saving

2017-03-28
2017-01-0898
The engine indicated torque is not delivered entirely to the wheels, because it is lowered by losses, such as the pumping, mechanical friction and front auxiliary power consumption. The front auxiliary belt drive system is a big power consumer-fueling and operating the various accessory devices, such as air conditioning compressor, electric alternator, and power steering pump. The standard fuel economy test does not consider the auxiliary driving torque when it is activated during the actual driving condition and it is considered a five-cycle correction factor only. Therefore, research on improving the front end auxiliary drive (FEAD) system is still relevant in the immediate future, particularly regarding the air conditioning compressor and the electric alternator. An exertion to minimize the auxiliary loss is much smaller than the sustained effort required to reduce engine friction loss.
Technical Paper

Influence of the Injector Geometry at 250 MPa Injection in a Light-Duty Diesel Engine

2017-03-28
2017-01-0693
This paper investigated the influence of the injector nozzle geometry on fuel consumption and exhaust emission characteristics of a light-duty diesel engine with 250 MPa injection. The engine used for the experiment was the 0.4L single-cylinder compression ignition engine. The diesel fuel injection equipment was operated under 250MPa injection pressure. Three injectors with nozzle hole number of 8 to 10 were compared. As the nozzle number of the injector increased, the orifice diameter decreased 105 μm to 95 μm. The ignition delay was shorter with larger nozzle number and smaller orifice diameter. Without EGR, the particulate matter(PM) emission was lower with larger nozzle hole number. This result shows that the atomization of the fuel was improved with the smaller orifice diameter and the fuel spray area was kept same with larger nozzle number. However, the NOx-PM trade-offs of three injectors were similar at higher EGR rate and higher injection pressure.
Technical Paper

Effect of Hydrogen as an Additive on Lean Limit and Emissions of a Turbo Gasoline Direct Injection Engine

2015-09-01
2015-01-1886
For gasoline engine, thermal efficiency can be improved by using lean burn. However, combustion instability occurs when gasoline engine is operated on lean condition. Hydrogen has features that can be used for improving combustion stability of gasoline engine. In this paper, an experimental study of hydrogen effect on lean limit was carried out using a four-cylinder 2.0L turbo gasoline direct injection engine. The engine torque was fixed at 110Nm on 1600RPM, 2000RPM and 2400RPM. The results showed that lean limit was extended and brake thermal efficiency was improved by hydrogen addition. Especially, at lower engine speed, the large improvement of lean limit was achieved. However, improvement of brake thermal efficiency was achieved at high speed. HC and CO2 emissions were decreased and NO emissions increased with hydrogen addition. CO emissions were slightly reduced with hydrogen addition.
Technical Paper

Assessing Panel Noise Contribution of a Car Engine Using Particle Velocity Sensors

2015-06-15
2015-01-2248
In order to apply an effective noise reduction treatment determining the contribution of different engine components to the total sound perceived inside the cabin is important. Although accelerometer or laser based vibration tests are usually performed, the sound contributions are not always captured accurately with such approaches. Microphone based methods are strongly influenced by the many reflections and other sound sources inside the engine bay. Recently, it has been shown that engine radiation can be effectively measured using microphones combined with particle velocity sensors while the engine remains mounted in the car [6]. Similar results were obtained as with a dismounted engine in an anechoic room. This paper focusses on the measurement of the transfer path from the engine to the vehicle interior in order to calculate the sound pressure contribution of individual engine sections at the listener's position.
Technical Paper

Closed-Loop Control for Diesel Combustion Noise Using Engine Vibration Signals

2015-06-15
2015-01-2297
The combustion noise of a diesel engine can be deteriorated by combustion characteristics such as the maximum rate of heat release and the start of combustion. These combustion characteristics in turn are influenced by the factors such as the engine NVH durability, driving conditions, environmental factors and fuel properties. Therefore, we need to develop the robust combustion noise that is insensitive to these factors. To achieve this aim, methods for predicting combustion characteristics has been developed by analyzing the vibration signal measured from the engine cylinder block. The closed-loop control of injection parameters through combustion characteristics prediction has been performed to produce the desired engine combustion performance. We constructed an ECU logic for the closed-loop control and verified the design in a diesel passenger car. We also evaluated the effect of combustion noise and fuel consumption by applying the closed-loop control.
Technical Paper

Effect of Injector Nozzle Hole Geometry on Particulate Emissions in a Downsized Direct Injection Gasoline Engine

2017-09-04
2017-24-0111
In this study, the effect of the nozzle tip geometry on the nozzle tip wetting and particulate emissions was investigated. Various designs for the injector nozzle hole were newly developed for this study, focusing on the step hole geometry to reduce the nozzle tip wetting. The laser induced fluorescence technique was applied to evaluate the fuel wetting on the nozzle tip. A vehicle test and an emissions measurement in a Chassi-Dynamo were performed to investigate the particulate emission characteristics for injector nozzle designs. In addition, the in-cylinder combustion light signal measurement by the optical fiber sensor was conducted to observe diffusion combustion behavior during the vehicle test. Results showed that the step hole surface area is strongly related to nozzle tip wetting and particulate emissions characteristics. Injectors without the step hole and with a smaller step hole geometry showed significant reduction of nozzle tip wetting and number of particulate emissions.
Technical Paper

Transient Nonlinear Full-Vehicle Vibration Analysis

2017-03-28
2017-01-1553
This paper presents a transient vibration analysis of a nonlinear full-vehicle. The full-vehicle model consists of a powertrain, a trimmed body, a drive line, and front and rear suspensions with tires. It is driven by combustion forces and runs on a road surface. By performing time-domain simulation, it is possible to capture nonlinear behavior of a vehicle such as preload due to gravitational force, large deformation, and material nonlinearity which cannot be properly treated in the conventional steady state analysis. In constructing a full-vehicle, validation process is essential. Validation process is applied with respect to the assembling sequence. The validation starts with component levels such as tires, springs, shock absorbers, and a powertrain, and then the full-vehicle model is constructed. Model validation is done in two aspects; one is model accuracy and the other is model efficiency.
Technical Paper

Development of High Efficiency Gasoline Engine with Thermal Efficiency over 42%

2017-10-08
2017-01-2229
The maximum thermal efficiency of gasoline engine has been improving and recently the maximum of 40% has been achieved. In this study, the potential of further improvement on engine thermal efficiency over 40% was investigated. The effects of engine parameters on the engine thermal efficiency were evaluated while the optimization of parameters was implemented. Parameters tested in this study were compression ratio, tumble ratio, twin spark configuration, EGR rate, In/Ex cam shaft duration and component friction. Effects of each parameter on fuel consumption reduction were discussed with experimental results. For the engine optimization, compression ratio was found to be 14, at which the best BSFC without knock and combustion phasing retardation near sweet spot area was showed. Highly diluted combustion was applied with high EGR rate up to 35% for the knock mitigation.
Technical Paper

Development New Organic Composite Materials with Excellent Long-Term High-Temperature Durability and Reliability for Automotive Parts

2018-04-03
2018-01-0151
In recent years, the emerging technology competitions in automotive industry are improving engine efficiency and electronizing for coping with stringent fuel-economy regulations. However, fuel-economy technologies such as engine down-sizing and numerous electronic parts entrust burden plastic materials acing as mainly electric insulation and housing to have to be higher performance, especially temperature endurance. Engineering plastics (EPs) have critical limitations in terms of degradation by heat. Heat-resisting additives in EP are generally used to be anti-degradation as activating non-radical decomposition of peroxide. However, it could not be effective way to impede the degradation in long term heat aging over 1,000 hours at high temperature above 180 °C. In this study, we suggested the new solution called ‘shield effect’ that is purposeful oxidation at the surface and local crystallization of EP to stop prevent penetrating oxygen to inside of that.
Technical Paper

A Study on Automated Tuning of the Head Gasket Coolant Passage Hole of the Gasoline Engine Cooling System Using Optimization Technology

2019-03-25
2019-01-1411
Tuning the size and position of the cooling water holes in the head gasket during engine cooling system development is generally positioned at the final stage of the cooling system hardware design. Until now, the gasket hole tuning operation was dependent on the case study through repetitive CFD analysis. In this process, there was a difference in the optimization level by know-how and expertise of the person in charge. In this study, a gasket hole tuning technique was developed using optimization algorithms to improve the level of optimization. First, select factors and perform screening using the DOE(Design Of Experiments) method, and then find the optimal gasket hole size and arrangement through the optimal design process based on the results of the CFD analysis planned by DOE.
Technical Paper

The Development of Gear Tooth Micro Geometry Analysis Method for the Transmission Gear Noise Robustness

2019-03-25
2019-01-1414
Transmission error has been well known as the main source of excitation about transmission gear whine noise. To minimize transmission error in the gear system, various analysis methods have been studied and applied for long time. Many researchers were focused on gear micro geometry to achieve the low level of transmission error. But, if the gear is misaligned by several factors such as clearance and manufacturing tolerance error, then the gear noise can rapidly and unexpectedly be increased. To overcome this problem, this new analysis method has been developed and introduced. A transmission system simulation model was constructed, which considers various factors of transmission components such as clearance, stiffness and so on. The deformation and vibration characteristics of finite element models were validated by making comparison with frequency response function experiment.
Technical Paper

A Study of the Half Order Modulation Control for Diesel Combustion Noise by Using Model Based Controller Design

2019-03-25
2019-01-1416
This model based investigation is carried out in order to control the half order modulation for diesel engines using by virtual calibration approach and proposes a feedback control strategy to mitigate cylinder to cylinder imbalance from asymmetric cylinders torque production. Combustion heat release analysis is performed on test data to understand the root cause of observed cylinder to cylinder pressure variations. The injected fuel variations are shown to cause the observed pressure variations between cylinders. A feedback control strategy based on measured crank shaft position is devised to control the half order modulation to balance the combustion pressure profile between cylinders. This control strategy is implemented in Simulink and is tested in closed-loop with the diesel engine model in AMESim. The closed-loop performance indicates that the half order modulation is considerably improved while having minimal impact on the fuel consumption.
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