Dynamic Torque Characteristics of the Hydrodynamic Torque Converter

<div class="section abstract"><div class="htmlview paragraph">Automatic transmission (AT) is a complex hydroelectromechanical system, since it consists of hydraulic, electrical and mechanical parts.</div><div class="htmlview paragraph">On cars produced by “UzAuto Motors” mainly AT of the 6T family, 6-speed AT family GM: 6T30, 6T40, 6T45, 6T50 “Hydra-Matic” are used.</div><div class="htmlview paragraph">Production of parts of these transmissions is carried out both at American GM plants and at GM plants in China and Korea.</div><div class="htmlview paragraph">The differences between AT 6T30/6T40/6T45/6T50 are in the thickness of the output chain and in the planetary gear, in the sizes of some other units and the housing itself. But the differences are much more influenced by the settings of the transmission unit, which select operating modes with different engines so as not to overload the thinnest places of the automatic transmission.</div><div class="htmlview paragraph">Automatic transmissions 6T30, 6T40, 6T45, 6T50 have the ability to manually shift gears and activate the “kickdown” mode (for quick acceleration of the car, when you sharply press the gas “all the way” it makes the automatic transmission downshift, and sometimes by two steps).</div><div class="htmlview paragraph">The operation of the transmission is controlled by various electronic systems that are responsible for the operability and structural integrity of the gearbox.</div><div class="htmlview paragraph">Failure of the automatic transmission can occur as a result of one or a combination of malfunctions of the following parts: in the torque converter; in the mechanical part of the gearbox; in the hydraulic part of the control system; one or more clutches of the gearbox; in the electrical part of the control system; in the electronic control unit.</div><div class="htmlview paragraph">The authors of the work investigated and determined the occurrence of malfunctions and failures depending on the temperature of the working fluid of the automatic transmission of a passenger car.</div><div class="htmlview paragraph">Also, the dependence of the resource of the automatic transmission on the temperature of the hydraulic fluid was obtained. High-quality diagnostics of the automatic transmission and its control system can in many cases save the car owner from expensive repairs: <ul class="list disc"><li class="list-item"><div class="htmlview paragraph">without thorough diagnostics, the automatic transmission cannot be subjected to routine or major repairs. Only on the basis of diagnostic information can a conclusion be made about the technical maintenance or repair of the automatic transmission;</div></li><li class="list-item"><div class="htmlview paragraph">based on real experience of operating passenger cars equipped with automatic transmission, we recommend changing the oil every 35000 miles under operating conditions in Tashkent. We also recommend conducting diagnostics of the automatic transmission every 12500 miles of the car's mileage.</div></li></ul></div></div>

<div class="htmlview paragraph">The improvement of the torque converter performance necessitates an optimized design of the torque converter stator blade on the basis of a full understanding of the internal flow conditions. However, it is difficult to analyze the flow experimentally or theoretically because the three elements (a pump, a turbine, and a stator) rotate at different speeds and the flow circuit and the blade shapes are complex. Enough explication of the internal flow has not yet been made.</div> <div class="htmlview paragraph">This research has developed a new method of calculating the torque converter performance by taking the stator blade profile into consideration. The internal flow through the torque converter stator can be treated as a two-dimensional flow, and here the flow was analyzed as a potential flow.</div> <div class="htmlview paragraph">The analysis of the torque converter stator blade was made as follows. First, the internal flow through the blade row was numerically analyzed by the boundary element method, and the numerical analysis was introduced into the one-dimensional performance analysis. Next, by this calculation method various stator blades were designed and manufactured by way of experiment. As compared with experimental results, it was verified that the torque converter performance can be calculated with satisfactory accuracy.</div> <div class="htmlview paragraph">This method was applied with success to optimizing the stator blade shape of the torque converter used for a forklift truck.</div>

<div class="htmlview paragraph">The performance of a large-volume production torque converter is slightly different from those of development prototype due to the core leakage flow. The sealing gap between the stator crown and pump or turbine core of the production converter is usually larger than that of prototypes because of fabrication method and tolerances. In this work, the core leakage flow of torque converter was investigated using CFD. The core region was modeled and coupled together with other three major components of a converter. Studies show that for a particular converter the core leakage flow could result in a 3.6% stall torque ratio reduction and a 2% peak efficiency decrease. The effects of sealing gap dimensions were also studied.</div> <div class="htmlview paragraph">Computational investigations in this work indicated that the variation of input K factor with input torque level observed in dyno tests is due to the cavitation in the torque converter. Cavitation occurs at high input torque and low speed ratio conditions because of the high volume flow rate and large incidence angle at the stator inlet. The torque converter performances at different input torque levels were predicted by CFD simulations with a cavitation model. A new concept of the maximum input torque of a torque converter, which is limited by cavitation, is presented. The engineering solutions to reduce converter cavitation are also discussed in this paper.</div>

<div class="htmlview paragraph">This paper presents a general discussion of automatic transmission parasitic losses and efficiency characteristics.</div> <div class="htmlview paragraph">Efficiency characteristics of the three major automatic transmission components-pump, torque converter, and gearbox-and their contribution to the transmission total torque losses are examined. A data reduction method for isolating gearbox torque losses from total transmission losses is also described.</div> <div class="htmlview paragraph">The information presented is based on pump, torque converter, and transmission testing performed at SwRI for Ford Motor Company. Test data was used to perform analytical fuel economy benchmarking studies. Testing included 13 transmissions manufactured by American, European, and Japanese manufacturers for 3.0-5.8L truck applications.</div>

<div class="section abstract"><div class="htmlview paragraph">This paper details testing for torque converter clutch (TCC) characterization during steady state and dynamic operation under controlled slip conditions on a dynamometer setup. The subject torque converter under test is a twin plate clutch with a dual stage turbine damper without a centrifugal pendulum absorber. An overview is provided of the dynamometer setup, hydraulic system and control techniques for regulating the apply pressure to the torque converter and clutch. To quantify the performance of the clutch in terms of control stability, pressure to torque relationship and the dynamic behavior during apply and release, a matrix of oil temperatures, output speeds, input torques, and clutch apply pressures were imposed upon the torque converter. The torque capacity of the clutch is estimated with the dimensions of the friction surfaces and pressure plate and an enhanced lookup data of K-factor obtained through testing of the hydrodynamics at input torques from 10 to 200 Nm over a speed ratio range consistent with controlled slip. The influence of controlled operating point parameters is reported as TCC apply pressure verse estimated TCC torque. The effect of temperature, output speed and the sign of input torque are shown to a departure from the normally assumed linear relationship between pressure and torque. The results and procedures presented can be utilized to improve in vehicle control schemes through more accurate pressure to torque gain scheduling.</div></div>

<div class="htmlview paragraph">A chemical and physical characterization of particulate emitted in undiluted exhaust of single cylinder direct injection (D.I.) diesel engine was made by an optical technique.</div> <div class="htmlview paragraph">On-line scattering and extinction measurements in the spectral range from 200 to 500nm were carried out in the exhaust ofthe engine operating under steady-state conditions. These measurements provided a useful tool for the comprehension of chemical and physical structure of the particulate. They allowed the evaluation in real time of the size, the concentration and also the optical properties. Preliminary results of size and mass concentration of particulate are presented.</div> <div class="htmlview paragraph">A good agreement was observed comparing the results with those obtained by gravimetric measurements, TEM and X-ray diffraction.</div> <div class="htmlview paragraph"><b>HIGH EFFICENCY OF DIESEL ENGINES</b> and their ability to burn heavy fuels make them ofgreat interest in the transportation field. On the other hand, present exhaust emission levels produced by this type ofengine will not satisfy stringent international regulations on environ- menta protection.</div> <div class="htmlview paragraph">The studies of the chemical and physical structure of diesel particulate in the exhaust of the engine help manufacturers both to optimize the efficiency of the combustion process and give useful information to designers of after-treatment devices.</div> <div class="htmlview paragraph">Historically, most studies on the particulate in the engine exhaust were carried out by electron microscopy and chemical analysis [<span class="xref">1</span>,<span class="xref">2</span>]<span class="xref">*</span>. These conventional techniques are time consuming, not real time, and not useful in transient operating conditions. Because the composition of the particulate materia depends on the collection system the data can be influenced by sampling procedures.</div> <div class="htmlview paragraph">Size distribution measurementtechniques of particulate based on electrical mobility, diffusion and inertial separation were proposed by Dolanetal.[<span class="xref">3</span>]. These techniques are real time but intrusive and can change the size distribution through collisions between particles.</div> <div class="htmlview paragraph">The recent advances in non-intrusive optical diagnostic techniques have made it possible to study on-line the evolution of particulate emitted in the exhaust with good temporal and spatial resolution.</div> <div class="htmlview paragraph">In the last decade, the optical measurements carried out in the exhaust, were made by nephetometry, transmissiometryor opacimetry, generally at a single wavelength in the visible range or in the infrared by photoacoustic and absorption measurements, These measurements are used to determine both the mass of particulate and the amount of dry soot and SOF [<span class="xref">4</span>,<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>.]</div> <div class="htmlview paragraph">In particular, simultaneous light scattering and extinction measurements at a single wavelength in the visible have provided a fast method to determine the dimension and concentration of soot particles i n flame [<span class="xref">8</span>].</div> <div class="htmlview paragraph">The purpose of the present study is to demonstrate the feasibility and flexibility of a new optical technique applied in the undiluted exhaustof a D.I. diesel engine. The technique consists of the use of simultaneous spectral measurements of scattering and extinction coefficients from the near ultraviolet to visible. These measurements allow the on-line simultaneous evaluation of the size, concentration and particulate mass as well as estimating the optical properties of the particulate. In particular, optical measurements in the near ultraviolet region are particularly promising because both graphite and large aro- maticmolecules exhibit absorption bands between 200 and 350nm [<span class="xref">9</span>,<span class="xref">10</span>].</div>

<div class="section abstract"><div class="htmlview paragraph">It is common that angular velocities can be different from time to time between an engine output and transmission input, because both are connected by a damper in torque converter with flexible elements in it. When this difference occurs abruptly for some reasons, an internal impact could start between the engine-attached members (also known as driving members) and the transmission-attached members (or driven members). The resulting impact load could be several times the torque an engine’s combustion force can generate, depending on the impact energy. An impact load can be very devastating to a torque converter and other power-train members, just as to all other mechanical systems. This work presents a comprehensive and interesting study to help understand the rotational impact behavior for a system where none of bodies is stationary at the onset of impact. Using an explicit finite-element solver for case studies, the author will assess what role a friction-based clutch, placed between the engine and vibration-isolating damper, will play, by limiting the passage of engine’s kinetic energy to some degree. It is interesting to find that it is the relative, not the absolute, angular velocities of impacting bodies that dictate the outcomes of an impact event.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Accuracy of clutch torque model which converts target torque to target stroke is essential to control the dry clutch system. Continuous Adaptation algorithm requires micro slip control during in-gear driving. Clutch judder during micro slip control can cause detrimental effect on the output of controller as slip speed is calculated by deviation of engine speed and clutch speed. Conventional approach to avoid clutch judder is using low pass filter to the input of controller which is slip speed. But this affect to the overall response time of slip controller.</div><div class="htmlview paragraph">In this paper, signal processing algorithm is design and tested for the clutch speed(Input shaft speed). With low pass filter in clutch speed, clutch judder signal is decreased but overall time delay creates static error during acceleration. Several phase advance algorithm is designed to overcome the static error during acceleration without disadvantage of decreasing clutch judder signal.</div><div class="htmlview paragraph">After the simulation, low pass filter with phase advance method which using wheel speed signal as source of phase advance shows optimal result considering judder signal decrease and minimal static error during acceleration. With the simulation result, low pass filter with phase advance method is implemented in mass production without any side effect.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Diesel aftertreatment (AT) systems are critical for controlling emissions of CO, HC, NO<sub>X</sub>, and PM in the on-road transportation sector. Ensuring compliance with regulatory standards throughout the AT system's lifespan requires precise prediction of various degradation mechanisms under real-world operating conditions and mitigating their impact through proper catalyst sizing and advanced controls. In the SwRI A2CAT-II consortium, a medium-duty diesel engine production aftertreatment system was subjected to full useful life aging, involving chemical poisoning with phosphorus (P) and sulfur (S) species, along with hydrothermal aging following the DAAAC protocol. This study was aimed to model and predict the aging trajectory of this production AT system thereby capturing changes in system dynamics under both steady-state and transient conditions. The system, designed to meet the 0.2 g/bhp-hr standard, comprised a Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and Ammonia Slip Catalyst (ASC). It was aged to 3600 hours equivalent to the DAAAC protocol and tested across a series of steady-state and regulatory cycles (HFTP, RMC, and LLC) at degreened, 33%, 66%, and 100% aging points. A linear decrease in system NOx conversion was observed between 0% to 66% aging, followed by a nonlinear drop from 66% to 100%. The cumulative decline in NOx conversion was 0.8%, which could significantly impact systems designed to meet a 0.05 g/bhp-hr target.</div><div class="htmlview paragraph">IntroductionAftertreatment durability demonstration is a mandatory validation exercise for on-road medium and heavy-duty diesel engine certification. This requirement ensures that the emission compliance can be achieved for the intended full useful life (FUL) of the engine system or multiple vehicle families. Conventional Deterioration Factor (DF) approach considers linear effect of sulfur and phosphorous poisoning on the catalysts over the entire useful life based on performance from 33% of aging the catalysts and extrapolating them to FUL. However, based on various studies, the impact of fuel derived Sulfur on diesel aftertreatment components was found to be exponentially significant particularly on the SCR due to the sulfur poisoning effect which require an active means to liberate sulfur to maintain appropriate SCR NOx conversion performance. Phosphorous from lubricating oil is known to adversely affect the activity of the oxidation catalyst in a catalyzed DPF thereby reducing the passive regenerative performance of DPF. For these reasons, an extensive understanding of chemical poisoning (particularly Sulfur and Phosphoros) and hydrothermal aging are warranted to design, validate and demonstrate the durability of aftertreatment components that are subjected to the prolonged chemical exposure.</div><div class="htmlview paragraph">To address the extensive challenges in durability demonstration, the Diesel Aftertreatment Accelerated Aging Protocol, or DAAAC, was developed by Southwest Research Institute as a part of consortium effort that includes input from diesel engine manufacturers [<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>]. DAAAC is an accelerated aging cycle developed for each application based on the available field data. It includes the exposure from hydrothermal aging, sulfur and lubricant derived poison at accelerated rates. The protocol also requires the entire aftertreatment system to be aged as a complete system, since the upstream components, such as DOC, can impact the chemical makeup of sulfur derived constituents.</div><div class="htmlview paragraph">The protocol does not introduce chemical constituents not normally observed in the field. The accelerated chemical exposure rate is limited only to a degree that has previously demonstrated successful correlation to normal, unaccelerated aging. The Protocol also requires that chemical aging mechanisms are to be introduced and / or consumed in a manner representative of the engine’s defined consumption pathways. Examples include sulfur exposure via high sulfur fuel or gaseous SO<sub>2</sub> and oil consumption via pre-combustion / post-combustion pathways. The Protocol also does not introduce chemical components that are not normally present in oil or fuel (other than doping the fuel with higher concentrations of sulfur, but this amount is relatively small). A comprehensive step by step breakdown of DAAAC protocol is presented elsewhere [<span class="xref">2</span>].</div><div class="htmlview paragraph">The primary objective of this paper is to disseminate the observation of long-term impacts of chemical poisoning and hydrothermal aging on a production aftertreatment catalyst subjected to FUL DAAAC protocol. The results of this experimental campaign were used to develop and validate a model capable of predicting hydrothermal and chemical aging mechanisms of conventional diesel aftertreatment to optimize long term emissions reduction performance. The paper is divided into following sections: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">Introduction: An overview of the system</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">Background: A review of literature in the field of diesel AT aging</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">Test Campaign: Description of experimental setup used for collection of both steady state and transient data.</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">Experimental setup: Description of burner stand used for data collection.</div></li><li class="list-item"><span class="li-label">5</span><div class="htmlview paragraph">Results and Discussion: Description of experimental results followed by discussion about underlying degradation mechanism identified through simulation work.</div></li><li class="list-item"><span class="li-label">6</span><div class="htmlview paragraph">Summary and conclusion</div></li></ol></div></div>

<div class="section abstract"><div class="htmlview paragraph">The forthcoming introduction of the EURO VII regulation requires urgent strategies and solutions for the reduction of sub-23 nm particle emissions. Although they have been historically considered as particulate matter-free, the high interest for Natural Gas (NG) Heavy-Duty engines in the transport sector, demands their compliance with the new proposed regulations.</div><div class="htmlview paragraph">In order to obtain high conversion of gas pollutants and a strong abatement of the emitted particles, the use of Particle Filters in NG aftertreatment (CPF) in conjunction with the Three-Way Catalyst (TWC) may represent an attractive and feasible solution.</div><div class="htmlview paragraph">Performances of a cordierite filter were explored through an extensive experimental campaign both in Steady-State conditions and during transient engine maneuvers that involved a whole analysis of the emitted particles in terms of number and mass.</div><div class="htmlview paragraph">This investigation assessed different emitted particle reduction efficiency, highlighting distinct levels between no-load (low idle phases) and load operating conditions.</div><div class="htmlview paragraph">The analysis was supported by the development of a specific 1D filtration model to evaluate the particles abatement. This model was also validated during a World Harmonized Transient Cycle (WHTC), proving to be a valuable tool for understanding filtration phenomena during critical phases of the cycle.</div><div class="htmlview paragraph">The tested filter technology showed high filtration efficiency with global levels approaching 90% over the whole cycle, without significant increase in backpressures and fuel consumption.</div><div class="htmlview paragraph">The performed analysis lays the foundation for the use of innovative and simplified filtration models to support the optimization process of this device in view of the next stringent regulations.</div></div>

<div class="htmlview paragraph">This paper presents the theory and experimental performance of a system for detecting engine misfires in automobiles. The method is potentially suitable for meeting the California Air Resources Board (CARB) requirements under On Board Diagnostics II (OBDII) rules.</div> <div class="htmlview paragraph">The instrumentation for the present method measures (noncontacting) crankshaft instantaneous angular speed. Highly efficient signal processing algorithms permit detection of each individual misfire.</div> <div class="htmlview paragraph">The performance of the present method is expressed in terms of error rates made in detecting individual misfires. Normal operating conditions yield error rates under 10<sup>-4</sup>. Under worst case conditions consisting of light load, high RPM and rough roads with the torque converter in lockup are under 10<sup>-3</sup>.</div>

<div class="section abstract"><div class="htmlview paragraph">Fundamental engine research is primarily conducted under steady-state conditions, in order to better describe boundary conditions which influence the studied phenomena. However, light-duty automobiles are operated, and tested, under heavily transient conditions. This mismatch between studied conditions and in-use conditions is deemed acceptable due to the fundamental knowledge gained from steady-state experiments. Nonetheless, it is useful to characterize the conditions encountered during transient operation and determine if the governing phenomena are unduly influenced by the differences between steady-state and transient operation, and further, whether transient behavior can be reasonably extrapolated from steady-state behavior.</div><div class="htmlview paragraph">The transient operation mode used in this study consists of 20 fired cycles followed by 80 motored cycles, operating on a continuous basis. The intention of the cycle is to provide a significant transient condition, namely the change from motored to knock-limited fired operation, while also maintaining a repeatable cycle that allows for the collection of statistics during quasi- steady-state operation.</div><div class="htmlview paragraph">This study investigates the effect of transient operation on Knock-Limited Combustion Phasing (KL-CA50) compared to steady-state operation. Three compositionally dissimilar matched Research Octane Number (RON) = 98 fuels are used in this study, allowing for the assessment of fuel-specific effects on differences between steady-state and transient operation.</div><div class="htmlview paragraph">This study first characterizes the 20/80 firing cycle described above, before comparing the transient KL-CA50 measurements to the steady-state KL-CA50 measurements. Analysis of both the steady-state and transient results are used to gain insights into the effects of transient operation on end-gas autoignition, relative to steady-state operation and as a function of fuel composition.</div><div class="htmlview paragraph">The results of this study indicate the significant effect that transient operation has on KL-CA50 behavior of a fuel. This is both universal, in that all fuels show responses to the differences in compression temperatures of the charge, as well as fuel specific, in that the fuel response varies based on the fuel’s sensitivity to temperature, [O2], and trace species. All fuels showed a significant load extension under transient operation, based on tolerance of higher intake pressures. However, transient operation moved operating conditions to “beyond RON” (Octane Index K < 0) conditions, which favored higher-sensitivity fuels. Based on the analysis of system time constants (e.g. cylinder head temperature dynamic response, exhaust gas temperature dynamic response), it is expected that transient operation, and the benefits for knock-limited operation, are highly influential on drive-cycle performance.</div></div>

<div class="section abstract"><div class="htmlview paragraph">In recent years, diesel engine emissions regulations have been strengthened worldwide, necessitating the evaluation of regulatory values under transient conditions. Consequently, the need to assess transient states in the development of diesel engines has increased significantly. The evaluation using MBD (Model Based Development) is considered a promising method for achieving both low fuel consumption and simultaneous reduction of NOx and soot emissions. However, the mechanism of soot formation is complex, making it challenging to model mathematically directly. In this paper, hybrid machine learning approaches combining a physical model and a machine learning model are used to validate the prediction of soot emissions under transient conditions in a diesel engine with an EGR system. Various parameters such as fuel consumption and emissions predicted by the physical model are compared with measurements to validate the accuracy of the physical model. The prediction of soot emissions by the physical model is based on the Hiroyasu model. From these results, it is demonstrated that the physical model has sufficient accuracy to be used in hybrid machine learning approaches. However, it is shown that the physical model is inadequate as a prediction approach for soot emissions. Gaussian Process Regression (GPR), Support Vector Regression (SVR), Random Forest (RF), and Gradient Boosting Decision Tree (GBDT) are used to develop the machine learning models, and each model is trained on data under steady-state conditions. The prediction accuracy of each model and the physical model is compared and validated. The results show that the hybrid machine learning approaches have higher predictive accuracy than the physical model for soot emissions predictions in both steady-state and transient conditions. The GPR model with the highest prediction accuracy shows a test R<sup>2</sup> of 0.87 under steady-state conditions and relative errors with the measured values of less than 10% for both Non-load Transient Cycle (NRTC) and Low Load Cycle (LLC), which are engine test cycles.</div></div>

<div class="section abstract"><div class="htmlview paragraph">According to the low efficiency of vehicle equipped with automotive transmission (AT) at launching conditions, the TCCs slip and lock up control technology was proposed and a TCC simulation model was established. The vehicle dynamics, torque fluctuation and efficiency were analyzed. Simulation results were obtained when taking the constant engine speed as the control target. The three-dimensional transient heat conduction finite element model using CFX was built. The slipping power was calculated and was converted to heat flux on the surface of TCCs friction plate model. The temperature of TCCs friction plate was obtained at different ATF oil temperature. Simulation results show that the TCCs slip and lock-up control technology at launching conditions can effectively solve the vehicles low efficiency problems caused by torque converter (TC). The maximum temperature rise of TCCs friction plate was 20°C. The TCCs slip and lock up control can be carried out with the temperature of TCCs friction plate within the allowable range when the ATF oil temperature is low; The TCCs slip and lock up control is no suitable because of high temperature of TCCs friction plate which exceeds its allowable when the ATF oil temperature reaches 100°C.</div></div>

<div class="section abstract"><div class="htmlview paragraph">In this paper, we consider the driveline oscillations for electric vehicles. The oscillations in the electric vehicle result from the lack of the damping component such as a torque converter. The oscillations should be suppressed for the ride comfort. The new method is suggested using wheel speeds and the newly designed filter. The method guarantees better performance to eliminate the oscillations and better robustness against disturbances such as a brake force, road slope, and so on. The effectiveness of the suggested method is verified by experimental results.</div></div>