Simulation of Wide-Open Throttle Vehicle Performance

<div class="htmlview paragraph">The most common driveline configurations in cars are the standard drive with front longitudinal engine and rear wheel drive and the front-transverse drive with east west installed powertrain as well as all-wheel drive variants derived from these. These driveline configurations are used in different vehicle segments. The transmission systems mainly used today are automatic transmissions with 4 or 5 speeds and manual transmissions with 4, 5 or 6 speeds. A small number of automated manual transmissions (AMT) and continuously variable transmissions (CVT) are in production. Various systems of automated manual transmissions, powershift transmissions designed as double clutch transmissions and toroidal transmissions are currently being developed.</div> <div class="htmlview paragraph">A brief explanation will be given about the structure of all different driveline configurations and the transmission systems will then be considered for specific applications in these different drivelines. The installation situation with transmission structure and space, potential for fuel savings with overall ratio and efficiency, reduction of emissions and noise levels, performance, drive comfort, transmission weight and manufacturing costs are considered as the main aspects within this paper. This leads to an assessment and recommendation for the use of certain transmission systems for the various driveline configurations.</div> <div class="htmlview paragraph">In the future, both 6-speed automatic transmissions and 6-speed manual transmissions will be used on a wider scale with standard drives. The use of continuously variable transmissions will increase for front transverse drive. In the field of manual transmissions the 5-speeds will dominate in front transverse drive applications. The degree of automation will increase in this segment. For torque levels of up to approximately 180 Nm, preference will be given to the use of automated manual transmissions. The range of up to 350 Nm will be predominantly covered by CVT's, five and six-speed automatic transmissions will subsist in the segment above 350 Nm for transverse installation.</div>

Examining drivers injury severity for manual and automatic transmission vehicles-involved crashes: Random parameter mixed logit model with heterogeneity in means and variances

<div class="htmlview paragraph">Most United States vehicle assembly plants produce significantly more automatic transmission equipped vehicles than manual transmission vehicles. Assembling these two vehicles on a common production line can create complexity problems. This paper describes the design and development of a pre-assembled manual transmission clutch and flywheel modular assembly which reduces most of these problems. This assembly is used on the 1993 model year mini-van with a 2.5L four cylinder engine.</div> <div class="htmlview paragraph">This modular clutch system utilizes the same starter ring gear carrier (driveplate) used on automatic transmission equipped vehicles. It pilots into the crankshaft similar to the automatic transmission torque converter. It is balanced as an assembly which results in a lower system imbalance. A significant system piece cost saving, in comparison with today's competitive market, was achieved. The production vehicle assembly technique is common between the automatic transmission torque converter and the manual transmission modular clutch. This assembly also eliminates three parts from the assembly plant and uses the same attaching bolts as the automatic transmission torque converter.</div>

<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="section abstract"><div class="htmlview paragraph">The parameters determining shift quality control in automatic transmissions are determined as part of the calibration of the transmission control. The resulting control system typically has three components: feedforward control, where the control output is determined before a gearshift; feedback control, where the control output is determined during the gearshift based on sensed feedback; and learning control (adaptation), where the feedforward or feedback controller parameters are modified after the current gearshift has ended and before the next similar gearshift begins. Gearshifts involving the same ratio change are referred to here as similar gearshifts, though such gearshifts may involve differences in other variables such as vehicle speed or engine torque. In most automatic transmissions, gearshifts are controlled by hydraulic clutches, and operating conditions for these clutches may vary widely, requiring a dedicated transmission controller involving significant calibration effort.</div><div class="htmlview paragraph">In the current work, novel model-based methods are used to accomplish feedforward control of gearshifts, involving offline calibration of fill and torque phase control parameters and learning control of the fill phase. Towards this end, a physics-based model of the oncoming clutch involved in an upshift of a production automatic transmission was developed and experimentally validated against test bench experiments for a wide variety of inputs and operating conditions. The resulting model is used to generate a feedforward controller, offline model-based calibration algorithm, and a learning controller that corrects for clutch under-fill and over-fill. The effectiveness of the resulting controller is validated by simulation studies using the experimentally validated transmission hydraulic system model, in conjunction with a powertrain model. In particular, it is demonstrated that the learning controller corrects for initial under- or over-fill error in two to three gearshifts. Convergence and robustness properties, and transient performance of the learning controller are also discussed.</div></div>

<div class="section abstract"><div class="htmlview paragraph">This paper presents a methodology to represent automatic transmission clutch-to-clutch shift dynamics with a two degree of freedom, lumped inertia model. The method of reducing the automatic transmission to a lumped, two inertia model as a function of shift and input shaft acceleration is detailed using a full kinematic representation of the automatic transmission. For a given clutch-to-clutch shift maneuver there are two dependent equations that utilize the two lumped inertias and represent the response of the transmission system from input to output shaft. Applicability of the method is shown for planetary automatic and layshaft dual clutch transmissions. Typical clutch-to-clutch shift maneuvers are illustrated with the two inertia model for power on upshifts and downshifts. The simplification of automatic transmission shift dynamics using this method enables rapid synthesis of a given transmission powerflow for estimation of shift quality potential, required clutching torques, inertia phase engine torque intervention and output torque through all phases of a shift event.</div></div>

<div class="htmlview paragraph">The paper presents the development of a methodology for the evaluation of the Wide-Open-Throttle (WOT) torque production when the engine is running free. Under such conditions the engine speed shows a sudden increase due to the high engine torque production associated with the WOT conditions, and to the absence of a load connected to the engine. The acoustic emission of the engine contains information related to this speed increase and thus to the engine torque production.</div> <div class="htmlview paragraph">The methodology unveils the information contained in the engine acoustic emission to estimate the torque produced under WOT operating conditions. This estimation can be performed without the need of coupling the engine to a brake, and does not require installing any additional sensor.</div> <div class="htmlview paragraph">For this reason the approach here presented could be very useful for engine testing at the end of the assembly line. In fact, since the test to be performed is very fast and does not require to couple the engine to a brake, it allows to dramatically reduce the time needed for the testing procedure. This means cost reduction and the possibility to perform such testing procedure on all the produced engines.</div> <div class="htmlview paragraph">Experimental tests have been performed in order to set-up the methodology on an L4 1.2 liter engine. The approach has been finally applied to the same engine, whose injection timing and spark advance were controlled to modify its torque production. The procedure showed a good capability to estimate WOT torque production, and to detect abnormal conditions that were induced by appropriately controlling injection and ignition.</div>

<div class="section abstract"><div class="htmlview paragraph">The use of small 2-stroke crankcase scavenged engines running on hydrogen is very attractive for low power rates, when low cost and compact dimensions are the fundamental design constraints.</div><div class="htmlview paragraph">However, achieving optimal performance with hydrogen fuel presents challenges, including uneven air-fuel mixtures, fuel losses, and crankcase backfiring.</div><div class="htmlview paragraph">This research focuses on a small 50cc 2-stroke loop-scavenged engine equipped with a patented Low-Pressure Direct Injection (LPDI) system, modified for hydrogen use. Experimental results demonstrate performance comparable to the gasoline counterpart, but further optimizations are needed. Consequently, CFD-3D simulations are employed to analyses the injection process and guide engine development.</div><div class="htmlview paragraph">The numerical analysis focuses on a fixed operating condition: 6000 rpm, Wide Open Throttle (WOT), with a slightly lean mixture and injection pressure fixed at 5 bar.</div><div class="htmlview paragraph">A numerical model of the entire engine is set up with the primary objective of improving injection efficiency by modifying the position and orientation of the injector, along with the piston dome shape. Seven configurations under the same operating conditions and injected mass are investigated to assess the impact of these modifications and find the best compromise. The methodology considers the following parameters: fuel trapped within the cylinder, fuel lost through the exhaust, fuel mass in the crankcase, and mixture uniformity before spark ignition. The best-performing configuration, featuring a standard piston dome but with a repositioned injector, achieves a notable reduction in fuel short-circuiting (up to 20%), while ensuring a relatively uniform air-fuel mixture at spark timing.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The worldwide increasing acceptance and success of modern automatic transmissions in passenger cars is based on innovative technology, driving comfort, shifting dynamic and - most important - fuel consumption reduction.</div><div class="htmlview paragraph">New concepts are facing the challenge of further improvements in internal efficiency and very tough future goals on CO2 emissions in connection with more sophisticated gasoline and diesel engine technologies. Based on the competition and current diversity in automatic transmission concepts, high investments in production facilities must be taken also well into account when thinking about follow-up technologies of installed 8-speed and 9-speed technologies. This must also be considered for the different demands in regions and markets.</div><div class="htmlview paragraph">So, how may a successful automatic transmission system look like in 2020 and beyond? Do we have even more gears than the current 8-speed and 9-speed? Does it make sense to increase the total gear ratio any further? Are there measures to improve the overall mechanical efficiency by several percent? What is the prevailing transmission system: torque converter planetary, dual-clutch countershaft or belt-type stepless transmission? How does the electrification and hybridization of the powertrain in the next years effect the system?</div><div class="htmlview paragraph">This article will give some brief answers on how ZF is planning the future of automatic transmissions and how successful systems should look like.</div></div>

<div class="htmlview paragraph">An automatic transmission for heavy duty trucks and buses has been developed. Automatically controlled dry clutch and synchromeshed gear transmission make driving easier, while maintaining good fuel efficiency of a mechanical transmission.</div> <div class="htmlview paragraph">The system consideration and design philosophies of the electronic controller are described here, as well as the mechanical hardware for conversion of a manual transmission into a fully automatic transmission.</div> <div class="htmlview paragraph">This transmission control system has not only the functions of an automatic transmission but also driveability and efficiency same as that of a skilled driver by incorporating various kinds of control logics.</div> <div class="htmlview paragraph">It is our fair judgement that this transmission can well meet market requirements in new age.</div>

<div class="section abstract"><div class="htmlview paragraph">This study investigates the effects of octane quality on the performance, i.e., acceleration and power, and fuel economy (FE) of one late model US vehicle, which is powered by a small displacement, turbocharged, gasoline direct injection (GDI) engine.</div><div class="htmlview paragraph">The relative importance of the gasoline parameters Research and Motor Octane Number (RON and MON) in meeting the octane requirement of this engine to run at an optimum spark timing for the given demand was considered by evaluating the octane index (OI), where OI = (1-<i>K</i>) RON <i>+ K</i> MON and <i>K</i> is a constant depending on engine design and operating conditions.</div><div class="htmlview paragraph">Over wide open throttle (WOT) accelerations, the average <i>K</i> of this <i>Pontiac Solstice</i> was determined as −0.75, whereby a lower MON would give a higher OI, a higher knock resistance and better performance. Over a part load cycle, a positive average <i>K</i> value was identified, whereby higher MON would give a (generally desirable) higher octane index, however, because lower load operation tends to be less constrained by knock, the impact of MON (high or low) on FE and efficiency under such conditions is smaller.</div><div class="htmlview paragraph">Results from the one car tested for this report support the observation that the <i>K</i> value of an engine depends on speed and load - a clear negative correlation between charge pressure and <i>K</i> value was recorded.</div></div>

<div class="htmlview paragraph">This paper deals with the use of SAE J1922 as a control data link. This application involves a direct data link connection between the ECU of an electronic engine and the ECU for an Antilock Braking System (ABS) with integrated Drive Slip Control-also referred to as Anti-wheel Spin Regulation (ASR), or as Automatic Traction Control (ATC).</div> <div class="htmlview paragraph">The application calls for an automatic reduction of engine output torque when the ABS/ATC controller determines excessive wheel spin has occurred. This most often occurs on slippery surfaces such as ice or snow when the vehicle is first started into motion, or on similarly slippery surfaces when accelerating or cornering. The engine torque reduction continues until wheel spin is brought within an acceptable limit. Control of engine output is then returned to the driver.</div> <div class="htmlview paragraph">Extensive testing was conducted at WABCO's winter test site in northern Finland. It was necessary to determine tradeoffs on performance as data update rates were altered. For some applications where the J1922 data link was multiplexed on the same line as the J1587 diagnostic data link, bus utilization was a prime consideration. To minimize the bus usage, the J1922 commands were reduced to the minimum required.</div> <div class="htmlview paragraph">Testing of the data link scheme was required to optimize the control algorithms. From a driver comfort perspective, harshness had to be eliminated in the control implementation to satisfy expectations and thus assure success of the system.</div>

<div class="section abstract"><div class="htmlview paragraph">The objective of this paper is to investigate the potential of lean burn combustion to improve the thermal efficiency of spark ignition engine. Experiments used a single cylinder gasoline spark ignition engine fueled with primary reference fuel of octane number 90, running at 4000 revolution per minute and at wide open throttle. Experiments were conducted at constant fueling rate and in order to lean the mixture, more air is introduced by boosted pressure from stoichiometric mixture to lean limit while maintaining the high output engine torque as possible. Experimental results show that the highest thermal efficiency is obtained at excess air ratio of 1.3 combined with absolute boosted pressure of 117 kPa. Three dimensional computational fluid dynamic simulation with detailed chemical reactions was conducted and compared with results obtained from experiments as based points. The potential to improve further the efficiency, exhaust gas recirculation (EGR), high engine swirl ratio and high research octane number are good candidates for this improvement.</div><div class="htmlview paragraph">In further calculations, we use simulated EGR ratio, high engine swirl ratio, RON95 fuels. To prevent the combustion from knock in the simulations when ignition timing is at maximum brake torque, simulated pressure probes are mounted on each side of intake and exhaust valves to detect knock pressure. By using these methods, spark timing of the engine can be advanced thus improve the thermal efficiency. It is found that, by combining lean-boosted/EGR and high octane-number fuel, higher thermal efficiency of spark ignition engine can be achieved.</div></div>

<div class="htmlview paragraph">This paper introduces mathematical equations for power loss calculations of major automatic transmission components.</div> <div class="htmlview paragraph">It also presents a theoretical investigation on contributions of each component's power loss to transmission total power losses.</div> <div class="htmlview paragraph">A computer program for automatic transmission efficiency calculation has been developed based on mathematical equations.</div> <div class="htmlview paragraph">Efficiency calculations for the Hyundai A4BF1 electronic 4 speed automatic transmission has been executed in order to validate the program.</div> <div class="htmlview paragraph">The calculated efficiency under various input and operating conditions - such as different input torque & RPM, transmission gear state, ATF temperature, torque converter clutch on/off - showed quite good agreement with the test results.</div>

<div class="section abstract"><div class="htmlview paragraph">Emissions and fuel economy certification testing for vehicles is carried out on a chassis dynamometer using standard test procedures. The vehicle coastdown method (SAE J2263) used to experimentally measure the road load of a vehicle for certification testing is a time-consuming procedure considering the high number of distinct variants of a vehicle family produced by an automaker today. Moreover, test-to-test repeatability is compromised by environmental conditions: wind, pressure, temperature, track surface condition, etc., while vehicle shape, driveline type, transmission type, etc. are some factors that lead to vehicle-to-vehicle variation. Controlled lab tests are employed to determine individual road load components: tire rolling resistance (SAE J2452), aerodynamic drag (wind tunnels), and driveline parasitic loss (dynamometer in a driveline friction measurement lab). These individual components are added to obtain a road load model to be applied on a chassis dynamometer. However, lab-tested quantities may not account for environmental noise factors and qualitative vehicle characteristics leading to a significant residual road load between the track-tested and lab-tested road loads. Regression modeling techniques are explored for estimating this residual road load and the challenges are discussed. Additionally, a technique is developed to choose feature selection metrics using simulation of multivariate non-gaussian continuous and discrete data having similar statistical properties as the data obtained from automotive road tests. Using the selected features, two regularized regression techniques are experimented with. The first technique models the residual road load power, while the second technique models a polynomial relationship between vehicle speed and residual road load.</div></div>