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Theoretical and Experimental Investigation on Power Loss of Vehicle Transmission Synchronizers with Spray Lubrication

SAE International Journal of Advances and Current Practices in Mobility

TU Darmstadt-Zhihong Liu, Ye Shen, Stephan Rinderknecht
  • Journal Article
  • 2019-01-0028
Published 2019-01-15 by SAE International in United States
Besides optimal engine systems, high-efficiency vehicle transmissions are generally also required to improve fuel economy in automotive applications. For the energy loss analysis in transmissions, most research focused on the major mechanical components, such as gears, bearings and seals, while the other mechanical losses, like synchronizer losses, were usually not considered. With increasing number of synchronizers in modern transmissions, a recent study indicates that the power loss analysis of synchronizers should also be developed and appended for a more accurate investigation on overall power losses in transmissions. The function of synchronizer is to equalize the different rotational speeds of shafts and gear wheels by frictional torques, for which the synchronizer must be cooled and lubricated in order to enhance the service life. With the supplement of lubricants, fluid friction is generated due to the differential speed, when the synchronizer is in neutral position. This fluid friction can be principally regarded as load-independent synchronizer power loss. In this paper, fluid states and fluid dynamics in synchronizers with spray lubrication are analyzed analogously to multiple-plate clutches. Based…
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Investigation of the Hybrid Operating Modes Regarding Efficiency, Emissions and Comfort for the Parallel-Series Hybrid Powertrain Concept DE-REX

TU Darmstadt-S. Fischer, A. Viehmann, C. Beidl, S. Rinderknecht
Published 2018-09-10 by SAE International in United States
The “Two-Drive-Transmission with Range-Extender” (called DE-REX) is an innovative hybrid powertrain concept using two electric motors and an internal combustion engine. The two electric motors are permanent magnet synchronous motors with a maximum power of 48 kW each. As combustion engine a 3 cylinder, turbocharged engine with a power of 65 kW is used. The aggregates are coupled to a transmission whose layout is characterized by consisting of two parallel 2-speed sub-transmissions. This layout offers a high flexibility and enables both parallel and series hybrid driving. The hybrid control unit (HCU) has to select the optimal driving mode and power distribution between the aggregates in regard to in some extend competing objectives like efficiency, emissions or driving comfort. In particular, the operation of the internal combustion engine with only two gear ratios is challenging. In the course of the publically funded DE-REX project, the DE-REX powertrain concept was designed, manufactured and set up at an X-in-the-loop test rig. In this paper, the operating point decision is investigated in selected driving situations focusing at the conflict…
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Strategies to Define Surrogate Fuels for the Description of the Multicomponent Evaporation Behavior of Hydrocarbon Fuels

TU Darmstadt-Andrea Pati, Sandro Gierth, Philip Haspel, Christian Hasse
Porsche AG-Jerome Munier
Published 2018-09-10 by SAE International in United States
The scope of this work is to propose a methodology to define multicomponent surrogate mixtures which describe the main evaporation characteristics of real gasoline fuels. Since real fuels are commonly complex mixtures with hundreds or thousands of hydrocarbons, their exact composition is generally not known. Only global characteristics are standardized. An accurate modeling of such complex mixtures in 3D-CFD requires the definition of a suitable surrogate. So far, surrogate mixtures have mostly been defined based on their combustion properties, such as ignition delay or burning velocity, irrespective of their evaporation characteristics. For this reason, in this work, a systematic study is carried out to develop a methodology to define mixtures of representative components that mimic the evaporation behavior of real fuels. Specifically, the following aspects are analyzed: the necessary number and type of the surrogate components, the definition of optimization targets representing the real fuel properties of interest (i.e. the vapor pressure and the distillation curve), the formulation of an appropriate numerical model to evaluate these quantities and the choice of a suitable optimization algorithm…
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Stochastic Synthesis of Representative and Multidimensional Driving Cycles

SAE International Journal of Alternative Powertrains

TU Darmstadt-Arved Esser, Stephan Rinderknecht
COMPREDICT-Martin Zeller, Stéphane Foulard
  • Journal Article
  • 2018-01-0095
Published 2018-04-03 by SAE International in United States
Driving cycles play a fundamental role in the design of components, in the optimization of control strategies for drivetrain topologies, and in the identification of vehicle properties. The focus on a single or a few test cycles results in a risk of non-optimal or even poor design regarding the real usage profiles. Ideally, multiple different driving cycles that are representative of the real and scattering operating conditions are used. Therefore, tools for the stochastic generation of representative driving cycles are required, and many works have addressed this issue with different approaches. Until now, the stochastic generation of representative testing cycles has been limited to low dimensionality, and only a few works have studied higher dimensionality using Markov chain theory. However, it is mandatory to create tools that can stochastically generate multidimensional cycles incorporating all relevant operating conditions and maintaining signal dependency at the same time. For this purpose, a new method to synthesize multidimensional and representative testing cycles that can handle constraints and is suited for many evaluation criteria is presented in this study. The…
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Modelling of Power Losses of Transmission Synchronizers in Neutral Position

TU Darmstadt-Stephan Rinderknecht
IMS,Technische Universität Darmstadt-Ye Shen, Zhihong Liu
Published 2018-04-03 by SAE International in United States
Developing an energy-efficient powertrain system is a solution for environment-friendly vehicles. Furthermore, it also enhances the performance of vehicles. In powertrain system, transmission plays an important role in terms of vehicle dynamic performance and energy consumption. Therefore, a lot of researches have been conducted on modelling power losses inside the transmission. Basically, the power losses in transmission consist of bearing losses, drag torque losses on gear blank that is immersed in the oil and gear mesh losses due to the sliding frictional force on gear flank. According to some experiments in the latest literatures, power losses of synchronizers cannot be neglected, when its shift sleeve is in neutral position. Principally, power losses of synchronizers in neutral position mainly come from load independent drag torque. The drag torque is generated by the shear torque of lubrication in the gap (or gaps) between synchronizer ring and synchronizer cone, which are rotating at different speed. In this paper, a drag torque model of synchronizer units in neutral position is built up based on mechanism of tribology lubrication. Several…
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Vehicle Mass Estimation from CAN Data and Drivetrain Torque Observer

TU Darmstadt-Stéphane Foulard, Rafael Fietzek
Politecnico di Torino-Jyotishman Ghosh
Published 2017-03-28 by SAE International in United States
A method for estimating the vehicle mass in real time is presented. Traditional mass estimation methods suffer due a lack of knowledge of the vehicle parameters, the road surface conditions and most importantly the effect of the vehicle transmission. To resolve these issues, a method independent of a vehicle model is utilized in conjunction with a drivetrain output torque observer to obtain the estimate of the vehicle mass. Simulations and experimental track tests indicate that the method is able to accurately estimate the vehicle mass with a relatively fast rate of convergence compared to traditional methods.
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Online and Real-Time Condition Prediction for Transmissions based on CAN-Signals

TU Darmstadt-Stephan Rinderknecht, Rafael Fietzek, Stéphane Foulard
Published 2017-03-28 by SAE International in United States
An online and real-time Condition Prediction system, so-called lifetime monitoring system, was developed at the Institute for Mechatronic Systems in Mechanical Engineering (IMS) of the TU Darmstadt, which is intended for implementation in standard control units of series production cars. Without additional hardware and only based on sensors and signals already available in a standard car, the lifetime monitoring system aims at recording the load/usage profiles of transmission components in aggregated form and at estimating continuously their remaining useful life. For this purpose, the dynamic transmission input and output torques are acquired realistically through sensor fusion.In a further step, the lifetime monitoring system is used as an input-module for the introduction of innovative procedures to more load appropriate dimensioning, cost-efficient lightweight design, failure-free operation and predictive maintenance of transmissions. This is based on damage-oriented operating strategies (so-called eLIFE) and a paradigm shift in the design philosophy relying on a smart big data approach (so-called ecoLIFE3 design procedure).The paper will present the lifetime monitoring system by the example of two concrete application cases, namely a manual…
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Impact of European Real-Driving-Emissions Legislation on Exhaust Gas Aftertreatment Systems of Turbocharged Direct Injected Gasoline Vehicles

TU Darmstadt-Sascha Bauer, Bernd Lenzen, Christian Beidl
Umicore AG & Co. KG-Jan Schoenhaber, Nikolas Kuehn, Bastian Bradler, Joerg Michael Richter
Published 2017-03-28 by SAE International in United States
Recently, the European Union has adopted a new regulation on Real-Driving-Emissions (RDE) and also China is considering RDE implementation into new China 6 legislation. The new RDE regulation is focused on measuring nitrogen oxides (NOx) and particulate number (PN) emissions of both light-duty gasoline and diesel vehicles under real world conditions. A supplemental RDE test procedure was developed for European type approval, which includes on-road testing with cars equipped with portable emission measurement systems (PEMS). This new regulation will significantly affect the engine calibrations and the exhaust gas aftertreatment. In this study the impact of the new RDE regulation on two recent EU 6b certified turbocharged direct injected gasoline vehicles has been investigated. A comparison of several chassis dyno drive cycles with two new defined on-road RDE cycles was performed. Moreover, different exhaust aftertreatment systems including state of the art three-way catalyst (TWC) and catalyzed gasoline particulate filter (cGPF) technologies were investigated under real world conditions. The results demonstrate that combined systems of TWC plus cGPF are robust aftertreatment solutions for both NOx and PN…
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Signal Generator for Prediction of Transient Control Signals of an Automotive Transmission Control Unit Depending on Scalar Calibration Parameters

SAE International Journal of Passenger Cars - Mechanical Systems

TU Darmstadt-Ivan Rot, Stephan Rinderknecht
  • Journal Article
  • 2016-01-2155
Published 2016-10-17 by SAE International in United States
In this investigation an innovative signal generator will be introduced, which enables the generation of transient control signals for the gearshift process. The signals are generated merely depending on scalar transmission control unit (TCU) calibration parameters. The signal generator replaces the comprehensive TCU software within the simulation environment. Thus no extensive residual bus simulation is required.Multiple experimental models represent the core part of the signal generator. To predict the system behavior of the underlying system, the models are trained using measured data from a powertrain with automatic transmission mounted on a test rig.The results demonstrate that the introduced signal generator is suitable to predict transient control signals for the gearshift operation accurately. In combination with an additional powertrain model it is possible to simulate the gearshift process and subsequently to evaluate the gearshift comfort. The signal generator allows a rapid implementation of a simulation environment for TCU calibration with less modeling effort in comparison with the implementation of the original TCU software. Due to a flexible approach, the signal generator offers to predict signals with…
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Comparison of Parameter-Identified Simulation Models with Different Detailing Level to Reproduce the Side Shaft Torque of an Automotive Powertrain with Automatic Transmission

SAE International Journal of Engines

TU Darmstadt-Leonard Yousif, Ivan Rot, Stephan Rinderknecht
  • Journal Article
  • 2016-01-1148
Published 2016-04-05 by SAE International in United States
The underlying basic model represents a powertrain with automatic transmission including a torque converter. It is based on a greybox-modeling approach, which refers to ordinary differential equations with identified parameters and characteristic curves. The validated basic model is extended in order to reproduce the system behavior and especially the side shaft torque during a gear shift process. Therefore the model is extended by a transmission model with clutches for gear shifting in order to simulate specific powertrain dynamics additionally. The parameters have already been determined for the basic model using a method for isolated and structured parameter identification based on measurement data of an automotive powertrain test bench. A comparable structured parameter identification method is applied to obtain the parameters of the extended model.The extended model will be compared with a state observer which is based on a low-order model and neglects the detailed consideration of submodels with nonlinear characteristics. The observer also reconstructs the side shaft torque during the entire maneuver and will be consulted as an alternative approach for estimating non-measurable states in…
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