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Technical Paper

Dynamic Characteristic Simulation of AT Hydraulic System

2008-06-23
2008-01-1683
Hydraulic system is very important for the performance of AT. The dynamic characteristics of automatic transmission hydraulic system are studied in this paper. Because the valves in the hydraulic system are not standard parts, ITI-SimulationX, the multi-domain physics simulation software from ITI GmbH, is used to build the dynamic model of the hydraulic system based on the basic elements in the library of SimulationX. And then the dynamic characteristics of the system are simulated. The simulation results and the test results from the test bench are compared to confirm the simulation model. The results show that the simulation model can couple with the real system very well and the simulation model can be confirmed. Based on the confirmed simulation model, the effects of different parameters of the hydraulic system on the characteristics of the system are analyzed.
Technical Paper

Mechanical Structure Analysis and Kinematic Simulation of the Satellite Star Gear Continuously Variable Transmission System

2008-06-23
2008-01-1688
Nowadays more and more in-depth study and continuous investigation is being carried out in the continuously variable transmission (CVT) field. A good continuously variable ratio changing action would greatly improve the performance of the transmission and offer a high fuel economy. So it would save energy and protect environment, furthermore it would reduce the working intensity and demands of driving skill on the driver. Therefore, a high efficiency and good performance continuously variable transmission (CVT) is urgently needed. This paper presents a new Satellite Star Gear (SSG) Continuously Variable Transmission System. It was created based on the Pulse Stepless Transmission with some improvements on the overrunning clutch, stepless speed change device etc. This paper introduces the basic mechanical structure and kinematical principle of a double eccentricity stepless speed change device, overrunning clutch and the whole mechanism (SSG).
Technical Paper

CFD Analysis of Oil/Gas Flow in Piston Ring-Pack

2011-04-12
2011-01-1406
The oil consumption and blow-by are complex phenomena that need to be minimized to meet the ever changing modern emission standards. Oil flows from the sump to the combustion chamber and the blow-by gases flow from the combustion chamber to the crank case. There are several piston rings on the piston, which form a ring-pack. The ring pack has to be efficiently designed to minimize the oil consumption and blow-by. Since it is difficult and extremely costly to conduct experiments on every series of engines to check for the blow-by and oil consumption, a CFD analysis can be performed on the ring pack to study the blow-by and oil-consumption characteristics. In the CFD analysis described here, the region considered is between the compression chamber and the skirt, between the piston (including the rings) and the cylinder liner. The 3D CFD analysis was conducted for the engine running conditions of 5000 rpm and load of 13.5 kPa, for a 2.4L gasoline engine.
Technical Paper

Particulate Characteristics for Varying Engine Operation in a Gasoline Spark Ignited, Direct Injection Engine

2011-04-12
2011-01-1220
The objective of this research is a detailed investigation of particulate sizing and number count from a spark-ignited, direct-injection (SIDI) engine at different operating conditions. The engine is a 549 [cc] single-cylinder, four-valve engine with a flat-top piston, fueled by Tier II EEE. A baseline engine operating condition, with a low number of particulates, was established and repeatability at this condition was ascertained. This baseline condition is specified as 2000 rpm, 320 kPa IMEP, 280 [°bTDC] end of injection (EOI), and 25 [°bTDC] ignition timing. The particle size distributions were recorded for particle sizes between 7 and 289 [nm]. The baseline particle size distribution was relatively flat, around 1E6 [dN/dlogDp], for particle diameters between 7 and 100 [nm], before dropping off to decreasing numbers at larger diameters. Distributions resulting from a matrix of different engine conditions were recorded.
Technical Paper

Study on the Exhaust System Parameters of a Small Gasoline Engine

2008-06-23
2008-01-1766
Intake and exhaust systems are significant components of an internal combustion engine. The design and operational variables of intake and exhaust systems are decisive to determine overall engine performance. The best engine overall performance can be obtained by proper design of the engine intake and exhaust systems. The intake system parameters have been studied by numerous researchers. Therefore, this paper pays attention to the exhaust system parameters. The effects of exhaust pipe length and exhaust valve timing on the performances of engine are investigated. The results demonstrate that the exhaust pipe length and exhaust valve timing exert great influences on the engine efficiency, volumetric efficiency, mean pressure loss for gas exchange, etc.
Technical Paper

Defining In-Vehicle Location and Functional Attributes of a ‘Button-Style Electronic Automatic Transmission Shifter’ Using DFSS Methodology with Customer Clinic Approach

2017-03-28
2017-01-1131
The implementation of electronic shifters (e-shifter) for automatic transmissions in vehicles has created many new opportunities for the customer facing transmission interface and in-vehicle packaging. E-shifters have become popular in recent years as their smaller physical size leads to packaging advantages, they reduce the mass of the automatic transmission shift system, they are easier to install during vehicle assembly, and act as an enabler for autonomous driving. A button-style e-shifter has the ability to create a unique customer interface to the automatic transmission, as it is very different from the conventional column lever or linear console shifter. In addition to this, a button-style e-shifter can free the center console of valuable package space for other customer-facing functions, such as storage bins and Human-Machine Interface controllers.
Technical Paper

Utilizing a Tracked 3-Dimensional Acoustic Probe in the Development of an Automotive Front-of-Dash

2017-06-05
2017-01-1869
During the development of an automotive acoustic package, valuable information can be gained by visualizing the acoustic energy flow through the Front-of-Dash (FOD) when a sound source is placed in the engine compartment. Two of the commonly used methods for generating the visual map of the acoustic field include Sound Intensity measurements and array technologies. An alternative method is to use a tracked 3-dimensional acoustic probe to scan and visualize the FOD in real-time when the sound source is injecting noise into the engine compartment. The scan is used to focus the development of the FOD acoustic package on the weakest areas by identifying acoustic leaks and locations with low Transmission Loss. This paper provides a brief discussion of the capabilities of the tracked 3-D acoustic probe, and presents examples of the implementation of the probe during the development of the FOD acoustic package for two mid-sized sedans.
Technical Paper

Experimental GT-POWER Correlation Techniques and Best Practices Low Frequency Acoustic Modeling of the Exhaust System of a Naturally Aspirated Engine

2017-06-05
2017-01-1793
As regulations become increasingly stringent and customer expectations of vehicle refinement increase, the accurate control and prediction of exhaust system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The goal of this project was to improve the predicative accuracy of the GT-power engine and exhaust model and to update internal best practices for modeling. This paper will explore the details of an exhaust focused correlation project that was performed on a naturally aspirated spark ignition eight-cylinder engine. This paper and SAE paper “Experimental GT-POWER Correlation Techniques and Best Practices Low Frequency Acoustic Modeling of the Intake System of a Turbocharged Engine” share similar abstracts and introductions; however, they were split for readability and to keep the focus on a single a single subsystem.
Technical Paper

Experimental GT-POWER Correlation Techniques and Best Practices Low Frequency Acoustic Modeling of the Intake System of a Turbocharged Engine

2017-06-05
2017-01-1794
As regulations become increasingly stringent and customer expectations of vehicle refinement increase, the accurate control and prediction of induction system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The goal of this project was to improve the predicative accuracy of a 1-D GT-power engine and induction model and to update internal best practices for modeling. The paper will explore the details of an induction focused correlation project that was performed on a spark ignition turbocharged inline four-cylinder engine. This paper and SAE paper “Experimental GT-POWER Correlation Techniques and Best Practices” share similar abstracts and introductions; however, they were split for readability and to keep the focus on a single a single subsystem. This paper compares 1D GT-Power engine air induction system (AIS) sound predictions with chassis dyno experimental measurements during a fixed gear, full-load speed sweep.
Technical Paper

Self-Certification Requirements for Adaptive Driving Beam Headlamps

2017-03-28
2017-01-1365
Vehicle certification requirements generally fall into 2 categories: self-certification and various forms of type approval. Self-certification requirements used in the United States under Federal Motor Vehicle Safety Standards (FMVSS) regulations must be objective and measurable with clear pass / fail criteria. On the other hand, Type Approval requirements used in Europe under United Nations Economic Commission for Europe (UNECE) regulations can be more open ended, relying on the mandated 3rd party certification agency to appropriately interpret and apply the requirements based on the design and configuration of a vehicle. The use of 3rd party certification is especially helpful when applying regulatory requirements for complex vehicle systems that operate dynamically, changing based on inputs from the surrounding environment. One such system is Adaptive Driving Beam (ADB).
Technical Paper

Traditional and Electronic Solutions to Mitigate Electrified Vehicle Driveline Noises

2017-06-05
2017-01-1755
Hybrid powertrain vehicles inherently create discontinuous sounds during operation. The discontinuous noise created from the electrical motors during transition states are undesirable since they can create tones that do not correlate with the dynamics of the vehicle. The audible level of these motor whines and discontinuous tones can be reduced via common noise abatement techniques or reducing the amount of regeneration braking. One electronic solution which does not affect mass or fuel economy is Masking Sound Enhancement (MSE). MSE is an algorithm that uses the infotainment system to mask the naturally occurring discontinuous hybrid drive unit and driveline tones. MSE enables a variety of benefits, such as more aggressive regenerative braking strategies which yield higher levels of fuel economy and results in a more pleasing interior vehicle powertrain sound. This paper will discuss the techniques and signals used to implement MSE in a hybrid powertrain equipped vehicle.
Technical Paper

Self-Tuning PID Design for Slip Control of Wedge Clutches

2017-03-28
2017-01-1112
The wedge clutch takes advantages of small actuation force/torque, space-saving and energy-saving. However, big challenge arises from the varying self-reinforced ratio due to the varying friction coefficient inevitably affected by temperature and wear. In order to improve the smoothness and synchronization time of the slipping process of the wedge clutch, this paper proposes a self-tuning PID controller based on Lyapunov principle. A new Lyapunov function is developed for the wedge clutch system. Simulation results show that the self-tuning PID obtains much less error than the conventional PID with fixed gains. Moreover, the self-tuning PID is more adaptable to the variation of the friction coefficient for the error is about 1/5 of the conventional PID.
Technical Paper

Analysis of a Coupling System of Aircraft Environmental Control and Fuel Tank Inerting Based on Membrane Separation

2019-09-16
2019-01-1895
This paper raises a coupling system of aircraft environmental control and fuel tank inerting based on membrane separation. The system applies a membrane dehumidifier to replace water vapor removal unit of heat regenerator, condenser and water separator, which is widely used in conventional aircraft environmental control system (ECS) nowadays. Water vapor can travel across the membrane wall under its pressure difference without phase change, so the dehumidification process consumes no cooling capacity as traditional ECS and the cooling capacity of the new system increases. This paper first compares the thermodynamic properties of ECS based on membrane dehumidification and the traditional ECS based on condensation. The results show that the membrane dehumidification system has larger cooling capacity and lighter weight. For a given cooling capacity requirement, the membrane dehumidification system can use less bleed air since the enthalpy of the outlet air is lower.
Technical Paper

A System of Systems Approach to Automotive Challenges

2018-04-03
2018-01-0752
The automotive industry is facing many significant challenges that go far beyond the design and manufacturing of automobile products. Connected, autonomous and electric vehicles, smart cities, urbanization and the car sharing economy all present challenges in a fast-changing environment which the automotive industry must adapt to. Cars no longer are just standalone systems, but have become constituent systems (CS) in larger System of Systems (SoS) context. This is reflected in the emergence of several acronyms such as vehicle-to-everything (V2X), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-grid (V2G) expressions. System of Systems are defined systems of interest whose elements (constituent systems) are managerially and operationally independent systems. This interoperating and/or integrated collection of constituent systems usually produce results unachievable by the individual systems alone, for example the use of car batteries as virtual power plants.
Technical Paper

System Engineering for Automated Software Update of Automotive Electronics

2018-04-03
2018-01-0750
In traditional automotive electronic design, software update has been a component oriented, manual process rather than a systematic designed in capability suitable for automation. In recent days as software content in vehicles grow, the need to update software in vehicles more frequently is becoming a necessity. Moreover, additional attributes for software updates, for example timely delivery of security related update for vehicles, desire to add features using software update, control cost of software updates, etc., requires a system engineered design rather than a component oriented approach. As the automobile domain utilizes various means of mobility (Combustion Engine, Hybrid, Battery, etc.) and various functional domains (Infotainment, Safety, Mobility, Telematics, ADAS (Advance Driving Assist service), Autonomous, etc.), to control the overall cost of future software update for such a diverse environment, it is beneficial to introduce automation in the software update process.
Technical Paper

Numberical Investigation of Water Droplet Impingement on Cylinder with Exterior Air Film

2017-09-19
2017-01-2141
For the ice protection of the engine air induction part manufactured with low thermal conductivity composite material, the combined heating method using interior impingement and exterior air film has certain advantages. To study the influence of the external jet air film on the impingement characteristics of droplets, the numerical simulation method of three dimensional water droplet impingement based on Eulerian method was developed and verified by experimental data from references. The droplets impingement characteristics under three different blowing ratios and two different velocities were then investigated based on the configuration of 3D cylinder with two parallel jet holes.
Technical Paper

Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet

2018-04-03
2018-01-1236
Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented.
Technical Paper

Spark Assist for CA50 Control and Improved Robustness in a Premixed LTGC Engine – Effects of Equivalence Ratio and Intake Boost

2018-04-03
2018-01-1252
Low-temperature gasoline combustion (LTGC) engines can deliver high efficiencies, with ultra-low emissions of nitrogen oxides (NOx) and particulate matter (PM). However, controlling the combustion timing and maintaining robust operation remains a challenge for LTGC engines. One promising technique to overcoming these challenges is spark assist (SA). In this work, well-controlled, fully premixed experiments are performed in a single-cylinder LTGC research engine at 1200 rpm using a cylinder head modified to accommodate a spark plug. Compression ratios (CR) of 16:1 and 14:1 were used during the experiments. Two different fuels were also tested, with properties representative of premium- and regular-grade market gasolines. SA was found to work well for both CRs and fuels. The equivalence ratio (ϕ) limits and the effect of intake-pressure boost on the ability of SA to compensate for a reduced Tin were studied. For the conditions studied, ϕ=0.42 was found to be most effective for SA.
Technical Paper

Supervisory Model Predictive Control of a Powertrain with a Continuously Variable Transmission

2018-04-03
2018-01-0860
This paper describes the design of a supervisory multivariable constrained Model Predictive Control (MPC) system for driver requested axle torque tracking with real-time fuel economy optimization that is scheduled for production by General Motors starting in 2018. The control system has been conceived and co-developed by General Motors and ODYS. The control approach consists of a set of linear MPC controllers scheduled in real-time based on powertrain operating conditions. For each MPC controller, a linear model is obtained by system identification with vehicle and dynamometer data. The supervisory MPC coordinates in real time desired Continuously Variable Transmission (CVT) ratio and desired engine torque to satisfy the system requirements, based on estimates of axle torque and engine fuel rate, by solving a constrained optimization problem at each sampling step. Each linear MPC controller is equipped with a Kalman filter to reconstruct the system state from available measurements.
Technical Paper

Learning Gasoline Direct Injector Dynamics Using Artificial Neural Networks

2018-04-03
2018-01-0863
In today’s race for improved fuel economy and lower emissions from gasoline engines, precise metering of delivered fuel is essential. Gasoline Direct Injection fuel systems provide the means for improved combustion efficiency through mixture preparation and better atomization. These improvements can be achieved from both increasing fuel pressure and using multiple injection events, which significantly reduce the required energizing time per injection, and in a number of cases, force the injector to operate at less than full stroke. When the injector operates in this condition, the influence of variation in injector dynamics account for a large percentage of the delivered fuel and require compensation to ensure accurate fuel delivery. Injector dynamics such as opening delay and closing time are influenced by operating conditions such as fuel pressure, energizing time, and temperature.
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