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Viewing 1 to 30 of 3590
2010-10-25
Technical Paper
2010-01-2200
Withit Chatlatanagulchai, Shinapat Rhienprayoon, Kittipong Yaovaja, Krisada Wannatong
From our experiences in converting diesel engine into diesel-dual-fuel engine with natural gas as primary fuel, accurate air/fuel ratio control is vital to the high engine performance, good vehicle drivability, and low emissions. Two components enter in calculating the air/fuel ratio, namely, the amount of fresh air and the amount of diesel and natural gas. Throttle and EGR valve are two actuators directly affect the amount of air, and the desired total fuel determines how much fuel should be injected at an instance. As opposed to inactive, fully opened throttle in typical diesel engine, the throttle in diesel-dual-fuel engine is regulated to cover wider range of desired air/fuel ratio. As a result, the problem of controlling the amount of air in diesel-dual-fuel engine becomes that of multi variables in which both throttle and EGR valve are involved. We present a novel algorithm that breaks the multi-variable control problem into two single-variable problems.
2010-10-25
Journal Article
2010-01-2203
Johan Wahlström, Lars Eriksson
In diesel engines with EGR and VGT, the gas flow dynamics has significant nonlinear effects. This is shown by analyzing DC-gains in different operating points showing that these gains have large variations. To handle these nonlinear effects, a nonlinear state dependent input transformation is investigated. This input transformation is achieved through inversion of the models for EGR-flow and turbine flow. It is shown that the input transformation handles the nonlinear effects and decreases the variations in DC-gains substantially. The input transformation is combined with a new control structure that has a pumping work minimization feature and consists of PID controllers and min/max-selectors for coordinated control of EGR-fraction and oxygen/fuel ratio. The EGR flow and the exhaust manifold pressure are chosen as feedback variables in this structure. Further, the set-points for EGR-fraction and oxygen/fuel ratio are transformed to set-points for the feedback variables.
2010-10-25
Technical Paper
2010-01-2210
Withit Chatlatanagulchai, Nitirong Pongpanich, Krisada Wannatong, Shinapat Rhienprayoon
In this paper, we investigate a multivariable control of air path of a diesel-dual-fuel (DDF) engine. The engine is modified from a CI engine by injecting CNG in intake ports. The engine uses CNG as its primary fuel and diesel as its secondary fuel, mainly for initiation of combustion. The modification is economically attractive because CNG has lower price than diesel and the modification cost is minimal. However, for DDF engine, control of the air path becomes more difficult because the engine now has combined characteristics of the CI and the SI engines. The combined characteristics come from the fact that diesel is still directly injected into cylinders (CI engine) while CNG is injected at the intake ports (SI engine.) In pure CI engine, throttle is normally fully opened for maximum air intake, while EGR valve is actively actuated to obtain low emissions. In pure SI engine, however, throttle is an active actuator, driven by pedal.
2010-10-25
Technical Paper
2010-01-2211
Fabrizio Ponti, Vittorio Ravaglioli, Davide Moro, Gabriele Serra
Proper design of the combustion phase has always been crucial for Diesel engine control systems. Modern engine control strategies' growing complexity, mainly due to the increasing request to reduce pollutant emissions, requires on-board estimation of a growing number of quantities. In order to feedback a control strategy for optimal combustion positioning, one of the most important parameters to estimate on-board is the angular position where 50% of fuel mass burned over an engine cycle is reached (MFB50), because it provides important information about combustion effectiveness (a key factor, for example, in HCCI combustion control). In modern Diesel engines, injection patterns are designed with many degrees of freedom, such as the position and the duration of each injection, rail pressure or EGR rate. In this work a model of the combustion process has been developed in order to evaluate the energy release within the cylinder as a function of the injection parameters.
2010-10-25
Technical Paper
2010-01-2220
Alessandro di Gaeta, Umberto Montanaro, Veniero Giglio
Idle Speed Control plays a crucial role to reduce fuel consumption that turns in both a direct economic benefit for customers and CO\d reduction particularly important to tackle the progressive global environmental warming. Typically, control strategies available in the automotive literature solve the idle speed control problem acting both on the throttle position and the spark advance, while the Air-Fuel Ratio (AFR), that strongly affects the indicated engine torque, is kept at the stoichiometric value for the sake of emission reduction. Gasoline Direct Injection (GDI) engines, working lean and equipped with proper mechanisms to reduce NOx emissions, overcome this limitation allowing the AFR to be used for the idle speed regulation.
2010-04-12
Technical Paper
2010-01-0564
Frank Willems, Erik Doosje, Frank Engels, Xander Seykens
This paper presents a cylinder pressure-based control (CPBC) system for conventional diesel combustion with high EGR levels. Besides the commonly applied heat release estimation, the CPBC system is extended with a new virtual NOx and PM sensor. Using available cylinder pressure information, these emissions are estimated using a physically based combustion model. This opens the route to advanced On-Board Diagnostics and to optimized fuel consumption and emissions during all operating conditions. The potential of closed-loop CA50 and IMEP control is demonstrated on a multi-cylinder heavy-duty EGR engine. For uncalibrated injectors and fuel variations, the combustion control system makes the engine performance robust for the applied variations and reduces the need for a time-consuming calibration process. Cylinder balancing is shown to enable auto-calibration of fuel injectors and to enhance fuel flexibility.
2010-04-12
Technical Paper
2010-01-0565
Bryan M. Knight, Joshua A. Bittle, Timothy J. Jacobs
The often-observed differences in nitrogen oxides, or NOx, emissions between biodiesel and petroleum diesel fuels in diesel engines remain intense topics of research. In several instances, biodiesel-fuelled engines have higher NOx emissions than petroleum-fuelled engines; a situation often referred to as the "biodiesel NOx penalty." The literature is rich with investigations that reveal many fundamental mechanisms which contribute to (in varying and often inverse ways) the manifestation of differences in NOx emissions; these mechanisms include, for example, differences in ignition delay, changes to in-cylinder radiation heat transfer, and unequal heating values between the fuels. In addition to fundamental mechanisms, however, are the effects of "system-response" issues.
2010-04-12
Technical Paper
2010-01-0566
Kilnam Kim, Sunghwan Cho
The LNT(Lean NOx Trap) system has been developed for NOx reduction to meet Tier2Bin5 by using 2.2ℓ-diesel engine which was recently introduced by Hyundai Kia Motor company. The compression ratio was adjusted to 15.5 and the trim size of the turbine was reduced to increase EGR rates. During the FTP75 mode test, the engine out NOx was reduced by about 30% compared to the standard engine. The rich mode combustion was developed for the wide operating range despite of the low compression ratio. It was accomplished by adjusting air and FIE system, mainly by increasing post2 injection quantity. The A/F (Air-to-Fuel) ratio was controlled by additional post2 injection quantity. The neutral transition between lean mode and rich mode combustion was completed. The noise and torque change could not be recognized by the drivers during the transition of combustion mode (lean-to-rich or rich-to-lean). The transition procedure was finished within about 1sec for the whole operating range.
2010-04-12
Journal Article
2010-01-0567
Naeim A. Henein, Walter Bryzik, Ahmed Abdel-Rehim, Ashish Gupta
Ion current sensors have been considered for the feedback electronic control of gasoline and diesel engines and for onboard vehicles powered by both engines, while operating on their conventional cycles or on the HCCI mode. The characteristics of the ion current signal depend on the progression of the combustion process and the properties of the combustion products in each engine. There are large differences in the properties of the combustible mixture, ignition process and combustion in both engines, when they operate on their conventional cycles. In SI engines, the charge is homogeneous with an equivalence ratio close to unity, ignition is initiated by an electric spark and combustion is through a flame propagating from the spark plug into the rest of the charge.
2010-04-12
Technical Paper
2010-01-0568
Riccardo Ceccarelli, Philippe Moulin, Carlos Canudas de Wit
In nowadays diesel engine, the turbocharger system plays a very important role in the engine functioning and any loss of the turbine efficiency can lead to driveability problems and the increment of emissions. In this paper, a VGT turbocharger fault detection system is proposed. The method is based on a physical model of the turbocharger and includes an estimation of the turbine efficiency by a nonlinear adaptive observer. A sensitivity analysis is provided in order to evaluate the impact of different sensors fault, (drift and bias), used to feed the observer, on the estimation of turbine efficiency error. By the means of this analysis a robust variable threshold is provided in order to reduce false detection alarm. Simulation results, based on co-simulation professional platform (AMEsim© and Simulink©), are provided to validate the strategy.
2010-04-12
Journal Article
2010-01-0569
Hanlong Yang, Christian Chimner
Future government emission regulations have lead to the development and implementation of advanced aftertreatment systems to meet stringent emission standards for both on-road and off-road vehicles. These aftertreatment systems require sophisticated control and diagnostic strategies to ensure proper system functionality while minimizing tailpipe NOx and PM emissions across all engine operating conditions. In this paper, an integrated algorithm design approach with controls and diagnostics for an aftertreatment system consisting of a fuel doser, fuel reformer, LNT, DPF, and SCR is discussed.
2010-04-12
Technical Paper
2010-01-0370
Maria Ivarsson, Jan Åslund, Lars Nielsen
For a fuel optimal gear shift control, when look ahead information is available, the impact of the automated manual transmission (AMT) gear-shifting process is analyzed. For a standard discrete heavy truck transmission, answers are found on when to shift gears, prior to or when in an uphill slope. The gear-shifting process of a standard AMT is modeled in order to capture the fuel and time aspects of the gear shift. A numerical optimization is performed by dynamic programming, minimizing fuel consumption and time by controlling fuel injection and gear. Since a standard AMT does not have look ahead information, it sometimes gears down unnecessarily and thus gives a significantly higher fuel consumption compared to the optimal control. However, if gearing down is inevitable, the AMT gear-shifting strategy, based on engine thresholds, is well-functioning so that the optimal control only gives marginal additional savings.
2010-04-12
Technical Paper
2010-01-0371
Heimo Hartlieb, Kyle Shawn Williams, Michael Hausmann
The majority of modern automatic transmissions make use of multiple Variable Force Solenoid (VFS) valves within the hydraulic controls. The requirements for the control of these valves are much more stringent in the latest transmission designs. This leads to challenging requirements for the electronic solenoid driver circuit used to regulate the current flowing through the solenoid valve coil. We have developed a current control method that is fundamentally different than those commonly used in solenoid driver circuits. This unique current control method results in several improvements in the key performance characteristics of the solenoid driver circuit, which in turn improves the performance of the transmission system. In addition, this new control method requires less effort to implement into a specific application than state of the art current control methods.
2010-04-12
Technical Paper
2010-01-0372
Baoyu Wu, Guo Xuexun, Jun Yan, Qi Sun
Speed ratio and clamping force are two of the metal-belt CVT control targets. Conventional control strategies can not correspond to the driver's intention or provide various driving environment. A fuzzy logic ratio control algorithm and a fuzzy logic clamping force control algorithm for a metal-belt CVT are proposed. Nevertheless, high-quality fuzzy control rule base and factors of FLC are difficult to gain because repeated tests and experts' experience are needed. Therefore, genetic algorithm (GA) is introduced to optimize the fuzzy control algorithms. Using the optimized fuzzy control algorithms, Metal-belt CVT control simulations were implemented. The results show that a faster response and better robustness can be gained when compared with those of the PID control.
2010-04-12
Technical Paper
2010-01-0457
Zhenhai Gao, Fei Gao, Lifei Duan
According to the process that a new driver becomes a low skill level driver and finally a skilled driver from learning how to drive, especially in light of the understanding on the vehicle lateral dynamics that will change from linear characteristic under low speed to strong nonlinear character under high speed, a novel driver model is established. At low speed linear range, off-line optimization based on genetic tuning is introduced into the model to get the optimal control parameters which is viewed as a basic understanding of the vehicle dynamic characteristics of a low skill level driver. On basis of the previous established model, neural network adaptive mechanism is introduced to the driver model which enables the driver to adjust the control online even at high speed non-linear area, reflecting a deeper understanding of the vehicle dynamic model. At last, simulation has been taken in order to verify the correctness and accuracy of the model.
2011-04-12
Technical Paper
2011-01-0444
Daniel Kästner, Marek Jersak, Christian Ferdinand, Peter Gliwa, Reinhold Heckmann
Developers of safety-critical real-time systems have to ensure that their systems react within given time bounds. Ideally, the system is designed to provide sufficient computing power and network bandwidth, is cost efficient and provides the necessary safety level. To achieve this goal, three challenges have to be addressed. First, it must be possible to account for timing during early development stages in the architecture exploration phase. Second, during software development, timing behavior and the effects of software changes on timing must be observable. Third, there must be a technology for formally verifying the final timing behavior for industry-size applications. In this article we present a comprehensive methodology for dealing with timing which addresses all three issues based on state-of-the-art commercial tools.
2011-04-12
Technical Paper
2011-01-0432
André Levesque, Jennifer Johrendt
The following paper presents an outline of the current state of driver modeling along with the various methods that are employed in their development. In recent years, vehicle manufacturers have implemented various systems that, in some manner, improve the operation of their vehicles. Many of these systems include an electronically controlled device which is capable of making decisions based on the immediate conditions affecting the vehicle. Much of the influence to develop such systems stems from the issue of safety: in emergency situations the control device is capable of making a decision quicker than the driver and thus reduces the potential for some form of collision. Another motivating factor behind these systems is to improve fuel efficiency, specifically in regard to hybrid vehicles where more than one form of propulsion is used and such devices can aid the driver to operate in a more efficient manner.
2011-04-12
Journal Article
2011-01-0431
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Following the developments in controlled suspension system components, the studies on the vertical dynamics analysis of vehicles increased their popularity in recent years. The objective of this study is to develop a semi-active suspension system controller using Adaptive-Fuzzy Logic control theories together with Kalman Filter for state estimation. A quarter vehicle ride dynamics model is constructed and validated through laboratory tests performed on a hydraulic four-poster shaker. A Kalman Filter algorithm is constructed for bounce velocity estimation, and its accuracy is verified through measurements performed with external displacement sensors. The benefit of using adaptive control with Fuzzy-Logic to maintain the optimal performance over a wide range of road inputs is enhanced by the accuracy of Kalman Filter in estimating the controller inputs. A gradient-based optimization algorithm is applied for improving the Fuzzy-Logic controller parameters.
2011-04-12
Technical Paper
2011-01-0456
Karthik Singaram Lakshmanan, Gaurav Bhatia, Ragunathan Rajkumar
Multi-core processors are becoming increasingly prevalent, with several multi-core solutions being offered for the automotive sector. Recognizing this trend, the AUTomotive Open System ARchitecture (AUTOSAR) standard Version 4.0 has introduced support for multi-core embedded real-time operating systems. A key element of the AUTOSAR multi-core specification is the spinlock mechanism for inter-core task synchronization. In this paper, we study this spinlock mechanism from the standpoint of timing predictability. We describe the timing uncertainties introduced by standard test-and-set spinlock mechanisms, and provide a predictable priority-driven solution for inter-core task synchronization. The proposed solution is to arbitrate critical sections using the well-established Multi-processor Priority Ceiling Protocol [3], which is the multiprocessor version of the ceiling protocol for uniprocessors [1, 2] used by AUTOSAR.
2011-04-12
Technical Paper
2011-01-0454
Matt Rings, Paul Phillips
The increase in the number of electronic control units (ECUs) in the modern vehicle, combined with increased software complexity and more distributed controls has led to an extreme testing challenge when it comes to the verification and validation of body-control ECUs. In general test engineers have to deal with more software configurations, more closed-loop interaction between ECUs, and more fault conditions than ever before. By adding Unified Diagnostic Services (UDS) over CAN to a Hardware-In-The-Loop (HIL) test system, Lear was able to increase test automation and provide wider test coverage by automating the ECU flashing process, adding diagnostic identifiers and trouble codes to their test scripts, and providing a quick and easy way to exercise ECU I/O. Lear chose to implement their HIL testers on the open PXI[1] hardware platform, utilizing National Instruments' VeriStand software framework.
2011-04-12
Technical Paper
2011-01-0449
Rafael Zalman, Alexander Griessing, Paul Emberson
1. ABSTRACT Automotive applications classed as safety-related or safety-critical are now important differentiating technologies in the automotive industry. The emergence of safety standard ISO 26262 underlines the increasing importance of safety in automotive software. As well as functional requirements, hard real-time requirements are of crucial importance to safety-related software as there is a need to prove that the system functionality is fulfilled, even in worst-case scenarios. Measurement-based WCET (Worst-Case Execution Time) analysis combines on-target timing measurements with static analysis of program structure to calculate predicted worst-case paths and times. This is in contrast to traditional end-to-end timing measurements, which give no confidence that the worst-case path is actually tested and no insight into the location of any timing problems that do emerge.
2011-04-12
Journal Article
2011-01-0450
Mina Khoee-Fard, Tarek Lahdhiri
As the new features for driver assistance and active safety systems are growing rapidly in vehicles, the simulation within a virtual environment has become a necessity. The current active safety system consists of Electronic Control Units (ECUs) which are coupled to camera and radar sensors. Two methods of implementation exists, integrated sensors with control modules or separation of sensors form control modules. The subsystem integration testing poses new challenges for virtual environment for simulation of active safety features. The comprehensive simulation environment for integration testing consists of chassis controls, powertrain, driver assistance, body and displays controllers. Additional complexity in the system is the serial communication strategy. Multiple communication protocols such as GMLAN, LIN, standard CAN, and Flexray could be present within the same vehicle topology.
2011-04-12
Technical Paper
2011-01-0447
Arkadeb Ghosal, Paolo Giusto, Prakash Peranandam, Purnendu Sinha, Haibo Zeng
Recent trends in the automotive industry show growing demands for the introduction of new in-vehicle features (e.g., smart-phone integration, adaptive cruise control, etc.) at increasing rates and with reduced time-to-market. New technological developments (e.g., in-vehicle Ethernet, multi-core technologies, AUTOSAR standardized software architectures, smart video and radar sensors, etc.) provide opportunities as well as challenges to automotive designers for introducing and implementing new features at lower costs, and with increased safety and security. As a result, the design of Electrical/Electronic (E/E) architectures is becoming increasingly challenging as several hardware resources are needed. In our earlier work, we have provided top-level definitions for three relevant metrics that can be used to evaluate E/E architecture alternatives in the early stages of the design process: flexibility, scalability and expandability.
2011-04-12
Technical Paper
2011-01-0397
Hiromichi Kawamura, Ken Ito, Takaaki Karikomi, Tomohiro Kume
This paper describes a shaking vibration suppression approach for electric vehicles to support their quick and smooth acceleration response. Applied to the Nissan LEAF that has been specifically designed as a mass-market EV, the shaking vibration control system achieves a balance between highly responsive acceleration obtained with the electric drive motor, producing maximum torque of 280 Nm and maximum power of 80 kW, and a comfortable ride. A vehicle powered by an electric motor can provide quick acceleration response, thanks to the motor's fast torque response. However, the fast rate of increase in motor torque causes an uncomfortable shaking vibration that originates in the torsional torque of the drive shaft. The unique shaking vibration control system has been developed to achieve a balance between vehicle acceleration performance and ride comfort. Driving test results have confirmed that highly responsive acceleration is obtained without any shaking vibration.
2011-04-12
Technical Paper
2011-01-0394
Zhe Xie
A system level analysis was carried out on the effect of flow forces on a flow control variable force solenoid (VFS) used in automatic transmissions. Classic flow force model was reviewed as a function of the pressure difference and the solenoid current. A force balance analysis was conducted on the spool valve in the VFS, in order to study the relationship among the control current, flow forces, spring forces, and flow area. Flow bench testing was used to characterize a specific flow control VFS by both the pressure drop and solenoid current, in forward and reverse flow directions. The behavior of flow control VFS valve is significantly affected by flow forces. A sub-system level model was thus created to predict the steady-state and dynamic behavior of the flow VFS valve, which can be used in a transmission system level analysis. The modeling results were compared against experimental data to show the validity of the methodology.
2011-04-12
Technical Paper
2011-01-0393
John Marano, Steven Moorman, John Czoykowski, Chinar Ghike
The achievable shift quality of a modern automatic transmission may be greatly affected by the equivalent rotational inertia of the gearbox and driveline components. New, more mass- and packaging-efficient higher number of gear powerflows are being developed. These new architectures often result in more components being attached to a given rotational node. The rotational speed multiplication of the components must be considered when determining their inertial torque contribution to a given speed change event. An example of this multiplication effect is presented, with a discussion of the resulting impact to shift quality disturbance. Opportunities to address the negative aspects of the higher inertial torque contribution to transmission output shaft disturbance are discussed. Coordination of engine torque control and clutch torque control is presented as a viable strategy to improve shift quality.
2011-04-12
Technical Paper
2011-01-0396
Kumaraswamy Hebbale, Chunhao Lee, Farzad Samie, Chi-Kuan Kao, Xu Chen, Jeremy Horgan, Scott Hearld
To realize better fuel economy benefits from transmissions, car makers have started the application of torque converter clutch control in second gear and beyond, resulting in greater demand on the torque converter clutch (TCC) and its control system. This paper focuses on one aspect of the control of the torque converter clutch to improve fuel economy and faster response of the transmission. A TCC is implemented to control the slip between the pump and turbine of the torque converter, thereby increasing its energy transfer efficiency and increasing vehicle fuel economy. However, due to the non-linear nature of the torque converter fluid coupling, the slip feedback control has to be very active to handle different driver inputs and road-load conditions, such as different desired slip levels, changes in engine input torques, etc. This non-linearity requires intense calibration efforts to precisely control the clutch slip in all the scenarios.
2011-04-12
Technical Paper
2011-01-0392
Dongxu Li, Kumaraswamy Hebbale, Chunhao Lee, Farzad Samie, Chi-Kuan Kao
Automobile drivers/passengers perceive automatic transmission (AT) shift quality through the torque transferred by transmission output shaft, so that torque regulation is critical in transmission shift control and etc. However, since a physical torque sensor is expensive, current shift control in AT is usually achieved by tracking a turbine speed profile due to the lack of the transmission output torque information. A direct torque feedback has long been desired for transmission shift control enhancement. This paper addresses a “virtual” torque sensor (VTS) algorithm that can provide an accurate estimate on the torque variation in the vehicle transmission output shaft using (existing) speed sensors. We have developed the algorithm using both the transmission output speed sensor and anti-lock braking system speed sensors. Practical solutions are provided to enhance the accuracy of the algorithm. The algorithm has been successfully implemented on both FWD and RWD vehicles.
2011-04-12
Technical Paper
2011-01-0391
Quan Zheng, Bruce Church, Ken Defore
Electro-hydraulic actuation has been used widely in automatic transmission designs. With greater demand for premium shift quality of automatic transmissions, higher pressure control accuracy of the transmission electro-hydraulic control system has become one of the main factors for meeting this growing demand. This demand has been the driving force for the development of closed loop pressure controls technology. This paper presents the further research done based upon a previously developed closed loop system. The focus for this research is on the system requirements, such as solenoid driver selection and system latency handling. Both spin-stand and test vehicle setups are discussed in detail. Test results for various configurations are given.
2011-04-12
Technical Paper
2011-01-0689
Vishwas Vaidya, Anand Patidar
Automotive embedded control systems need to implement real-time closed-loop control strategies for controlling valves, motors, etc. The implementation needs to focus on use of low cost hardware and efficient software with minimal foot-print so as to adequately meet the application requirement. This paper highlights the low cost hardware and software design concepts by way of a case study related to control of progressive EGR valve. The control strategy is based on "map-driven set-points" where percentage opening of the valve is stored in the form of 16x16 matrices. The set-points are accessed based on instantaneous throttle and engine rpm values which form the row and column indices of the map. The closed loop control algorithm eliminates the need for multiplication by implementing "feed-forward with integral control algorithm." A feed-forward map specifies the most likely PWM duty cycle to be applied to the valve for a given set-point.
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