Showing papers by "Giorgio Rizzoni published in 2003"

Supervisory control of fuel cell vehicles and its link to overall system efficiency and low-level control requirements

Abstract: In this paper, we address the benefits of hybridization of fuel cell vehicles. These benefits are not only in efficiency gains but also result in a significant lessening of the dynamic control requirements for automotive fuel cell systems.

Dynamic Modeling of a Hybrid Electric Drivetrain for Fuel Economy, Performance and Driveability Evaluations

Abstract: Both automakers and customers keep on pursuing better fuel economy, performance and driveability. A “mild” hybrid drivetrain is of great interest due to its potential capability on improving these targets. This drivetrain contains a spark ignition (SI) engine, an integrated starter/alternator (ISA), a torque converter (TC), a continuously variable transmission (CVT), a final drive (FD), a driveshaft, a brake-by-wire (BBW) system and wheels. While the challenge is to model and to develop an optimal control algorithm for this hybrid electric vehicle (HEV), this paper will focus only on the modeling aspect. Model-based control design and the nature of human perceptible driveability issues require low-frequency dynamic models. Therefore, a nonlinear control-oriented model which is sufficiently accurate but not excessively complicated is proposed here. Simulation results demonstrate that this model is effective to capture the main behaviors of vehicle dynamics and to evaluate fuel economy, performance and driveability objectively.© 2003 ASME

A LMI-based supervisory robust control for hybrid vehicles

Abstract: The aim of this paper is to propose a robust approach to the development of supervisory control strategies for hybrid-electric drivetrains. The objective is to determine an output feedback controller that minimize fuel consumption with respect to a family of possible torque/power input profiles, e.g. urban driving cycles. A quasi-static energy model for the hybrid vehicle, based on a Willans lines model of the IC engine and electric motor, is derived. Sufficient conditions for the existence of a robust controller satisfying stability, L/sub 2/ gain attenuation between inputs and outputs of interest, and input/output bound constraints are derived by means of a set of linear matrix inequalities (LMIs).

In-Depth Analysis of the Influence of High Torque Brakes on the Jackknife Stability of Heavy Trucks

Abstract: Published NHTSA rulemaking plans propose significant reduction in the maximum stopping distance for loaded Class-VIII commercial vehicles. To attain that goal, higher torque brakes, such as air disc brakes, will appear onprime movers long before the trailer market sees significant penetration. Electronic control of the brakes on prime movers should also be expected due to their ability to significantly shorten stopping distances. The influence upon jackknife stability of having higher performance brakes on the prime mover, while keeping traditional pneumatically controlled s-cam drum brakes on the trailer, is discussed in this paper. A hybrid vehicle dynamics model was applied to investigate the jackknife stability of tractor-semitrailer rigs under several combinations of load, speed, surface coefficient, and ABS functionality. These simulations were run to simulate brake-in-turn (B.I.T.) scenarios for a tractor-semitrailer articulated vehicle which is near the maximum drive-through speed limit for various vehicle weight / surface coefficient conditions. ECBS-disc brake equipped tractors were directly compared to those having s-cam drum brakes. This study shows that the simulated presence of ECBS-disc brakes on the tractor results in no degradation of the performance of the rig, in terms of jackknife stability, while braking in a turn. Furthermore, the elaborate vehicle simulations showed significant reduction in the tractor maximum yaw rate and hitch articulation angle seen during the simulation, for those simulated vehicles equipped with disc brakes and electronically controlled braking systems (ECBS).

Empirical Models for Commercial Vehicle Brake Torque from Experimental Data

Abstract: This paper introduces a new series of empirical mathematical models developed to characterize brake torque generation of pneumatically actuated Class-8 vehicle brakes. The brake torque models, presented as functions of brake chamber pressure and application speed, accurately simulate steer axle, drive axle, and trailer tandem brakes, as well as air disc brakes (ADB). The contemporary data that support this research were collected using an industry standard inertia-type brake dynamometer, routinely used for verification of FMVSS 121 commercial vehicle brake standards.

New Model for Simulating the Dynamics of Pneumatic Heavy Truck Brakes with Integrated Anti-Lock Control

Abstract: This paper introduces a new nonlinear model for simulating the dynamics of pneumatic-over-mechanical commercial vehicle braking systems. The model employs an effective systems approach to accurately reproduce forcing functions experienced at the hubs of heavy commercial vehicles under braking. The model, which includes an on-off type ABS controller, was developed to accurately simulate the steer, drive, and trailer axle drum (or disc) brakes on modern heavy commercial vehicles. This model includes parameters for the pneumatic brake control and operating systems, a 4s/4m (four sensor, four modulator) ABS controller for the tractor, and a 2s/2m ABS controller for the trailer. The dynamics of the pneumatic control (treadle system) are also modeled. Finally, simulation results are compared to experimental data for a variety of conditions.

Identification of a Mean Value Model of a Modern Diesel Engine for Control Design

Abstract: The modern diesel engine with its multiple subsystem interactions is a very complex plant. Especially fascinating are the interactions of the VGT and EGR control actions in their cumulative effect on the overall air loop dynamics. To circumvent the problem of manpower intensive engine mapping for determining the best operating control map, a generic mean value model of a diesel engine, based on physical principles and empirical definitions where necessary, was developed. In this paper we present the identification of this model with respect to a Fiat 2.4L JTD 166. It will be shown that there is an essential set of parameters that must be identified in order to model processes that are too complicated for physics based modeling. The parameter set is utilized in simplified empirical relationships to model complex engine phenomena such as combustion and orifice flow through the EGR and VGT, facilitating model portability. Results from matching these empirical relationships to the engine of interest and model predictions of air loop system response to EGR and VGT control inputs show good agreement with actual engine performance and are presented in this paper.Copyright © 2003 by ASME

Development and Validation of a Control-Oriented Model of a Spark-Ignition Direct-Injection Engine

Abstract: Due to the increasing demands on improved fuel economy and stringent government regulations on tailpipe emissions, many automotive industries and research institutes have been looking for alternative solutions, such as diesel engines, hybrid-electric vehicles, and fuel cell technologies, over conventional port fuel injection (PFI) gasoline engines to meet the demands. On the other hand, many people in the automotive community also realize that there are still a lot of room for improvements in gasoline engine technologies, such as utilizing direct injection and/or variable valve actuation. In order to fully realize the potential benefits of such advanced technologies in gasoline engines, a well-coordinated complex control system design is essential. This paper describes the development and validation of a control-oriented mean-value model for a spark-ignition direct-injection (SIDI) engine to assist and accelerate such coordinated control system design and calibration processes via use of an engine model. The performance and accuracy of the dynamic engine model are evaluated and validated against a set of data for an engine running on a transient driving cycle.Copyright © 2003 by ASME

Supervisory Robust Control of Hybrid Electric Vehicles

Abstract: The control problems that arise in connection with hybrid powertrains are significant, and pose great challenges to power-train control engineers. Big obstacles to the control design are the model complexity, and the necessity of a knowledge “a priori” of torque and velocity profiles for optimal fuel consumption and exhaust emissions. The aim of this paper is to propose a robust approach to the development of supervisory control strategies for hybrid-electric drivetrains. The objective is to determine an output feedback controller that minimize fuel consumption with respect to a family of possible torque/power input profiles, e.g. urban driving cycles. Sufficient conditions for the existence of a robust controller satisfying stability, L 2 gain attenuation between inputs and outputs of interst, and input/output bound constraints are derived by means of a set of linear matrix inequalities (LMIs).Copyright © 2003 by ASME

High-power High-speed Road Train System

Abstract: This paper presents the design and development of a high-power, high-speed "road train" (with both on- and off-road applications). The system looks to optimize both high-speed operation and low-speed, close-quarters driving with the introduction of autonomous power modules. Each trailer in the road train has it own electric traction system. When driving on open roads or in open areas, each traction system receives electric energy from the high-powered tractor. However, the individual traction systems allow for distributed tractive effort, improving upon the classic road train. Further, each module has its own independent steering system, allowing for practical implementation of longer trains. Use of longer trains in open areas allows for reduced operational costs, and increased efficiency. When mobility becomes a primary concern or zero emissions operation is needed, small power supplies can allow independent trailer operation. This paper presents the design and layout of the road train system. Details are provided about the tandem electric axles, with electric differentials and independent steering. New innovations in power electronics, providing high power operation and affordable production costs are discussed. The paper also describes some new concepts for a high-powered tractor.

The 2002 Ohio State University FutureTruck - The BuckHybrid002

Abstract: This year, in the third year of FutureTruck competition, the Ohio State University team has taken the challenge to convert a 2002 Ford Explorer into a more fuel efficient and environmentally friendly SUV. This goal was achieved by use of a post-transmission, charge sustaining, parallel hybrid diesel-electric drivetrain. The main power source is a 2.5-liter, 103 kW advanced CIDI engine manufactured by VM Motori. A 55 kW Ecostar AC induction electric motor provides the supplemental power. The powertrain is managed by a state of the art supervisory control system which optimizes powertrain characteristics using advanced energy management and emission control algorithms. A unique driver interface implementing advanced telematics, and an interior designed specifically to reduce weight and be more environmentally friendly add to the utility of the vehicle as well as the consumer appeal. The BuckHybrid002 achieves 23 mpg city and 32 mpg highway, meets ULEV emissions standards and meets or exceeds all of the performance and customer demands embodied in the stock Explorer.