Shawn Midlam-Mohler

Study of PEV Charging on Residential Distribution Transformer Life

Due to the characteristics of electric power generation, transmission and distribution in the U.S., experts have identified local distribution as a likely part of the chain to be adversely affected by unregulated PEV (Plug-in Electric Vehicle) charging. This paper presents a study performed to assess the impact of PEV charging on a local residential distribution transformer.

Ceramic-based chemical sensors, probes and field-tests in automobile engines

The monitoring and control of combustion-related emissions is a top priority in many industries. The major methods used to detect combustion gases fall short of practical applications for in-situ measurements in industrial environments involving high temperature and chemical contaminants. The real challenge is not only to develop highly sensitive and selective sensors, but to maintain long-term stability in such aggressive environments. This article presents an overview of a multidisciplinary research effort in ceramic-based chemical sensors, highlighting opportunities as well as challenges. The group of sensors (CO, NOx, O2, and CO2) selected for this article can, in general, be used to determine the state of combustion in a wide variety of applications. Fabrication of sensor probes and their field-test results in automobile engines are also presented.

Mean Value Modeling and Analysis of HCCI Diesel Engines With External Mixture Formation

Homogeneous charge compression ignition (HCCI) is a promising concept for internal combustion engines that can considerably decrease NO x and soot emissions in part-load operations without penalizing fuel consumption. The HCCI combustion can be implemented in direct injection diesel engines without major modifications by introducing a specialized fuel injector in the intake port. This decouples the homogeneous mixture formation from the traditional in-cylinder injection, thus providing two fueling systems that can be used to optimize exhaust emissions and fuel consumption over the engine operating range. However, understanding and controlling the complex mechanisms and interactions driving the HCCI combustion process is still a difficult task. For this reason, it is essential to identify the most important control parameters and understand their influence on the auto-ignition process. The current work analyzes HCCI combustion with external mixture formation through experimental investigation and the definition of a control-oriented model. An extensive testing activity was performed on a passenger car diesel engine equipped with an external fuel atomizer to operate in HCCI mode. This provided an understanding of the process as well as experimental data to identify a mean value model of the system and its parameters. The model includes a thermodynamic combustion calculation that estimates the heat release, cylinder pressure, and the relevant variables for combustion control. The tool developed was then validated and used for analyzing the system behavior in steady state conditions. Finally, a description of the HCCI system behavior in transient operations is presented.

A control-oriented model of combustion process in a HCCI diesel engine

Homogeneous charge compression ignition is a promising concept for achieving low emissions at part-load operations. This technique can be successfully applied to traditional direct injection diesel engines with low extra costs and no modification to the DI system by performing the mixture formation in the intake manifold. The present paper describes the development of a control-oriented model for the study of the combustion process in a HCCI diesel engine with external mixture formation. The model is based on a first-law thermodynamic analysis of in-cylinder processes in order to identify the influence of the main control parameters on HCCI auto-ignition. The combustion process is modeled through the definition of a gross heat release rate, avoiding a detailed description of the chemical reactions that could increase the complexity and the computation time. The model is then validated against experimental data obtained on a diesel engine equipped with an external fuel atomizer. The satisfactory agreement obtained and the low calibration effort make the model a useful tool for the development of applications related to HCCI engine control and diagnostics.

Supervisory control for NO/sub x/ reduction of an HEV with a mixed-mode HCCI/CIDI engine

In this paper, we present a supervisory control strategy for a hybrid electric vehicle which best exploits the NO/sub x/ characteristics of such a mixed-combustion mode engine, while optimizing fuel economy and meeting drivers demand. This strategy is an extension of our adaptive equivalent consumption minimization strategy (A-ECMS) control strategy, suitably modified to explicitly minimize NO/sub x/ emissions. The HEV configuration, coupled to this control strategy, allows to very effectively manipulate the operating points of the engine to be primarily constrained in the HCCI regime, with very low NO/sub x/ emissions. This results in dramatically reduced NO/sub x/ emissions during actual driving conditions, while retaining the high fuel economy of CIDI engines and hybrids and maintaining the performance envelop of the vehicle. In summary, the control strategy automatically exploits the relatively small region of HCCI operation to minimize NO/sub x/ emissions.

PHEV fleet data collection and analysis

This paper deals with a project related to Plug-in Hybrid Electric Vehicles fleet studies. The project is part of a broader research consortium underway at Ohio State Universitys Center for Automotive Research called SMART@CAR. Main goals are to create and maintain a database containing all charging and duty cycle data collected from a growing PHEV fleet. Real-world data provided by these vehicles will be collected, archived, organized and analyzed. The availability of real world data will also help estimate the effects of PHEV penetration on the utility energy sales, generation capacity, the transmission grid, market economics, and environmental emissions.

Statistical analysis of PHEV fleet data

The added load that a PHEV (Plug-in Hybrid Electric Vehicle) fleet imposes on the existing electrical grid is of great concern to the electric utility industry. In this paper, analysis was done for a PHEV fleet which consists of 6 PHEVs that were instrumented using data loggers for a period of approximately one year. Systematic analysis using a clustering approach was carried out for the real world velocity profiles. A driving pattern recognition algorithm was developed based on the clustering of the results and Markov-chain model was used for the stochastic velocity generation for different driving patterns. The work of this paper is a part of a larger project in which a mass simulation of a neighborhood of PHEVs will be conducted based on statistical representations of key factors such as vehicle usage patterns, vehicle characteristics, and market penetration of PHEVs.

Theoretical and experimental investigation on diesel HCCI combustion with external mixture formation

Homogeneous Charge Compression Ignition (HCCI) is a concept for achieving ultra-low NOx and particulate matter emissions at part-load operations. HCCI combustion can be obtained on conventional diesel engines by premixing the charge in the intake manifold with a dedicated fuel atomiser. The paper describes experimental and modelling activities oriented to understanding and controlling diesel HCCI combustion with external mixture formation. Results obtained on different engines showed that stable diesel HCCI combustion could be achieved over a range of operating conditions, and confirmed its benefits in terms of NOx and soot reduction. The theoretical activity is focused on HCCI combustion modelling for control by means of a mean-value model of a complete engine system, which imbeds a thermodynamic combustion calculation. The satisfactory agreement with experimental data as well as the low computation time indicate the model suitable for HCCI engines control and diagnostics.

The role of ITS in PHEV performance improvement

Driving patterns have great impact on fuel economy or power split control decisions of PHEV (Plug-in Hybrid Electric Vehicle) energy management. In this paper, a statistical approach was used to analyze real world velocity profiles to gather traffic information such as average speed, speed limits, segment length, etc. A Markov chain model was developed to make use of such information for generation of random velocity profiles that are representative of real world driving scenarios. The velocity profiles generated using the Markov chain models are used to calculate vehicle fuel economy by means of a validated through the road parallel PHEV model and ECMS (Equivalent Consumption Minimization Strategy) control strategy. The end goal of the research is to find mathematical, statistical or heuristic relationships between road events and the performance of PHEV energy management.

PEV charging control for a parking lot based on queuing theory

PEV (Plug-in Electric Vehicle) charging control is important due to the fact that the unregulated charging can have a great impact on current power grid system. This paper concerns the PEV charging control for a case study of a shopping center parking lot. A queuing model is used to predict the temporal evolution of the number of PEVs in the parking lot. The charging control considers the loss of life of a dedicated distribution transformer for the facility. The objective of the control algorithm is to balance the minimization of the transformer loss of life and the maximization of charging service quality. The queuing theory is also used to estimate the waiting time under different number of chargers. The simulation results of the proposed smart charging strategy show the effectiveness of the methodology.