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SAE 2011 High Efficiency IC Engines Symposium - Session 3 - Advanced Diesel Engine Technologies Presenter Andrew Brown, Delphi Corp.

Consumers design different PHEVs than expert analysts assume. Experts almost uniformly assume PHEVs that offer true all-electric driving for 10 to 60 miles; consumers are more likely to design PHEVs that do not offer true all-electric driving and have short ranges over which they use grid-electricity. Thus consumers? PHEV designs are less expensive. These consumer PHEV designs do, or don?t, produce lower GHG emissions than experts? PHEVs over the next ten years. The devil is in the details, i.e., which powerplant emissions to assign to new electricity demand: marginal or average. If (based on marginal powerplant emissions) it makes almost no difference whether we sell consumer-designed or expert-assumed PHEVs over the next ten years, yet as the grid continues to de-carbonize all-electric PHEV designs emerge as clearly the better option, there is a trajectory we could be on from blended, ?short range? PHEVs to all-electric ?long range? PHEVs.

Hybrid systems have been available for several years now, and offer customers a decrease in fuel consumption and CO2 emissions at an incremental price. Hybrids, in some cases, have offered improved other customer benefits such as reduced noise, vibration and harshness or better acceleration and the satisfaction of increased societal benefit. Sometimes the vehicle utility is compromised by the volume dedicated to energy storage systems. Several hybrid architecture arrangements exist in the market, and offer various levels of hybrid feature. But considering acquisition cost and operating expense, most hybrid vehicles have not offered a direct total cost advantage when compared to non-hybrids. GM's new e-Assist system is highly integrated with the engine and transmission functionality, and takes advantage of the highest value fuel economy enablers available with light electrification.

Advanced vehicular thermal management system can improve engine performance, minimize fuel consumption, and reduce emissions by harmoniously operating computer-controlled servomotor components. In this paper, a neural network-based optimal control strategy is proposed to regulate the engine temperature through the advanced cooling system. Presenter Asma Al Tamimi, Hashemite University

There are now a wide variety of Hybrid and Electric Vehicles in or near production. They reduce or displace petroleum consumption with of various combinations of conventional IC engine, mechanical transmission, liquid fuel storage, electrical energy storage, electrical and electro-mechanical energy conversion, and vehicle-to-grid energy interface. These Electrified types of vehicles include Mild Hybrid, Full Hybrid, Plug-In Hybrid, Extended Range Electric, and Battery Electric. Some types differ in their actual usability for the real mixes of driving trips, and further that differ in their effectiveness to reduce or displace fuel in actual real world driving use. Vehicle size is also a factor in total vehicle utility in transporting people. If we may segment drivers by their driving needs, in each segment, we see a particular type of electrified vehicle that is better suited than others at minimizing fuel cost and petroleum consumption for the purposes of transporting people.

Hybrid technology has the potential to enable dramatic reductions in greenhouse gases (GHG), such as the California goal of reducing GHG by 80 percent from 1990 levels by 2050. As a result it is expected that hybrid systems will occupy a growing proportion of the market. However, introducing a hybrid system in a vehicle may adversely affect the performance of the engine OBD system in monitoring malfunctions impacting pollutant emissions. For example, a hybrid system that reduces time of the engine in idle or deceleration overrun conditions could make a well-performing engine OBD system noncompliant, by reducing in-use frequency of some OBD monitors below acceptable levels. In this presentation, Ricardo will present a process for evaluating the impact that a hybrid system which has been optimised to minimise GHG emission over a specified drive-cycle will have on the effectiveness of engine OBD monitors.

This paper presents a low-cost path for extending the range of small urban pure electric vehicles by hydraulic hybridization. Energy management strategies are investigated to improve the electric range, component efficiencies, as well as battery usable capacity. As a starting point, a rule-based control strategy is derived by analysis of synergistic effects of lead-acid batteries, high efficient operating region of DC motor and the hydraulic pump/motor. Then, Dynamic Programming (DP) is used as a benchmark to find the optimal control trajectories for DC motor and Hydraulic Pump/Motor. Implementable rules are derived by studying the optimal control trajectories from DP. With new improved rules implemented, simulation results show electric range improvement due to increased battery usable capacity and higher average DC motor operating efficiency. Presenter Xianke Lin

The Pennsylvania State University is one of 16 North American universities that participated in the EcoCAR advanced vehicle technology competition (http://www.ecocarchallenge.org/). A series-hybrid-electric vehicle based on a General Motors crossover SUV platform has been designed, built and tested for this purpose. The powertrain features a 1.3 L turbodiesel engine running on a B20 fuel system, a 75kW generator directly coupled to the engine and advanced lithium-ion batteries. In this paper, the vehicle architecture and control strategy are detailed and performance predictions (e.g., acceleration, fuel consumption and emissions) are presented. This includes discussion of the development process that led to the selected designs. The predicted performance is compared with data obtained on a chassis dynamometer and during on-road measurements over specified drive cycles. Presenter Shawn Getty

The Hybrid Electric Vehicle Team of Virginia Tech participated in the three-year EcoCAR Advanced Vehicle Technology Competition organized by Argonne National Laboratory, and sponsored by General Motors and the U.S. Department of Energy. The team established goals for the design of a plug-in, range-extended hybrid electric vehicle that meets or exceeds the competition requirements for EcoCAR. The challenge involved designing a crossover SUV powertrain to reduce fuel consumption, petroleum energy use, regulated tailpipe emissions, and well-to-wheel greenhouse gas emissions. To interface with and control the hybrid powertrain, the team added a Hybrid Vehicle Supervisory Controller, which enacts a torque split control strategy. This paper builds on an earlier paper [1] that evaluated the petroleum energy use, criteria tailpipe emissions, and greenhouse gas emissions of the Virginia Tech EcoCAR vehicle and control strategy from the 2nd year of the competition.

Cycle-to-cycle variations of combustion processes strongly affect the emissions, specific fuel consumption as well as work output. Especially Direct Injection Spark-Ignition (DISI) engines are very sensitive to cyclic fluctuations within the combustion chamber. Multi-cycle Large Eddy Simulation (LES) based analysis has been used for investigating unsteady effects of spray combustion processes and misfires. A realistic four-stroke DISI internal combustion engine configuration was taken under consideration. The effects of variable spray boundary conditions on spray combustion are discussed first. A qualitative analysis of the intensity of cycle-to-cycle variations of in-cylinder pressure is presented for various combinations of injection parameters and ignition points. Finally, the effect of ignition probability and analysis of misfires are pointed out. The described above processes were discussed in terms of mean and standard deviation of temperature, velocity and pressure.

This study undertakes an investigation of the effect of battery charge balance in hybrid electric vehicles (HEVs) on EPA fuel economy label values. EPA's updated method was fully implemented in 2011 and uses equations which weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. For the US06 and UDDS cycles, the test results used in the computation come from individual phases within the overall certification driving cycles. This methodology causes additional complexities for hybrid vehicles, because although they are required to be charge-balanced over the course of a full drive cycle, they may have net charge or discharge within the individual phases. As a result, the fuel consumption value used in the label value calculation can be skewed.

In support of the U.S Department of Energy's Vehicle Technologies Program, numerous vehicle technology combinations have been simulated using Autonomie. Argonne National Laboratory (Argonne) designed and wrote the Autonomie modeling software to serve as a single tool that could be used to meet the requirements of automotive engineering throughout the development process, from modeling to control, offering the ability to quickly compare the performance and fuel efficiency of numerous powertrain configurations. For this study, a multitude of vehicle technology combinations were simulated for many different vehicles classes and configurations, which included conventional, power split hybrid electric vehicle (HEV), power split plug-in hybrid electric vehicle (PHEV), extended-range EV (E-REV)-capability PHEV, series fuel cell, and battery electric vehicle.

Software products in the automotive industry are by nature widely distributed and costly to update (recall), so high reliability is clearly of utmost importance. Just as clearly, the increasing reliance on remote access to such systems, for diagnostic and other purposes, has made security an essential requirement, and traditional techniques for software development are proving to be inadequate in dealing with these issues. Correctness by Construction is a software design and development methodology that builds reliability and security into the system from the start. It can be used to demonstrate, with mathematical rigor, a program's correctness properties while reducing the time spent during testing and debugging. This paper will discuss the use of Correctness by Construction, and its accompanying SPARK language technology, to improve automotive systems' security and reliability. (The approach can also account for safely issues, although that is not the focus of this paper.)

In this paper we present the results of full-scale chassis dynamometer testing of two hybrid transit bus configurations, parallel and series and, in addition, quantify the impact of air conditioning. We also study the impact of using an electrically controlled cooling fan. The main trend that is noted, and perhaps expected, is that a significant fuel penalty is encountered during operation with air conditioning, ranging from 17-27% for the four buses considered. The testing shows that the series hybrid architecture is more efficient than the parallel hybrid in improving fuel economy during urban, low speed stop and go transit bus applications. In addition, smart cooling systems, such as the electrically controlled cooling fan can show a fuel economy benefit especially during high AC (or other increased engine load) conditions.

In order to extend the CAI operation range in 4-stroke mode and maximize the benefit of low fuel consumption and emissions in CAI mode, 2-stroke CAI combustion is revived operating in a GDI engine with poppet valves, where the conventional crankcase scavenging is replaced by boosted scavenging. The CAI combustion is achieved through the inherence of the 2-Stroke operation, which is retaining residual gas. A set of flexible hydraulic valve train was installed on the engine to vary the residual gas fraction under the boosting condition. The effects of spark timing, intake pressure and short-circuiting on 2-stroke CAI combustion and its emissions are investigated and discussed in this paper. Results show the engine could be controlled to achieve CAI operation over a wide range of engine speed and load in the 2-stroke mode because of the flexibility of the electro-hydraulic valvetrain system. Presenter Yan Zhang, Brunel University

This paper presents the first results of an experimental study into a hybrid combustion concept for next-generation heavy-duty diesel engines. In this hybrid concept, at low load operating conditions, the engine is run in Pre-mixed Charge Compression Ignition (PCCI) mode, whereas at high load conventional CI combustion is applied. This study was done with standard diesel fuel on a flexible multi-cylinder heavy-duty test platform. This platform is based on a 12.9 liter, 390 kW heavy-duty diesel engine that is equipped with a combination of a supercharger, a two-stage turbocharging system and low-pressure and high-pressure EGR circuitry. Furthermore, Variable Valve Actuation (VVA) hardware is installed to have sufficient control authority. Dedicated pistons, injector nozzles and VVA cam were selected to enable PCCI combustion for a late DI injection strategy, free of wall-wetting problems.

Gasoline engines continue to suffer from significant pumping losses despite decades of effort focused on reducing throttling. Honeywell Turbo has developed a throttle with an integrated turbine/generator that generates electricity by recovering pumping work. This energy offsets power normally provided by the crank driven alternator, thereby saving fuel. It integrates well with modern electrical systems which employ smart charging and idle stop strategies. The ThrottleCharger provides fuel economy benefits up to 5% over federal test cycles and in real world conditions. Presenter Mike Guidry, Honeywell Int'l (Turbo Technologies)

Abstract Investigation of vehicle resistant forces and power losses is of crucial importance owing to current state of energy consumption in transport sector. Meanwhile, considerable portion of resistant forces in a ground vehicle is traced back to tires. Pneumatic tires are known to be a source of energy dissipation as a consequence of their viscoelastic nature. The current study aims to provide a modification to tire resistance by considering the power loss in a tire due to longitudinal slip. The modified tire resistance is comprised of rolling resistance and a newly introduced resistance caused by tire slip, called slip resistance. The physical model is chosen for parameters sensitivity study since the tractive force is described in this model via tangible physical parameters, e.g. tire tangential stiffness, coefficient of friction, and contact patch length.

Abstract Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating tread from sidewalls would maintain tire’s profile effectively.

Abstract To reduce fuel consumption and carbon dioxide (CO2) emissions from mobile air conditioning (A/C) systems, “U.S. Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards” identified solar/thermal technologies such as solar control glazings, solar reflective paint, and active and passive cabin ventilation in an off-cycle credit menu. National Renewable Energy Laboratory (NREL) researchers developed a sophisticated analysis process to calculate U.S. light-duty A/C fuel use that was used to assess the impact of these technologies, leveraging thermal and vehicle simulation analysis tools developed under previous U.S. Department of Energy projects. Representative U.S. light-duty driving behaviors and weighting factors including time-of-day of travel, trip duration, and time between trips were characterized and integrated into the analysis.