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Hybrid electric vehicles (HEV's) offer additional flexibility to enhance the fuel economy and emissions of vehicles. The Real-Time Control Strategy (RTCS) presented here optimizes efficiency and emissions of a parallel configuration HEV. In order to determine the ideal operating point of the vehicle's engine and motor, the control strategy considers all possible engine-motor torque pairs. For a given operating point, the strategy predicts the possible energy consumption and the emissions emitted by the vehicle. The strategy calculates the "replacement energy" that would restore the battery's state of charge (SOC) to its initial level. This replacement energy accounts for inefficiencies in the energy storage system conversion process. Userand standards-based weightings of time-averaged fuel economy and emissions performance determine an overall impact function. The strategy continuously selects the operating point that is the minimum of this cost function. Previous control strategies employed a set of static parameters optimized for a particular drive cycle, and they showed little sensitivity to subtle emissions tradeoffs. This new control strategy adjusts its behavior based on the current driving conditions. Simulation results of the RTCS and of a static control strategy on a PNGV-type baseline parallel HEV (42 kW engine and a 32 kW motor) using ADVISOR are presented. Comparison of the simulations demonstrates the flexibility and advantages of the RTCS. Compared to an optimized static control strategy, the RTCS reduced NOx emissions by 23% and PM emissions by 13% at a sacrifice of only 1.4% in fuel economy.

How much fuel does vehicle air conditioning actually use? This study attempts to answer that question to determine the national and state-by-state fuel use impact seen by using air conditioning in light duty gasoline vehicles. The study used data from US cities, representative of averages over the past 30 years, 1X-see Definitions, the Toyota Prius, the Honda Insight, a 3X Hybrid, and a Fuel Cell Hybrid) with a varying auxiliary load. For a conventional 1X vehicle, using the AC increases fuel consumption by 35% (or drops fuel economy by 26%). For the Honda Insight, using the AC increases fuel consumption 46%. For a 3X Hybrid, using the AC increases fuel consumption 128%. 10% Rolling Acc. Engine Aero. Driveline Brak ng 21.3 city, 39 highway: 26.7 mpgge 11 city, 6 highway: 8.8 l 100km Energy Usage for Composite FTP & H ghway addit ona accessory With AC Figure 1: Percent Vehicle Energy Uses/Losses in a Conventional 27-mpg (8.7-l/100km) Vehicle resulted in a state-by-state estimate of fuel used for air 100 conditioning in vehicles. The study showed that the US uses 7.1 billion gallons (27 billion liters) of gasoline every year for air conditioning vehicles, equivalent to 6% of domestic petroleum consumption, or 10% of US imported crude oil.

The National Renewable Energy Laboratory has recently publicly released its second-generation advanced vehicle simulator called ADVISOR 2.0. This software program was initially developed four years ago, and after several years of in-house usage and evolution, this powerful tool is now available to the public through a new vehicle systems analysis World Wide Web page. ADVISOR has been applied to many different systems analysis problems, such as helping to develop the SAE J1711 test procedure for hybrid vehicles and helping to evaluate new technologies as part of the Partnership for a New Generation of Vehicles (PNGV) technology selection process. The model has been and will continue to be benchmarked and validated with other models and with real vehicle test data. After two months of being available on the Web, more than 100 users have downloaded ADVISOR. ADVISOR 2.0 has many new features, including an easy-to-use graphical user interface, a detailed exhaust aftertreatment thermal model, and complete browser-based documentation. Future work will include adding to the library of components available in ADVISOR, including optimization functionality, and linking with a more detailed fuel cell model.