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In order to allow continued production of the AM General Optimizer 6500 during MY 2007 through 2010 this IDI engine (Indirect Injection - swirl chamber) requires sophisticated aftertreatment controls while maintaining its fuel economy and durability. The main purpose of the development program was to retain the relatively inexpensive and simple base engine with distributor pump and waste-gated turbocharger, while adding hardware and software components that allow achievement of the phase-in emission standards for 2007 through 2010. The aftertreatment system consists of Diesel Oxidation Catalyst (DOC), NOx Adsorber Catalyst (or DeNOx Trap - DNT) and Diesel Particle Filter (DPF). In addition to the base hardware, an intake air throttle valve and an in-exhaust fuel injector were installed. The presented work will document the development process for a 2004 certified 6.5 l IDI heavy-duty diesel engine to comply with the 2007 heavy-duty emission standards.

This paper describes the results of a liquefied petroleum gas (LPG) fleet test conducted using para-transit, medium-duty vehicles. The vehicles were part of an active municipal fleet providing daily service on varying operating routes. Over a period of nine months, each vehicle was fueled with a series of butane/propane mixtures. The mixtures tested were HD5 LPG as the baseline fuel, 20 percent butane/80 percent propane, 30 percent butane/70 percent propane, and a final blend of 50 percent butane/50 percent propane by volume. The test vehicles showed improved fuel economy as the butane content increased in the fuel mixture, even without modification to existing LPG fuel systems. The improved fuel performance was consistent with the higher energy content of butane, compared to an equal volume of propane. The vehicles displayed no symptoms of performance or maintenance problems that would be related to operation of the fuel mixtures.

Vehicle exhaust emissions measurements are reported for full-size panel vans operating on four alternative motor fuels and control gasoline. The emissions tests produced data on in-use vans. The vans were taken directly from commercial delivery service for testing as they accumulated mileage over a 24-month period. The alternative fuels tested were compressed natural gas, propane gas, California Phase 2 reformulated gasoline (RFG), and methanol (M-85 with 15 percent RFG). The control gasoline for the emissions tests was an industry average unleaded blend (RF-A). The vehicle technologies tested represent those options available in 1992 that were commercially available from Ford, Chrysler, and Chevrolet or which these manufacturers agreed to provide as test vans for daily use in commercial service by FedEx.

Fuel economy estimates are provided for the CleanFleet vans operated for two years by FedEx in Southern California. Between one and three vehicle manufacturers (Chevrolet, Dodge, and Ford) supplied vans powered by compressed natural gas (CNG), propane gas, California Phase 2 reformulated gasoline (RFG), methanol (M-85), and unleaded gasoline as a control. Two electric G-Vans, manufactured by Conceptor Corporation, were supplied by Southern California Edison. Vehicle and engine technologies are representative of those available in early 1992. A total of 111 vans were assigned to FedEx delivery routes at five demonstration sites. The driver and route assignments were periodically rotated within each site to ensure that each vehicle would experience a range of driving conditions. Regression analysis was used to estimate the relationships between vehicle fuel economy and factors such as the number of miles driven and the number of delivery stops made each day.

The Diesel Emission Control - Sulfur Effects (DECSE) program is a joint U.S. government/industry program that studies the impact of diesel sulfur levels on four types of emission control systems. One type of system, Diesel Particulate Filters (DPF), removes particulate matter (PM) from the exhaust stream by collection on a filter. The critical operating issue for DPF technology is the cleaning or regeneration of the control device (by oxidation of the collected PM) to prevent plugging. However, oxidation of sulfur in the exhaust forms sulfates, which are measured as PM. Two types of tests are conducted to evaluate the impacts of fuel sulfur on DPF performance: (1) emissions tests for PM components and gases, and (2) experiments to measure the effect of fuel sulfur on the regeneration temperature required by the filter devices.

Due to the stringent emission regulations, On-Board Diagnostics II (OBD II) and the requirement of enhanced evaporative emissions test procedure, an aggressive canister purge control strategy is required for automotive vehicles. The enhanced evaporative emissions test procedure has forced car manufacturer to purge the carbon canister in the vehicle idle condition so that production vehicles meet the SHED and hot soak test requirements. This not only worsens the idle speed quality but also tends to increase exhaust emission levels. Using analytical models of evaporative air and fuel, feed-forward control strategy for both idle by-pass air and air to fuel ratio can be improved. This paper demonstrates an application of evaporative system modeling to the idle air and air to fuel ratio control.