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In recent years emission control agencies have turned their attention to to the cleanup of diesel engines, both mobile and stationary. This paper is one of the first attempts to characterize the load and emissions of a subsection of stationary diesel emissions, specifically Truck/Trailer Refrigeration Units (TRUs). These devices are used to keep refrigerated or frozen cargo cold when it is being shipped/delivered. Two general sizes of TRUs were tested, smaller TRUs for cooling box trucks, used for local deliveries, and large TRUs, used for long hauling and very large deliveries. After observing a matrix of these units over a large spectrum of temperatures it was found that, although there were multiple control strategies, they all heavily relied on pulling the trailer down to the set point temperature as fast as the engine and refrigeration unit would allow.

As part of a California Selective Catalyst Reduction (SCR) system demonstration and evaluation project [13], the authors and their industrial partners have conducted engine dynamometer emissions tests of SCR systems. The transient Federal Test Procedure (FTP) cycle and 13 Mode European Stationary Cycle (ESC) were conducted using certification diesel fuel with 300-500 ppm of sulfur. This paper reviews the performance of the first system to meet the goal of attaining 1 g/bhp-hr NOx emissions in the transient FTP cycle on a 1999 DDC Series 60 engine that has an initial 4 g/bhp-hr level. This paper discusses key characteristics of a typical automotive SCR system and then presents the results and analysis of the engine dynamometer emission testing of a SCR system. The paper concludes with a discussion of the challenges involved in on-road operation of the system.

California Air Resources Board's transit bus fleet regulation required public transit fleets in California to reduce emissions starting in 2002 [1]. In response to this rule, San Francisco Municipal Railway (Muni) launched the “Alternative Fuel Pilot Project”. The objective of the project is to compare the on-road performance, emissions, maintainability, safety, and costs of advanced diesel and alternative fuel buses over a two-year period. This paper discusses the preliminary emissions results from chassis dynamometer testing conducted during the first six months of the emissions study. The California Truck Testing Service's dynamometer facility tested four types of buses: conventional diesel, conventional diesel with particulate traps, compressed natural gas, and hybrid-electric transit buses.

A novel ambient dilution tunnel has been designed, tested and employed to measure the emissions from active parked regenerations of Diesel Particulate Filters (DPFs) for 2007 and 2010 certified heavy duty diesel trucks (HDDTs). The 2007 certified engine had greater regulated emissions than the 2010 certified engine. For a fully loaded 2007 DPF there was an initial period of very large mass emissions, which was then followed by very large number of small particle emissions. The Particle Size Distribution, PSD, was distributed over a large range from 10 nm to 10 μm. The parked regenerations of the 2010 DPF had a much lower initial emission pattern, but the second phase of large numbers of small particles was very similar to the 2007 DPF. The emission results during regeneration have been compared to total emissions from recent engine dynamometer testing of 2007 and 2010 DPFs, and they are much larger.