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In 2009 - 2011, a comprehensive project on urban buses was carried out in cooperation with IEA's Implementing Agreements on Alternative Motor Fuels and Bioenergy, with input from additional IEA Implementing Agreements. The objective of the project was to generate unbiased and solid data for use by policy- and decision-makers responsible for public transport using buses. The project comprised four major parts: (1) a well-to-tank (WTT) assessment of alternative fuel pathways, (2) an assessment of bus end-use (tank-to-wheel, TTW) performance, (3) combining WTT and TTW data into well-to-wheel (WTW) data and (4) a cost assessment, including indirect as well as direct costs. Experts at Argonne National Laboratory, Natural Resources Canada and VTT worked on the WTT part. In the TTW part, Environment Canada and VTT generated emission and fuel consumption data by running 21 different buses on chassis dynamometers, generating data for some 180 combinations of vehicle, fuel and driving cycle.

Major part of the research work on particulate emissions has been carried out at normal ambient temperature (about +23 °C). In real life, the average day temperatures, especially in the winter season, are far below the “normal” temperature of the exhaust emission test procedures. For many years, it has been obvious that the knowledge of the total particulate mass emissions is not enough. Quality of these particles, e.g. polyaromatic hydrocarbon content and mutagenicity, has been studied. Now there is also a need to gain more information on fine particles, which can penetrate lungs more easily. International Energy Agency's Committee on Advanced Motor Fuels sponsored this study of the possible effect of ambient temperature on particle emissions. Also aldehydes and speciated hydrocarbons were studied. Several different engine and fuel technologies were covered, including gaseous fuels and biodiesel. Research work focused on light-duty technologies.

The emissions of heavy-duty engines have traditionally been measured in Europe by using steady-state engine dynamometer tests. However, several studies have proved that emissions of real stop-and-go driving are much higher than the steady-state results indicate. In this study, a mobile measurement system, located inside a vehicle, was utilized. The emissions and energy consumption of different gaseous fuel powered transit buses were measured by using two duty cycles, and the results were compared with diesel technology. The results indicated that NOX emissions of gaseous fuels were in the range of 30-90 % lower than diesel, depending on vehicle technology and fuel. However, energy consumption of gaseous fuels was found to be around 20-45 % higher than in the case of diesel.

Cold operating environment has many kinds of negative effects on the use of automobiles. Low ambient temperature degrades start-up performance and increases fuel consumption. Hence, the amount of harmful exhaust emissions is also elevated. In particular, high concentrations of carbon monoxide (CO) and unburned hydrocarbons (HC) are present. The continuously widening implementation of US-type emission regulations around the world has brought emission control technology based on the use of three-way catalyst (TWC) even to the Nordic countries having cold climate. Cold-start increases emissions from conventional cars, and especially the performance of TWC type of emission reduction has been shown to be quite susceptible to low ambient temperature. Therefore, an increasing emphasis has been set to the testing of exhaust emissions also at sub-normal temperatures, i.e. below the range of +20 …+30°C widely designated by the legislative procedures.

Propane is considered to be a viable fuel alternative for low-emission heavy-duty vehicles in Finland. Natural gas and propane have roughly the same potential for reduced exhaust emissions. Since natural gas and propane are both imported fuels in Finland, there is no preference between these two fuels. Propane, however, is much more easy to distribute, refuel and store onboard the vehicle. This is why propane has received more attention than natural gas as an automotive fuel. Work to develop a low-emission propane fueled truck started back in 1988 with engine tests. The first prototype, a 17-ton SISU truck was built in 1990, and was operated until September 1992. This truck was equipped with a 7.4-liter Valmet-engine, a closed-loop controlled IMPCO-fuel system and a three-way catalytic converter (TWC). The experience with this propane fueled truck was good. The driveability was excellent, and both noise level and exhaust emissions were low.

Cold operating environment has many kinds of negative effects on the use of automobiles. Low ambient temperature degrades start-up performance and increases fuel consumption. Hence, the amounts of exhaust emissions are also elevated. In particular, high concentrations of CO and HC are present in the exhaust. Cold-start derates especially the performance of a TWC type of emission reduction. Therefore, an increasing emphasis has been set to the testing of exhaust emissions even at sub-ambient temperatures, For this reason, US-EPA has recently revised US emission regulations by comprising an additional low ambient temperature (20°F = -7°C) test for CO emissions. Apart from the regulated components, other poisonous compounds have been detected from the exhausts, although usually in very small quantities, A cold-start may have an increasingly strong effect even to the emission of these substances.

When evaluating fuels and engine lubricants in respect of, for example, fuel economy, high accuracy is required. In any engine testing, the best accuracy and repeatability are obtained with a test engine installed in an engine dynamometer, and not in a car on a chassis dynamometer. At the Technical Research Centre of Finland, a special cold chamber suitable for engine and transmission component testing was built in 1985. The equipment consists of a 75 m3 cold chamber, a powerful cooling machinery, a computer-controlled engine dynamometer, a hydrostatic propulsion unit and a versatile data acquisition system. This paper describes the structure of the system (cold chamber, cooling machinery and its control system, engine and engine dynamometer installation, instrumentation). Special problems like controlling engine operation point during warm-up, handling of fuels, lubricants and batteries, and measuring fuel consumption without disturbing the fuel system are discussed.

A low ambient temperature increases wear and fuel consumption in vehicle engines. The startability of the engine and the start-up of lubrication are highly dependent on the type of engine oil (mineral, semisynthetic, synthetic), whereas fuel consumption depends more on the engine type and driving conditions. The research work in a special cold chamber equipped with a powerful cooling system has so far involved three gasoline engines and two diesel engines. One gasoline engine was also tested in combination with an all-mechanical transaxle. Tests were carried out within the temperature range of +20…−30 °C using different engine lubricants in order to evaluate both lubrication during the initial start-up and fuel consumption during a test period of 30 minutes. Engines were run under both constant and cyclic load. Effects of auxiliary electrical block and oil sump heaters were also studied.

Since 2013, Euro VI heavy-duty on-road vehicles have been on the market in the Europe. Regulated exhaust emissions, including nitrogen oxides and particulate matter, have been cut down to a very low level, independent of fuel (diesel or natural gas). Multiple research papers have shown that the regulated emissions from the Euro VI and US 2010 heavy-duty on-road vehicles tested on chassis dynamometers really deliver emission levels which correspond the type approval requirements, independent of the test cycle used. In-service conformity (ISC), which is included in the Euro VI legislation, requires heavy-duty on-road engine manufacturers to test and prove their engines to comply with the emission legislation during the engine in-use period. The measurements are carried out in the field using PEMS (Portable Emission Measurement System) equipment. This kind of testing, depicting real-world emissions is the final stage to confirm low real-life emissions.

The Finnish pulp and paper company, UPM, will start a biorefinery in Finland in 2014 to produce advanced renewable diesel in commercial scale. The fuel production is based on using crude tall oil (CTO), a wood-based residue of pulping process, as a raw material. The end product, CTO based renewable diesel called UPM BioVerno, is a novel high quality drop-in diesel fuel resembling fossil diesel. It reduces greenhouse gas emissions by up to 80 % when compared to fossil fuels. In this study, the CTO renewable diesel was studied as a blending component in regular mineral-oil based fossil diesel fuel in field testing. The functionality and performance of four (4) passenger cars was evaluated by comparing e.g. fuel consumption and exhaust emissions of CTO renewable diesel blend (R20UPM) with fossil reference fuel. The field test included 20.000 km on-road driving with each car by experienced drivers from VTT Technical Research Centre of Finland.