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It is well known that most of the emissions from TWC cars are emitted during the cold start period. These emissions increase considerably at decreased ambient temperatures. To reduce cold start emissions an engine block heater may be used. In this present study the effects on the exhaust emissions of using a block heater were investigated. The exhaust was characterized by both regulated and some unregulated exhaust components. The car was tested according to the FTP-75 test procedure for regulated emissions at +22, +5 and -15°C ambient temperatures. At +5°C additional analysis of Polycyclic Aromatic Compounds (PAC) and 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD) receptor affinity test was carried out. The test results showed reductions of CO and HC emissions when using a block heater. The reductions of these emissions were 60 and 65% respectively at the lowest ambient temperature investigated. NOx emissions were less affected and even increased marginally in some cases.

Number concentration of particles emitted by combustion engines has recently attracted attention, due to the fact that particles of the size range found in tail pipe emissions are suspected of being hazardous to human health. This paper describes the application of an Electrical Low Pressure Impactor (ELPI) to the measurement of number concentrations of diesel exhaust particles. The size distribution of particles as fine as 30 nm is determined using the aerodynamic diameter as the characteristic dimension. Results were obtained on both the engine and chassis dynamometer, in real-time, for steady state and transient tests. Swedish Environmental Class 1 diesel fuel was used, having a sulfur content of less than 10 ppm wt. A scheme for the calculation of particle losses in the sampling system was developed, showing high penetration of particles under the conditions examined.

A commercially available exhaust aftertreatment system, DNOX™, comprising exhaust gas recirculation (EGR), an oxidative catalyst and a continuously regenerating diesel particulate filter (DPF) were tested. The test object was a 9-litre ethanol-fueled diesel engine from Scania equipped with turbocharger and aftercooler. A similar diesel engine from Scania, but running on ordinary Swedish diesel fuel, was used as a reference and a reminder of “the state of the art”. The tests involved two different ethanol fuels containing various ignition improvers, Beraid 3540 and rapeseed methyl ester. Test conditions for the engines were those specified in the European Stationary Cycle (ESC). The aftertreatment system reduced the emissions of HC, CO and NOX, down to 0.15, 0.04 and 2.54 g/kWh, respectively, while the estimated particle mass was reduced by 67%. Actually, by using the DNOX™ system, the engines became Euro IV engines regarding the emissions of HC, CO and NOx.

The introduction of the three way catalyst (TWC) has considerably reduced emissions from gasoline fueled cars. Most of the pollutants from these cars are emitted during the cold start period. At lower ambient temperatures (below +20°C), as in the Northern part of Europe, these emissions increase considerably. In Sweden engine block heaters, mostly in combination with compartment heaters, are often used to increase the driver's comfort. The increased engine temperature also reduces emissions. Block heaters are also suitable for after-market installations, and can thus reduce emissions from in-use cars. This paper reports the investigations of the effects of a block heater on emissions and fuel consumption. It was decided to conduct tests on three types of light duty vehicles: cars with TWC, cars without TWC, and one car with very low emissions (i.e. TLEV). The cars were tested according to the FTP-75 test procedure at +22, +5 and -15°C ambient temperature.

Experiments were performed to investigate the potential to achieve low emissions from a diesel engine fueled by ethanol and equipped with a commercially available exhaust after-treatment device, DNOX™ from STT Emtec. The DNOX™ system includes exhaust gas recirculation (EGR) catalysts and a continuously regenerating diesel particulate filter (DPF). Two Euro III classified 9-liter turbocharged, after-cooled diesel engines from Scania were used for the task. One engine was fueled by ethanol and the other by Swedish diesel fuel, EC1. Engine operating conditions of a 22-mode test cycle, including the 13 modes of the European Stationary Cycle (ESC cycle), were used for the tests. The emissions of NOX and HC were small for the ethanol-fueled engine, 3.48 and 0.53 g/kWh, respectively, while the emission of CO was higher, 2.07 g/kWh. Estimations of emitted particle mass were calculated by using the software supplied in the Scanning Mobility Particle Sizer (SMPS).

Ethanol-fueled engines are considered to be low particulate emitting engines. This study was performed to investigate the potential to achieve even lower particulate emission if a 9-liter Scania diesel engine, running on ethanol fuel is equipped with emission control. State-of-the art technology in emission control was applied, e.g., exhaust gas recirculation, EGR, catalysts and a continuous regenerating particle filter, DPF. Particulate emissions were compared with emissions from a 9-liter Scania diesel engine from the same engine family, running on Swedish environmental class 1 diesel fuel. Tailpipe measurements of particle size and distribution were performed with a scanning mobility particle sizer, SMPS, instrument together with filter sampling. An evaluation of SMPS measurements was performed for test conditions specified according to a 22-mode test cycle, which included the test modes in the European Stationary Cycle, ESC.