Cold Start Emissions Investigation at Different Ambient Temperature Conditions

Bielaczyc, Piotr; Merkisz, Jerzy

doi:10.4271/980401

Cited by 49 publications

(21 citation statements)

References 6 publications

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“…The effi ciency of the fuel delivery process is hindered by low temperatures. When the injectors (and the fuel itself) are at low or sub-zero temperatures, fuel atomisation is impeded and a fi lm of liquid fuel may accumulate on cold metal surfaces [3,4,6]. Impaired atomisation reduces the surface area to volume ratio of the droplets, making the air/fuel mixture less combustible.…”

Section: Hc and Co Emissions Results From Mpi And Disi Vehicles Obtainementioning

confidence: 99%

“…Both hot and cold start events can be classifi ed as transient operation of an internal combustion engine [4,6,9]. Cold start can be defi ned as when an engine is started with the temperatures of the oil, coolant and all elements of the engine (T) at the ambient temperature (T a ) [3,4,6]. During hot start, the temperature of all these elements will be very close to those observed during fully warmed-up operation (T w ).…”

Section: Cold Start Events and The Resulting Emissionsmentioning

confidence: 99%

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Cold Start Emissions of Spark-Ignition Engines at Low Ambient Temperatures as an Air Quality Risk

Bielaczyc¹,

Szczotka²,

Woodburn³

2014

Archives of Environmental Protection

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Keywords: Cold start, low ambient temperature, direct and indirect injection spark ignition engine, exhaust emissions.Abstract: SI engines are highly susceptible to excess emissions when started at low ambient temperatures. This phenomenon has multiple air quality and climate forcing implications. Direct injection petrol engines feature a markedly different fuelling strategy, and so their emissions behaviour is somewhat different from indirect injection petrol engines. The excess emissions of direct injection engines at low ambient temperatures should also differ. Additionally, the direct injection fuel delivery process leads to the formation of PM, and DISI engines should show greater PM emissions at low ambient temperatures. This study reports on laboratory experiments quantifying excess emissions of gaseous and solid pollutants over a legislative driving cycle following cold start at a low ambient temperature for both engine types. Over the legislative cycle for testing at -7°C (the UDC), emissions of HC, CO, NO x and CO 2 were higher when tested at -7°C than at 24°C. Massive increases in emissions of HC and CO were observed, together with more modest increases in NO x and CO 2 emissions. Results from the entire driving cycle showed excess emissions in both phases (though they were much larger for the UDC). The DISI vehicle showed lower increases in fuel consumption than the port injected vehicles, but greater increases in emission of HC and CO. DISI particle number emissions increased by around 50%; DISI particle mass by over 600%. The observed emissions deteriorations varied somewhat by engine type and from vehicle to vehicle. Excesses were greatest following start-up, but persisted, even after several hundred seconds' driving. The temperature of the intake air appeared to have a limited but signifi cant effect on emissions after the engine has been running for some time. All vehicles tested here comfortably met the relevant EU limits, providing further evidence that these limits are no longer challenging and need updating.

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Section: Hc and Co Emissions Results From Mpi And Disi Vehicles Obtainementioning

confidence: 99%

Section: Cold Start Events and The Resulting Emissionsmentioning

confidence: 99%

Cold Start Emissions of Spark-Ignition Engines at Low Ambient Temperatures as an Air Quality Risk

Bielaczyc¹,

Szczotka²,

Woodburn³

2014

Archives of Environmental Protection

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“…The gas speed through the sample pipes is produced by the vacuum pressure generated by the gas analyzer pump, which remains equal during the whole cycle. Some authors have implemented behavior models [20] while other authors analyze the delay by correlation methods comparing the pollutant measurement with other related variables like engine speed [21][22]. In this study a correlation method is used, previous to the assessments it was studied the second source delay by carrying out NEDC cycles in order to compare the pollutant pick emissions against the power pick demands.…”

Section: Repeatability and Pollutant Emissions Calculationmentioning

confidence: 99%

Potential of exhaust heat recovery for intake charge heating in a diesel engine transient operation at cold conditions

Luján

Climent

Dolz

et al. 2016

Applied Thermal Engineering

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In this paper, an experimental facility is implemented with the aim of improving the performance of internal combustion engines working at low ambient temperatures. Pollutant emissions and fuel consumption are one of the major issues that automotive engineers have to face. Cold engine start and warming up analysis have become important topics for researches. In this work, an exhaust heat recovery system for a diesel engine has been proposed as a solution to cold operation negative effects. The energy obtained from the exhaust gases was used to increase the intake air temperature. The experiments were carried out in transient load conditions at three different levels of ambient temperature (up to-7ºC). Exhaust heat recovery was combined with different strategies of exhaust gas recirculation. Intake air heating results with the heat recovery system show a reduction of 65% in unburned hydrocarbons, 40% in carbon monoxide and 10% in fuel use compared to standard air-air intercooler.

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“…Therefore, the fuel mixed with air forms a sufficiently ignitable mixture during the ignition delay period; further, a large premixed combustion phase is expected. 2 In this condition, the autoignition delay, which is highly dependent on the injection parameter, [3][4][5][6][7][8] the engine speed, 4,5 the fuel properties, 2,9 the combustion chamber conditions [3][4][5][6][7][8]10 and its design, 11 becomes longer owing to the reductions in the starting pressure and temperature for combustion. Simultaneously, the portion of stoichiometric air-fuel mixture is reduced with a lower combustion rate.…”

Section: Introductionmentioning

confidence: 99%

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

Suh

2014

Proceedings of the Institution of Mechanical Engineers, Part D:

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An investigation of twin-pilot-injection strategies was performed in a low-compression-ratio engine in order to improve the combustion performance and to reduce the exhaust emissions. All tests were conducted on a modified four-cylinder test engine running on only one cylinder with a reduced compression ratio (15.3:1), and analyses of the combustion pressure, the heat release rate and the net work output in the cylinder were performed. At the same time, the reduction in the exhaust emissions such as carbon monoxide, hydrocarbons and soot under different twin-pilot-injection strategies was compared with other combustion cases (single-injection strategy and one-pilot-injection strategy). Higher combustion pressures, lower heat release rates, shorter ignition delay times, higher indicated mean effective pressures (about 2.1%) and lower coefficients of variation in the indicated mean effective pressure (approximately 29.4%) in all multiple-injection (one-pilot-injection or twin-pilot-injection) cases, which indicated improved operation of the low-compression-ratio engine, were observed. Retarded injection timing ( tp,SOE = 20–10° crank angle before top dead centre) in the twin-pilot-injection case proved to the best timing for reduction in the carbon monoxide emissions because the relatively short ignition delay with the high in-cylinder temperature enhanced the carbon monoxide oxidation rate. Twin-pilot-injection strategies formed higher hydrocarbon emissions because of the rich fuel mixture during the ignition delay time than one-pilot-injection combustion did. As more multiple injections were applied, lower nitrogen oxide emissions (up to 45.7%) were observed because the early termination of the first injection event and the restart of injection created a time interval between injections in which freshly charged air could be entrained into the flame.

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Cold Start Emissions Investigation at Different Ambient Temperature Conditions

Cited by 49 publications

References 6 publications

Cold Start Emissions of Spark-Ignition Engines at Low Ambient Temperatures as an Air Quality Risk

Cold Start Emissions of Spark-Ignition Engines at Low Ambient Temperatures as an Air Quality Risk

Potential of exhaust heat recovery for intake charge heating in a diesel engine transient operation at cold conditions

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

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