Comparison of diesel and natural gas bus performance

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)

Abstract

Over the years, natural gas has been promoted as a clean-burning fuel, especially for transit buses. A decade ago one could claim that natural gas buses deliver significant emission benefits over diesel buses, especially regarding particulate emissions. The spread in nitrogen oxide emissions has always been significant for natural gas engines, high for lean-burn engines and low for three-way catalyst equipped stoichiometric engines. With the introduction of US 2010 and Euro VI (effective as of 2014) exhaust emission regulations, independent of the fuel, the regulated emissions of all engines have been brought close to zero level. This means that the advantage of natural gas as a clean fuel is diminishing, especially in a situation in which electric transit buses are also entering the market. The motivation to use natural gas could still be diesel fuel substitution and to some extent, also reduction of greenhouse gas emissions. However, looking at the full fuel cycle and also taking into account methane leakages in various part of the fuel cycle, natural gas is, at its best, comparable to diesel regarding greenhouse gas emissions, not better. One of the reasons for this is the low fuel efficiency of spark-ignited gas engines compared to diesel engines. To deliver an advantage regarding greenhouse gas emissions, the efficiency of the gas engines should be significantly improved. Alternatively natural gas should be replaced with biogas. The paper presents a comparison of diesel and natural gas buses for regulated emissions, selected unregulated emission components, greenhouse gas emissions and energy efficiency.
Original languageEnglish
Number of pages11
JournalSAE Technical Paper Series
Issue number2014-01-2432
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed
EventSAE 2014 Commercial Vehicle Engineering Congress - Rosemont, United States
Duration: 7 Oct 20149 Oct 2014

Fingerprint

Natural gas
Gas emissions
Greenhouse gases
Gas engines
Engines
Particulate emissions
Biogas
Nitrogen oxides
Diesel fuels
Electric sparks
Energy efficiency
Diesel engines
Methane
Substitution reactions
Catalysts

Cite this

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title = "Comparison of diesel and natural gas bus performance",
abstract = "Over the years, natural gas has been promoted as a clean-burning fuel, especially for transit buses. A decade ago one could claim that natural gas buses deliver significant emission benefits over diesel buses, especially regarding particulate emissions. The spread in nitrogen oxide emissions has always been significant for natural gas engines, high for lean-burn engines and low for three-way catalyst equipped stoichiometric engines. With the introduction of US 2010 and Euro VI (effective as of 2014) exhaust emission regulations, independent of the fuel, the regulated emissions of all engines have been brought close to zero level. This means that the advantage of natural gas as a clean fuel is diminishing, especially in a situation in which electric transit buses are also entering the market. The motivation to use natural gas could still be diesel fuel substitution and to some extent, also reduction of greenhouse gas emissions. However, looking at the full fuel cycle and also taking into account methane leakages in various part of the fuel cycle, natural gas is, at its best, comparable to diesel regarding greenhouse gas emissions, not better. One of the reasons for this is the low fuel efficiency of spark-ignited gas engines compared to diesel engines. To deliver an advantage regarding greenhouse gas emissions, the efficiency of the gas engines should be significantly improved. Alternatively natural gas should be replaced with biogas. The paper presents a comparison of diesel and natural gas buses for regulated emissions, selected unregulated emission components, greenhouse gas emissions and energy efficiency.",
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Comparison of diesel and natural gas bus performance. / Nylund, Nils-Olof; Karvonen, V.; Kuutti, H.; Laurikko, J.

In: SAE Technical Paper Series, No. 2014-01-2432, 2014.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Karvonen, V.

AU - Kuutti, H.

AU - Laurikko, J.

PY - 2014

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AB - Over the years, natural gas has been promoted as a clean-burning fuel, especially for transit buses. A decade ago one could claim that natural gas buses deliver significant emission benefits over diesel buses, especially regarding particulate emissions. The spread in nitrogen oxide emissions has always been significant for natural gas engines, high for lean-burn engines and low for three-way catalyst equipped stoichiometric engines. With the introduction of US 2010 and Euro VI (effective as of 2014) exhaust emission regulations, independent of the fuel, the regulated emissions of all engines have been brought close to zero level. This means that the advantage of natural gas as a clean fuel is diminishing, especially in a situation in which electric transit buses are also entering the market. The motivation to use natural gas could still be diesel fuel substitution and to some extent, also reduction of greenhouse gas emissions. However, looking at the full fuel cycle and also taking into account methane leakages in various part of the fuel cycle, natural gas is, at its best, comparable to diesel regarding greenhouse gas emissions, not better. One of the reasons for this is the low fuel efficiency of spark-ignited gas engines compared to diesel engines. To deliver an advantage regarding greenhouse gas emissions, the efficiency of the gas engines should be significantly improved. Alternatively natural gas should be replaced with biogas. The paper presents a comparison of diesel and natural gas buses for regulated emissions, selected unregulated emission components, greenhouse gas emissions and energy efficiency.

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