Editing Propane (section)

=== Motor fuel ===
{{more citations needed section|date=October 2009}}
{{Main|Autogas}}

In the U.S., over 190,000 on-road vehicles use propane, and over 450,000 forklifts use it for power. It is the third most popular vehicle fuel in the world,<ref name="propane-as-fuel" /> behind [[gasoline]] and [[diesel fuel]]. In other parts of the world, propane used in vehicles is known as autogas. In 2007, approximately 13 million vehicles worldwide use autogas.<ref name="propane-as-fuel">{{cite web|author1=Propane Education |author2=Research Council |name-list-style=amp |title=Autogas |url=http://www.propanecouncil.org/propane-as-fuel/ |publisher=PERC |access-date=2012-05-17 |url-status=dead |archive-url=https://web.archive.org/web/20100923030304/http://www.propanecouncil.org/propane-as-fuel/ |archive-date=September 23, 2010 }}</ref>

The advantage of propane in cars is its liquid state at a moderate pressure. This allows fast refill times, affordable fuel cylinder construction, and price ranges typically just over half that of gasoline. Meanwhile, it is noticeably cleaner (both in handling, and in combustion), results in less engine wear (due to carbon deposits) without diluting engine oil (often extending oil-change intervals), and until recently{{When|date=July 2021}} was relatively low-cost in North America. The [[octane rating]] of propane is relatively high at 110. In the United States the propane fueling infrastructure is the most developed of all alternative vehicle fuels. Many converted vehicles have provisions for topping off from "barbecue bottles". Purpose-built vehicles are often in commercially owned fleets, and have private fueling facilities. A further saving for propane fuel vehicle operators, especially in fleets, is that theft is much more difficult than with gasoline or diesel fuels.

Propane is also used as fuel for [[small engine]]s, especially those used indoors or in areas with insufficient fresh air and ventilation to carry away the more toxic exhaust of an engine running on gasoline or diesel fuel. More recently,{{When|date=July 2021}} there have been lawn-care products like [[string trimmer]]s, [[lawn mowers]] and [[leaf blowers]] intended for outdoor use, but fueled by propane in order to reduce [[air pollution]].<ref>{{Cite web|url=http://www.allpropanemowers.com/wp-content/uploads/2014/06/Facts_About_Propane.pdf|title=Facts About Propane: America's Exceptional Energy|date=April 2001|publisher=National Propane Gas Association|access-date=December 15, 2016|archive-date=December 21, 2016|archive-url=https://web.archive.org/web/20161221104931/http://www.allpropanemowers.com/wp-content/uploads/2014/06/Facts_About_Propane.pdf|url-status=dead}}</ref>

Many heavy-duty highway trucks use propane as a boost, where it is added through the turbocharger, to mix with diesel fuel droplets. Propane droplets' very high hydrogen content helps the diesel fuel to burn hotter and therefore more completely. This provides more torque, more horsepower, and a cleaner exhaust for the trucks. It is normal for a 7-liter medium-duty diesel truck engine to increase fuel economy by 20 to 33 percent when a propane boost system is used. It is cheaper because propane is much cheaper than diesel fuel. The longer distance a cross-country trucker can travel on a full load of combined diesel and propane fuel means they can maintain federal hours of work rules with two fewer fuel stops in a cross-country trip. Truckers, tractor pulling competitions, and farmers have been using a propane boost system for over forty years{{When|date=July 2021}} in North America.