motorcycles. Should the U.S. become embroiled in an extended war in
the Middle East, oil prices are likely to go quite high. Should that
happen, fuel economy, and sources of fuel outside the Middle East will become
increasingly important. Judged by these two criteria, diesel engines
have a number of advantages relative to gasoline engines.
Today's diesel engine operates at up to 55% fuel efficiency, compared
with only 35% for modern gasoline engines. Preliminary research
indicates that diesel efficiency can be increased to perhaps as high
as 63%. Diesel engines, because of their simpler design, also tend to be more
durable than gasoline engines.
Diesel engines are more efficient because
diesel engine employ direct fuel injection in which fuel is injected directly into the engine cylinder rather than indirectly through a
carburetor system. As a result of the higher temperature and
compression pressures created in the diesel engine cylinders a higher
percentage of the fuel is burned than in a comparable gasoline engine.
Diesel fuel also has a higher energy density than gasoline. On
average, a gallon of diesel fuel contains approximately 155x10^6
joules (147,000 BTUs), while a gallon of gasoline contains 132x10^6
joules (125,000 BTUs). As a result of the higher fuel density and
more efficient engine design, diesels get better mileage than
equivalent gasoline engines. Light-duty diesels use 30-60% less fuel
than gasoline engines of similar power. For example, the
European-market Audi A2 achieves 86 mpg on the highway. The 4 passenger diesel A2 is 23% more fuel efficient than the 2 passenger Honda Insight, which is the most fuel efficient car sold in America with a combined City/Highway mileage of 64 mpg.
Finally, diesel fuel is also easier to handle,
as it has a higher boiling point than water, and can be stored for
long periods of time without special treatment.
Disadvantages of diesels? Historically, diesel engines have had the
1. Higher production of nitrogen oxides and particulate matter
2. Bad smelling exhaust.
3. Poor acceleration ability.
4. Fewer fuel stations carry diesel.
5. Difficult to start in cold weather.
Due to these historical disadvantages, diesels have captured less than 1% of the consumer auto market in the
However, diesels have enjoyed much greater success in Europe--over
1/3rd of the autos sold there are diesels. Several reasons have
contributed to their success in Europe:
1. Higher fuel prices.
2. Less stringent regulation of nitrogen oxide and particulate matter
3. Tax subsidies for diesel fuel.
4. Improved engine design has improved acceleration and cold-start ability.
Most importantly from my perspective, diesel fuels can be created from
biological products such as soybeans. With minor modifications,
engines designed for petroleum derived diesel fuel can be converted to
plant derived diesel fuel. Although cost prohibitive now, if
petroleum based fuel prices rise substantially, biodiesel will seem
increasingly attractive. In a pinch, you can also make your own
diesel fuel from waste vegetable and animal oils. In the event of a
catastrophic economic collapse this may be a useful feature.
I'm particularly interested in motorcycles because a)
I'm probably going to be commuting into San Francisco,
and even after the dotcom crash, parking is a bitch b)
motorcycles can use roads that would be impassable in an
automobile c) they're fun to drive.
During a major disaster, motorcycles are likely to be one of the few
vehicles capable of exiting a major metropolitan area. In addition,
their fuel economy makes them an good choice, should protracted
fighting cause large increases in gasoline prices.
Unfortunately, it appears that there are no diesel-powered motorcycles
in civilian production. Royal
Enfield the last manufacturer of civilian diesel motorcycles (in
India) appears to have stopped
However, the U.S. and British armies are attempting to standardize on diesel as a single fuel source. Therefore they have spent about
£250,000 on the development of a motorcycle that can run on
either diesel or aviation kerosene. Developed jointly by
Californian firm Hayes Diversified Technologies and the British Army
College at Shrivenham, the design is based on the current M1030
Marine Corps Motorcycle (Kawasaki KLR650). The bike has a range of
120 miles per gallon, and a top speed of 85 MPH.
So if you're hankering for a diesel powered bike, you may want to purchase a Kawasaki KLR650--in a couple of years, you may be able to get it modded for diesel. If you have to have a diesel now, a Royal Enfield is probably the best choice. However, I've read that they're quite cantankerous, and it's likely to be difficult to find parts for them in the U.S.
Some of the stuff above was plagairized from:
- Marshall Brains' How
- Diesel Technology Forum report Demand
for Diesels: The European Experience July 2001.
Here's the Hayes Diversified announcement:
Hayes Diversified Technologies
10844 Suite A1
Hesperia, CA 92345
Project Manager: Fred Hayes
The objective of this proposal is to develop a method to convert a
modern, gasoline powered motorcycle engine to operate on JP8/Diesel
fuel. The effort will focus on the use of conventional compression
ignition (C.I.) diesel technology that will faciliate component design
that maintains the integrity of the unit construction of the
motorcycle's engine and transmission and allows integration into an
existing motorcycle that meets the performance and operability of the
current M1030 Marine Corps Motorcycle. The method of converstion must
also be cost-effective to retain the value of the military motorcycle
and be a viable alternative to gasoline powered vehicles in other
related markets. Previous studies done by the Royal Military College
of Science, Cranfield University, UK determined that current
C.I. diesel technology can be used to meet established performance
standards. This effort will focus on the cost-effective integration of
this technology into modern motorcycle engine design with minimum
impact on size and weight. It is anticipated that component redesign
will include the cylinder head, piston, crankshaft/connecting rod and
crankcase. Design criteria will include the use of existing components
to the maximum extent practical.