The First Natural Gas Vehicles
As natural gas vehicles gain more
attention in the transportation industry, we’re seeing more examples of
cutting-edge technology harnessing the power of this abundantly-available fuel.
But where did the idea of powering a
vehicle with natural gas come from? In every successful invention there’s a
history of thwarted attempts and modest origins, and natural gas-powered
vehicles are no different.
The Origins Natural Gas Vehicles
Natural gas-powered vehicles can be traced
back to World War I and World War II, when the shortage of gasoline was felt worldwide.
Developed out of necessity, “Gas Bag Vehicles” began to appear in France,
Netherlands, Germany and England.
Automobiles, buses and trucks were powered
by “town gas” or “street gas,” a by-product of the process of turning coal into
cokes (used to make iron), captured in a balloon that was usually carried on
the roof of the vehicle.
While today’s natural gas passenger
vehicles are quite practical, with advanced technologies that compress natural gas (CNG) so more fuel can be
carried in the tank, the ‘gas bag’ fuel tanks of the past needed to be much
larger to house the uncompressed gas. For every one litre of gasoline, about two
to three cubic metres of gas was needed, meaning that an extremely large fuel
tank was needed for any sort of reasonable range. The solution came in the form
of a gas storage bag mounted to the roof rack of the vehicle.
The Dutch old-timer pictured here carried a gas storage bag of 13 cubic metres, an installation that gave it a range of about 50 km (30 miles) at an energy consumption of 13 litres per km (22 mpg). |
Buses were best suited for this, and had a full-length gas storage bag
on their roofs, sometimes enclosed in a streamlined fairing. Private
automobiles, however, had a wooden frame fastened to the vehicle’s roof and the
reinforced bumpers. The vehicles were easy to spot and had terrible fuel economy due
to the aerodynamics of the balloon-like gas bags.
Because of the visibly exposed gas bag, it was easy to see how
much fuel the vehicle had at any given time: the gas bag would be fully
inflated at the start of the trip, and it would deflate with every mile that
was driven. For all gas bag vehicles, the bag was
anchored to the roof using rings and straps. Some gas bag vehicles could
operate alternatively on gas or gasoline, switching between the two options
from inside the vehicle.
The gas storage bags themselves were made of silk and other
fabrics, which were then soaked in rubber. These bags were much cheaper and
easier to build than metal tanks, and could be repaired in a similar way to
bicycle tires.
Compressed Gas
Although it was technically possible to compress town gas or
street gas, it wasn’t done. Carbon monoxide, one of the components of town gas
and street gas, disintegrates quickly when compressed, while hydrogen gas,
another component, leaks away through steel tanks when it is compressed. What
could have been a solution to the large bags would’ve inhibited the fuel from working.
France, the only exception, used gas cylinders during World War
Two (picture above), allowing for a smaller fuel tank or a better range.
Natural gas was used, which could be compressed without the drawbacks of
compressing town gas. However, this turned out to be more expensive and more
dangerous.
Risks
Gas bag vehicles weren’t without danger.
The most obvious was fire, which could cause an explosion. Because of this,
people waiting for the bus were encouraged not to smoke! (below)
Bridges and other overhead obstacles were
another risk due to the height and fragility of the gas bags. The driver of the
vehicle needed to know the exact height of his vehicle and the bridges he
planned to drive under.
High speeds were also ill-advised. A
speed of more than 50km/h wouldn’t only impact the fuel efficiency, but the
fuel tank could also fly off the vehicle. Strong side winds presented similar
hazards, and gas bag vehicles were prone to carburator fires, loud bangs and
engine damage.
Evolution
Gas bag buses were still used in China in the 1990s as a cheap
public transportation option, particularly in the Sichuan province of China
(just south of China's geographical center) where natural gas is a relatively
cheap substance.
We’ve come a long way in natural gas transportation technology
from these earlier models, but a brief glimpse into the history and ancestry shows
us that like most other inventions, NGVs were born from necessity.
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