April 27, 2012

The First Natural Gas Vehicles

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.

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.

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.

More Pictures:

No comments:

Post a Comment