Why CNG Cars are Not Automatic
Compressed natural gas (CNG) is becoming an increasingly popular alternative to gasoline and diesel-powered vehicles. It is clean, efficient, and produces significantly less emissions. However, one of the limitations of CNG is that it is not compatible with automatic transmissions.
The Science Behind CNG
Before we dive into why CNG cars are not automatic, let’s first understand how CNG works. CNG is a fuel that is compressed to a pressure of around 20-25 MPa (200-250 bar) and stored in high-pressure tanks in the vehicle. When the engine needs fuel, the CNG is released from the tank, passed through a regulator which reduces the pressure, and injected into the engine.
Why CNG is Not Compatible with Automatic Transmissions
The reason CNG cars are not automatic has to do with the way CNG behaves at low temperatures. CNG is stored in a gaseous state at a very high pressure, which means that it is at a very low temperature. In fact, CNG is typically stored at around -160°C (-256°F) or lower. When CNG is injected into the engine, it must be converted from a gas to a liquid state in order to be burned. This process is called “vaporization.”
Now, the problem with automatic transmissions is that they require a fluid that can operate effectively at low temperatures. Automatic transmission fluid (ATF) is designed to operate at temperatures as low as -40°C (-40°F) or lower. However, if CNG were to be used as a fluid in an automatic transmission, it would quickly turn back into a gas when it is released from the high-pressure environment of the transmission. This would cause a loss of pressure and the transmission would not work properly.
Therefore, CNG cars are typically equipped with manual transmissions. Manual transmissions do not require a fluid that can operate at low temperatures, so they are compatible with CNG.
The Future of CNG Cars
Despite the limitations of CNG, it is still a promising alternative fuel source. In fact, many countries around the world are investing in infrastructure to support CNG-powered vehicles. In India, for example, there are around 3.3 million CNG vehicles on the road, making it the world’s largest CNG market. As technology continues to improve, it is possible that CNG cars may become compatible with automatic transmissions in the future.
Until then, if you are in the market for a CNG car, you will have to settle for a manual transmission. But don’t let that discourage you from considering CNG as a viable alternative to gasoline or diesel-powered vehicles. With its many advantages, CNG is an attractive option for environmentally conscious drivers.
