Cng buses

Types of CNG Buses

CNG buses are buses powered by compressed natural gas. They are greener alternatives to diesel buses and are becoming popular in many countries. There are several types of CNG buses, including the following.

• Light-Duty CNG Buses

  CNG is used to power light-duty buses, which are smaller than regular transit buses. These buses can carry up to 30 passengers. School buses and shuttles are some examples of light-duty CNG buses. They are known for their quieter operations and low emissions.

• Transit CNG Buses

  Transit buses are the ones used for public transport services. CNG transit buses have become popular in many cities due to their environmental benefits. They release fewer emissions compared to diesel-powered transit buses. They also have lower operating costs compared to diesel buses.

• Motor Coach CNG Buses

  Motor coach buses are larger compared to transit and CNG light-duty buses. They are mainly used for long-distance travel. CNG motor coach buses are more environmentally friendly compared to diesel motor coach buses. They have similar benefits to light-duty CNG buses, such as quieter operations and low emissions.

• Double-Decker CNG Buses

  These buses are two-tier buses that are mainly used for public transport in many cities. They are known for their high seating capacity. CNG double-decker buses are more efficient and environmentally friendly compared to diesel double-decker buses.

• Articulated CNG Buses

  Regular CNG buses can be converted into articulated CNG buses by adding a flexible joint between two bus sections. They are useful for public transport services, especially in crowded cities, due to their high capacity. They can carry more passengers compared to regular CNG buses.

• Trolebús

  Trolebuses are buses that are powered by electricity from overhead wires. They are known for their low emissions. In some cases, CNG can be used as a backup power source in case there is no electricity from the overhead wires.

Specifications and Maintenance of CNG Buses

Specifications of CNG buses vary depending on their size and the manufacturer’s specifications. However, here are some general specifications:

• Engine

  The engine of a CNG bus is designed to be more powerful than that of a conventional bus. It has a horsepower rating of 250 to 350 hp. The bus also has a torque rating of between 700 and 900 lb-ft.

• Emission Control System

  The emission control system in CNG buses is designed to comply with EPA and CARB regulations. It has a catalytic converter, an O2 sensor, and a closed-loop fuel control system. The buses also have low NOx and particulate matter emissions.

• Fuel System

  The fuel system in a CNG bus consists of fuel tanks, fuel lines, and fuel valves. The fuel tanks have a capacity of 60 to 120 diesel gallons equivalent. The tanks are also designed to withstand high-pressure CNG.

• Transmission

  CNG buses use automatic transmissions. The transmission is designed to be more efficient and has a rating of 6 to 12 speeds.

• Chassis

  The chassis in a CNG bus is designed to be more robust. It has a gross vehicle weight rating (GVWR) of 26,000 to 45,000 pounds. The chassis also consists of a frame, suspension, steering, and axles.

• Electrical System

  The electrical system in a CNG bus includes an electrical panel, a power distribution system, a starting system, and an electrical system for communication. The electrical system is designed to power the bus and its components.

• Safety System

  The safety systems in CNG buses include fire suppression, emergency exit, first aid kit, warning signals, and safety equipment. These systems have been installed to help save lives in case of an emergency.

• Passenger Amenities

  Passenger amenities in a CNG bus include an air conditioning system, a heating system, interior lighting, a public address system, and electronic displays. These amenities are installed to enhance passenger comfort.

CNG buses have different maintenance needs. The maintenance needs depend on the bus model and the CNG system. Below are the general maintenance requirements:

• 1. CNG buses should be serviced regularly. The service should at least be done once every 30 days or after every 1,000 miles. The maintenance service should include checking the engine oil, engine oil filter, air filter, fuel filter, cabin air filter, and tire pressure.
• 2. The CNG bus fuel system should be inspected regularly for leaks. All leaks found should be repaired immediately. Also, all hoses and fittings in the fuel system should be replaced after every 60,000 miles.
• 3. CNG buses should have their spark plugs and ignition wires replaced after every 30,000 miles.
• 4. The engine valve clearance and timing belt in the CNG bus should be inspected after every 60,000 miles.
• 5. Once every 100,000 miles, the CNG bus should have its emissions control system inspected. The bus emissions control system should also comply with EPA and CARB regulations.
• 6. The CNG bus exhaust system should be inspected regularly. The exhaust system should be free from leaks, cracks, and rust.
• 7. The CNG bus transmission fluid and filter should be replaced after every 50,000 miles.
• 8. CNG buses should have their wheel bearings and brake pads inspected regularly. The bus brake pads and wheel bearings should be replaced if worn out.
• 9. The bus suspension system, steering system, and safety system should be inspected periodically. Any damaged or worn-out components should be replaced.

How to Choose CNG Buses

When buying buses for CNG, it’s important to understand the needs of the target market. Here are key factors to consider:

• Bus Size and Capacity

  The first thing to consider is the size of the bus and how many passengers it can carry. CNG buses come in different sizes. There are small buses that are ideal for short routes and bigger ones that are good for long distances.

• Type of CNG Bus

  CNG buses are made for different purposes. Some are only meant for public transport. Others are used in schools, tour buses, or in hotels. The buyer's main use should determine the type of bus to go for.

• Safety Features

  Consider the safety features of the CNG bus. Look for buses that have Emergency exits, fire extinguishers, safety belts, and first aid kits. The safety features should be in line with the buyer's needs.

• Comfort and Amenities

  CNG buses have different levels of comfort. For instance, some have air conditioning, reclining seats, entertainment systems, and WiFi. These amenities are important for long-distance travel.

• Bus Performance

  The performance of a CNG bus is determined by its engine power, transmission system, and suspension. A good CNG bus should be able to navigate different road conditions and cope with traffic jams.

• Cost and Budget

  Consider the cost of purchasing and maintaining the CNG bus. Some buses are more expensive than others. Find a CNG bus that fits the budget.

• Environmental Regulations

  Different regions have specific environmental regulations that need to be followed. Before purchasing a CNG bus, ensure that it meets the set environmental standards of that region.

• Warranty and After-Sales Service

  When buying a CNG bus, consider the warranty and after-sale services. This will prevent extra costs in case of mechanical failure. Choose a bus manufacturer who will offer maintenance and repair services.

• Bus Design

  Consider the bus design. Some buses are designed to be more fuel-efficient and to reduce emissions and noise. The engine of such buses is more efficient compared to the others.

How to DIY and Replace CNG Buses

Replacing CNG bus parts can be a complex process that requires specialized knowledge and tools. It is generally recommended to have CNG bus parts replaced by trained technicians at an authorized service center. However, for some minor replacements or maintenance tasks, here's a general guide:

Before attempting any replacements, ensure that you have the necessary tools and safety equipment. This may include wrenches, sockets, screwdrivers, torque wrench, safety glasses, gloves, and fire extinguisher. Gather the replacement parts that are compatible with the CNG bus model and ensure they meet safety and regulatory standards.

• Engine Oil and Filter: Turn off the engine and let it cool. Use a wrench to remove the oil drain plug and let the engine oil completely drain into a suitable container. Install the new oil drain plug and torque it to the manufacturer's specifications. Use a wrench to remove the old oil filter. Lubricate the gasket of the new oil filter with a small amount of new engine oil. Install the new oil filter and tighten it according to the manufacturer's recommendations. Fill the engine with new oil through the oil filler cap.
• Air Filter: Locate the air filter housing, which is usually a plastic or metal box with clips or screws holding it closed. Open the housing and remove the old air filter. Clean the inside of the housing. Install the new air filter and close the housing.
• Fuel System Cleaning: Start the bus and let it idle. Slowly add the recommended amount of fuel system cleaner to the fuel tank while following the manufacturer's instructions. Continue to let the bus idle for the recommended time or until the cleaner is fully utilized. Do not rev the engine or put excessive load on it during this process.
• Brake Pads: Lift the bus and secure it with jack stands. Remove the wheel covering the brake assembly. Use a wrench or socket to remove the brake caliper bolts and carefully slide the caliper off the brake pads. Replace the old brake pads with new ones and reattach the brake caliper.
• Check Tire Pressure: Use a tire pressure gauge to measure the pressure in each tire. Compare the measured values with the recommended tire pressures. If any tire is below the recommended pressure, use an air compressor or manual pump to inflate it.

It's important to note that working on CNG bus systems, especially related to the fuel system or high-pressure components, can be dangerous if not done correctly. If there is any doubt or uncertainty, it's best to consult a professional mechanic or CNG-certified technician.

Q&A

Q1: How long does a CNG bus last?

A1: The durability of CNG buses depends on several factors, including the bus design, maintenance level, and operating conditions. Generally, CNG buses are designed to last up to 12 years or 500,000 miles. However, with proper maintenance, the buses can exceed the mileage.

Q2: Are CNG buses good for the environment?

A2: Yes, CNG buses are good for the environment. They emit low harmful emissions compared to diesel-powered buses. The buses help reduce air pollution, improving public health and the environment.

Q3: Why are CNG buses popular?

A3: CNG buses are becoming popular because of their lower operating costs, reduced emissions, and quieter operations. Many transit agencies use CNG buses to cut down fuel costs and meet their environmental goals.

Q4: Do CNG buses require special training?

A4: Yes, CNG buses require training for maintenance and operation. The training helps ensure safety when handling CNG buses because CNG is flammable. It also equips the trainees with knowledge on how to maintain and operate the buses effectively.

Q5: Are CNG buses suitable for long-distance travel?

A5: Yes, CNG buses are suitable for long-distance travel. However, the range of the buses on a single tank of gas is less than that of diesel buses. Frequent refueling is necessary for long-distance travel.