What is a natural gas vehicle?

Natural gas use

In natural gas vehicles, natural gas is the most environmentally friendly fossil fuel. The use of natural gas in cars can reduce the content of carbon dioxide in exhaust gases by 25%, carbon monoxide by 75%. The main component of natural gas is methane. Natural gas is stored at a pressure of 200 bar, hence its other name is compressed natural gas, CNG. Currently, more than 15 million vehicles around the world run on natural gas. Another advantage of natural gas is its low price. Methane is 2-3 times cheaper than gasoline. The disadvantages of using natural gas include a reduction in vehicle power, up to 20% depending on the project. Increased valve wear when the engine is running on gas and the high cost of gas equipment. Separately, it should be said about the safety of cars running on natural gas.

Studying a car on gas

Studies by the German Automobile Club (ADAC) show that the risk of fire in front and side vehicles does not increase. That is, in the event of an accident, a car running on natural gas behaves like a regular car. The following types of natural gas vehicles are available. Production of cars mass-produced at car manufacturers. Modified cars are turning into specialized enterprises. Natural gas production machines are available in two versions. Dual fuel, gas and gasoline are used on an equal footing, you can change modes and mono-fuel, base fuel, there is an emergency gas tank, automatic switching of gasoline. Mono-fuel cars are more suitable for natural gas, have optimal fuel consumption and low emissions.

Gas petrol cars

To transform into a natural gas vehicle, automakers are using existing gasoline engines. These are spark ignition engines. Turbocharged engines are best suited for gas conversion. Adaptation of the turbocharger operation, greater compression, additional pressure, allows you to achieve the same power and torque characteristics for gas and gasoline. The characteristics of compressed natural gas are increased resistance to detonation, an octane rating of 130 and lack of lubricating properties, which leads to increased load on the engine. To counteract these factors, various changes are made to the mechanical part of the engine. Increased strength of individual elements and components, piston pins and rings, washer inserts, valve guides and seats.

Series Gas Machines

If necessary, the thermal conductivity of gasoline injectors increases, the performance of water and oil pumps increases, spark plugs are replaced. Natural gas vehicles are offered by most car manufacturers including Audi, BMW, Citroen, Chevrolet, Fiat, Ford, Honda, Hyundai, Mercedes-Benz, Opel, Peugeot, Seat, Skoda, Toyota, Volkswagen, Volvo. Cars are sold in areas where natural gas is most common. Natural gas vehicles are not officially sold in our country. A production natural gas vehicle can be introduced in the country. Modified natural gas vehicles. In theory, all gasoline-powered vehicles can be converted to natural gas. Specialized centers offer installation of gas equipment for natural gas from different manufacturers.

Gas automotive equipment

As a result, you get a dual-fuel car that can run on gas and gasoline. Due to the high cost of natural gas, gas equipment is installed mainly on commercial vehicles, taxis, buses, and trucks. Where it pays off faster and provides significant benefits. Diesel engines can also be converted to natural gas. There are two approaches. Forced ignition of the air-fuel mixture to install an ignition system with gas equipment. And spontaneous combustion of the fuel-air mixture, an engine for working on a mixture of diesel and natural gas. Due to the high price, diesel engines for buses and trucks are converted to natural gas.

Car gas supply system

Gas equipment. Balloon equipment (HBO) for moving on compressed natural gas is combined with a gas supply system and an electronic control system. The composition of the equipment for the production of liquefied petroleum gas and modified vehicles is essentially the same and may have a different design depending on the manufacturer of HBO. The natural gas supply system includes a filling door, gas cylinders, a high pressure gas pipeline, a gas pressure regulator, a gas distribution pipe, and gas valves. The neck for filling gas, the nozzle for filling gas, is located next to the neck for filling fuel. Gas cylinders enter through it when filling gas under pressure. Depending on the size of the engine, one or more thick-walled gas cylinders of various capacities are mounted in the vehicle structure.

Where is the gas cylinder of gas machines installed

In serial cars, the cylinders are usually located under the bottom of the car, in modified ones - in the luggage compartment. The cylinders are attached to the body brackets. From the cylinders, gas enters the high-pressure pipeline to the gas pressure regulator, which ensures that the gas pressure drops to the nominal working pressure. In gas equipment, diaphragm or plunger type pressure regulators are used. The decrease in gas pressure is accompanied by its strong cooling. To prevent freezing, the housing of the gas pressure regulator is included in the engine cooling system. Gas at rated working pressure enters the gas distribution pipe and then to the gas supply valves to the intake manifold. The gas supply valve, in some sources the gas nozzle, is a solenoid valve.

Gas system operation

When current is supplied to the electromagnetic coil, the armature rises and the hole opens. Impulse gas enters the intake manifold and mixes with air. In the absence of current, the spring holds the valve in the closed position. The electronic gas control system includes input sensors. For production vehicles, the gas control system is an extension of the engine control system. Modified cars have a separate control system. Input sensors include a cylinder pressure sensor and a gas pressure sensor. The pressure sensor in the cylinder is located on the pressure regulator. It determines the gas supply to the cylinder by the amount of gas, as well as by the density of the cylinder. The pressure sensor in the gas distribution pipe detects the gas pressure in the low pressure circuit.

Gas Machines

On the basis of what the duration of the opening of gas supply valves is determined. Signals from the sensors are sent to the electronic control unit. The control unit uses information from another system, sensors to control the engine, engine speed, throttle position, oxygen sensor. And others, in accordance with the included algorithm of the control unit, rad performs functions. Monitor gas injection according to engine speed, load, gas quality and pressure. Regulation of lambda gas, ensuring the operation of a homogeneous mixture, high-quality gas adaptation. Cold start of the engine, at an air temperature of 10 ° C under the engine that starts gasoline. Emergency start of the engine, if gas escapes, the gas mileage produced is not performed for several seconds. These functions are performed using drive mechanisms.