□ 1. Gasoline car modification
□ use of natural gas as a fuel and the original works of the same gasoline engine . The high-pressure gas cylinders stored after decompression to the mixer , where mixed with air into the cylinder . Ignition system is still used in the original gasoline spark ignition . Original gasoline engine compression ratio does not change the original structure of the engine is essentially the same , just another plus natural gas storage cylinders , valves and the corresponding switch. Lower conversion costs , and two natural gas or gasoline fuel can work, although natural gas antiknock well , allowing a higher compression ratio to work , but because in order to make the original gasoline engine is still working at the time of modification, the original does not change the engine compression ratio , the engine power loss of 10 % to 20% . In order to reduce the power loss can be modified at the time of the original gasoline engine compression ratio increases ( the easiest way is to go to a part of the cylinder head plane ) , and change the ignition timing to suit the operational needs of natural gas. While this may reduce the rate of loss of work , but there will be a risk of detonation and then gasoline when working , even not work. Gasoline is difficult to return to the original work . So now when the gasoline car modification, engine compression ratio generally remain unchanged.


□ 2. Diesel car modification


□ There are two possible methods . The first method is the original structure is essentially the same engine , modified by the electric ignition , that according to the principle of gasoline ( Otto cycle ) work . The original diesel fuel systems are all removed, the compression ratio is reduced to the value of the natural gas can bear ( higher than gasoline , typically ( 8 to 10 ) : 1 ) In addition to the natural gas fuel system components installed - cylinder , less outside pressure valve , mixer , etc., but also coupled with the electric ignition system , becoming only the single- burning natural gas fuel natural gas vehicles . This modification method is relatively simple , relatively mature technology , but can not be reused diesel work, and a larger engine power loss , only about 65% to 70 % of the original diesel engine.


□ The second method is to change the original diesel fuel system , the same as above plus a fuel gas system, generally do not change the compression ratio . The engine cylinder intake air and gas mixture , the original diesel fuel injector spray a small amount of diesel fuel used as the ignition . After pressing the fire burning diesel , natural gas and air ignited combustible mixture into the work, which is dual-fuel gas engines .


□ The basic working principle is: When you start with a full diesel , plus loads when negative pressure air and gas mixer spread to the diaphragm mechanism , through the pump lever on diesel high pressure pump rack limit , when the driver depresses the accelerator again would only increase the flow of natural gas fuel pedal .


□ dual fuel work not only does not lose power , and natural gas from the combustion performance is good , but also a slight increase over the original power of the diesel engine.


□ This is because the diesel engine compression ratio , the original excess air ratio greater reason. This modification changes the way for at least the original diesel engine , and in turn , can have insufficient gas supply full diesel work . But this way of working in the medium and low load , economy and emissions are not very good . Therefore, without an additional means of overcoming these deficiencies , does not apply to city buses. The best are those that are in the long , high-load vehicles and long-distance transport cars using this modified approach .


□ modern technologically advanced automotive fuel system is electronic fuel injection systems are mostly computer -controlled . Is used to automatically change the time of the electronic computer spray valve body out of petrol or diesel , and the ignition timing according to the flow conditions used . If switching to natural gas as fuel , the need to petrol or diesel electronic injection valve replaced or additional installation of gas electron injection valve , and then changes the control software and other computer programs , they can become natural gas combustion engines . Of course, the natural gas fuel system components and other gas cylinders , valves , etc., or indispensable.