what is the difference between carburator to MPFI system?

Carburettors mix fuel with air as air passes through, multi point fuel injection meters fuel to the inlet ports in the cylinder heads.Fuel injection is a far more precise method of controlling fuel air ratio, resulting in cleaner more fuel efficient engines which last much longer between overhauls.You wont find a carburettor on a car built after 1992 in the developed world.

a carburator just puts fuel into the cylinders, MPFI is a precise metered mixture of fuel to each cylinder, based on what the computer senses. It is a more precise mixture than sequential fuel injection.

The carburetor, carburettor, or carburetter (see spelling differences), also called carb (in North America) or carbie (chiefly in Australia) for short, is a device that blends air and fuel for an internal combustion engine. It was invented by Hungarian scientists Donát Bánki and János Csonka in 1893. Carburetors are still found in small engines and in older or specialized automobiles such as those designed for stock car racing. However, fuel injection, first introduced in the late 1950s and first successfully commercialized in the early 1970s, is now the preferred method of automotive fuel delivery. The majority of motorcycles still are carbureted due to lower cost but as of 2005 many new models are now being introduced with fuel injection.

Most carbureted (as opposed to fuel-injected) engines have a single carburetor, though some engines use multiple carburetors. Older engines used updraft carburetors, where the air enters from below the carburetor and exits through the top. This had the advantage of never "flooding" the engine, as any liquid fuel droplets would fall out of the carburetor instead of into the intake manifold; it also lent itself to use of an oil bath air cleaner, where a pool of oil below a mesh element below the carburetor is sucked up into the mesh and the air is drawn through the oil covered mesh; this was an effective system in a time when paper air filters did not exist. Beginning in the late 1930s, downdraft carburetors were the most popular type for automotive use in the United States. In Europe, the sidedraft carburettors replaced downdraft as free space in the engine bay decreased and the use of the SU-type carburetor (and similar units from other manufacturers) increased. Some small propeller-driven aircraft engines still use the updraft carburetor design, however many use more modern designs such as the Constant Velocity (CV) Bing(TM) carburetor.

The carburetor works on Bernoulli's principle: the faster air moves, the lower its pressure. The throttle (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburettor mechanisms which meter the flow of air being sucked into the engine. The speed of this flow, and therefore its pressure, determines the amount of fuel drawn into the airstream.

M.P.F.I. means Multi Point Fuel Injection system. In this system each cylinder has number of injectors to supply/spray fuel in the cylinders as compared to one injector located centrally to supply/spray fuel in case of single point injection system.

Advantage of M. P. F. I.

(1) More uniform A/F mixture will be supplied to each cylinder, hence the difference in power developed in each cylinder is minimum. Vibration from the engine equipped with this system is less, due to this the life of engine components is improved.

(2) No need to crank the engine twice or thrice in case of cold starting as happens in the carburetor system.

(3) Immediate response, in case of sudden acceleration / deceleration.

(4) Since the engine is controlled by ECM* (Engine Control Module), more accurate amount of A/F mixture will be supplied and as a result complete combustion will take place. This leads to effective utilization of fuel supplied and hence low emission level.

(5) The mileage of the vehicle will be improved.

http://www.indiacar.com/infobank/mpfi.htm

in carburaor,the inlet of the air is allowed to mix with the petrol being supplied through differant sized jets and the admixture is then sent to the combustion chamber for ignition and then power.

in the MPFI ystem,the fuel[petrol] is injected in the combustion chamber directly where sufficient quantity of air is already waiting dduly compressed sufficiently for the ignition.thie happens slightly before the piston comes to top dead centre,and as soon as the piston reaches top dead centre the admixture is ignited,and to power.

the later is providing beter quality of igniton and is more advanced method now in use over the earlier which is almost obsolate now.

in mpfi engine solonoid oprating valves are used