MPFi V/S CRDi. V/S. in petrol engine for gaining more uniform Air Fuel blending fuel is injected at various point in the path of air. but in case of DTSI(digital twin. Know everything about Multi Point Fuel Injection (MPFI) system on CarTrade Blog. Fi EFi MPFi GDi. EFi stands for Electronic Fuel injection (EFi) whereas MPFi or MPi stands for Read more: How CRDi technology works?>>.

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EFi vs MPFi vs GDi: How Electronic Fuel Injection Technology Works?

Your email address will not be published. Fuel always remains under such pressure even in stand-by state. The microcomputer regulates the amount of time the valves stay open and thus the amount of fuel injected, depending on operating conditions and how much output is needed. Newer CRDI engines feature maximum pressures of bar. Particulates of exhaust are reduced.

Common Rail Direct Injection – CRDi Technology Working Explained – CarBikeTech

Log In Sign Up. These particles are mainly composed of carbon and hydrocarbons. In common-rail system; the fuel pressure is implemented by a very strong pump instead of fuel injectors. CRDI system that uses an ion sensor to provide real-time combustion data ahd each cylinder. This division of labor necessitates a special chamber to maintain the high injection pressure of up to 1, bar.

Benefited by the precise timing, common-rail injection system can introduce a “post-combustion”, which injects small amount of fuel during the expansion phase thus creating small scale combustion after the normal combustion takes place. Basically, particle filter is a porous silicon carbide unit; comprising passageways which has a property of easily trapping and retaining particles from the exhaust gas flow. Engine crank not necessary during cold start. The fact that there is no glow plug lowers the maintenance costs and the fuel consumption.

The PF unit needs to be cleaned up every 80, km by high-pressure water, to get rid of the deposits resulting from the additive. More pulverization of fuel is obtained in this system. That is where the common fuel line rail comes cddi. Leave a Reply Cancel reply Your email address will not be published.

The new common-rail injection technology helps solving this problem. Therefore whenever the injector which acts as a valve rather than a pressure generator opens, the high-pressure fuel can be injected into combustion chamber quickly.


Srinivasan Automotive Mechanics. A few advantages of MPFI over carburetor is. Diesel particles are larger and heavier than petrol, thus more difficult to pulverize. The system realizes high output and torque, superb fuel economy, emissions low enough to achieve Euro Stage IV designation and noise levels the same as a gasoline engines. Common rail refers to the single fuel injection line on the CRDI engines.

These days, even cc powered engine bikes are equipped with fuel injectors for improving performance and fuel efficiency but with increase in cost. Click here to sign up. A major drawback if I have to pinpoint one is if the distributor fuel rail fails, the engine comes to a grounding halt which is in turn overcome by a new technology in place called unit injectors, which intakes fuel from the high pressure fuel pump and has the distinct advantage of operating even when one or two unit injectors fail.

The electronic control unit ECU modifies injection pressure precisely and as needed, based on data obtained from sensors on the cam and crankshafts. CRDI system is more complex when compared with MPFI, but yet is more efficient, offers more power and has good response to no or part engine loads which makes the diesel engine deliver more power even at low engine RPM. This further eliminates the unburned particles and also increases the exhaust flow temperature thus reducing the pre-heat time of the catalytic converter.

The high-pressure injectors are available with different nozzles for different spray configurations. In this system it is seen that the CRDI engine developed more power and also increased the fuel efficiency. The powerful microcomputer makes the whole system more perfect and doubles the torque at lower engine speeds. MPFI came into play as a means to meet emission norms set by various countries and in addition it also helps in deriving out good vehicle performance and minimum quantity of fuel.

When the timing shuts the solenoid valves, fuel injection ends immediately.

Common-rail engines are thus clearly superior to ordinary motors using either direct or indirect fuel-injection systems. But in the CRDI engines the pressure is built up independently of the injection sequence and remains permanently available in the fuel line.


The drive torque and pulsation inside the high-pressure lines are minimal, since the pump supplies only as much fuel as the engine actually requires. This site uses Akismet to reduce spam. Whereas ordinary diesel direct fuel-injection systems have to build up pressures a new for each and every injection cycle, the new common rail line engines maintain constant pressure regardless of the injection sequence.

Fuel rail is an accumulator which stores the high pressure fuel and releases it to the injector nozzle based on inputs from ECU. In simple terms, for the engine to produce power, proper amount of air-fuel mixture is required to be injected through the nozzle injector, which atomizes the fuel into tiny droplets into the combustion chamber, thereby spark plug ignites the mixture to propel the piston.

Compared with petrol, diesel is the lower quality fuel from petroleum family. Particle emission is always the biggest problem of diesel engines. Here high-speed solenoid valves, regulated by the electronic engine management, separately control the injection timing and the amount of fuel injected for each cylinder as a function of the cylinder’s actual need.

Common Rail Direct Injection – CRDi Technology Working Explained

Imperfect pulverization leads to more unburned particles, hence more pollutant, lower fuel efficiency and less power. In other words, compression and injection occur independently of each other. As a result, not only pulverization is improved by the higher fuel pressure, but the duration of fuel injection can be shortened and the timing can be more precisely controlled.

CRDI — many must have come across seeing it behind cars boot and wondering what is it. Gosavi3 1 Assistant Professor,krunalp.

The high-pressure fuel is fed to individual fuel injectors via a common rigid pipe hence the name of “common-rail”. Abstract Common-rail technology is intended to improve the pulverization process. Sensor data from the camshaft and crankshaft provide the foundation for the electronic control unit to adapt the injection pressure precisely to demand.

The common rail upstream of the cylinders acts as an accumulator, distributing the fuel to the injectors at a constant pressure of up to bar.