gdi engine compression ratio than mpi engine compression ratio is higher than the reason why

Intake multi-point EFI gasoline engine English said MPI, cylinder direct injection gasoline engine referred to as GDI, intake multi-point EFI gasoline engine is in the intake manifold, i.e., in the position before the valves to inject fuel, and then through the valves into the cylinder; and cylinder direct injection gasoline engine, as the name implies, is the direct injection of fuel in the cylinder. First of all, MPI when the intake valve is closed when the engine will spray fuel on the back of the intake valve of each cylinder, in the intake stroke before the fuel-gas mixture into the cylinder. During cold start, as evaporation is not complete at this time, the fuel will form a film and puddle on the surface of the intake tract and the back of the intake valve, making the actual amount of fuel injected far exceed the theoretical value, so that misfire or partial combustion phenomenon will be obvious in the first 4-10 cycles of startup, resulting in a significant increase in HC emissions. GDI, on the other hand, avoids the intake wet wall due to direct in-cylinder injection and does not have the MPI problem, thus HC emissions are not high during cold start, and it can run normally during the 2nd working cycle.

Secondly, another limitation of MPI is that load changes rely on throttle regulation, although throttle control for MPI has been developed into a very mature technology, but it brings considerable thermodynamic losses, the use of throttle to regulate the parasitic pumping losses, and will make the engine in the low load when the thermal efficiency is reduced. GDI, on the other hand, does not require a throttle to regulate load, which improves volumetric efficiency at part load and improves fuel economy.

In addition, in terms of utilizing fuel to cool the charge, the evaporation of fuel in MPI relies primarily on heat transfer to the oil film from heat sources such as the intake tract and intake valves, and thus does not significantly cool the charge, whereas with GDI, the fuel enters the cylinder in the form of fine atomized particles and obtains heat energy from the surrounding air, effectively cooling the charge.

From the above comparison, we can clearly understand that GDI is a significant improvement over MPI in terms of fuel economy as well as emissions.

In terms of fuel economy, the GDI has even surpassed the diesel, and has successfully realized the rarefied combustion of the gasoline engine; and in terms of power output, the GDI is also far ahead of the MPI.

The evil of the stick, their own use of the GDI, so-called imported original to China will be converted to the MPI to cheat the money, after cheating the money, and then in a couple of years a small change in the models and then come back to the GDI to cheat the money again! The first is the GDI, and the second is the MPI, and the third is the MPI.

In addition, we all know that the Yazun GDI horsepower 310N/M, and changed into MPI after 280N/M, see GDI relative to the MPI fuel economy is greatly improved and a large degree of enhancement of automotive power it