This article is an attempt to consider the types of fuel injection on this engine..
Special thanks Alexander Pavlovich Chuvilin (car service “Abris-Ama, Moscow city, Pomorskaya st. – 29), in the “territory” of which, using the MotoDoc motortester, all the measurements described below were carried out.
Since the advent of cars with the engine of the Common Rail system, in particular 1 CD-FTV, only a few “about” notes have been published on the Internet.
Readers may get the impression that this engine is “as simple as three rubles,” because it injects fuel by analogy with the already “chewed” injection of GDI engines .
This is not entirely true, as we will try to make sure.
Let’s look at photo1:
Here we see the so-called “two-stage” diesel fuel injection.
But before proceeding further in our reasoning, let’s recall why this type of fuel injection began to be used and whether it is needed?.
. Back in the 90s of the last century, when this site was just being created, the following words sounded on its “open spaces”: “At the request of the Greens.”.
Because in a diesel engine during the combustion process a lot of harmful substances are formed:
– sulfur dioxide
– nitrogen oxide
– unburned hydrocarbons
– carbon monoxide
– soot particles
– and much more, but in smaller proportions
Two-phase fuel injection designed to minimize harmful emissions.
Photo 1 just shows the waveform of the engine 1 CD-FTV idling.
Position 1 – preliminary (or “pilot”) fuel injection
Position 2 – main fuel injection
In time, these phases of fuel injection also differ, see photo 2:
Preliminary (“pilot”) fuel injection:
A small amount of fuel is injected into the combustion chamber: from 1 to 5 cubic millimeters (different numbers give different numbers, but we have nowhere to check this, so we’ll believe).
Injection can be carried out within 90 degrees to TDC.
Feature: if the injection occurs in the range from 20 to 45 degrees to the TDC, then in this case a quick failure of the engine itself and its mechanical part is quite possible, since at these injection angles the fuel does not have time to evaporate and will form in the form of droplets on the walls of the cylinder and the surface piston, which will lead to dilution of engine oil.
We are used to the fact that the “diesel” is noisy and soot.
But the use of preliminary fuel injection makes it possible to obtain a smoother “curve” of pressure increase, which affects both the noise level of the engine and the emission of harmful exhaust gases.
It also reduces the ignition delay period of the main fuel injection phase..
A very important condition for reducing engine noise is the exact time and mass dosing of fuel for the first phase of fuel injection (pre-injection). In case of violation of these conditions, the engine noise and its smoke increase..
All this has the ultimate goal of reducing emissions of harmful exhaust gases..
When you press the gas pedal, the type of injection begins to change:
In photo 3 we see how, when you press the gas pedal, two-phase injection (photo 3, position 1) goes into single-phase (photo 3, position 2).
The time between pulses also changes (photo 4 and 5):
The nozzle opening time for single-phase injection at 1250 RPM is 1.09 ms (measurement error of about 10 μs).
This engine has a so-called “cut-off” that is familiar to us by “normal” injection (we gain speed, and then we suddenly “throw” the gas pedal):
The “cut-off” for different adjustments is also different, but in principle it should start from 1800 revolutions and continue up to 1200 revolutions.
And hereinafter, the analogy can no longer be drawn, because after the “cut-off” the type of injection differs significantly from the “normal” one, look:
We see “bursts” of pulses by means of which the control system smoothly transfers the engine to work at XX.
When starting the engine, two-phase fuel injection is also used:
This allows you to achieve the reliability of the “cold” start of the engine, the stability of revolutions for another
“not hot” engine and emission reduction CH_x .
The time indicators in Figure 1 are not set due to the fact that they will be different for different temperatures, for different grades of “diesel” fuel, for different grades of used motor oil, and so on. For the same reasons, the engine speed during a cold start will also be different..
In figure 1 it is written: “two-phase injection – 1” and “two-phase injection – 2”.
None of the “manuals” have written about this and such words are not given.
But it was experimentally established that such expressions should be introduced into everyday life.
“Two-phase injection – 1” – an injection that occurs in two stages, but without the possibility of its transition into a single-phase injection.
“Two-phase injection – 2” – an injection that occurs in two stages, but with the possibility of its transition into a single-phase (main) injection.
It all depends on many factors, but the main one is the temperature of the coolant and the temperature of the fuel.
The development of the automotive industry can be compared with a spiral that “rests” on Eternity. The Greens demanded – the automotive industry completed. In a few years, when the Greens find something else, they will pass through the Law other restrictions on exhaust emissions from cars..
And then we will see another type of engine and a different type of fuel injection. Everything is connected, everything is natural, but
the whole basis is not care about people, as you might think, no. The basis of the basics are the numbers in the checkbook. And everything else is “attached” to them.
Such engines with this type of fuel injection would significantly help improve the environment in our country..
If our fuel were “normal”.
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