Why Do Diesel Engines Use Air Flow Meters and Throttles If Fuel Amount Is Controlled?

I wish you that too. You don't even know how much. You're right, I don't know what to discuss. I am blown away by your knowledge advantage in this post. If you find anything else on the net, be sure to write here. Greetings.

Interesting, I saw at Abram's if that means anything to you. No, I will not pretend to be smarter than I am here. No, I haven't serviced it. I saw something like that at Stanik, if that means something to you. I have not serviced this either. I saw something I know. I know more than you do. I rely on knowledge, maybe just any knowledge. You are left with the internet and pseudo-automotive ragged newspapers.

Hello, colleagues, the idea of new generation engines, of course, diesels is such that the amount of air sucked into the cylinder per cycle determines the amount of fuel injected, even up to 5 doses per cycle with piezoelectric injections which have lower inertia and thus faster response to the control signal it is about the most effective fuel combustion and a higher degree of efficiency, to get it, you need to measure how much air is flowing into the system at a given moment and at what temperature to calculate the mass of it, the throttle is used to signal the driver's intention to load the engine, because the fuel pressure in the system is CONSTANT and not the amount of air, the constant pressure is realized by the CR pump and the high rail through a pressure sensor and a system that can regulate the efficiency of the high pump and the amount of fuel needed to implement the engine load is regulated by the time and the number of injectors opening, so many theories because there is still ecology and this is only a chance for disputes on exhaust emissions from EU directives and standards and everything is based on the basic assumption that 15 kg of air is needed for total combustion, i.e. ideal for 1 kg of fuel, best regards

buddy wopor - you write nonsense!
The fuel pressure in the system is VARIABLE! It ranges from about 250 bar to about 1500 bar (for example IVECO Daily) and varies depending on RPM, load, top-up pressure, temperatures, etc.
It is regulated by a valve on the CR pump. In the first generation of systems, the valve is on the high pressure side, in the second generation the amount of fuel supplying the pump is controlled on the low pressure side.
The pressure sensor is in the rail to measure the pressure and correct the pump actuation to obtain the pressure assumed for the given engine operating conditions.
The flowmeter is usually only available in engines with EGR (euro 4), i.e. secondary exhaust gas circulation. In such a system, we have an additional valve introducing the exhaust gas to the intake manifold to reduce the amount of oxygen in the air supplied to avoid the combustion of poor mixtures at idle speed and to reduce the toxicity of exhaust gases.
In addition, in such a system there is a throttle to facilitate the intake of exhaust gases and reduce the supply of fresh air.
Referring to the question of the main topic, the purpose of the flowmeter is to determine the amount of fresh air supplied to the engine and the amount of exhaust gas recirculated into the engine. The air load without the EGR system the cartridge is able to calculate on the basis of air pressure and temperature.
In addition, in euro 5 cars we have a solid particle filter, and the controller is enriched with the so-called post-injection to increase the temperature of the exhaust gas to burn out soot and clean the particle filter behind the catalyst.
I see that most people have a strict idea of what it fixes ...

You exaggerated with this Euro 5, but in general you are right the flow meter allows the controller to determine and control the amount of exhaust gases and control the EGR valve.

Exactly, buddy. The flow meter allows you to determine the percentage of exhaust gas based on the amount of air. That's the whole philosophy.

And it was used in ordinary atmospheric diesel which had a controller and EGR valve + throttle which increases the amount of exhaust gas.

As for diesel, I agree that the MAF is used to control the EGR.
But in gasoline there is probably a slightly different use for calculating the fuel dose?
And is MAF + Lambda used in gasoline engines or either?

greetings

The MAF is used together with the throttle position sensor and the RPM sensor to determine the engine load and thus calculate the required fuel dose. Lambda is used only for correction - such a control feedback, whether the calculated value of the mixture composition is correct.

OK, thanks, that's what I thought.
I have one more question.

Why can't a diesel solution be used in gasoline? So the engine speed is regulated only by increasing the fuel dose. Or, in diesel, use a throttle solution. What does it depend on?

From the type of fuel and its combustion characteristics.