If you think that replacing the nozzles, the fuel pump, putting the RTD, the flow rail, you can easily fall apart in a comfortable chair and drink brandy / beer / milk / lemonade (cross out unnecessary) - then you are very mistaken.
Continuing Fuel system for supercharged internal combustion engines. Few formulas., I can say that the modernization of the systems of the initially "atmosphere" of the car in the "turbo" did not quite simply screw the turbine and rushed off. This is actually a complete change of everything.
And of course, this entry can be useful not only for tuning people, but also for ordinary people.
As the name implies, today we will focus on powering the fuel pump. What is it and why is it so important?
The power supply of the gasoline pump is primarily a line that transfers electric current from the power source to the consumer of this current.
Having considered in the last entry the formulas for choosing the performance of a gasoline pump, let's say that we thought of a power of several thousand horsepower in our head, and chose a gas pump of the appropriate performance.
They stuck it into the system of their car and rushed off … somewhere …
It must be said here that miracles do not happen, and you have to pay for everything;
In the case of an increase in pump performance, it begins to consume more electricity …
What's wrong with that? Everything is physically correct and justified.
The following statement is also physically justified.
In accordance with the Joule-Lenz law, the amount of heat generated in a conductor depends on the value of the current passing through the conductor and the resistance value of the conductor. The greater the current and resistance of the conductor, the more the conductor heats up. Heating for heat, in this case, empty work. The value of the resistance of the conductor depends on its cross section. The larger the cross section, the lower the resistance of the conductor.
Why should a manufacturer spend copper on wires with a large cross-section, if in the case of using a factory gas pump, the wire cross-section is sufficient?
That's right - not why. And it is economically justified :)
So. After reading a lot of "water", I see that you are ready to proceed to the laboratory work.
We start the engine, and measure the voltage at the battery terminals, and at the fuel pump power supply chip.
We get the following input data:
Battery terminals = 13.6 Volts
Fuel pump chip = 12.5 Volts
It is probably worth picking your nose with your finger and muttering thoughtfully "It's funny, Sherlock, why are you writing quietly, and I'm so loud?" … "But this is elementary Watson, you write my boots. "
And this is a drop at idle, when the current consumption of the pump is not the greatest.
Having considered the graph of Valbra, one can understand how strongly the performance depends on the voltage, for example, when the voltage "drops" by 1 volt, at a back pressure of 3 atmospheres, the pump performance drops by 15% of the nominal.
As consumption increases, things get worse.
The power supply to the pump sank - its performance sank - the pressure sank - the mixture became lean - the temperature rose - the combustion rate of the mixture changed - inappropriate ignition timing - detonation - the pistons were poured into the pan … :)
Having also carefully looked at this diagram, you can see that the consumption of the pump is 14-15 amperes, while the factory fuse is 7.5A. Imagine the moment when you rush in a 90-degree turn, and playing with gas, maintains the optimal skid angle, suddenly, the native fuse for the non-pump burns out …) Then we read one paragraph higher :)
What to do? We call the store and talk. I need wires 10-12 squares, to the question "Why?"
We boldly answer - for a gasoline pump …
Introducing amazed eyes) What are the words and objections that so much is not needed, we ignore.
We buy a power wire for car audio and a fuse with a bulb.
Lay the wire - feel like an electrician We catch the
mass to the body where the thread is not very far
In a comparison of new wires and old ones,
I think that will be enough, although in fact 12 squares is an excess cross section … (6 is enough)
Right at the gas pump, we put a relay, the control of which is entrusted to the drain wiring (on the gas pump, a 7.5A fuse is for control relay with excess)
A bottleneck, this is a native chip, the terminals will not allow you to cram 12 squares into them instead of 2 :)
For good, you need to take the terminals (contacts) and crimp the maximum possible cross-section (2,3,4 drain wires for example) and already connect a thick cable to them.
We proceed to the second part of the laboratory work.
And we measure the voltage at the battery terminals
began to lie on the Power Fc fuel pump chip - but this is normal.
The main thing is that now the voltage drop at the gasoline pump is less than 1 tenth of a Volt, and it does not change much from the current load.
If you liked it, you can safely press the button, if you don’t like it, I am waiting for angry comments, for the opportunity to rehabilitate myself in a tough polemic))