34

Simple reason: volume. @ 14.7:1 stoich, your input into the cylinder would need to be 14.7x bigger (or push that much more) through a nozzle than you would the fluid which is fuel. You state it would have fewer mechanical parts, but is that true? You'd have to furnish a mechanical method to create the high pressure air as well as introduce it into the ...


26

You have almost but not quite described the operation of either a Turbocharger or Supercharger. The idea of the air under pressure being injected from a common fuel rail would likely not work as it would be difficult to guarantee decent atomization.


16

In many ways, you're describing a 5 stroke engine 5 Stroke engines are using a piston to provide a secondary means of compression for the AFR. Although, not injecting air they are compressing the air by mechanical means. What you describe with air injection requires massive volumes of air. Think of a 5.0 Liter engine requiring 5 liters air every 720 ...


11

Background You asked Why is the effect of a bad fuel pump more noticeable at higher speeds? I assume that by 'higher speeds' you mean engine speeds or RPM's. During high RPM operation an ICE consumes more fuel so the flow rate into the fuel injection system or carburetor increases at higher RPM's. This taxes the fuel system and puts more load on the ...


11

High pressure gas is very difficult to create, much harder than high pressure liquid. It's because liquids are not compressible, so you can squirt them virtually as hard as you want, while gas will just absorb most some of your compressing effort and convert rest of it to heat (adiabatic heating). To compress air to the pressure necessary would require a ...


10

You have a qualitative description of what happens, but let's break it down to a smaller scale. When we talk about "temperature" of something, we are really talking about how fast the molecules are moving around and bouncing off each other. "Temperature" is really "kinetic energy". And it turns out that there are other types of energy besides moving around ...


10

On a car with fuel injection there can be two fuel pumps, one high-pressure and one low-pressure. The low-pressure pump moves the gas from the tank up to the high pressure pump. The high pressure pump then raises the pressure to a level that will be useful to the injectors. The two PIDs reflect those two different systems. PID Description Min ...


9

tl dr - To directly answer the question, SeaFoam is a pure petroleum product. If an alternative product is made up the same as Seafoam, then I'd think it would work just fine. If its makeup is not similar, you probably won't see the same results. Below is what you are looking for and a recipe for making your own substitute. I found this answer for a SeaFoam ...


9

The gas gauge is just an indicator and each vehicle is going to be different. I know the older Datsun Z cars had two gas gauges, one was the main one which showed the volume of gas down to 1/4 tank, while the secondary one showed from 1/4 down to empty. The secondary gas gauge was very accurate to give the driver a true indication of how much fuel was in the ...


9

I will try to answer this as best as possible. There are a few factors that come into play here (Mainly the manufacturer of said engine). Direct injection petrol engines work much like a diesel. You have a low pressure fuel pump that resides in the fuel tank itself, and a super high pressure pump that sits near the fuel rail that delivers fuel to the ...


9

In cylinder pressure is in the 200 psi range. GDI fuel pressure is varied from 500 up to around 3000 psi. This alone is enough to keep fuel blow-back to a minimum. Carefully engineered injector pintle shape also helps. This is no different than port injectors. What is unusual is how the pintle is moved in a GDI injector. In the most successful designs the ...


9

Here's a variation that I've thought about at great lengths. Even doing some of the preliminary math. IC engines don't need air. They need oxygen. So... eliminate the valvetrain entirely, and have two sets of injectors: One for liquid hydrocarbons, and one for liquid oxygen. Granted, I'm not considering the expense or safety issues in this brainstorm (I ...


9

To be honest, if part of the fuel line is rotten, I'd be tempted to replace the whole line - chances are the rest isn't far behind... Modern rubber hoses should last a decent amount of time, they're made of better rubber than they used to be, and are reinforced to take the extra pressure of modern injection systems.


8

Direct Injection has a lot of advantages over the MPFI or port injection and its the way of the future. It improves mileage through a stratified charge engine process(basically staying as close to the stochiometric ratio as possible this achieving better burn. Lower emissions. Prevents engine knocking/detonation. Better control of the engine since before ...


8

There are several issues with what you are planning to do. If you haven't done so already, please read this answer I wrote about using E85 instead of non-E or E10 fuel. While ethanol fuels do clean and have a higher octane rating, they also don't have the energy density of gasoline. To make it run stoich, you have to use more of it (higher ratio of fuel to ...


7

The injector has a plunger/pintle which is controlled by an electromagnet. The humming you heard is from that. The plunger/pintle has a spring which pushes back against the electromagnet so when the power is shut off, the plunger will close and stop the flow of fuel. This causes the hum. Here is an example of how an injector is built: When the power is ...


7

Funny you should ask this Max :) First lets make sure of our definition. Running an engine lean means changing the air / fuel ratio to have more air than is ideal (14.7:1 air to fuel). In my reading there are two effects. First, the fuel is an atomized liquid which has a cooling effect on the combustion chamber. So less fuel, less cooling effect. Second, ...


7

Keep in mind that at high loads/WOT, the injector may be open nearly constantly - during all four strokes. (Injector Duty Cycle >90%) In fact, many systems switch from sequential port to bank and then continuous fire (all injectors firing at the same time) when high fuel demands are called for. The difficultly is balancing WOT needs with idle with only ...


7

Put simply, an engine's compression ratio is the ratio between the volume of a cylinder with the piston at the down position (position 1 and 4 in the pic below) and the volume of the same cylinder with the piston in the up position (position 2 and 3 in the pic below). So, basically, the volume of the cylinder with the piston in the down position is the ...


6

Those are metric screw dimensions. M10 means a 10 millimeter outer diameter for the bolt or whatever piece it is; M12 means 12 millimeters. The part after the 'x' is the pitch -- how many mm a thread is wide. To figure out which you have, you can measure the existing part with calipers and a thread gauge. You might also try calling your local VW dealer with ...


6

With your added information, this sounds like there is a definite problem with the transmission. Your description leads me to believe it probably has something to do with the clutches being worn out in conjunction with low line pressures (or some such). I would definitely believe the transmission is due for an overhaul. If you pull the dipstick, does the ...


6

That pipe probably goes to the tank too, it is just there to let air out of the tank while adding fuel down the main pipe. I believe that your additive will be in the fuel.


6

It's a demand vs supply deal The fuel pumps found in most OEM fuel delivery setups today are driven by an electric motor that is running at a fixed speed. This effectively fixes the flow rate provided by the fuel pump. The majority of fuel-delivery systems found in fuel-injected vehicles are return-style. What this means is that the fuel injectors will ...


6

Assuming this is for a naturally-aspirated application, your calculations are reasonable. I think you just missed dividing the value obtained by the number of cylinders. Usually 2.5 L engines have 4 cylinders and (subsequently) 4 injectors. So 1328 cc/min / 4 = 332 cc/min You would select the next biggest injector size available (although 330 cc/min ...


6

I've had to deal with rotten fuel lines on my '94 Nissan. Took me a year to find a suitable solution. Like you, I was considering steel lines to replace the entire thing, but the steel lines I found were shorter than what I needed, so I needed to splice several lengths together. The issue I had was how to splice them together. The sections I could buy didn'...


6

Consequently, you get a superrich part of mixture together with just air in the cylinder. These still have to mix/homogenize in the cylinder to get a good combustion. This is already handled by both flavors of pulsed fuel injection: In port injection Fuel and air are mixed before they enter the intake valve, so the incoming charge is already fairly ...


6

The difference between FI and Ride by Wire Fuel injection means that the flow of fuel to the engine is controlled by the ECU, as opposed to a carburetor. (of course, there's more to it than that) Ride by wire means the butterfly is opened by an electronic motor, as opposed to a cable. Fuel injector does a lot than just injecting the fuel into the engine ...


5

I've had this problem with my Honda accord 96 for an entire year and just figured out what was causing the vibration in idle mode. Changed mounts, cleaned air idle control valve and throttle body . Took it to a friend who in no time told me it was a BAD COIL not producing enough power. So check out your COILS


5

Thanks for the great detail. Considering this is a bit of an odd issue, I'll try thinking outside the box a little. But first I would use a multimeter to test the coolant temp sensor, then o2 sensors. Perhaps even a quick check of the upper radiator hose to make sure the thermostat isn't stuck open. I say to check these first because it sounds like you'...


5

If you have ever seen an oxy-acetylene torch being used, you will have noticed that before the oxygen is turned on, the torch has a bright yellow flame. This is the fuel burning in a less than ideal amount of oxygen. The flame is relatively cool and it produces a lot of soot. When the oxygen is turned on, tthe flame turns blue and becomes hot enough to ...


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