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It's worth noting that the engine illustrated is a gasoline direct injection engine, which are fairly common on new cars but historically not so. Until the ear
by sitharus 13y ago
It's worth noting that the engine illustrated is a gasoline direct injection engine, which are fairly common on new cars but historically not so.
Until the early 2000s most fuel injected gasoline engines were multi-point injection - the fuel was injected in to the incoming air stream immediately before the cylinder, and before that indirect injection which injected where the carburettor was.
Then there are carburettor engines.
Most diesel engines have been direct injection for many decades now, due to the behaviour of the fuel.
- elnate 13y agoThe other difference is Diesel engines ignite the fuel by compressing it rather than with a spark. (Also Diesel is the engine type not the fuel http://en.wikipedia.org/wiki/Diesel_engine http://en.wikipedia.org/wiki/Diesel_engine)
- Peroni 13y agoWell they both work on compression, diesels simply rely on it more than gasoline engines. Diesel engines work on what's called adiabatic compression heating. In other words, the compression causes the air to heat to a point higher than the ignition point of the fuel. Diesel engines usually use glow plugs to compensate for the lack of adiabatic compression heating when the engine is cold.
- adolph 13y agoSee also the awesome fire piston, a relatively ancient technology using the same principles: https://en.wikipedia.org/wiki/Fire_piston https://en.wikipedia.org/wiki/Fire_piston
- ams6110 13y agoyep the original diesel engine was designed to run on coal dust, unlike the modern light fuel oil diesels (kerosene, jet-A, home heating oil, and diesel fuel are all very close to the same thing, differing mainly in additives).
- xd 13y agoAre you sure this is a direct injection? I'm seeing the injector directly behind the inlet valves which would make it multi point.
- sitharus 13y agoI just took a close look at it, and I think you're right. It's not the easiest thing to see due to the wireframe, but with a second look it does appear that the injectors are just behind the valve. So yes, it's multi-point injection, rather than direct injection which is the new hotness for gasoline. Formula 1 will allow it from next year with the new V6 formula!
- techdmn 13y agoV6 formula!?!? Validating my decision several years ago to quit following F1. ;-)
- arjunnarayan 13y agoFor me it was when they kept changing the rules (in 2005) just to ensure that Schumacher lost. Haven't looked back since. I hear they can't even refuel these days (the horror!)
- sitharus 13y agoV6 turbo with energy recovery on the turbo itself. They're also allowed to use that energy to re-spool the turbo to eliminate lag. They've also hugely bumped the KERS and built it in to the throttle map - no more button for it. I can't remember the exact figures, but it means that they have so much torque when they go full throttle it'll spin the wheels at almost any speed. I'm looking forward to them slipping around the corners again. Also to engines blowing up, since that doesn't happen much due to 5 year old engine designs.
- xd 13y agoI'm currently rebuilding a 2.0 TDCI engine .. an interesting feature is the crowns of the pistons. With direct injection the fuel is aimed at specifically shaped depressions in the piston crowns which causes vortices between the atomised fuel and air improving the mix for a cleaner burn.
- jcampbell1 13y agoDirect injection implies the fuel is injected at the top of compression stroke, but the animation shows the fuel being added during the intake stroke. This is just an inaccurate drawing showing the injector attached to the cylinder rather than the intake manifold. Interestingly, this could be a drawing of a ultra modern gas direct injection system running in classic mode. Ford's EcoTech will, under certain conditions, operate like this picture, though I am sure that is not what the author had in mind.
- njoubert 13y agoBeat me to it! This totally amazed me when I started working on cars. Both carburetors and direct injection creates a mixture of gasoline and air BEFORE this mixture enters the cylinder. Direct injection now seems like a misnomer ;) It makes a lot of sense if you think about the incredibly violent conditions inside the cylinder head though. I'm always surprised that spark plugs survive as easily as they do, I imagine a high accuracy injector nozzle in that situation would not last as long as current injectors. Has anyone done a true direct-injection design? Jacob, can you update the drawing slightly? "The fuel injectors spray gas into the cylinder..." is incorrect, it should be closer to "The fuel injectors spray gas into the intake manifold where it mixes with air before being sucked into the cylinder"
- sitharus 13y agoThere are true common-rail direct cylinder injection gasoline engines out there. They're not so common though, since there aren't as many advantages to it compared to a diesel engine. Cars marketed as GDI, such as the Ford EcoBoost, inject directly in the cylinder.
- stevehawk 13y agomaybe also worth noting that this is OHC and not pushrod
- jpindar 13y agoAlso note that it has a distributor, which is uncommon on new cars. New cars generally have one coil for each cylinder (or pair of cylinders that fire 360 degrees apart).
- jotm 13y agoAh, carburetors - how I hated those things. Simple in theory, yet so complicated and fickle in practice... I do love old diesel engines with mechanical belt-driven high pressure pumps and mechanical injectors - those things were easy to fix and built to last...
- ams6110 13y agoI drive a 30 year old Mercedes diesel as my primary car and it still runs like a swiss watch. You do have to adjust the valve clearance every so often, which is not necessary in a modern diesel or even ones slightly newer than mine.
- a8da6b0c91d 13y agoI drive a seven year old motorcycle and carburetors + ethanol = nightmare. A tank of gas with the ethanol admixture will often go bad enough to gum up the carbs in just a few weeks. I've had the engine stall out under me in potentially dangerous situations twice because of this. Damn corn farmer lobby.
- jotm 13y agoIf it's the 3.0 liter 5 cylinder diesel (OM617) - those are considered to be some the most reliable diesel engines ever made :-)