The Evolution of Fuel Injection in Vehicles

Direct injection, a technology that has become increasingly popular in recent years, is not the first fuel injection method to be invented. Diesel engines have been using direct fuel injection for decades, and even before traditional gasoline engines.

Diesel engines have a higher viscosity than gasoline, which means they require a high-pressure spray of fuel to mix with air. This allows for better combustion and more power. The shape of the swirl cavity in diesel engines is also different from that of gasoline engines, which affects the way fuel is injected into the cylinder.

However, direct injection has its own set of advantages over port-and-indirect injection systems. For one, it doesn't require the intake valves to be open for it to function, which means better fuel economy and more power. The injectors also don't have to wait for the timing of the intake valves, which can lead to a slight delay in fuel delivery.

On the other hand, direct injection has its own set of drawbacks. The extra fuel squirts created by this system can lead to higher temperatures and pressure, which can stress out the cylinders. Additionally, carbon buildup in the cylinder is more common in direct injection systems due to the high compression ratio.

The third type of fuel injection is indirect, which is specific to diesel engines only. Indirect fuel injection uses a pre-ignition chamber located above and outside the cylinder. The swirl chambers, air-cell chambers, and pre-ignition chambers all perform the same function in indirect fuel injection systems: to create a turbulent airflow that ensures complete mixing of fuel with air.

The pre-ignition chamber in these indirect systems means that pressure can be lower than in other diesel engines, making them simpler and less expensive to manufacture. However, this also requires the use of glow plugs to start the engine, which are not something that grows on trees.

Mazda's recent development of the SkyActiv-X HCCI engine is a notable example of how fuel injection technology can be combined with lean combustion for improved efficiency. This system takes advantage of turbulence in direct fuel injection to create a highly efficient and environmentally friendly engine.

In conclusion, the evolution of fuel injection has led to significant improvements in vehicle performance and efficiency. From diesel engines that have been using direct fuel injection for decades, to Mazda's innovative SkyActiv-X HCCI engine, the quest for better combustion and reduced emissions continues.

WEBVTTKind: captionsLanguage: en- Fuel rails, fuel pumps,throttle body, multipoint, direct.That's right, we're talkingabout fuel injectors.Thanks to Squarespace forsponsoring this video.From websites and online storesto marketing tools and analytics,Squarespace is the all-in-one platformto build a beautiful online presenceand run your business, if you got one.Squarespace.If you don't know by now,engines run on fuel and air.And there's a bunch ofways to get fuel-air mixinto the engine.Sometimes, it's a carburetor,but more often, it's fuel injection.Somebody get me some coffee?Just like the right mix of coffee and cakecan get me going in the morning,an engine needs a perfectmix of fuel and oxygento function efficiently.Fuel injectors are engineeredto deliver this mixto the cylinder to create an explosionthat produces the most powerand least amount of dirty,dirty exhaust as possible.This ideal fuel to airratio is 14.7 to one.That means for every one unit of fuel,14.7 equivalent units of air at sea levelare needed to achieve complete combustion.This is referred to asa perfectly balancedstoichiometric air-fuel ratio.My ideal ratio is 36, 24, 36,36 parts flour, 24 partschocolate, and 36 parts sugar.I love cake.Engines didn't always havefuel injectors though.Before fuel injections,engines needed carburetors.Check out the episode on carburetors.Fuel injection has a numberof benefits over carburetors.Benefits include easier cold starts,better fuel efficiency,and more consistenttransient throttle response,like quick throttle transitions.And sometimes, evenvariability of fuel delivery,depending on drive modes.Fuel injectors also make surethat the amount of fuelbeing sent to the engineis consistent across all cylinders,preventing inconsistent fuel distributionand inconsistent power delivery.Get it.There are three types of fuel injectionsthat you're likely to see on modern cars.Port, direct, and indirect.But let's start with the injector itself.Fuel injection is fed by the fuel rail,which sits atop the cylinder bay.Because of the pressurefrom the fuel pump,fuel gets forced in theinjector from the fuel railand through a small filterinside the injector.Oh crap, I just said fuel fivetimes in the same sentence.If I don't say the counter-spell,the pig's gonna appear.Nickelback, Nickelback, Nickelback.Okay, alright.Once inside the injector, thegas hangs out in the reserve,says hi, grabs a drink,and maybe a small bite,waiting for the moment to spray.Then, when it comes time,an electromagnetic coilpulls the plunger up,opening the pintle injector,spraying fuel out of the nozzle.Sprays happen multiple times every second,and every spray's an exact amount of fuel.The timing's controlledby an electrical signalfrom the car's computer,and it works in concertwith the spark plugto create the sweetest music.Early fuel injection systemsworked much the same waythat a distributor capfires at spark plugs.It was mechanically timed.So you're probably thinking, okay,now I know how a fuel injector works,but what are the differenttypes of fuel injection, Nolan?Well, I'm going to get toit, and my name's not Nolan.Port injection,sometimes referred to asmultipoint port fuel injection,means that fuel is deliveredvia separate fuel injectorsfor each cylinder deliveredwith the fuel rail.Port injection startsat the intake manifold,where the injector's housedright above the intake valvefor the cylinder.When the throttle body opensand allows the air intothe intake manifold,the fuel injector sprays gasoline,and a slurry is created.No, I'm talking about Steph Slurryof the Golden Slate Slurriers.I'm talking about a mixof air and vaporized fuel.During the intake stroke of the cylinder,the intake valve opens,allowing the air-fuelslurry into the chamber,where it's then exploded.Port injection has a number of upsides.For one, it's cheaper to producethan any other type of fuel injectionbecause you don't haveto worry about protectingthe fuel injector from thepressure of the cylinder.Additionally, the force of the slurrybeing sucked into the cylinderthrough the intake valvehelps to clean the valve itself.A downside to port injectionis that it's not as efficientas other fuel delivery systems.If port injection was a type of cake,it'd be store-bought yellow cake,you know, like from a box.It might not be homemade,but you know the icing'sgonna be evenly distributed,and every bite you take'sgonna be the perfect ratioof cake to icing.Cake Garage.Another type of fuel injectionis direct fuel injection.This category's a little more broad,and it's used in bothgasoline and diesel engines.There's two different typesof direct fuel injectionfor gasoline engines.What are they?Well, I'm glad you asked.The two types are wallguided and spray guided.In a wall guided fuel injection,the fuel nozzle's notabove the intake valve,it's inside the cylinder.After the air rushes induring the intake stroke,gas shoots out from the side.It hits a specially shaped cylinder head,also called a swirl cavity,and that mixes it with the air.The angle of the cylinderhead creates a vortex of air,and this vortex helps mixvaporized fuel within the cylinderso when the spark ignites the mix,the explosion is (kiss) oh so beautiful.Side note, my dentist keeps yelling at mebecause the cake vortex in my mouthis causing swirl cavities.I might have a problem.Spray guided fuel injections,similar to wall guided,but it doesn't use a swirl cavityto create the air-fuel mix.Spray guided uses a special nozzlethat sprays perpendicularto the cylinder head,so it can vaporize thefuel and mix with the airbefore it gets ignited.Alright, you might recognize this.We're going to see what happens firstwhen we just put gas in without a vortex.(explosion)- Whoa.- We've created this little mock upto see if we can create a vortexto ignite some gas.Let's do this fellows.Give me like eight squirts.(explosion) Oh.We got a pretty sweetexplosion with the vortex,so because we can, let'slaunch this cutie into space.Gentlemen.I think we're probably good.(explosion)- Oh. (laughs)- I think we're probably good.Direct injection also has a diesel cousin.In fact, diesel engineshave been fuel injectedlong before traditional gasoline engines.The biggest difference betweenthe diesel and gas versionsof direct injection is theshape of the swirl cavityand the pressure at whichthe diesel's sprayed into the cylinder.Because diesel's got ahigher viscosity than gas,a high pressure spray isvital to mix it with the air.I can relate.My cousin Jason's beenputting pressure on meto take his CrossFit class,keeps spraying me with Muscle Milkand telling me to trust the process.CrossFit.No thanks Jason.I don't want to do 200 of anything.Direct injection's gotan advantage over portand indirect injectionbecause the intake valvesdon't have to be open for it to function.This translates to betterfuel economy, more power,and the injectors don't have to waitfor the timing of the intake valves.After the initial blast of fueland the ignition of the air-fuel mixture,some extra fuel can bereleased mid power stroketo give a little more oomph.You take your good with the bad though.A direct injection isn't perfect.All those extra gas squirtscreates higher temperaturesand pressure, which can seriouslystress out the cylinders.In addition to beingmore costly to produce,carbon buildup in the cylinder,mainly around the intake valves,really common in direct injection systems.Carbon is a byproduct ofcombustion, you silly geese.The third type of fuelinjection is indirect,which is specific to diesel.Not all diesels useit, but only diesels dobecause of how diesel fuel ignites.Indirect fuel injectionuses a pre-ignition chamberlocated above and outside the cylinder.Swirl chambers, aircell chambers,and pre-ignition chambersare all different components,but basically perform the same functionin indirect fuel injection systems.In these chambers, gasand air are pre-ignitedbefore being delivered to the cylinder.Fuel's released, air'spumped in from the piston,compressing air in the cylinder,and the device called a glow plugcompletes the ignition of the mixture.The shape of this chamber'sdesigned to swirl the airand make it as turbulent as possible,ensuring that the fuel completely mixesand has the added effectof making the combustion more efficient.The pre-ignition chamberin these indirect systemsmeans that pressure can be lowerthan other diesel engines,which, in turn, makesmanufacturing them more simpleand less expensive.Indirect injection also makes it possibleto make smaller diesel motorsthat can produce higher engine speeds.Pretty good.The downside?Glow plugs are neededto start these engines,and those only grow on trees.Mazda's doing some crazythings with their prototypeSkyActiv-X HCCI engine.It takes the best of both worlds,combining the high compression,very fuel efficient,lean combustion of diesel engineswith the availability inreduced pollutants in gasoline.It wouldn't be possiblewithout some tricksthat they use involving turbulencein direct fuel injection.You want to learn aboutthe SkyActiv engine?Well, get a time machineand travel to the futurebecause I haven't made that episode yet.Fuel injectors.Thanks to Squarespace forsponsoring this video.From websites and online stores,to marketing tools and analytics,Squarespace is the all-in-one platformto build a beautiful online presenceand run your business, if you got one.They got sweet, sweet templateto make creating a powerfulonline identity even easier.And it's an all-in-one platform.I wonder what anall-in-one platform means.Well, it means you cancreate a beautiful websiteand then use the samething to grab your domain,set up an online store.They've even got marketingtools to help you drive traffic.Look at all these tools.Now they have domain transfer in.So let's say you got awebsite somewhere else.Well, now you can transferit into Squarespace.So get the heck tosquarespace.com for a free trial.And when you're ready to launch,go to squarespace.com/sciencegarageto save 10% off your firstpurchase of a website or domain.Squarespace.Miracle Whip, Science Garage,New Car Show, Up to Speed,Car Boy, Frenemy.Click this little yellow subscribe buttonand you can get access to all these shows.It means a ton to us that youguys support us and watch us.Tell your friends.Follow us on Twitter andInstagram @DonutMedia.You can follow me @BidsBarto.Not only do we have great content,but we've got things youcan wear and put on your carat shop.donut.media.Don't tell my wife about my cake habit.