Gadgetory

the first experimental engine was built valves Bergen Germany during 1893 most people were convinced that no machine would work at the high pressures which diesel insisted were necessary let's start our little journey into diesel learning here at an unusual diesel to the chevy cruze diesel not only are diesels rare in America but this one's made by an American company they can get twice as rare but the principles are the same a diesel engine starts its combustion cycle by compressing air and just air highly twenty two to one can be as much of a compression as you find in here compare that to a gas engine around eight or nine to one so it's night and day then it's a very top of that compression cycle the diesel fuel is injected and it all combust spontaneously because the temperature is so high because the pressures been raised so much there are no spark plugs that's how a regular gas engine gets combustion going but these guys do it spontaneously by heat then at the very last minute is that piston comes up and compresses the hell out of that air what happens then is this blast of power it's a really high explosion because of that high compression rate and you get that characteristic not related to that whole idea of spontaneous combustion so notice that one of the key timing factors that makes a diesel run well is the timing of that fuel injection as opposed to the timing of a spark that's why very precise direct high pressure injection is key to these motors in the modern era also because they compress their charge so much before combusting they tend to ring more out of the fuel up to 50% of the energy in a droplet of diesel gasoline cars nearly that well if you think Diesel's are noisy stinky and slow you're probably over 40 old enough to remember when they were modern diesels like a Mercedes GLK a Volkswagen Jetta TDI or even the chevy cruze are none of the above and there are three important technologies you can thank for that first off is common rail direct injection the common rail part means you've got this metal plenum are basically pipe that has the fuel pumped in with under extremely high pressure of the 29,000 psi from there it is direct injected into the cylinders with extreme precision partly because it has that high pressure behind it and partly because they're now using piezo electric injectors which open and close extremely quickly sometimes multiple times in one combustion cycle precise injection means better use of fuel lower emissions more power better economy win-win-win-win-win the second big tech trick is turbo charging this complex turbo charging is key because a diesel without it will tend to bunch up all its power down at the bottom of the tach what the turbo does is up to spread the power further up the RPM range and get it delivered faster get it off the line quicker these things are not slugs anymore that's an old-school ID the last technology trick is exhausted scrubbing this Mercedes for example uses urea injection urea fluid is vaporized and sprayed into the hot exhaust which catalyzes it to convert those nasty nitrous oxides into pretty benign water vapor and nitrogen secondly there is additional sort of cooking of the exhaust hot catalysts downstream actually recoup it a couple of times in some cases to cause a chemical reaction that also reduces the nasty stuff coming out of the tailpipe and thirdly ultra-low sulfur diesel fuel has become pretty much the rule in the US Europe and many other areas by not having so much sulfur it is innately cleaner and by not having so much sulfur it doesn't clog up the other two technologies I just mentioned allowing them to work now I can talk to you about high compression ratios and common rail injection and blah blah blah till I'm blue in the face but all you really want to know is does a diesel car drive and feel like a UPS truck or is it actually a nice car let's go for a ride I think you're gonna be pleasantly surprised now the first thing you figure out in a diesel is commoner is different the redline is much lower you don't run these cars up as high there's no reward they're like on this jetta TDI you get you about 4000 and basically game over it's time to shift these are low-end grunt engines compared to a gas motor and even if you do run them out there's not much payoff which is actually a very easy way to drive we're just not so much used to it the torque in the low to low mid is just a delight and it makes everyday driving a lot of fun it's also that kind of acceleration that we all love you will notice in really every diesel I've driven less so at the high end more at the low end but there is a different engine note there is a diesel rattle that is innately in there and depending how well the car is isolated and insulated you will detect more or less of that you have to get used to that but it's not a bad sound as what's the difference beyond that one of the other things you have to get used to is the back of that damned fuel gauge hardly ever moves I didn't know if this one was broken in this car until I driven it for an hour and finally saw it come off the full peg and start to work its way down Diesel's tend to have tremendous range seven and eight hundred miles is not unusual because they have normal sized tanks and can get great long leg highway economy in particular in all if you're in the market for a very efficient car and you enjoy the real joy of driving which comes from torque you owe it to yourself to drive a couple of today's modern diesels see what they're like I think diesels have a lot going for them and in many ways have got better market legs and a lot of the hybrids and highly electrified cars out there you