Autoblog

Hang around internet fora dedicated to increasing internal combustion performance long enough and you'll eventually run across this type of perpetual-motion misunderstanding. Seems a Vette 'boarder over at the GMModernMuscle Forum needs to study up on several principles before heading out half-cooked, wrench in hand. The brilliant idea that dawned above the poster's head like a 3-watt bulb was that instead of messing around with those ever so inefficient turbochargers, it'd be a simpler route to just run the exhaust back into the intake manifold to put the intake tract under positive pressure. Reading through the multitudinous pages of fodder, this is either someone with "issues" or just a jokester troll.

If he is serious, let's lay out a few simple things here. Firstly, there's not very much oxygen in the exhaust gas, which would make recombustion rather difficult. Second, it's tremendously hot. Third, his assumption that a turbocharger is driven by high-pressure exhaust gas pulses is incorrect. What drives a turbocharger is the expansion of the exhaust gas as it cools and depressurizes. It's the same way an air conditioner works, and it's really thermodynamic theory when you get right down to it. Sure, the exhaust gas is under pressure, but if you think that a turbine is an inefficient way to compress air, pistons are only more so. There's a lot of mass to swing around, and the poppet valves in an automotive cylinder don't improve airflow versus what a compressor housing of a turbo can do, either. Before you raise the EGR flag, let's note that exhaust gas recirculation is used to control combustion pressure and temperature, and since it takes up space that would otherwise be occupied by oxygen-rich intake charge, it's a performance detriment. Finally, how is the engine going to breathe when you've basically set up an infinite feedback loop? We're sure that these sticky engineering challenges are all easily worked out on a bar napkin, though. Why have automakers been denying us the pleasure of this simple high performance option for so long? They must be in cahoots with turbo manufacturers, that's all there is to it.

Thanks for the tip, Richard

[Source:GMModernMuscle]!

Ford is looking for ways to pack their automobiles with innovative technology that achieves the seemingly impossible goal of using smaller, more efficient engines while still delivering the performance wallop customers are demanding. Not only is the Blue Oval seeking more involvement from their suppliers to push new technology and techniques forward, but the automaker's also looking outside the typical realm of automotive OEMs.

One promising new technology is a system developed by a Massachusetts Institute of Technology startup company. Putting a modern-day spin on the concept of water or alcohol injection to either boost octane or cool the cylinder charge (or both), the MIT developed fuel injection system uses direct injection to deliver a shot of ethanol when the engine is under heavy load. The intravenous drip allows turbocharger boost pressure to be cranked way up, adding a significant amount of power gain. Normally, with your wastegate actuators cranked all the way down, you'd discover new and exciting ways to ventilate the crankcase, but this system keeps detonation at bay, which keeps the pistons in the block.

[Source: Automotive News - Sub. Req.]

Diesel technology has improved by leaps and bounds, but the trouble is, it still runs on diesel. In the American market, at least, finding a diesel pump is still a pain compared to filling up with conventional gasoline. Mercedes-Benz says it's found the solution with a new developmental powertrain concept it calls DiesOtto.

We first reported on the project a couple of years ago, but the German automaker now has a functioning prototype. Rather than actually running on diesel, the DiesOtto engine is said to incorporate the benefits of a diesel engine, but runs on regular old unleaded. The prototype is a 1.8-liter four-cylinder engine that uses direct injection, variable compression, turbocharging and something MB calls "controlled auto ignition" to deliver 238 horsepower and 295 lb-ft of torque, with a claimed return of "less than 6 liters per 100 kilometers", which translates to 39.2 mpg. Those numbers, Benz claims, are not based on a small car (like the C-Class or smaller) but on a large sedan (like the S-Class). They may not be entirely revolutionary figures, but any way you look at it, they're damn impressive.

Mercedes hasn't put a timeline on producing and marketing a powertrain based on the DiesOtto prototype, but says it's a "feasible proposition in the midterm". We certainly hope so.

[Source: Edmunds' Inside Line]

Every car on the road now has fuel injection. There was no real battle royale between electronic systems and mechanical, though both flavors saw plenty of development. Rochester's Ramjet system was effective and quite slick, contained in a special intake manifold. Bosch had K-Jetronic which was a mechanically metered system that later gained some feedback electronics, becoming the very first FI system to utilize an exhaust gas oxygen sensor for fine mixture control. Fuel injection systems have now gone the way of all-encompassing powertrain management setups, controlling ignition and fuel; as well as talking to the transmission, anti-lock braking system and stability control. Electronic systems all owe something to the first successful electronic fuel injection rig to be mass-produced: Bosch D-Jetronic. DJet, in turn, has its own piper to pay.

More after the jump