Green Options » engines

Low Cost Gas Engine Innovation Doubles Fuel Economy

Nick Chambers — Thu, 26 Jun 2008 15:15:02 +0000

Revetec, a little known company from the Gold Coast region of Australia, may be on to something huge: they’ve created an engine that is 50% smaller, 50% lighter, has 50% lower emissions and is cheaper to manufacture than a conventional internal combustion engine of the same horsepower. Oh yeah, did I mention that it doubles the fuel economy too.

What that means is a car like the 2007 Toyota Yaris, which is rated at 40 mpg on the highway, would get 80 mpg with a Revetec engine.

This isn’t some hoax… They have a prototype which has been attached to an actual vehicle and independently tested to substantiate their claims.

In personal communication with Mr. Brad Howell-Smith, the Chairman, Inventor and CAD Designer for Revetec, he says “road tests have estimated that [the engine] uses around 50% less fuel than a conventional engine” and if it were converted to run on diesel, that performance gain could be much higher.

Also, because the engine delivers higher torque, and can perform and operate well at much lower rpm’s than a conventional one, the noise levels are lower.

To illustrate how serious he is, Mr. Howell-Smith said that since 2001 his company has been in touch with the US Military Head of R&D for the Southern Hemisphere on a “regular basis” for the purpose of developing one of their engines for light aircraft.

The current prototype engine, the X4v2, is what Revetec calls a “controlled combustion engine.” The meat of the engine comprises two counter rotating multilobate cams, which are acted upon by two pairs of diametrically opposed pistons which are rigidly interlinked by connecting rods.

If that sounds like complete gibberish to you, you’re not alone. Which is why I included an animation of the process to the left. A more simplified animation of the general motion of an engine of this sort is also included below.

Mr. Howell-Smith said that “if [the engine] uses 50% less fuel given that it has the same top end as a conventional engine, emissions would be reduced by 50% if the bottom end was utilized.”

What does all that stuff about “bottom end” and “top end” mean? The X4v2 has a huge amount of torque over a much larger range of rpm’s than a conventional internal combustion engine.

If a person were to drive a vehicle fitted with this engine in a non-aggressive fashion and keep the rpm’s at the “bottom end” (meaning no “jack-rabbit” starts) they could expect to see a 50% reduction in emissions.

Alternatively, according to Mr. Howell-Smith, a person could see a 30% reduction in fuel use and a 30% reduction in emissions if they used the full acceleration power of the X4v2 all the time. This would provide a 20% increase in acceleration capabilities.

We could debate about whether or not the internal combustion engine has a place in the future of transportation or whether it’s going to be all-electric or fuel cell or whatever… but in the meantime, Revetec has a product that could revolutionize the the transportation industry now, and provide a much needed large reduction in fuel consumption and emissions.

Just imagine a bunch of 80 mpg Toyota Yarises (Yarisi??) running around all over the place. A little scary, I know, but… an 80 mpg conventional automobile? I must be dreaming, wake me up before I get too excited.

Posts Related to Engines and Fuel Economy:

Image Credits: Revetec

Turbine Engine: No Pistons, No Lube, 30% Better Fuel Economy

Nick Chambers — Mon, 09 Jun 2008 16:58:03 +0000

There are more than 5,000,000 heavy duty trucks running up and down US highways each day. Every one of those trucks gets an average of 7 mpg, carries upwards of 200-300 gallons of diesel, and spews out potentially harmful emissions.

Like it or not, we depend on them to bring us our food, fuel, and products for everyday living. It’s a connection that most of us often forget about, only remembering it long enough to curse them as they slow us down on the highway.

It’s also an industry that has recently been hit hard by soaring fuel prices, and now, with the average price of diesel in the US at $4.70/gallon and climbing, it’s sure to get worse.

Needless to say, there’s a rising cacophony of voices within the trucking industry clamoring for relief. Most of this noise currently comes in the form of wanting a break in fuel prices, but really that’s just a temporary fix. Any solution with sticking power would have to offer both economic and environmental benefit — you know, win-win.

Enter Turbine Truck Engines. The company has developed an engine for heavy duty trucks called the Detonation Cycle Gas Turbine (DCGT). Key features of this engine technology include:

Uses over 30% less fuel than current heavy duty engines
30%+ fewer emissions including nitrogen oxide (NO, NO₂, N₂O₂) and carbon monoxide (CO)
Operates on all fuels and mixtures of fuels: biofuels, hydrocarbon fuels, hydrogen and synthetic
Has few moving parts, requiring much less maintenance
Has no pistons or valves, and uses no lube oil, filters or pump
Is air cooled and lightweight (less than 2 lbs. per hp)

The company has been aggressively seeking investors recently and last year won the prestigious Frost and Sullivan Award for Technology Innovation.

Currently Turbine Truck Engines holds several patents and has a few prototypes under its belt. When (and if) their technology finally reaches the market, the combined savings on maintenance and fuel, as well as environmental benefits, could make this engine extremely popular with truck drivers and trucking companies worldwide.

What do you think? Is it worthwhile to invest in this type of technology, or should we move past fuel altogether and focus on other things such as our rail infrastructure for movement of goods? Is that even possible? Are big rigs a permanent feature of our society? Is there any way to run them entirely on electricity?

Post Related to Engines and Fuel Economy:

Image Credit: Turbine Truck Engines

Six New Technologies Will Help Manufacturers Reach the 35 MPG Goal (Without Hybrids)

Benjamin Jones — Thu, 01 May 2008 14:45:33 +0000

As the automakers scramble to make plans for achieving 35 MPG by 2020, it seems that our suspicions that the task is entirely possible without fancy hybrids or hydrogen cars has been confirmed. The manufacturers been achieving high mileage in Europe and Japan for years now, so I expect to see it in the US eventually. Luckily, there are six exciting new technologies that are going to make it possible in the US.

These technologies are interesting because they come without the paradigm shift that seems to accompany buying a hybrid or a small economy car. Cars equipped with this green tech will be just like any other car, just more efficient.

More on the six new engine technologies after the break.

Multistage oil pump: Oil pumps usually only pump oil out through one port, meaning that under every circumstance the pump ends up doing about the same amount of work. Multistage oil pumps, like those that are beginning to be released with some Toyotas, use two oil ports, one small and one larger, to make sure that the amount of oil being pump is optimized based on the operating conditions of the engine. During low-stress operation, only the smallest pump will be used. As the engine is put through its paces, it will switch to the large port, and finally, if you’re really going all out, both ports will open up to allow maximum flow.
Shortened cylinder head: In the past, cylinder heads have remained a certain height in order to keep the valves aligned in operation. While this presents and issue for shorter cylinder heads (which save weight), guides on the top of the valve springs can be used in conjunction with standard valve guides to ensure smooth operation. The weight difference might not be that dramatic, but at the very least, it will cut down on some materials usage.
Variable compression ratio: Engines are more efficient at higher compression ratios, but that doesn’t mean it’s always best to be running at the highest compression ratio you can. With that in mind, several manufacturers have begun exploring variable compression ratio engines, where the connecting rod length can be changed using an actuator so that during low-load operation (like driving on the freeway) compression ratio is reduced and fuel economy improves dramatically.
Guided-spray turbo: The most important thing here is not the turbo, but the method of creating the air-fuel mix in the combustion chamber. The injectors and chamber have been redesigned so that spark plugs are positioned to more efficiently ignite the fuel-air mix and pistons have also been redesigned to create a swirling in the chamber (something that’s been used since Honda since 1992 in fuel economy-conscious engines). Together, all these designs make for incredibly efficient combustion, resulting in impressive power output and comparably good fuel economy numbers.
Electromagnetic valve actuators: In my opinion, this is probably one of the neatest new technologies out there. By using electromagnets to control the valve train, the camshaft and all its friction losses and rotating mass would be replaced with a system of almost no moving parts that can also precisely control valve timing and adjust it to run the most efficiently in any condition. While expensive, this change could bring up to a 19% improvement in fuel efficiency, and might very well be implemented down the road.
Hydraulic power electrification: Car makers have already begun this switch-over, as it is one of the most common-sense, and easiest things to do. Beginning with the move from belted radiator fans to electric, car makers have started trying to reduce parasitic loads on the engine. Because electric versions of things like power steering and A/C are more efficient (and run when the engine isn’t on, which is necessary for full hybrids), we’re already starting to see these things popping up on Honda and Toyota hybrid models. Soon manufacturers will be moving even to electric water pumps, which are more efficient and precise.

So, do we at Gas 2.0 anticipate seeing these technologies any time soon, or are they just more pie in the sky stuff that the automakers like to trot out to “prove” they’re “doing something.” Well, several of these we have seen already, and with the automakers scrambling to make 35 MPG in a very unfriendly market, it seems like the cheapest way to do so will be to use some of these tricks rather than trying to upgrade everyone to hybrids. Hopefully we’ll begin seeing these technologies in run-of-the-mill engines sooner, rather than later.

Source: PopMech

Posts Related to Fuel Economy and Engine Technology:

Formula 1 Racing to Go Hybrid from 2009-2013

Benjamin Jones — Tue, 22 Apr 2008 15:02:01 +0000

It’s not quite the same type of hybrid drive-train you’d see in street vehicles, but in an exciting announcement, Max Mosely of F1 has announced that all cars will become hybrid by 2013, along with other changes to the vehicles.

The hybrid system that will be phased in is known as KERS, which stands for Kinetic Energy Recovery System. KERS doesn’t store as much energy as a traditional hybrid system, but it only weighs 55 pounds and the limited energy storage capacity is well suited for Formula-style racing.

The biggest difference between KERS and a regular battery-electric hybrid is that KERS stores recovered waste energy in a rotating flywheel. Instead of converting waste energy into electricity and than back into useful energy again with an electric motor, KERS simply transfers the kinetic energy to a ~5kg flywheel in the F1 car’s transmission. The energy stored in the flywheel can then be used by the driver by pushing a “boost” button.

KERS is particularly exciting for us regular car drivers because the creators have claimed that it is twice as efficient as a standard hybrid system. If this system can be applied to production vehicles, it will be possible to realize huge improvements in fuel economy and pretty respectable reductions in GHG emissions.

Scania’s Ethanol Diesel-Engine, Runs On Biodiesel Too

Clayton B. Cornell — Tue, 15 Apr 2008 20:26:28 +0000

Scania (part of Volkswagen) builds modified, heavy-duty diesel engines designed to run on almost pure ethanol (E95, or 95% ethanol, with a 5% ignition improver).

If that sounds weird, that’s because it is. US auto manufacturers make a big deal out of converting cars and trucks to run on ethanol/gasoline blends of up to 85% ethanol. Scania has done better than that for 15 years, and guess what, their engines can run on 100% biodiesel too, without any modification.

Scania’s compression-ignition (CI) ethanol engine is a modified 9-liter diesel with a few modifications. Scania raised the compression ratio from 18:1 to 28:1, added larger fuel injection nozzles, and altered the injection timing. The fuel system also needs different gaskets and filters, and a larger fuel tank since the engine burns 65% to 70% more ethanol than diesel (whoa! see below). The thermal efficiency of the engine is comparable to a diesel, 43% compared to 44%.

While Scania originally introduced this technology for “heavy commercial vehicles in urban operation” (city buses), they’re now extending it to trucks as well. Scania maintains that with existing technology, the transition to renewable fuels can be painless. Since in the last 15 years they’ve put 600 ethanol buses on the road (mostly in Sweden), the company seems to know what it’s talking about.

Scania is also working to develop ethanol refueling infrastructure, which should make it easier for smaller transport companies to invest in ethanol-powered vehicles.

But why not use biodiesel, since ethanol requires about 1.5x more fuel usage? Scania’s answer may raise a few eyebrows: “the farming capacity [for biodiesel] is insufficient for the huge need foreseen for the transport industry.”

Unless you take EU spokesman Michael Mann’s comments seriously (he said that Europe can grow enough fuel to meet 10% of it’s transportation fuel), Scania must be betting on cellulosic ethanol. The intensifying food vs. fuel debate isn’t taking this issue lightly, as I’ve written about here and here.

In any case, Scania’s work seems to indicate it might not be as hard to create engines that run on alternative fuels as auto manufacturers maintain.

Posts related to Ethanol and Biodiesel:

European Union Defends Biofuel Targets As Food Prices Soar
Biodiesel Myth (Or Fact?) #23: Biodiesel is Raising Food Prices
Mercedes 40-MPG Diesel Hybrid: Cleanest SUV on the Planet
How Biodiesel Fuel-Cells Could Power The Future (And Your Car)

[Via]