A new engine design could significantly improve fuel efficiency

[Argos]

...at a fraction of the cost of today's hybrid technology.

Read more (http://www.technologyreview.com/Energy/18304/)

[cjl]

I'm not entirely sure it could give as much of a gain as they are claiming, but it would certainly boost efficiency and power. The real question is simply how much more would it actually cost to add to a car. The additional cost of manufacture is not necessarily the additional cost in the finished car. I would definitely like to see this applied though - it looks quite interesting.

[sarongsong]

...The additional cost of manufacture is not necessarily the additional cost in the finished car...Ha!---remember when GM started making Suburbans in Mexico, citing lower production costs? Sounded like a 'good' idea at the time, however GM kept all the savings for themselves, never passing on any to the consumer.

[Frantic Freddie]

A turbocharger and a direct-­injection system would add to the cost of an engine, as would strengthening its walls to allow for a higher level of turbocharging.

Which increases the weight of the engine,which then requires it to use more fuel just to haul itself around,which means it uses more fuel & is less efficient...I'm not an engineer,just a shadetree mechanic & I can see that.
Diesels operate with far higher compression levels than gas engines,that's why they weigh so darn much,the Cummins 5.9 in my Dodge truck weighs approx. 950 lbs,almost twice as much as a comparably sized V8 gas engine.
I don't buy their claims of 25% efficiency,maybe 5%,but you can get that from any engine with improvements to the intake & exhaust for less than $1000.

[cjl]

I could see 15-20% efficiency gains with a 2 stroke direct injected turbodiesel of fairly large size. The problem with this however is the weight of a large diesel engine, as well as the fact that most cars don't need an engine that large. For the same process in gas, the biggest gain would be horsepower, as there would now be a way to create a 2 stroke motor without the normal problems of two strokes (inefficient and messy). With a good design, a 3L engine with 400hp naturally aspirated would not be unthinkable. I would be a little more skeptical about the efficiency claims however. Certainly there would be some gain, but I couldn't see more than 12 or 13%. It's hard to say however until more tests are done.

[SeanF]

Ha!---remember when GM started making Suburbans in Mexico, citing lower production costs? Sounded like a 'good' idea at the time, however GM kept all the savings for themselves, never passing on any to the consumer.
I'm not sure why that makes it not a good idea. Sounds like it was good for GM! ;)

[mike alexander]

Ethanol Boosting Systems, a company the researchers have started in Cambridge, MA, is working to commercialize the technology. Cohn says that with an aggressive development program, the design could be in production vehicles as early as 2011.

While Cohn applauds the benefits of hybrids and says his technology could be used to improve them, too, he notes that the popularity of hybrid technology is still limited by its cost. Cheaper technology will be adopted faster, he suggests, and will thus reduce gasoline consumption more rapidly. "It's a lot more useful," he says, "to have an engine that a lot of people will buy."


...from me!

[Dr Nigel]

However efficient your infernal combustion engine, the hybrid still has one big advantage: zero emissions in the urban setting. Plus, it's quieter at low speed (< 30 mph) than a petrol engine, and way, way quieter than a diesel.

[cjl]

Note however, that the hybrid is less efficient than the highest efficiency internal combustion engines, and that hybrids actually make significant quantities of pollution when you have to replace all the lead-acid batteries (a lot more than in a traditional car).

[shatdow]

Interesting article, but I don't think it's as revolutionary as it's made out to be. Alcohol and water injection have been common for years in high-performance circles as a means of keeping combustion chamber temperatures down and achieving higher compression. The new ideas are the direct injection of alcohol and the application to passenger/economy cars.

A distinct advantage to cooling the charge air is that you can build a naturally higher compression motor (say 11:1 vs 7-8:1 for usual turbo motors), which gives you greater efficiency aside from power gains. I think this is the key to efficiency gains, though I have to agree with cjl that gains there is secondary to power. There are moderate efficiency gains to using a smaller, higher-compression motor, but at the end of the day, they're still burning fuel to make all their power. They key to hybrids is that they recover energy from braking that would be lost as heat and convert it to useful mechanical energy.

Here's the other thing:
"An engine this size," he says, pointing out an ordinary-looking 2.4-liter midsize gasoline engine, "would be a rocket with our technology."
This is definitely not new; small, high-compression/turbocharged engines have been common in racing for a long time. The turbo days of F1 had 1.5 liter turbocharged engines pushing over 500hp, of course on race fuel. This technology they're talking about is a way to get higher pressures with lower octane fuel. And, as already mentioned, higher pressures mean more strain on the motor. In race motors, they use expensive, strong, light parts, and also don't care if they only last 1 race (they rebuild after every race, anyway). But for consumer-grade vehicles and materials, you're limited to cheaper, heavier parts to get the same strength, and to last for tens of thousands of miles. This doesn't matter much when you're talking about the block (a matter of pounds/tens of pounds), but it decreases efficiency when it comes to moving parts, like valves, pistons, and rods.

OK, I confess: this was a very negative-sounding post, but really, I'm all for adopting this kind of technology in general as an alternative to big, thirsty v8's in sedans and sports cars, and smaller SUV's (but not larger SUVs and trucks that might need towing torque, which these little motors just don't have). But, I don't think it's as attractive as hybrid technology when it comes to ultimate efficiency.

[Glom]

I think being quieter is a double edged sword. It might sound good, but it can be dangerous. With a good old noisy car, you know when it's coming.

[Dr Nigel]

I think being quieter is a double edged sword. It might sound good, but it can be dangerous. With a good old noisy car, you know when it's coming.

True. I once test drove a Lexus RX400h (Lexus's first hybrid to be launched in the UK) and the salesman had to ensure that I was aware that pedestrians would not hear the vehicle approaching.

[Dr Nigel]

OK, I confess: this was a very negative-sounding post, but really, I'm all for adopting this kind of technology in general as an alternative to big, thirsty v8's in sedans and sports cars, and smaller SUV's (but not larger SUVs and trucks that might need towing torque, which these little motors just don't have). But, I don't think it's as attractive as hybrid technology when it comes to ultimate efficiency.

I largely agree with this.

The other way to improve fuel efficiency is to make cars lighter. I recall when BBC's Top Gear recorded a programme in the US: the presenters each had to buy a used car. Two of these had engines of greater than 4 litre capacity, and it was amazing how slow they were, purely because they were heavy. In the UK, a 2-litre engine is big enough to make a car relatively fast, because most British cars weigh only about 1 tonne.*

*Not counting the trend toward SUVs, MPVs and pick-up trucks. When I use the word "car" these days, I do not think of these vehicle types.

[cjl]

Most british cars are only 2200lbs?

That I have a hard time believing...

That must be a pretty dinky car. Most "cars" (again, no pickups, SUV's, etc) are around 3400lbs here, and with a 4L engine, they are pretty fast unless it's a very poorly designed 4L.

[Glom]

My car has a 1L engine and gets 45 mpg.

[Delvo]

I've been looking at weights of cars for a while, in connection to a concept I want to flesh out for a completely new transportation system, and found that practically all are between 1.2 and 1.9 tons (American tons: 2000 pounds). The lightest of all, subcompacts like the Chevrolet Aveo (2343 pounds), are just a bit under 1.2 tons. But that's 1.06 "metric tons" (2205 pounds), which does round off to 1 pretty well.

This wouldn't be the "average" in a country wtih any significant number of cars that aren't subcompact, but it could very well be the "most common" in a country where subcompact cars were the most common type.

[Dr Nigel]

Most british cars are only 2200lbs?

That I have a hard time believing...

That must be a pretty dinky car. Most "cars" (again, no pickups, SUV's, etc) are around 3400lbs here, and with a 4L engine, they are pretty fast unless it's a very poorly designed 4L.

Define "dinky". It all depends on what you're used to.

Taking 1 kg = 2.2 lb, your figure gives 1,545 kg as a typical car weight.

My present car weighs 1300 kg, has a 2 L engine and is (a) larger than the average car on Britain's roads, and (b) faster than the average car on Britain's roads (again, excluding SUVs etc.).

In the past, for several years, I used a Fiat Uno, which weighed about 750 kg and had a 1.1 L engine. It was a bit slow (0 - 60 mph took the best part of 17 seconds), but it could happily cruise at 75 mph and did about 40 mpg (Imperial gallon, that is, or about 4.5 L). On the road, I would judge this car to have been a little bit smaller than the average, and a bit slower than the average.

I reiterate that a typical "family" car in Britain weighs in at about 1 tonne.

In Britain, anything equipped with an engine over 4L should be very fast, even if it is an SUV or a pick-up truck. On the Top Gear show, this was not the case, because the vehicles were so big and heavy (I would hazard a guess that the saloon car was about 2000 kg and the pick-up truck between 2500 kg and 3000 kg).