7 ms·

Next-Gen Mazda2 Will Return 70 MPG, Without An Electric Motor

19 points by coreyrecvlohe 16y ago

simonsarris 16y ago
No it won't. The 70mpg figure is from the Japanese test. The Mazda release said the car would achieve 70 miles per gallon, but that number was based on the Japanese test cycle, meaning American mileage would be lower. A 15 percent increase from the existing Mazda 2 would result in a combined 37 m.p.g. (For comparison, the Toyota Prius, which gets a combined 50 m.p.g. from the Environmental Protection Agency, achieves 89 m.p.g. in the Japanese test.) More accurate article here: http://wheels.blogs.nytimes.com/2010/10/21/mazda-next-generation-mazda-2-will-get-70-m-p-g/ http://wheels.blogs.nytimes.com/2010/10/21/mazda-next-genera...
JofArnold 16y ago
As I often say "My 7 year old Rover 25 diesel gets actual 50mpg with 115hp (0-60 approx 9s)... And the wreck only cost me $1500 (£1000 in UK)". I've a career in Mech/Auto Eng, so I know it's more complicated than that. Nonetheless, it shows how the car industry can confuse with these headline figures. I will add that I'd probably rather breathe the exhaust of my Rover (with micron-scale smoke particles) than that of a modern car (with more biologically-active nano-scale particles)
- simonsarris 16y ago
  Just a note for the American thread readers, 50mpg in UK imperial gallons = 41.6mpg in US gallons. (And the petrol version of his car gets 31.4 US mpg. I blame the US not getting really clean diesel until the mid-2000s for the lack of mini-diesel engine'd cars in the US.) edit: the US did not get ultra-low-sulfur-diesel as a standard until 2007.
  - JofArnold 16y ago
    Thanks! :)
- cullenking 16y ago
  Actually, the soot in diesel exhaust is much more carcinogenic than that of a (well tuned) gas engine. There are various studies, one california based study showed diesel soot was up to 70% of cancer for californians. Not saying that I want to breath either, but i'd rather suck down a mouthful of gasoline engine exhaust than diesel soot while on my morning bike commute. Edited to add: After reading a bit more, I see your point. I guess there have been new studies since I last read that show that per unit of mass, the volatile organic compounds in gasoline exhaust are more harmful, they just have less volume than diesels. Seems to be about a draw.
  - simonsarris 16y ago
    In the US, yes, but thats a US problem. But diesel in the UK now has 10 ppm sulfur. In the US it used to be higher than 500 ppm, now its regulated to 500ppm for some vehicles and lower for some other classes. Starting in 2014 all US will be 15ppm.
    - cullenking 16y ago
      Actually, in the US it was 500ppm in 2007 (LSD), and by the end of 2010 it will all be ULSD (15ppm sufur) for onroad vehicles. 2014 is when the exemptions for some small offroad vehicles and the like are removed. http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_States http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_... Also, soot isn't directly related to sulfur in fuels. It's the suit removing mechanisms in newer diesel vehicles that are ruined by sulfur, so newer vehicles can't run fuel with sulfur in it without incurring a large repair bill. An older diesel vehicle that belches out soot will continue to do so, regardless of sulfur content.
  - JofArnold 16y ago
    If I remember when I get back, I'll try to find the article I read about nano-scaled particles from gasoline combustion (I think it focussed on mutagenic properties and in particular the body's inability to move them out of the lungs versus micron-scale which can be expelled more easily). But the VOCs definitely not great. Plus, presumably (I'm guessing), the NOxs from high temp lean combustion in modern gasoline engines are an important factor too?
cullenking 16y ago
People still won't buy it unless it is decent sized and powerful. The same reasons why VW didn't bring in the 1 liter turbo diesel that got something like 100mpg. The fuel has been available since 2007, there just isn't much market yet. Drive fuel prices sky high again and maybe...
- elai 16y ago
  Then why do you see smart cars everywhere? They're millage isn't that much better than a yaris! I would love to have a climate controlled aerodynamic motorcycle (which is what he 1L car is) A ton of people would purchase the car. Hell you can go from SF to NY on 13 gallons of gas with it. Hell you could put 2 Jerry cans in the trunk and never have to stop at a gas station! Most of the time when I'm driving, it's just one or two people plus a few bags of groceries, it's a great second car for anybody who has to commute 1 or 2 hours every day and have a family pile into the sedan when you all want to go together.
  - cullenking 16y ago
    I live here in the northwest and I don't see smart cars everywhere. Sure, I see them here and there but nothing approaching enough to call them ubiquitous. A brief check in sales figures shows 12,421 sold in 2009. Seriously, why wouldn't VW and the like bring over ultra efficient cars if they would sell? Reason being is it costs $$$ to license a car for import, to get DOT stamps of approval etc. If sales won't cover those costs, it's a loss for the company.
  - jws 16y ago
    I think 13 gallons will get from SF to western Nebraska at 100 mpg. SF to NY is 2900 miles. Oh wait, you jumped to the Volkswagen L1 concept vehicle and its 230mpg. I don't understand the Smart car. The Honda Fit costs about the same and has 4 seats or a good deal of indoor space. Probably a style thing. I switched from a 3/4 ton 4 door pickup to a Honda Fit, and am not looking back. I've got more indoor cargo space in the Fit and don't need to bring a book to read while pumping diesel into the truck. (But I can still borrow the truck the once or twice a year when I need it.)
  - 16y ago
Construct 16y ago
With a compression ratio of 14:1, it will be interesting to see if this car requires 91+ Octane (Premium Unleaded). Higher compression ratios are a great way of squeezing more power out of the same amount of gasoline, but raising the compression ratio also raises the risk of detonation. Detonation occurs when the pressure and temperature inside the cylinder cause the air-fuel mixture to literally detonate, rather than burn (relatively) slowly and evenly as desired. If this occurs before the spark, it is called pre-ignition. When it occurs after the spark, while the flame front is progressing through the cylinder, it is referred to as detonation. Higher octane fuels are more resistant to detonation and pre-ignition, and usually go hand-in-hand with higher compression ratios. As a side note, E85 Ethanol has a ridiculously high octane rating, among other things, which allows for higher compression ratios and much higher boost in forced-induction engines. I keep hoping E85 will catch on outside of the corn belt so I can effectively get race gas performance from pump gas in my turbocharged motor, but no such luck yet. There are plenty of tricks that can be played to reduce the risk of detonation using low-octane fuels in high compression motors. Efficient head design with excellent cooling will reduce cylinder temperatures and minimize hot spotting within the cylinder head, reducing the risks of detonation and pre-ignition. Getting the heat out of the valves is particularly challenging as they only meet the cylinder head in a relatively small contact patch. The valves can be filled with sodium, which turns to liquid as the motor reaches operating temperature and circulates within the valve, cooling the valve and further reduce hot spots (pre-ignition points) within the motor. Also, designing the piston and head to thoroughly mix and swirl the intake charge helps create a quick, even, clean burn. However, to get up to 14:1 on a production motor, I wonder if Mazda is playing serious games with the intake camshaft timing to reduce the effective compression ratio. If you leave the intake valves open long enough after the piston begins the compression stroke, it will actually push a tiny amount of air back out of the intake valves, reducing the effective compression ratio of the motor at top dead center. With variable valve timing, Mazda could just be doing this near full load, where detonation and pre-ignition are problems. At partial load, you can get away with much higher compression ratios (up to 20:1 in certain cases, IIRC) with associated increases in efficiency (and thus higher MPG). Either way, I'm glad to see more efficient internal combustion engines. The internal combustion engine is a 100+ year old technology, so significant improvements are hard to come by without drastically increasing the cost of the motor. Good stuff.

19 points by coreyrecvlohe 16y ago

No it won't. The 70mpg figure is from the Japanese test. The Mazda release said the car would achieve 70 miles per gallon, but that number was based on the Japanese test cycle, meaning American mileage would be lower. A 15 percent increase from the existing Mazda 2 would result in a combined 37 m.p.g. (For comparison, the Toyota Prius, which gets a combined 50 m.p.g. from the Environmental Protection Agency, achieves 89 m.p.g. in the Japanese test.) More accurate article here: http://wheels.blogs.nytimes.com/2010/10/21/mazda-next-generation-mazda-2-will-get-70-m-p-g/ http://wheels.blogs.nytimes.com/2010/10/21/mazda-next-genera...

JofArnold 16y ago

As I often say "My 7 year old Rover 25 diesel gets actual 50mpg with 115hp (0-60 approx 9s)... And the wreck only cost me $1500 (£1000 in UK)". I've a career in Mech/Auto Eng, so I know it's more complicated than that. Nonetheless, it shows how the car industry can confuse with these headline figures. I will add that I'd probably rather breathe the exhaust of my Rover (with micron-scale smoke particles) than that of a modern car (with more biologically-active nano-scale particles)

simonsarris 16y ago
Just a note for the American thread readers, 50mpg in UK imperial gallons = 41.6mpg in US gallons. (And the petrol version of his car gets 31.4 US mpg. I blame the US not getting really clean diesel until the mid-2000s for the lack of mini-diesel engine'd cars in the US.) edit: the US did not get ultra-low-sulfur-diesel as a standard until 2007.
- JofArnold 16y ago
  Thanks! :)
cullenking 16y ago
Actually, the soot in diesel exhaust is much more carcinogenic than that of a (well tuned) gas engine. There are various studies, one california based study showed diesel soot was up to 70% of cancer for californians. Not saying that I want to breath either, but i'd rather suck down a mouthful of gasoline engine exhaust than diesel soot while on my morning bike commute. Edited to add: After reading a bit more, I see your point. I guess there have been new studies since I last read that show that per unit of mass, the volatile organic compounds in gasoline exhaust are more harmful, they just have less volume than diesels. Seems to be about a draw.
- simonsarris 16y ago
  In the US, yes, but thats a US problem. But diesel in the UK now has 10 ppm sulfur. In the US it used to be higher than 500 ppm, now its regulated to 500ppm for some vehicles and lower for some other classes. Starting in 2014 all US will be 15ppm.
  - cullenking 16y ago
    Actually, in the US it was 500ppm in 2007 (LSD), and by the end of 2010 it will all be ULSD (15ppm sufur) for onroad vehicles. 2014 is when the exemptions for some small offroad vehicles and the like are removed. http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_States http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_... Also, soot isn't directly related to sulfur in fuels. It's the suit removing mechanisms in newer diesel vehicles that are ruined by sulfur, so newer vehicles can't run fuel with sulfur in it without incurring a large repair bill. An older diesel vehicle that belches out soot will continue to do so, regardless of sulfur content.
- JofArnold 16y ago
  If I remember when I get back, I'll try to find the article I read about nano-scaled particles from gasoline combustion (I think it focussed on mutagenic properties and in particular the body's inability to move them out of the lungs versus micron-scale which can be expelled more easily). But the VOCs definitely not great. Plus, presumably (I'm guessing), the NOxs from high temp lean combustion in modern gasoline engines are an important factor too?

cullenking 16y ago

People still won't buy it unless it is decent sized and powerful. The same reasons why VW didn't bring in the 1 liter turbo diesel that got something like 100mpg. The fuel has been available since 2007, there just isn't much market yet. Drive fuel prices sky high again and maybe...

elai 16y ago
Then why do you see smart cars everywhere? They're millage isn't that much better than a yaris! I would love to have a climate controlled aerodynamic motorcycle (which is what he 1L car is) A ton of people would purchase the car. Hell you can go from SF to NY on 13 gallons of gas with it. Hell you could put 2 Jerry cans in the trunk and never have to stop at a gas station! Most of the time when I'm driving, it's just one or two people plus a few bags of groceries, it's a great second car for anybody who has to commute 1 or 2 hours every day and have a family pile into the sedan when you all want to go together.
- cullenking 16y ago
  I live here in the northwest and I don't see smart cars everywhere. Sure, I see them here and there but nothing approaching enough to call them ubiquitous. A brief check in sales figures shows 12,421 sold in 2009. Seriously, why wouldn't VW and the like bring over ultra efficient cars if they would sell? Reason being is it costs $$$ to license a car for import, to get DOT stamps of approval etc. If sales won't cover those costs, it's a loss for the company.
- jws 16y ago
  I think 13 gallons will get from SF to western Nebraska at 100 mpg. SF to NY is 2900 miles. Oh wait, you jumped to the Volkswagen L1 concept vehicle and its 230mpg. I don't understand the Smart car. The Honda Fit costs about the same and has 4 seats or a good deal of indoor space. Probably a style thing. I switched from a 3/4 ton 4 door pickup to a Honda Fit, and am not looking back. I've got more indoor cargo space in the Fit and don't need to bring a book to read while pumping diesel into the truck. (But I can still borrow the truck the once or twice a year when I need it.)
- 16y ago

Construct 16y ago

With a compression ratio of 14:1, it will be interesting to see if this car requires 91+ Octane (Premium Unleaded). Higher compression ratios are a great way of squeezing more power out of the same amount of gasoline, but raising the compression ratio also raises the risk of detonation. Detonation occurs when the pressure and temperature inside the cylinder cause the air-fuel mixture to literally detonate, rather than burn (relatively) slowly and evenly as desired. If this occurs before the spark, it is called pre-ignition. When it occurs after the spark, while the flame front is progressing through the cylinder, it is referred to as detonation. Higher octane fuels are more resistant to detonation and pre-ignition, and usually go hand-in-hand with higher compression ratios. As a side note, E85 Ethanol has a ridiculously high octane rating, among other things, which allows for higher compression ratios and much higher boost in forced-induction engines. I keep hoping E85 will catch on outside of the corn belt so I can effectively get race gas performance from pump gas in my turbocharged motor, but no such luck yet. There are plenty of tricks that can be played to reduce the risk of detonation using low-octane fuels in high compression motors. Efficient head design with excellent cooling will reduce cylinder temperatures and minimize hot spotting within the cylinder head, reducing the risks of detonation and pre-ignition. Getting the heat out of the valves is particularly challenging as they only meet the cylinder head in a relatively small contact patch. The valves can be filled with sodium, which turns to liquid as the motor reaches operating temperature and circulates within the valve, cooling the valve and further reduce hot spots (pre-ignition points) within the motor. Also, designing the piston and head to thoroughly mix and swirl the intake charge helps create a quick, even, clean burn. However, to get up to 14:1 on a production motor, I wonder if Mazda is playing serious games with the intake camshaft timing to reduce the effective compression ratio. If you leave the intake valves open long enough after the piston begins the compression stroke, it will actually push a tiny amount of air back out of the intake valves, reducing the effective compression ratio of the motor at top dead center. With variable valve timing, Mazda could just be doing this near full load, where detonation and pre-ignition are problems. At partial load, you can get away with much higher compression ratios (up to 20:1 in certain cases, IIRC) with associated increases in efficiency (and thus higher MPG). Either way, I'm glad to see more efficient internal combustion engines. The internal combustion engine is a 100+ year old technology, so significant improvements are hard to come by without drastically increasing the cost of the motor. Good stuff.