After all these years of hybrids hogging ouf “car pool” lanes as well as huge subsidies, we learn: The new Chevrolet Cruze Eco can reach eye-popping fuel economy levels of more than 50 miles per gallon on the highway, which even in this era of hybrid-electric cars stands among the best. But here’s the real trick: The Cruze Eco is neither a hybrid nor electric. It runs on that “old” technology, the conventional gasoline engine. … This year, General Motors, Ford and Hyundai began selling cars with conventional engines that achieve 40 mpg or more on the highway, exceeding the fuel efficiency of some hybrids. … The new fuel-efficient gasoline cars, critics say, raise doubts about government efforts that favor any one technology over another. If subsidies are to be made, they argue, they should go to efficient cars, no matter what their power source. (
Back in 1984, I bought a Honda CRX, which was rated at 63 MPG highway. (Yes, I know that the EPA's rating system has changed since then - but I did get more than 60 MPG when on long trips).
How did Honda do that - in the early 80s, while no one can do that today?
Simple: The car weighed less than 1800 lbs. It had no air conditioner, no anti-lock brakes, no back seat, no side impact air-bags (no air bags at all!), no cruise control, manual windows, no "crumple-zones", and it had a 1300cc (58hp) engine and a manual transmission.
To expand on what Jimmy, below, says: the Prius' gasoline engine uses the Atkinson cycle instead of the more-usual Otto cycle, which gives greater mileage, but poorer power. The electric motor(s) of course have lots-o-torque at the low end so help you keep reasonable performance with a higher-mileage gasoline engine.
Regenerative breaking, which Constant describes, above, only recovers about 35-40% of the energy from deceleration, which is better than most cars' 0%, but not a magic bullet, either.
As Jimmy says, below, the gasoline engine and two electric motors are used in combination so that you can keep the engine running at maximal efficiency. (The three motors are continuously adjusted to conditions, so within a couple of seconds, you might go from pulling electricity from the battery to dumping excess energy into the battery, to running only on battery.)
I love my Prius. I averaged 48 MPG last year, and it's like driving a video game every day.
That's not quite right. For a given engine/transmission the hybrid offers no advantage on the freeway, but because you can use the electric motor for accelleration, you can size the engine smaller and/or pulse width modulate the engine power to keep the engine running near its maximum efficiency.
Robin, the underlying assumption is incorrect, at least here in California.
Low emissions was the criteria for allowing the Prius et al. into the carpool lanes, not fuel efficiency. The 2004 Prius that had come on the market at that time has a triple-stage catalytic converter that, along with the low fuel consumption, drove harmful emissions (not counting carbon, of course) to less than 10% of other new cars on the road and put the Prius into the PZEV (Partial Zero-Emissions Vehicle) category.
California already had carpool lane waivers in place for zero-emissions vehicles (i.e., all electric cars), so it was fairly short from allowing ZEVs to PZEVs.
Europe generally builds light cars that are very efficient, and puts very good drivers behind them.
The US generally builds light tanks but allows almost anyone the opportunity to drive them.
A good example of the difference is the Smart Car which in Europe is a very efficient vehicle, but because of the tremendous extra weight required to achive US crash test and emissions standards the US model isn't an exceptionally efficient car.
As Constant said, the Prius gets good highway mileage because of aerodynamics and other non-hybrid issues.
To elaborate on Vladimir M's comment, many European cars get good efficiency by being light, but are illegal in the US, nominally because they aren't safe enough. For example, Fiats were imported in the 70s, but largely banned in the 80s. This is probably mostly protectionism, but there are some reasonable differences in usages between the US and Europe.
Personally, I think the mild hybrid approach will turn out to be a winner.
Every car has a small electric start motor, to start the engine, and a small generator to load the battery.In mild hybrid designs this engine is increased slightly in size and functions both as generator and as motor.
It allows energy recuperation when braking, so less energy is wasted. And this recuped energy then powers all the electrics in the car (A/C anyone?).
VW built a car that used 1L/100 KM with this tech. And production vehicles now use about 3 L/100 KM.
Combine this tech with smart cars that automatically drive themselves and I'm sure 2 L/100 KM will be the new normal.
(Unlike human drivers, smart cars only need to leave an inch between them, reducing drag on the highway and smoothing out stop&go traffic in the city.)
But yeah: incentives should reward good mileage and low pollution, regardless of the underlying technology.This is how it's done in Europe.
I live by an extremely busy intersection in a notoriously smoggy inner city. You wouldn't believe how smelly and noisy it is. Personally, I absolutely don't care about fuel efficiency. I only care about the fact that hybrids don't pollute the air while waiting for the green light in front of our house.
There's something to be said if everyone was really interesting in fuel efficiency then we'd use motor scooters, motor bikes and, shock and horror, pushbikes.
On the other hand, what about this video about a fellow who in the '70s created a rather fuel-efficient, steam-powered engine for an ordinary car?
This is correct. In steady-state cruise, a hybrid powertrain offers no advantage (unless you consider plug-in power an advantage, which of course depends on its power source).
The basics of good highway mpg are good aero, gearing for low-RPM cruise and low displacement. Weight affects rolling resistence, but at highway speeds this is a minor effect compared to aerodynamic drag.
In the city weight is very important, because a lot of energy is expended accelerating the car (only to be wasted during braking). A non-hybrid car is going to be significantly lighter than a hybrid, but I doubt it will ever be enough to challenge similarly-sized hybrids for the city MPG crown.
The basic problem is that the straightforward way to encourage fuel efficiency, increasing gasoline taxes, sounds Bad to people, so politicians don't do it. Instead we get a patchwork of subsidies and requirements, mostly requirements for incremental improvements (efficiency standards for gasoline vehicles) and subsidies for new types of technologies (like hybrids).
Vladimir, be very careful about comparing US and European fuel economy numbers. the EPA changed its test in 2008, and the newer ratings are much more conservative (cars look less efficient) than either pre-2008 numbers or the EU test numbers. Wikipedia's article claims, as an example, that the Honda CR-Z has highway ratings of 4.4 l/100 km in Europe, and 6.4 l/100 km in the US.
You'll have to compare those figures to US ratings of efficient vehicles to figure out where the Eco Cruze rates: the Prius is rated at 48 mpg Hwy, though it does get 51 mpg on the city cycle (almost all cars get better mileage on the highway cycle, an indication of just how unusual the Prius is).
HOWEVER, the WaPo is giving "as high as" numbers for the Eco Cruze. The actual EPA-rated highway cycle number is 42 mpg.
It's also worth noting that while the Cruze is sold as a "small" car in the US, the EPA calls it a mid-size, and it really is quite large. Of course, the Prius is also rated as mid-size.
One more comical government ratings folly: cars are given their size rating by INTERIOR VOLUME, not by exterior dimensions or weight. As a result, the Aston Martin DB9 is a "minicompact," complete with a V12 engine.
Unless my information is obsolete, hybrids aren't supposed to get especially good fuel economy on the highway. Their specialty is city traffic. It should be trivial for a regular gas powered car to match or best a hybrid on the highway.
The way I understand it is this: the energy that a hybrid uses all ultimately comes from burning gasoline (except for plug-in hybrids). The advantage of the hybrid is that it captures energy that would otherwise have been wasted as heat. Specifically, the energy that is lost to heat when the car brakes. Every time a regular car brakes, its kinetic energy is converted to heat at the brake pad, and to bring the car back up to speed requires fresh energy from burning more gas. But when a hybrid brakes, a portion of its kinetic energy is used to charge the battery, which is then discharged when the car speeds up again.
So in essence the hybrid slows down the increase in entropy, i.e., the loss of useful energy to heat.
But this doesn't work on the highway, because the brakes are hardly being used (with the obvious exception of stop and go traffic).
Bikes are a great idea, right up until reviewing the safety statistics.
Back in 1984, I bought a Honda CRX, which was rated at 63 MPG highway. (Yes, I know that the EPA's rating system has changed since then - but I did get more than 60 MPG when on long trips).
How did Honda do that - in the early 80s, while no one can do that today?
Simple: The car weighed less than 1800 lbs. It had no air conditioner, no anti-lock brakes, no back seat, no side impact air-bags (no air bags at all!), no cruise control, manual windows, no "crumple-zones", and it had a 1300cc (58hp) engine and a manual transmission.
To expand on what Jimmy, below, says: the Prius' gasoline engine uses the Atkinson cycle instead of the more-usual Otto cycle, which gives greater mileage, but poorer power. The electric motor(s) of course have lots-o-torque at the low end so help you keep reasonable performance with a higher-mileage gasoline engine.
Regenerative breaking, which Constant describes, above, only recovers about 35-40% of the energy from deceleration, which is better than most cars' 0%, but not a magic bullet, either.
As Jimmy says, below, the gasoline engine and two electric motors are used in combination so that you can keep the engine running at maximal efficiency. (The three motors are continuously adjusted to conditions, so within a couple of seconds, you might go from pulling electricity from the battery to dumping excess energy into the battery, to running only on battery.)
I love my Prius. I averaged 48 MPG last year, and it's like driving a video game every day.
That's not quite right. For a given engine/transmission the hybrid offers no advantage on the freeway, but because you can use the electric motor for accelleration, you can size the engine smaller and/or pulse width modulate the engine power to keep the engine running near its maximum efficiency.
Robin, the underlying assumption is incorrect, at least here in California.
Low emissions was the criteria for allowing the Prius et al. into the carpool lanes, not fuel efficiency. The 2004 Prius that had come on the market at that time has a triple-stage catalytic converter that, along with the low fuel consumption, drove harmful emissions (not counting carbon, of course) to less than 10% of other new cars on the road and put the Prius into the PZEV (Partial Zero-Emissions Vehicle) category.
California already had carpool lane waivers in place for zero-emissions vehicles (i.e., all electric cars), so it was fairly short from allowing ZEVs to PZEVs.
Europe generally builds light cars that are very efficient, and puts very good drivers behind them.
The US generally builds light tanks but allows almost anyone the opportunity to drive them.
A good example of the difference is the Smart Car which in Europe is a very efficient vehicle, but because of the tremendous extra weight required to achive US crash test and emissions standards the US model isn't an exceptionally efficient car.
As Constant said, the Prius gets good highway mileage because of aerodynamics and other non-hybrid issues.
To elaborate on Vladimir M's comment, many European cars get good efficiency by being light, but are illegal in the US, nominally because they aren't safe enough. For example, Fiats were imported in the 70s, but largely banned in the 80s. This is probably mostly protectionism, but there are some reasonable differences in usages between the US and Europe.
Heck, just shutting the engine off when a vehicle is stopped would save a ton of fuel.
That's a good point - too bad the article didn't give the city MPG for those cars.
Personally, I think the mild hybrid approach will turn out to be a winner.
Every car has a small electric start motor, to start the engine, and a small generator to load the battery.In mild hybrid designs this engine is increased slightly in size and functions both as generator and as motor.
It allows energy recuperation when braking, so less energy is wasted. And this recuped energy then powers all the electrics in the car (A/C anyone?).
VW built a car that used 1L/100 KM with this tech. And production vehicles now use about 3 L/100 KM.
Combine this tech with smart cars that automatically drive themselves and I'm sure 2 L/100 KM will be the new normal.
(Unlike human drivers, smart cars only need to leave an inch between them, reducing drag on the highway and smoothing out stop&go traffic in the city.)
But yeah: incentives should reward good mileage and low pollution, regardless of the underlying technology.This is how it's done in Europe.
I live by an extremely busy intersection in a notoriously smoggy inner city. You wouldn't believe how smelly and noisy it is. Personally, I absolutely don't care about fuel efficiency. I only care about the fact that hybrids don't pollute the air while waiting for the green light in front of our house.
There's something to be said if everyone was really interesting in fuel efficiency then we'd use motor scooters, motor bikes and, shock and horror, pushbikes.
On the other hand, what about this video about a fellow who in the '70s created a rather fuel-efficient, steam-powered engine for an ordinary car?
http://www.youtube.com/watc...
This is correct. In steady-state cruise, a hybrid powertrain offers no advantage (unless you consider plug-in power an advantage, which of course depends on its power source).
The basics of good highway mpg are good aero, gearing for low-RPM cruise and low displacement. Weight affects rolling resistence, but at highway speeds this is a minor effect compared to aerodynamic drag.
In the city weight is very important, because a lot of energy is expended accelerating the car (only to be wasted during braking). A non-hybrid car is going to be significantly lighter than a hybrid, but I doubt it will ever be enough to challenge similarly-sized hybrids for the city MPG crown.
The basic problem is that the straightforward way to encourage fuel efficiency, increasing gasoline taxes, sounds Bad to people, so politicians don't do it. Instead we get a patchwork of subsidies and requirements, mostly requirements for incremental improvements (efficiency standards for gasoline vehicles) and subsidies for new types of technologies (like hybrids).
Vladimir, be very careful about comparing US and European fuel economy numbers. the EPA changed its test in 2008, and the newer ratings are much more conservative (cars look less efficient) than either pre-2008 numbers or the EU test numbers. Wikipedia's article claims, as an example, that the Honda CR-Z has highway ratings of 4.4 l/100 km in Europe, and 6.4 l/100 km in the US.
You'll have to compare those figures to US ratings of efficient vehicles to figure out where the Eco Cruze rates: the Prius is rated at 48 mpg Hwy, though it does get 51 mpg on the city cycle (almost all cars get better mileage on the highway cycle, an indication of just how unusual the Prius is).
HOWEVER, the WaPo is giving "as high as" numbers for the Eco Cruze. The actual EPA-rated highway cycle number is 42 mpg.
It's also worth noting that while the Cruze is sold as a "small" car in the US, the EPA calls it a mid-size, and it really is quite large. Of course, the Prius is also rated as mid-size.
One more comical government ratings folly: cars are given their size rating by INTERIOR VOLUME, not by exterior dimensions or weight. As a result, the Aston Martin DB9 is a "minicompact," complete with a V12 engine.
Unless my information is obsolete, hybrids aren't supposed to get especially good fuel economy on the highway. Their specialty is city traffic. It should be trivial for a regular gas powered car to match or best a hybrid on the highway.
The way I understand it is this: the energy that a hybrid uses all ultimately comes from burning gasoline (except for plug-in hybrids). The advantage of the hybrid is that it captures energy that would otherwise have been wasted as heat. Specifically, the energy that is lost to heat when the car brakes. Every time a regular car brakes, its kinetic energy is converted to heat at the brake pad, and to bring the car back up to speed requires fresh energy from burning more gas. But when a hybrid brakes, a portion of its kinetic energy is used to charge the battery, which is then discharged when the car speeds up again.
So in essence the hybrid slows down the increase in entropy, i.e., the loss of useful energy to heat.
But this doesn't work on the highway, because the brakes are hardly being used (with the obvious exception of stop and go traffic).