Michigan State's team of engineers hope to have a car-sized 25-kilowatt version of the prototype ready by the end of the year.
It should be noted than 25kW is 33HP. Though it's possible to make a useful car with that little power, 33HP is generally considered an appropriate power level for a beginner's motorcycle, not a car. Even if it's much lighter than a piston engine and has such a wide powerband that it doesn't need a gearbox, it's likely they'd need a lot more power for consumer acceptance even in small cars.
Edit: I googled this and found that the intent is to use this engine to run generators to charge batteries in hybrid cars, not for direct propulsion. In that case, the cars probably won't be much, if any lighter than standard cars since all the weight savings will be replaced with batteries. Power output could, of course be lower than a standard car engine and still provide good performance since the electric motors could have peak outputs far exceeding the sustained output of the generator.
33HP in an electric vehicle is actually not as bad as it sounds. Most of the horsepower needed in a vehicle is to overcome inertia (e.g. starting from a standing stop) and electric motors can output full power at 0 RPM unlike an internal combustion engine. So a car driven by an electric motor would not need a clutch or transmission, which eliminates a significant inefficiency in the drivetrain.
Internal combustion engines and electric motors are also not rated in the same way. Electric motor HP is "rated" horsepower (what it can produce continuously without overheating; generally it's capable of more for short periods) while internal combustion horsepower tends to be "maximum" horsepower and there are a lot of different ways to come up with a number, some purely based on calculations and some on actual measurement. So unfortunately HP is not an apples-to-apples number between electric and combustion engines.
Yes. However lets consider this: If it meets 80% of the population's 100% needs then its good enough for me. Imagine a ~60% or so reduction in co2 emissions world wide. Sure 20% of people still need their big trucks, but at least not everyone. Not to mention shaving 1000 pounds off the weight of the car not only gives fuel gains, but lowers power requirements to move that vehicle. Now I was going to say... take that, combine it with tesla's engine, and now you have potentially a long-range vehicle, a vehicle that can already do 300 miles on a charge and potentially a gas engine that can charge it up so you get a nice and unlimited mileage as long as you refuel.
It is not likely that a hybrid car with no direct propulsion from the combustion engine will be 1000 pounds lighter than a comparable conventional car, even if its combustion engine weighs next to nothing. Batteries are heavy, and this type of hybrid needs more of them than the more common type that uses electric to augment the power of a combustion engine.
I'm not saying this won't be an improvement. I'm just saying some of the claims seem a little extravagant.
Even if you discount the batteries entirely, 1000 lbs seems a bit high for the weight of an engine (or even engine and transmission). I suppose maybe a big block V8 with a very strong Ford pickup transmission could weight that much; but it would be more fair to use a figure for the weight of an I4 engine with front wheel drive transaxle, which would probably closer to 600 lbs than 1000.
I don't think you're giving it quite enough credit. For a hybrid car what you can do is marry this to a more powerful electric motor (say, 40HP). When the car is cruising at a constant speed it's running on the engine and charging the batteries (or using just the batteries with the motor off). When the car is accelerating a lot it's using the batteries/motor and the engine at the same time (generating say 70HP or more). Given the lower weight and higher efficiency of this engine that's pretty significant. If it's possible to create a hybrid drive-train (including batteries) that weighs only as much or only a little more than a pure gasoline drive-train that could translate into much cheaper hybrid vehicles on the market.
P.S. For clarity's sake, modern hybrids are enormous compromises due to the weight of the battery and electric motor. For a hybrid you want the highest efficiency possible and thus the lowest total vehicle weight you can manage without compromise safety. The necessity of heavy batteries fights in the opposite direction, so in order to produce a fuel efficient vehicle car makers use more expensive, lighter weight materials in the construction of the vehicle. This increases the complexity of manufacturing (more different materials are being used) and raises the price of the vehicle. If you could drop in a drive-train which kept the weight the same that would change the industry dramatically.
Further research in to this engine design suggests it has a very narrow efficient range and the intended application is as a generator only, not to directly power the wheels. The electric motor would have to provide all the power required to propel the car. Of course, pure electric cars have already been done with some success, and a hybrid based on this system could have electric motors with a lot more than 33, 40 or 70 hp.
That's modern power creep speaking. You don't need the massive power of modern automobiles. That 7 second 0-60 on your mid-sized sedan? Faster than nearly all sports cars 30 years ago. Absolutely blistering compared to any car 50 years ago.
40hp is about what you use on the freeway, or at least it used to be before the average car came to weight 2 tons. You don't need a whole lot more than that. Hell, the MG Midget was offered with a 30HP engine once, IIRC.
I'm quite sure in a decade or two we're going to have people saying things like, "It's true you CAN make a car with only 200hp, but it's generally accepted you need at least 800hp for any car"...
I had an air-cooled Vanagon for a while. It was 2½ tons, due to aftermarket camper modifications, and could manage a bit over 60mph on its 70-horsepower 2-liter air-cooled engine, despite having the aerodynamics of a brick. Something with half the frontal surface area or half the drag coefficient, such as basically any modern vehicle, could manage quite well with half that horsepower.
I think the average US car weighed a lot more in the 1960s than in the 1970s, 1980s, or 1990s. Maybe widespread SUV use is pushing that average back up.
Reading the content of the article you linked, the first version had 9hp and was "notoriously underpowered". Most 2CVs actually came with engines around 30 HP. This car also weighed only 560kg, which is lighter than even a Smart Fortwo. Modern crash safety standards mean it's effectively impossible[0] to produce street legal cars that weigh less.
The fact that a car was once successfully sold in Europe with such a low power to weight ratio doesn't mean it would succeed in today's market. Consumer expectations have changed. They could change again, but there would have to be a good reason.
[0] Lighter cars could be made from more exotic materials, but those would drive the price out of reach of the average buyer.
The engine used in the original VW Beetle was about 40 HP (started out even less, and later models were 60 HP, but for many years it was 40). I have heard that it only takes about 18 HP to overcome air resistance at highway speeds for a small car.
Also, it's important to note the reason for the big discrepancy between the "inflated" horsepower ratings modern cars have vs. the lower HP in older classic cars: power is RPM * torque, and gas engines are rated in peak horsepower. To reach the advertised peak horsepower of modern engines, you have to be fairly high RPM (5K to 6K) whereas an older, lower horsepower rated engine might start to drop off its power curve after 4K. But at lower RPM the torques may be similar, or even higher for some older engines (the VW engine in particular with its Boxer configuration was optimized to have good torque for its size). What this means is that unless you are driving full throttle all the time at high RPM, you're not necessarily pushing all 100+ horsepower or whatever that your modern engine is capable of in theory, and so conversely an engine with smaller max horsepower is not as much worse as you'd think it would be.
> It should be noted than 25kW is 33HP. Though it's possible to make a useful car with that little power ...
Not only it's possible, but many successful european cars hadn't more : Citröen 2CV, Renault 4CV, Fiat 500 and 600, and most other economy cars of the 50s and 60s hadn't even that power, and sold by the millions.
But, if such an engine, with two-three times(!!!) the efficiency of a standard gasoline engine with a lower power to weight ratio, were to be producible at 25kW, all the (hypothetical underpowering) problems could be solved by ...
... using ...
TWO engines!! (or three engines)
... jeesh ...
It's for hybrids. Each engine would just charge a battery.
My first car, and one that I'm still very fond of, had 29HP [0]. I'm 31, so I'm not talking with a 'get off my lawn' 'glorify the past' attitude. In fact, I liked the car that much, that I had several of those in my life.
Oh - yeah: I drove a hell of a lot on the German Autobahn with it as well. Fast? Hell no. But I still have that speeding ticket (went just a tiny bit faster than 100km/h) somewhere as a nice souvenir.
But the design obviously isn't limited to this? A bigger engine could give more power yet still consume less than a regular piston engine. Or 1-2 of these running in parallel, depending on the load.
Comments
Michigan State's team of engineers hope to have a car-sized 25-kilowatt version of the prototype ready by the end of the year.
It should be noted than 25kW is 33HP. Though it's possible to make a useful car with that little power, 33HP is generally considered an appropriate power level for a beginner's motorcycle, not a car. Even if it's much lighter than a piston engine and has such a wide powerband that it doesn't need a gearbox, it's likely they'd need a lot more power for consumer acceptance even in small cars.
Edit: I googled this and found that the intent is to use this engine to run generators to charge batteries in hybrid cars, not for direct propulsion. In that case, the cars probably won't be much, if any lighter than standard cars since all the weight savings will be replaced with batteries. Power output could, of course be lower than a standard car engine and still provide good performance since the electric motors could have peak outputs far exceeding the sustained output of the generator.
33HP in an electric vehicle is actually not as bad as it sounds. Most of the horsepower needed in a vehicle is to overcome inertia (e.g. starting from a standing stop) and electric motors can output full power at 0 RPM unlike an internal combustion engine. So a car driven by an electric motor would not need a clutch or transmission, which eliminates a significant inefficiency in the drivetrain.
Internal combustion engines and electric motors are also not rated in the same way. Electric motor HP is "rated" horsepower (what it can produce continuously without overheating; generally it's capable of more for short periods) while internal combustion horsepower tends to be "maximum" horsepower and there are a lot of different ways to come up with a number, some purely based on calculations and some on actual measurement. So unfortunately HP is not an apples-to-apples number between electric and combustion engines.
If you live anywhere with mountains, it's exactly as bad as it sounds though.
Yes. However lets consider this: If it meets 80% of the population's 100% needs then its good enough for me. Imagine a ~60% or so reduction in co2 emissions world wide. Sure 20% of people still need their big trucks, but at least not everyone. Not to mention shaving 1000 pounds off the weight of the car not only gives fuel gains, but lowers power requirements to move that vehicle. Now I was going to say... take that, combine it with tesla's engine, and now you have potentially a long-range vehicle, a vehicle that can already do 300 miles on a charge and potentially a gas engine that can charge it up so you get a nice and unlimited mileage as long as you refuel.
Not to mention cheaper cars!!!!!
shaving 1000 pounds off the weight of the car...
It is not likely that a hybrid car with no direct propulsion from the combustion engine will be 1000 pounds lighter than a comparable conventional car, even if its combustion engine weighs next to nothing. Batteries are heavy, and this type of hybrid needs more of them than the more common type that uses electric to augment the power of a combustion engine.
I'm not saying this won't be an improvement. I'm just saying some of the claims seem a little extravagant.
Even if you discount the batteries entirely, 1000 lbs seems a bit high for the weight of an engine (or even engine and transmission). I suppose maybe a big block V8 with a very strong Ford pickup transmission could weight that much; but it would be more fair to use a figure for the weight of an I4 engine with front wheel drive transaxle, which would probably closer to 600 lbs than 1000.
I don't think you're giving it quite enough credit. For a hybrid car what you can do is marry this to a more powerful electric motor (say, 40HP). When the car is cruising at a constant speed it's running on the engine and charging the batteries (or using just the batteries with the motor off). When the car is accelerating a lot it's using the batteries/motor and the engine at the same time (generating say 70HP or more). Given the lower weight and higher efficiency of this engine that's pretty significant. If it's possible to create a hybrid drive-train (including batteries) that weighs only as much or only a little more than a pure gasoline drive-train that could translate into much cheaper hybrid vehicles on the market.
P.S. For clarity's sake, modern hybrids are enormous compromises due to the weight of the battery and electric motor. For a hybrid you want the highest efficiency possible and thus the lowest total vehicle weight you can manage without compromise safety. The necessity of heavy batteries fights in the opposite direction, so in order to produce a fuel efficient vehicle car makers use more expensive, lighter weight materials in the construction of the vehicle. This increases the complexity of manufacturing (more different materials are being used) and raises the price of the vehicle. If you could drop in a drive-train which kept the weight the same that would change the industry dramatically.
Further research in to this engine design suggests it has a very narrow efficient range and the intended application is as a generator only, not to directly power the wheels. The electric motor would have to provide all the power required to propel the car. Of course, pure electric cars have already been done with some success, and a hybrid based on this system could have electric motors with a lot more than 33, 40 or 70 hp.
That's modern power creep speaking. You don't need the massive power of modern automobiles. That 7 second 0-60 on your mid-sized sedan? Faster than nearly all sports cars 30 years ago. Absolutely blistering compared to any car 50 years ago.
40hp is about what you use on the freeway, or at least it used to be before the average car came to weight 2 tons. You don't need a whole lot more than that. Hell, the MG Midget was offered with a 30HP engine once, IIRC.
I'm quite sure in a decade or two we're going to have people saying things like, "It's true you CAN make a car with only 200hp, but it's generally accepted you need at least 800hp for any car"...
I had an air-cooled Vanagon for a while. It was 2½ tons, due to aftermarket camper modifications, and could manage a bit over 60mph on its 70-horsepower 2-liter air-cooled engine, despite having the aerodynamics of a brick. Something with half the frontal surface area or half the drag coefficient, such as basically any modern vehicle, could manage quite well with half that horsepower.
I think the average US car weighed a lot more in the 1960s than in the 1970s, 1980s, or 1990s. Maybe widespread SUV use is pushing that average back up.
Did the http://en.wikipedia.org/wiki/Deux_Chevaux really have only two horsepower?
Reading the content of the article you linked, the first version had 9hp and was "notoriously underpowered". Most 2CVs actually came with engines around 30 HP. This car also weighed only 560kg, which is lighter than even a Smart Fortwo. Modern crash safety standards mean it's effectively impossible[0] to produce street legal cars that weigh less.
The fact that a car was once successfully sold in Europe with such a low power to weight ratio doesn't mean it would succeed in today's market. Consumer expectations have changed. They could change again, but there would have to be a good reason.
[0] Lighter cars could be made from more exotic materials, but those would drive the price out of reach of the average buyer.
> I'm quite sure in a decade or two
I can't wait, thanks for the cheery prediction!
The engine used in the original VW Beetle was about 40 HP (started out even less, and later models were 60 HP, but for many years it was 40). I have heard that it only takes about 18 HP to overcome air resistance at highway speeds for a small car.
Also, it's important to note the reason for the big discrepancy between the "inflated" horsepower ratings modern cars have vs. the lower HP in older classic cars: power is RPM * torque, and gas engines are rated in peak horsepower. To reach the advertised peak horsepower of modern engines, you have to be fairly high RPM (5K to 6K) whereas an older, lower horsepower rated engine might start to drop off its power curve after 4K. But at lower RPM the torques may be similar, or even higher for some older engines (the VW engine in particular with its Boxer configuration was optimized to have good torque for its size). What this means is that unless you are driving full throttle all the time at high RPM, you're not necessarily pushing all 100+ horsepower or whatever that your modern engine is capable of in theory, and so conversely an engine with smaller max horsepower is not as much worse as you'd think it would be.
> It should be noted than 25kW is 33HP. Though it's possible to make a useful car with that little power ...
Not only it's possible, but many successful european cars hadn't more : Citröen 2CV, Renault 4CV, Fiat 500 and 600, and most other economy cars of the 50s and 60s hadn't even that power, and sold by the millions.
Geeks? Smart guy/gals?
I couldn't tell you if the thing is real or not.
But, if such an engine, with two-three times(!!!) the efficiency of a standard gasoline engine with a lower power to weight ratio, were to be producible at 25kW, all the (hypothetical underpowering) problems could be solved by ...
... using ...
TWO engines!! (or three engines)
... jeesh ...
It's for hybrids. Each engine would just charge a battery.
My first car, and one that I'm still very fond of, had 29HP [0]. I'm 31, so I'm not talking with a 'get off my lawn' 'glorify the past' attitude. In fact, I liked the car that much, that I had several of those in my life.
Oh - yeah: I drove a hell of a lot on the German Autobahn with it as well. Fast? Hell no. But I still have that speeding ticket (went just a tiny bit faster than 100km/h) somewhere as a nice souvenir.
0: https://secure.wikimedia.org/wikipedia/en/wiki/Citro%C3%ABn_...
It should be noted than 25kW is 33HP.
But the design obviously isn't limited to this? A bigger engine could give more power yet still consume less than a regular piston engine. Or 1-2 of these running in parallel, depending on the load.