In America the diesel engine still has the bad reputation of being loud, noisy, offering not much dynamic power, and having a very bad emission behavior. Plus based on some unsuccessful introduction attempts decades ago the diesel engine is also believed to be very unreliable and to easily break down compared to a gasoline motor. Unfortunately the countrywide diesel image in America seems to have stopped with this negative experience.
Not many people seem to realize or followed the tremendous success story of the diesel engine in Europe over the past decades. Today’s turbocharged and direct fuel injected diesel engines don’t have to fear the comparison with any high end gasoline motor in terms of power, performance, quietness and comfort. Plus year of experience in Europe seem to have proven that a well engineered diesel engine is normally at least as reliable and rugged as its gasoline peers. Often diesel engines actually run many more miles over lifetime than a comparable gasoline motor.
So it is a pity that, in the U.S., people do not yet see the benefits and values of a diesel engine which could show their strengths, especially in the very common long-distance highway commutes.
Encouraged and supported by the recently released highly efficient “clean diesel” generations, like the BLUETEC concept from Mercedes, many European manufacturers are now trying again to enter the American market with their most recent diesel fleets. The efforts and improvements on emissions due to improved filter and exhaust technologies make the diesel comparably clean and environmentally friendly to gasoline cars—meeting the more stringent regulations of states like California. But still it will likely take quite some marketing efforts, promotion campaigns, and very credible advertisements to convince the population of diesel engine efficacy.
But if the U.S. market and car buyers indeed pick up the new trend and start valuing the benefits and the performance of modern European designed diesels, then suddenly North America could indeed become the next huge market for diesel cars. This on the other hand could lead to a major push back on the penetration ratio of HEVs in the market.
At least one big obstacle that can prevent the introduction and penetration of diesel engines in less developed/emerging countries should not be a problem for the U.S.—namely the availability of high-grade clean diesel fuel.
As will be explained later, modern diesel engines draw their performance out of a sophisticated motor control strategy that is based on high pressure fuel injectors. These highly precise masterpieces of electro-mechanical engineering can be contaminated or clogged by unsuitable fuel. So the availability of quality fuel and the corresponding infrastructure of fueling stations could become a major decision criterion whether a diesel engine may or may not be penetrating a country's market.
The HEV introduction and penetration in emerging countries like China or India is probably quite fast and not too much endangered by diesel since there are still some limits to a broad countrywide availability of clean fuel. These countries need environmentally friendly transportation means but the infrastructure and the availability of higher grade fuel seems to be problematic, especially when you look outside of the metropolitan areas. So countrywide improvements in the fuel supply chain would be needed, which now puts the diesel solution on par with electric vehicles—which themselves need major improvements in the electric supply infrastructure.
Coming back to the U.S., availability of clean diesel fuel is not an obstacle. This fact could give diesel an additional advantage vs the electrical infrastructure improvements that are required if the country wants to be ready for charging a major volume of plug-in hybrid or fully-electric vehicles. Therefore diesel seems to be a very logical and reasonable solution for our highway-driving nation. The diesel engine just needs to overcome the prejudice in the U.S. market.
Nice profile of the potential of diesel. And, fortunately, given that as the author states, his company wins with wide-spread adoption of either diesel or HEV, I'm betting this is more balanced than so much of what we read on the subject these days.
I think it is important to have a lot of research going into HEV and pure electrics, and we need early-adopter purchases, but in the near-term, the planet could probably get the best reduction in fuels use and pollutants per buck by looking to solutions like modern diesel and super efficient gas power plants. I wonder how much fuel we could save simply by reducing the horsepower in all vehicles by ten or twenty percent.
That's probably the real hold-up. We want power and lots of it. To satisfy that desire, we have big gas engines and hybrids that are more about increasing horsepower than fuel economy.
I think HEVs will benefit once solar has dropped in cost to the point that consumers have excess power and need a place to put it.
I drive a Jetta TDI myself, powered by B100 biodiesel produced from recycled fryer oil.
I drive one of the Citroen babies (1.2L turbo-deisel) 5 years ago in Spain for several weeks over 4000Km; less than 4L/100km doing 120Km/hr. Experience: smooth, powerful, miserly like US automakers / customers don't have a clue.
We don't get out enough nor realize the joke we are. Thanks for your article and quiet significant observation.
ps: did you ever have to change one of those HEV batteries, do you know how often you have to in the car's life & related $, any idea of that environmental overall impact? Time to look at the numbers (all of them including 'electric vehicles').
I also converted/drove a Natural Gas conversion dual fuel minivan; a local after-market update shop on a Pontiac minivan. Technology easily applied ($2500) after mfg. and paid-for using a local sales-tax rebate, that is developed to production levels in Italy (over .5M NG vehicles in use). I can gas-up at home with a compressor appliance outside my garage. Engine life is extended with higher octane rating / cleaner burn. Gasoline is still there with a dash-mounted switch.
It's out there, just get to it. Good hunting .. & travelling.
I drove a Citroen 1.2L Diesel in Spain more like 15 years ago. At the time, one of my other cars had a Chevy 350 cu in (that's about 5.7L for you kids). At first, I though I might as well get out and walk. But once I figured out that I couldn't shift it like an American sports car, the Citroen and I came to a pleasant understanding: it was a wonderful, if small, car. Bell hops at the hotels would ask me where I was from, how I liked the car, and usually, what I drove at home in the US. I would tell them that my engine at home was 5 times as large, and some would wonder at my Spanish: once, a fellow said "Chevy?" and I smiled yes... it was fun.
I miss that car: it was well built, and I couldn't complain of the fuel economy. I wouldn't buy a hybrid: for one thing, I tend to tow a trailer once in a while, and my tastes run to an FJ Cruiser, but I'd certainly consider a large-enough vehicle with a Diesel powerplant.
Nice article.. I recently moved from a Gasoline car to a Diesel..and never once regretted. It's pheomenal torque, performance and low emission will put a gasoline to shame. And contrary to popular belief you do get quality fuel in India- and India' commercial tansports run on diesel.. The only reason diesel cars sell less in India than gaoline is due to the premium you pay for Diesel. And given that US does not have such issues, Diesel could make a killing if the mindset could change.
Hi guys and girls (if any...). The higher carnot efficiency of diesels is obvious. Europe is typical diesel country about 1/3rd of all ordinary cars is a diesel here. Why? because of fuel efficiency. Only the taxation of these diesel cars holds us back otherwise they would be the majority. We drive two VW diesels, a polo 1.8 sdi doing 20 km/l if driven in a sporting manner but well behaved 24 km/l if you hold back on the paddles. Not slow at all. Second is a two-metric-tonne T5 transporter van. Big thing. Drives 13 km on a liter of diesel. Thats a lot of cargo bay + 5 person seats (double cab version) and yet using less than the average SUV. And it does not drive like an old truck, no it is actually like a nice car. Silent, reasonably fast, has airco, cruise control etc. No big deal. This how we keep our holidays affordable...
Best regards Henk Mol
As a customer, I can understand the comparison between HEV and diesel cars. As an engineer, I don't. Diesel cars are competing with gasoline or fuel cells. They are a way to store energy. HEV are not storing energy, but are providing a way to transform chemical energy into mechanical motion. They are competing with the standard mechanical powertrain.
What about an HEV powered by a diesel engine?
Well that is what PSA in france is going to do later. Use a diesel + electric to recuperate the brake energy. At present the HEVs is mainly used by major auto oems to get the fleet averge CO2 emission into the legally prescribed level. Read well, the fleet average. So you start by cleaning up your prestigious models that people want to buy because it confirms the status they want to display... Why would you buy a gas guzzling large car or SUV? Its just Human to do so! It is beatifull, mighty, rich in its expression of your status and an expression of your wealth and social position. Look at the LX400H series hybrid SUVs - drive a large heavy car and yet have a CO2 performance of a middle size car.
The article has three major mistakes.
First, the advantage of HEV is well beyond the start-stop in urban traffic. I won't go in details, but that sentence is simply misleading.
Second, I doubt that the cost of a modern diesel engine is so much lower than a HEV powertrain. When you make comparisons with Europe, please bear in mind a simple fact: Europe lags USA and Japan on emission limits by 10 years. A modern diesel "Euro 4" can be readily sold in Europe (up to this December) but the same car would never pass the EPA rules. Europe has always had a very permissive policy on diesel emissions, that's why these cars are so common here. But when you want to compare apples to apples, then you have to consider the price of SCR and urea injection: the car becomes an expensive chemical laboratory.
Three: about the reliability. In the recent 10 years, the biggest part of problems came from the diesel powered cars (please check with ADAC statistics if you don't believe me). It is true that basically the diesel engine should be more sturdy and massive, but the "add-ons" have proven very unreliable: turbine stators stuck, particulate filters clog (especially on short travels), debimeters get dirty, electronics goes crazy (I think the Ford Focus 1.8 tdci was maybe the first case of problem solved only by a firmware update).
I don't want to bash the diesel, it DOES have some advantages, especially for the typical American way of driving, just bear in mind these issues when comparing solutions.
PS for a pure serial hybrid, a diesel, constant RPM, downsized engine would be the best solution, IMHO.
Hello Markogts, of course you have good points here. My reaction.
1. Emissions other than CO2. Sure the diesel engine running on diesel fuel has an issue reaching Euro 5. Fine soot particles and NOx emission are traditional problems of (not yet warm running) diesels. However, the R&D is now turning to running diesel combustion process with petrol like fuels or also very well possible running it on methane. This relieves the catalytic converter from having to deal with the soot. The CNG way is high potential with "big gas" replacing "big oil".
2. Energy efficiency. The average petrol engine otto cycle efficiency is under 22% mechanical output. This is why Toyota went to the Atkinson cycle which reaches nearly 31 % at its sweet spot. Combine this with electric traction to extend the rpm-torque range et voila overall 25% performance is feasible. Add brake energy recuperation and you gain another 10%.
3. A major hurdle in upscaling HEVs is the scarcity of technology metals, in particular the heavy rare earth additions needed to get high coercitive field strength at automotive temp of the rotors (typ 150 -180 deg C peak). The lack of in particular dysprosium is strangling the future motor production volume. Batteries may be a major problem today but there are at least alternatives such as the bipolar lead acid (weighing 50% more than same size same power same power density yttrium doped lithium iron phosphor oxide)
Based on this I think that HEVs and complete EVs will evolve much slower than we would like to. In 2020 potential volumes run in the 10 million vehicles/year. So, remains for us as ordinary consumers the other 55+ million cars/year... the smelly old petrols and diesels. Whats your opinion?
The lack of rare earth seem really a big problem, along with the peak of many other resources, oil in the first place (but copper too seems precious). My opinion is that there is no "one-size-fits-all" solution. Several options look promising: for the mum that goes daily from home to school and backwards, a pure electrical car may be enough. For a truck that crosses the continent two times a month, we'll have to stick to diesel, maybe turbo-compounded with several intercooling stages. If I had to buy today a large van, I'd get it diesel, for sure, but for a city-car, I'd prefer a hybrid one. BTW Let's see how the new Peugeot diesel-hybrid fares. Many of the solutions, however, are outside the mere automotive technology: for example, kids can just simply walk to school or use public transportation, trucks can be loaded on electrical trains etc, but these issues are a bit OT :-)
About big cars being hybrid: that's a move that I really do not understand. Yes, the fleet average has to be the main driving force, and the wide margin on price. I really don't see the point of making a Lexus LS hybrid. It's an "autobahn" car, it doesn't need hybrid. Fortunately, small hybrids are finally arriving: Honda Jazz/Fit and Toyota Corolla.
First off, I welcome everything being done to improve diesel efficiency, especially in the urban driving. However, I note that GM killed their belt-assisted, auto-stop cars in May. One reason being the lack of usable, regenerative braking that saves vehicle kinetic energy instead of just heating the brakes. But it is also important to understand user efficiency versus EPA lab test results.
If you go to www.fueleconomy.gov, you'll find not only the vehicle specifications but actual owner reported milage:
MPG(vehicles) - Model
38.4(004) - VOLKSWAGEN Golf2L, 4cyl
40.6(002) - AUDI A3, 4cyl, 2.0L
--.-(000) - AUDI Q7, 3.0L
49.2(104) - TOYOTA PRIUS, 4 cyl, 1.8L
49.5(015) - HONDA Insight, 4 cyl, 1.3L
28.3(002) - LEXUS RD 450h AWD, 6cyl, 3.5L
23.6(003) - TOYOTA Highlander, 6cyl, 3.3L
The low numbers of diesel owner reports is consistent with the USA diesel skepticism. But the reason we bring up user mileage is the hypothesis of "equivalent highway mileage" between a diesel and hybrid falls apart in practice when the car is in the driveway and the kids have to get to school. So ask someone making that claim, "What is your urban car?"
In reality, very few can afford separate highway car and urban cars but must mix both urban and highway traffic. That is OK with hybrid owners who believe diesel ownership, like chastity, is its own reward . . . and punishment at the pump.
Bob Wilson, Huntsville AL
The www.fueleconomy.gov is certainly the best website that I've seen for making apples to apples comparisons to all types of cars. I think Chevy has the right idea with the Volt (and similarly, the plug in hybrids). That way we can take advantage of cheaper electricity, regenerative braking and still have the convenience of gas (or diesel). Until we can effectively use hydrogen as a storage medium or we make some signficant electrical storage breakthroughs, gas is required for the American culture.
Addressing the big car hybrid comment, if MOMS are insisting on using SUVs to take their one or two kids to school, why not use 30-50% less gas by having a hybrid. The price today is overly inflated because most add signicant other amenities along with the hybrid features.
I spent some time between Texas and Colorado, and I noticed very few "corvette" or stuff with high torque around. Some were stopped by Police or stuck at 55mph speed limit...
What I did notice is the high number of pick-up that were running empty. Here you need big engines to carry stuff, but most of the time people use the pick up as a standard car and that creates the false illusion that a "chevy" may be a cheap alternative. Seen form outside, the impression is that in States beople simply tend to buy "big". Coming to horsepower, you will be amzed to see a "Corvette" outperformed by a Porche or Ferrari and discover 30% less gasoline consumption on the latters. TESLA is an US company making business in electrical sport cars. That is amazing as horsepower and drive torque, even better than a Ferrari. Just, try to plan a trip longer than 300mls with it...
Commenters & author, I am an engineer, and I am going to learn a lot at the EVS25 conference in Shenzhen, China, where the state of the art of hybrids, EVs and anything around it is displayed from the perspective of the far east situation. Visiting similar conferences in the EU I find a discrepancy between political fanfare that is broadcasted in the media, and the engineering, technical, physical, sociological, and financial reality presented on the conferences. Three major misconceptions about electric traction seem to live in the media (1) massive use of overnight charging is cheap and under the consumer's control (2) affordable accumulators are ready for the job (3) the battery and electric motor metal supply line of such vehicles is sufficiently large and is affordable. It is amazing how far we are from this state of affairs. The required performance and cost levels, as well as the 10s of thousands of tons of high-tech metals and chemicals, are factors if not an order of magnitude away from what the media proclaim. Welcome to the real world. So lets observe on the conference in November how human inventiveness copes with this. Regards Henk Mol
In France and Italy, most of people I know drive Diesel, even turbo-diesel sport cars of 150 HP or more, in spite of higher taxes on the fuel. I tend to say that, dropping motorcycles and a handful of Porsche or Ferrari the penetration diesel is much around 80%. Also, 100 of european trucks are diesel. Diesel has the reputation to be much more reliable than gasoline. For example Mercedes-Benz Diesel are well sold after 250k Kilm (150k Miles) since the buyerknow they can easily go up to 450-500k before starting worry.
I recently had the opportunity to drive the new Volvo S70 (Diesel), not in such benchmark, that actually did implement the start-stop functionality. I had the amazed surprise to run more than 1,000Km (630mls) without stopping for re-fuel, in urban and extra-urban cycle on smooth and very silent cruise speed of 140 km/h (87mph). The tank was 75 liters (20 US gallons).
Autonomy is a weak point for HEV: on long trip, if you cannot recharge, than you are using conventional fuel AND bringing the additional weight of your empty batteries. Diesel stations are already everywhere, electrical network must be created and, more, a standard way to replenish your battery in sort term is yet to be available.
For HEV, I confirm that they need much more electronics, but the demand is now growing and already the related prices are moving down pretty fast.
I don't understand why everyone thinks that diesel is so clean. Go look at the data. EPA certification data is here:
If that URL gets filtered you can get there from epa dot gov, then search for "Annual Certification Test Results Data"
Not all models are in there. For example I don't see the Prius or the TDI. But I do see a hybrid Lexus and Diesel Audi Q7, which should be pretty comparable. Here are some numbers:
CO: Audi .3 Lexus .2
NMOG: Audi .023 Lexus .006
NOX: Audi .045 Lexus 0
FYI A suburban comes in at:
The numbers are in grams/mile, measured following one of several driving test procedures.
So we see that for NMOG and NOX, the important compounds, we see that an anemic luxury diesel that barely seats 5 is comparable to a luxury full size SUV that seats 8 in comfort and can tow a boat or travel trailer to boot.
This is a dramatic improvement from the past. If you were to look at data from early 2000s you'd find diesels at least an order of magnitude worse then gas. But diesels aren't the "new hybrid", they're not even the "new gas".
Nice article Henning. The only downside of Diesel here in the UK is that it is more expensive than petrol (gasoline). Do not know why since it's cheaper than petrol elsewhere in Europe (to my knowledge).
Price depends mainly on taxes (in EU). Moreover, there could be a refining capability limitation: the ratio of diesel/gasoline production is heavily dependent on refinery technology and oil quality, can't be changed so easily.
To a certain extent the figures mentioned in the article make sense. IC engines rely on an optimum RPM for efficiency which is not exaclty the start-stop city traffic's cup of tea. So choosing a prime mover for those sections of driving is defntly going to make sense and micro-hybrid indeed serves the purpose at those points.
but to downplay the HEVs by pointing to microhybrids is a negative route to take. hybrids are a precursor to the EVs, a stop-gap arrangement till battery chemistry is gud enough and we have the infrastructure on the freeways to support it. As a general rule the rational mind shud favor the direction we are on, instead out pointing out things like 'they have the same mileage on a highway' .. hope we all realize hydrocarbon prices will only go up and electricity price can only come down, so no matter how strong the statistical figures at this point, they will always fails in favor of the EVs at some point of time.
What has held diesels back, at least here in California, is not prejudice, but emissions. When diesels can meet California's strict emissions standards, then they will be sold in the state. Until then, they can't be sold here. No prejudice--just cold hard numbers. Their are a few cars that now meet this and more are coming.
What about an HEV powered by a diesel engine?--roldan
Great idea. Haven't they been doing that with trains for decades now?
Get your facts straight first. Current new diesels are extremely low in emissions now 2011 are availabe from many manufacturers with low sulfur diesel or biodiesel it is much easier now to meet the emissions. most manufacturers have met the federal requiremnts years ahead of schedule in order to meet the stricter Cal. requirements. I agree it is rather stupid to require older vehicles to comply with standards that they were not designed to meet. Diesel hybrids
would require much smaller diesel engines since acceleration could be from battery power and diesel power combined and then recharge when power is not needed. Box trucks could be powered from a small direct injection turbodiesel. California is a bit out of hand with their emissions laws. They seem to mandate things that are difficult to achieve but then the rest of the country does not have a legendary smog problem as they do.
I have to disagree with the author on one fundamental point. The city driving advantage is due to recovering the energy during the stop, not from stopping the engine. Simply shutting off the engine at stop signs is likely to provide marginal benefit. If you calculate the energy used to accelerate, being able to recover that dwarfs other effects.
@nando basile: Autonomy? You have poor information. HEV's don'T EVER need to be plugged in. You simply put gas in like any other car. With my commute, I travel about 500 miles/week in my civic hybrid. I put about 10.5 gallons on Monday's. I also occasionally drive from SF to Mesa, AZ to work on our rental. Almost 800 miles. I have to stop for a body break more than to get gas (one gas stop does the trick for my 12+ hour trek).
@ Steve Ravet. You can't look blindly on the data. It may appear that diesel has higher emissions. But consider this. As others I drive the TDI Jetta. I manage to make a tank last two weeks before fill-up commuting to work. I would use twice the amount of gas which would cost me twice as much and I would burn up twice as much fuel. See where I'm going? More fuel burned = more emissions.
I see two problems with the way we "quantify" things.
1. MPG is ok but it needs to be more like MilesPerDollar/Gallon.
2. When comparing emissions MPG should be taken into consideration
@Majestek: "More fuel burned = more emissions", sorry but this is not true. Quality of fuel and combustion type are way more important factors. And care has to be taken when speaking generally of "emissions". One thing is C02 emission, which is heavily (but not exclusively) linked to the amount of fuel burned; one other thing are pollutant emissions, which are higher in diesel engines, no matter how you measure it. A typical gasoline car has no particulate emission whatsoever, and HC/CO/NOx are quickly removed with a catalitic converter, while diesel engines require expensive exhaust treatment, subjected to maintenance and failures, and still leak some particulate. Moreover, while CO2 emissions are size-dependent, this is not the case for pollutant emissions: a recent huge SUV may well have lower pollutant emissions of an older compact.
i would think that you also need to include the mass of waste per mile in the calculation. A lightweight hybrid that is scrap metal after 100,000 miles or a solid diesel that is still working just fine at 300,000 miles are going to be different in the amout of total pollution generated per fucntional passenger mile.
The total energy bill, of manufacture, operation and disposal should be considered when looking at efficiency of the car as a system.
This is certainly quite a surprising data to me. Who knew that the old diesel engine could be comparable to hybrids in terms of fuel efficiency. A driver that is looking to save money on fuel costs in the long term will certainly take this into account. Still, the amount of emissions that a diesel engine emits is largely over a hybrid engine, so in a way, hybrids are still better.
Peter - http://www.pmwltd.co.uk/