"Are diesel vehicles a viable alternative to hybrids?"
#11
Re: "Are diesel vehicles a viable alternative to hybrids?"
Originally Posted by bwilson4web
The obvious answer is to put a diesel in for the ICE and use a hybrid-electric drive. This is not an 'either' / 'or' but more correctly, an 'and'. Heck, there already are diesel-electric drive systems in wide spread use, they are called trains.
Bob Wilson
Bob Wilson
#12
Re: "Are diesel vehicles a viable alternative to hybrids?"
Those are good points. Though being able to replace some of that low end torque will still help mileage. Any wasted energy you can recoup will always increase your FE no mater what kind of engine you have.
#13
Re: "Are diesel vehicles a viable alternative to hybrids?"
Los Angeles is the home of LOVECRAFT biofuels (www.lovecraftbiofuels.com) which is an indy-garage that "converts" diesel engines to run on Waste veggie oil. (the conversion is a relatively simple process - my school bus only took 1/2 day to convert). This is better and cleaner than biodiesel because you are using a waste product and there is no need for processing. I urge those considering diesel & biodiesel to look at Waste Veggie OIl (WVO) as a great local option.
#15
Re: "Are diesel vehicles a viable alternative to hybrids?"
Hi,
So how much expense is too much??? Just enough to require an either or decision? From what I can tell, the diesel premium is rapidly disappearing. The cost of stronger journals and engine blocks for a diesel is relatively small. As for the injectors, some of the common rail, electric valved systems (a high pressure version of the low-pressure fuel injectors) should solve that problem, especially if enhanced with a spark, pre-heater (aka., ink jet printer technology.)
My thinking is the ultimate answer is a Sterling, external combustion ICE feeding an electric drive train. External combustion means complete combustion with minimal, post combustion scrubbers or converters. It also means ultimate 'flex fuel' since if it burn it churns. In fact it would be two Sterling engines of 1 cylinder and 2 cylinder size. This would let them generate 0%, 33%, 66% and 100% of their maximum rating. Finally, Sterling engines have excellent thermodynamic efficiency so you get out about as much energy as can be extracted from a heat engine. Their only drawback is a fixed speed and three cylinders gives four power levels.
So take a Volt (a PowerPoint version will do for now) and replace whatever ICE they put in with a three-cylinder, variable cylinder operating Sterling and modify the control laws to run the Sterling when the battery drops in proportional to the energy drop rate. The EV part otherwise works as before. As for the Sterling, it quietly sits in the rear and efficiently makes electrons move.
Bob Wilson
I completely agree that the diesel hybrid would be the greatest pick for MPG. However, the main explanation I have heard for why a diesel hybrid might not work out is that it would be too expensive once you include the cost of the clean diesel emissions equipment, and the hybrid drivetrain. It would be similar to paying a "hybrid" premium twice. Also, the hybrid assist would not lead to as much of an improvement for a diesel as a gasoline engine hybrid -- one of the major benefits of the hybrid is that it makes up for poor low-end torque found on efficient gasoline engines. Diesel engines already excel in low end torque though, so there would not be as much room for improvement from adding the motors.
My thinking is the ultimate answer is a Sterling, external combustion ICE feeding an electric drive train. External combustion means complete combustion with minimal, post combustion scrubbers or converters. It also means ultimate 'flex fuel' since if it burn it churns. In fact it would be two Sterling engines of 1 cylinder and 2 cylinder size. This would let them generate 0%, 33%, 66% and 100% of their maximum rating. Finally, Sterling engines have excellent thermodynamic efficiency so you get out about as much energy as can be extracted from a heat engine. Their only drawback is a fixed speed and three cylinders gives four power levels.
So take a Volt (a PowerPoint version will do for now) and replace whatever ICE they put in with a three-cylinder, variable cylinder operating Sterling and modify the control laws to run the Sterling when the battery drops in proportional to the energy drop rate. The EV part otherwise works as before. As for the Sterling, it quietly sits in the rear and efficiently makes electrons move.
Bob Wilson
#17
Re: "Are diesel vehicles a viable alternative to hybrids?"
Honda has a diesel Civic selling in Europe that gets 78 US mpg - I can't wait until it's clean enough to ge the EPA's blessings. 5-speed Insight fuel economy in a 4-5 seater - leadfooted drivers might still get 60mpg...still would not have emissions as clean as a Prius, but a step in the right direction.
#18
Re: "Are diesel vehicles a viable alternative to hybrids?"
A big plus to deisels:
The more clean minded diesel owners out there, the more the US will focus on biodiesel. Sure, the exhaust smells like hamburgers, but there are no, repeat NO sulfates in a pure biodiesel engine. Though, most biodiesel users mix with regular diesel, this is not needed. The University I attend uses biodiesel in every diesel burning vehicle they own. Personally, I own an HCH-II, but would seriously consider getting a diesel VW or most definitely a diesel Accord if biodiesel were made readily available.
The more clean minded diesel owners out there, the more the US will focus on biodiesel. Sure, the exhaust smells like hamburgers, but there are no, repeat NO sulfates in a pure biodiesel engine. Though, most biodiesel users mix with regular diesel, this is not needed. The University I attend uses biodiesel in every diesel burning vehicle they own. Personally, I own an HCH-II, but would seriously consider getting a diesel VW or most definitely a diesel Accord if biodiesel were made readily available.
Scott
#19
Re: "Are diesel vehicles a viable alternative to hybrids?"
One thing that never seems to be considered in this issue is the evaporative emissions resulting from the extremely volatile fuel that gasoline vehicles, including the hybrids currently available, use – gasoline and/or gas-ethanol blends. These are the evaporative emissions from the “handling” of gasoline – from the storage of gasoline and distribution/transportation of gasoline to gas stations, so they’re in addition to the emissions that come directly from the vehicle itself. Due to the very low volatility of diesel fuel (essentially non-volatile), these evaporative emissions would be virtually eliminated if we hypothetically turned over the entire U.S. light-duty fleet to diesel.
We keep hearing about “smog-forming” NOx, which is typically the most problematic emission for diesel engines. However, NOx is also “smog-destroying” since it readily reacts with ozone (the primary constituent of “smog”). NOx in and of itself will destroy ozone as fast as it makes it.
Anthropogenic hydrocarbons (HC/VOC) on the other hand, are also ozone precursors (i.e., produce ozone), but they don’t react with ozone at all, so they’re almost perfect “smog-forming” substances. On top of that, these VOCs oxidize in the atmosphere (creating ozone as they do) into formaldehyde, and ultimately, organic particulate matter (PM). This secondarily-form PM (called secondary organic aerosols - SOA) is mostly in the nanoparticle and ultrafine size range, which are suspected of being the most dangerous to health. So there are two major air quality issues associated with evaporative VOC emissions – smog and ambient PM2.5.
Studies have shown that about 80% of the ambient HC concentrations in the South Coast Air Basin in California (around Los Angeles) comes from gasoline vehicles (as direct emissions and indirect emissions from the evaporation of gasoline). The most recent studies show that about 2/3 of that 80% are from evaporative gasoline emissions. This is where I think the regulators, especially CARB, are out-to-lunch. Their arbitrary set of emission regs (LEV II and Tier 2) that favor gasoline engines (i.e., mainly focusing on NOx emissions) and that have essentially banning light-duty diesel vehicles, are actually hampering improvement in air quality, in my opinion.
EPA recently proposed to reduce some of these evaporative-emissions-from-gasoline-distribution (Federal Register, Nov 9, 2006), but that would amount to less than a 10% reduction. Of course, gas-hybrids would help here just from the fact that they use less gasoline. But these indirect evaporative emissions really need to be taken into account when evaluating how “green” a specific line of vehicle is.
Again, I think hybrid technology is very promising. I’d just like to see the U.S. move away from gasoline as the primary fuel for light-duty vehicles, even in hybrid applications, from an air quality perspective.
#20
Re: "Are diesel vehicles a viable alternative to hybrids?"
2% biodiesel? 20% biodiesel? what a joke! it's got too be 100% biodiesel (from WASTE veggie oil) or this is just another scam! Until that is mandatory (not voluntary) i will not endorse diesel cars coming to LA. I hope we keep the freedom for individuals to get their own waste oil for personal use AND have 100% biodiesel @ the pump for school buses, big rigs, ships, etc. Now that would be progress.