Questions that Anyone Discussing the Future of Personal Transportation Should Be Able to Discuss Knowledgeably

August 19, 2011

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by Joanne Ivancic (Advanced Biofuels USA) Background: With the understanding that if auto makers selling in the US intend to meet new 54.5 mpg CAFÉ standards, it is likely that they will build lighter weight, high performance engines that require high octane fuels. If domestic fuel producers, especially the renewable ones, want to provide those high octane fuels, it seems logical that all those involved in all elements of the value chain to create those fuels should know a bit about how they work and what their end customers, the ones buying vehicles with these new engines, will need.

In order to achieve the most efficient, effective, sustainable (economically, environmentally and socially) engine/fuel systems, it also seems prudent that those designing the engines and those making the molecules for the fuels should speak the same language and should develop sophisticated working, technological relationships and collaborations.

At Advanced Biofuels USA, we have a board member and volunteer who is very conversant in both the language of biofuels and that of automotive engine performance. As one who has witnessed conversations among automotive technicians, engineers and other professionals on these topics, I have the feeling that people like me who don't speak "automotive" need more education about how engines use or could use renewable fuels.

I hope that workshops and “automotive language” training is soon provided to people in all aspects of the renewable transportation fuels value chain. As one who would benefit greatly from such training, I’ve listed some questions that I think should be covered. Some of the questions I might be able to answer on some level of sophistication. Others include concepts that remain difficult for me to grasp.

I imagine many people, like me, have never changed a spark plug, have never changed their own oil or air filter, never took a shop or automotive class and restrict their activities “under the hood” to filling the windshield washer fluid containers.

However, if you want to be involved in developing biofuels for use in tomorrow’s vehicles, you might look for classes that help you understand the following concepts and processes. Remember, the “car guy” in the organization did not come up with these questions. He would probably think some of them are silly—or poorly worded. There are probably multiple answers to some of the questions. I came up with them, a life-long “non-car guy” and I’m presenting them like this because I think many will find them to be questions that you would also like to understand.

And if you are a “car guy,” laugh all you want. But don’t be surprised if your colleagues start to ask you for answers.

In no particular order:

What is torque?

What is horsepower?

What do torque or horsepower mean to me as a driver?

What do they mean to me as an automotive engineer?

How do different mixtures of gasoline molecules and ethanol influence torque or horsepower?

How does torque created by an electric engine in a hybrid influence the type of engine design (cycle—otto, atkins, etc.)?

What is octane? What does an octane number measure? What does it mean?

Why are higher octane fuels more expensive?

What is power-to-weight ratio?

What does power-to-weight ratio have to do with choice of fuel?

What do cylinders have to do with fuel performance?

Do high ethanol blends add benefit, subtract benefit to electric hybrid engines or does the gasoline/ethanol ratio make no difference?

Why are emissions tests done not with gasoline that I buy from the local retailer, but with a certification fuel, something called Indolene?

Does this test give any information relevant to "low carbon standards?"

Are official EPA mileage numbers (that you see on the sticker when you buy a car) based on Indolene, on gasoline that you buy at the local retailer, on E0, on E10, or on some other fuel?

Same question with regard to emissions result. Are EPA emission tests based on Indolene, on gasoline that you buy at the local retailer, on E0, on E10, or on some other fuel?

Does EPA, when figuring the emissions from E85 in a specific model vehicle, use a mixture of 85% ethanol and 15% Indolene? If yes, what are the results? If no, why not?

When EPA calculates an auto manufacturer’s compliance with CAFÉ standards, does EPA give any credit/benefit to use of renewable fuels, even if they get less mileage? Or does EPA only use tests of vehicles using Indolene as their “score” for compliance certification?

If a vehicle running on E30 gets mileage within about 5-6% of the mileage it gets using E10 (regular in most retail stations in the US), is that substantially the same for the consumer? That is, will a consumer notice if his/her mileage using E10 is usually 30 mpg; and with E30, h/she gets 5% (1.5mpg) less mileage? Or will that consumer say the mileage is substantially the same, not varying more than mileage difference between highway and city driving?

If you are a fleet owner and pay 10-30% less for E30 and get the kind of mileage difference described above, would you consider this substantially the same mileage? Would you consider powering your fleet with E30 instead of E10 a better financial deal?

If you are a car manufacturer and have to stretch all of your resources and talent to meet the new CAFÉ standards (54.5 mpg fleet-wide); would you build cars to optimize mileage using the certification fuel (Indolene) or to optimize mileage using renewable fuels if the mileage with the renewable was even 5% lower?

What is compression ratio?

What are typical compression ratios?

Does the kind of fuel you are using have anything to do with compression ratios?

What does “displacement” mean? What is being displaced?

What is Reid vapor pressure or rvp?

What does Reid vapor pressure have to do with ethanol blends?

Do other molecules in gasoline have any effect on rvp?

What is fuel injection? What differences does fuel injection make to a consumer’s or an engine designer’s choice of fuel mixture?

If an internal combustion engine (ICE) or diesel engine is not just a series of things that happen one after another, but a system of processes and feed-back loops, what’s the best system? Does it matter what the purpose of the vehicle is; what the expected use will be?

If we can describe a best engine system, can we describe a best fuel? What would the “recipe” of molecules for a best fuel be? Would the answer change if the seasons, altitude or typical use of the vehicle changes?

What is the relationship between emission testing and mileage testing?

For purposes of meeting proposed CAFÉ standards, how is mileage calculated for all electric/plugin electric vehicles; for plug-in hybrids; for flywheel/regenerative braking hybrids? Does the calculation take into account the emissions released in production of the fuel used to generate the electricity for these vehicles?

Why aren’t all new vehicles flex-fuel, i.e., E85 compatible?

What would it take to make all new cars or all new vehicles flex-fuel?

Why are hybrids in particular not flex-fuel? If they are marketed to people who are environmentally conscientious and early adopters, why not offer them the choice of filling up with E85?

Do cars, trucks, buses and other equipment get counted all together to determine CAFÉ compliance by manufacturers?

If one policy goal of CAFÉ standards is to clean the air; another to get off or to reduce our “addiction to oil” and other imports; and if other goals are to reduce use of fossil fuels, should renewable energy used to power vehicles be recognized in assessing compliance with CAFÉ standards?

Final Exam:

After being comfortable answering these questions, work on this word problem:

If a vehicle weighs 4500 lbs (say an SUV or big BMW), to get basic performance, takes 300 horsepower (hp). If this vehicle gets 22 mpg and the vehicle can be made lighter weight, say 600 lbs is shaved from its weight, it will weigh 3100 lbs. To get the same performance, how much power do you need?

Think of this: a 15% weight reduction means you should be able to reduce the needed horsepower by 15% . So, you only need an engine that will produce 255 hp to give you the same performance you had before.

However, since you can go to a smaller engine with a lighter transmission system, you might increase your mileage to 28 mpg. If you add turbos to get higher compression ratios and make other engine adjustments that you learned about in the class, and improve the aerodynamics, you may find that the fuel you need to meet the demands of the new engine must have high octane.

Is the logic of this proposal sound, based on what you have learned? If not, where are the weaknesses?

The bonus question: Can a fuel supplier supply higher octane fuel at the same cost as regular fuel; at the same price relative to mid-grade or premium? If we benchmark against gasoline, what would the price of gasoline (regular (E10), mid-grade, premium) have to be for a high octane fuel to be competitive? How much of the "gallon" can be provided by renewable fuels?

If you want to do a bit of “home study” on this topic, here are some suggested resources to get you started:

Advanced Biofuels USA Publishes Paper and Slide Presentation on Truly Optimized Flex Fuel Vehicles: Benefits and How to Achieve Them https://advancedbiofuelsusa.info/advanced-biofuels-usa-publishes-paper-and-slide-presentation-on-truly-optimized-flex-fuel-vehicles-benefits-and-how-to-achieve-them

What’s the Difference between Biodiesel and Renewable (Green) Diesel? https://advancedbiofuelsusa.info/what%E2%80%99s-the-difference-between-biodiesel-and-renewable-green-diesel

Gasoline Ethanol Blends and the Classic Auto (Renewable Fuels Association) https://advancedbiofuelsusa.info/gasoline-ethanol-blends-and-the-classic-auto

GM, Coskata Join Forces to Correct Misconceptions about Ethanol https://advancedbiofuelsusa.info/uploads/old/11-0400-Ethanol-The-Primary-Renewable-Liquid-Fuel-CoskataGM.pdf and https://advancedbiofuelsusa.info/gm-coskata-join-forces-to-correct-misconceptions-about-ethanol

If you find other useful references, or maybe some Community College non-credit courses, please let me know and I’ll add them to the list.

Also, if you want to add questions that I will give to anyone who might let me know that they are teaching such a course, please send them to info@advancedbiofuelsusa.org.

Additional suggested resources:

Petroleum Production, Distribution and Discussion of the use of Ethanol Blended Gasoline by Gold Eagle Company

On how turbochargers can increase the efficiency of internal combustion engines and diesels: "Are turbos killing the electric car?" http://www.iol.co.za/motoring/industry-news/are-turbos-killing-the-electric-car-1.1137526

Also from the Renewable Fuels Association:

For information on how engines and fuels work together to achieve mobility, see “Changes in Gasoline IV: The Auto Technician’s Guide to Spark Ignition Engine Fuel Quality” a manual (which is also available in CD form from the Renewable Fuels Association) used by the biofuels industry, auto mechanics, oil refinery personnel training programs, etc., worldwide. It includes information on, for example, “Fuel Specifications and How They Affect Vehicle Performance.” “The Use of Ethanol Blended Fuels in Non-Road Engines”explains ethanol in small engine use.

A presentation of a study by Ricardo for RFA: Influence and Importance of Fuel Octane in Future Engine Developments