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Delphi Developing Direct Injection Systems to Support Flex-Fuel Engines

Delphi Multec Direct Injection Gasoline (DIG) Injector.

Delphi is developing flex-fuel capability for its coming Multec direct injection gasoline (DIG) systems, thereby giving automakers the ability to extend the performance and efficiency benefits of direct injection gasoline engines into a flex-fuel application.

The current Delphi Multec gasoline multi-port injector systems can be used with global gasoline-alcohol mixtures of up to 100% (also factoring in the differing qualities of alcohol fuels in the global market) and on single- or multi-intake valve spark ignition systems.

Delphi fuel rails and Multec 3.5 E85 injectors allow for increased flow capacity for ethanol. Additionally, they are designed with additional resistance to ethanol corrosion. Delphi has supplied E85-compatible technology to more than 2 million vehicles. In South America, Delphi has produced systems and components for more than 430,000 ethanol compatible vehicles since 1991.

The current ethanol direct injection work is to ensure that Delphi’s upcoming DIG system for homogeneous combustion systems (homogeneous charge spark ignited), due to begin production in 2009, will also support global flex-fuel applications.

As [automakers] are responding to the market forces in their markets, higher fuel economy requirements, gas prices and those things, technologies are being implemented onto vehicles such as direct injection engines. Certain manufacturers want to make sure that they can offer the flex-fuel option with those as well.

—Michael Frick, Delphi’s Chief Engineer for direct injection gasoline systems

The Multec DIG Homogeneous Combustion Injector features an inwardly opening valve group that can be configured either with a swirl type atomizer for a traditional hollow-cone spray, or with a multi-hole atomizer that provides improved spray stability (cone shape) versus counter pressure.

The stratified spray created by the DIG Spray Stratified Injector enables fuel combustion to occur with sufficient energy to meet an expanded range of engine performance requirements while helping minimize fuel consumption.

Delphi will follow this system in 2010 with the introduction of its first spray-guided system, the Multec Direct Injection Gasoline Spray Stratified Injector, which will operate at 200 bar. Its enhanced linear flow range will be suitable for turbocharged engines. The small particles in the spray will optimize charge distribution for future combustion processes such as gasoline homogeneous charge compression ignition (HCCI).

Delphi is taking the approach that material selection for the DIG systems right from the beginning of design has to be compatible with alcohol, according to Frick.

This drives certain decisions such as the use of stainless steel, minimizing the number of elastomers, and putting more attention on the wear surfaces that experience increased forces from increased fuel pressure in a flex-fuel environment.

Ethanol has a higher octane rating than gasoline, and can be used at a higher compression ratio than its petroleum-fuel counterpart. Because of that, even though ethanol has a lower heating value that gasoline, it can actually deliver higher efficiency than a gasoline engine—given the appropriate engine configuration.

For example, a 2002 study by the EPA on the use of 100% alcohol fuels in a port-injected engine found that a turbocharged, 1.9-liter engine with a 19.5:1 compression ratio demonstrated better than 40% brake thermal efficiency with low emissions when using methanol. Ethanol produced similar emissions levels, but with slightly higher fuel consumption.

By way of comparison, Saab’s E100 400hp Aero X concept car (earlier post) uses a 12:1 compression ratio and twin turbochargers running at 1.0 bar boost. Both the Aero X and E100 Saab BioPower Hybrid concept (earlier post) use a Spark Ignited Direct Injection (SIDI) system.

MIT researchers have been investigating the use of a parallel ethanol direct injection (DI) system to support the use of small, highly turbocharged engines with substantially increased efficiency as a downsizing strategy to reduce fuel consumption and emissions. (Earlier post.)

In this scheme, the ethanol direct injection system is controlled separately from the gasoline injection system, and the ethanol is stored in a separate tank. The gasoline system can continue to use conventional port-injection.

The requirements of a flex-fuel system, however, are more constraining than those of running pure ethanol. The engine can’t be fully optimized to run either alcohol or gasoline.

But endowing a more efficient engine technology—such as gasoline direct injection—with the ability to support a flex-fuel application allows the flex-fuel platforms to take advantage of more general improvement in efficiencies provided by that engine technology. In the case of gasoline direct injection, that results in an estimated improvement in fuel economy of between 5% to 15%, depending upon the drive cycle.

Furthermore, researchers are still looking into ways to further optimize a flex-fuel engine for an ethanol blend. Saab introduced a concept Variable Compression Ratio engine in 2000 that, while definitely not a current high priority, is still being investigated, according to a company spokesperson.

Delphi is also interested in seeing if it can use its variable cam phasing system as a mechanism to get some additional small benefit out of the use of a fuel with higher alcohol content.

Siemens VDO, a Delphi competitor, has  indicated that its direct injection systems also will be E85 capable.




Hmm... if an E100 engine can be operated at compression ratios reaching up to 20:1 - comparable with diesel engines - without sacrificing clean exhaust emissions, that same engine could be used by means of a THS-Atkinson like valve timing (ie. extremely retarded intake valve close timing) to run on gasoline without pinging - and achiving higher efficiency also with gasoline due to the longer power stroke part (normal exhaust valve opening).

As the compression ratio is very close that of a diesel, the same engine blocks could be used with only minimal modification to the zylinder heads (spark plug), valve train (adjustable intake valve open / close timing) and zylinder heads (to guide the fuel/air flow within the zylinder).

That way european manufactuers could safe face, as not the entire money spent on diesel development needs to be written off in 6 years (when EU fleet consumption / emission limits get very much stricter).


Direct injection gasoline engines with stratified charge currently work on overall-stoichiometric fuel mixture with compression ratio of about 12 (on gasoline), with possible increase to 13-14 using different alcohol mixtures to suppress detonation. It provides up to 10% fuel saving, and increases max power for about 5%. In near future such engines will be equipped with developing 4-way catalytic converters (with NOx absorbers), and it will allow to use overall-lean mixture without increase in emissions. Such engine have up to 25% reduced fuel consumption.

Lean homogenous charge engines, capable to utilize up to 20:1 compression ratio currently capable to achieve this only on GASEOUS fuel with dual fuel ignition (pilot diesel fuel injection), or on most advanced models – spark ignition. Nobody yet has built working prototype of such engine working on liquid (gasoline or alcohol) fuel with spark ignition, let alone "holy grail" compression ignition (HCCI).


The problem is that automotive engine is mobile engine. Non of existing technologies are effective enough to justify carrying along additional weight of bottoming cycle device. Even on really big engines, like marine diesels, wasteheat is used for secondary purposes such as sea water distillation or adsorption chillers, but not for propulsion or electricity generation.
Thermal photovoltaic could change this equation, hopefully.


Thermal Electric devices are still a bit pricey but there is atleast one company who has done testing for the military on a muffler replacement TE setup which provides nearly one kW of energy from TE devices. They are also concurrently testing the same setup for heavy duty tractor trailer trucks. A 250W setup may be possible on a passenger vehicle but I'm not sure what the cost would be.

no more wars

Albeit a little dated, a report from the respected Environment and Forecasting Institute in Heidelberg, Germany puts the car right back at the centre of the transport debate and raises fundamental questions about a society increasingly adapting itself to the car. The world is now approaching 1 BILLION cars at the rate of 50 MILLION new cars every year, plus trucks, ships, airplanes, lawnmowers, tractors, ole ! The German analysts take a medium-sized car and assume that it is
driven for 13,000 km a year for 10 years. They then compute its financial, environmental and health impacts "from cradle to grave". Long before the car has got to the showroom, they find it has produced significant amounts of damage to air, water and land
ecosystems. Each car produced in Germany (where environmental standards are among the world's highest), produces:

25,000 kg of waste
422 million cubic metres of polluted air
160,000 liters of polluted water

in the extraction of raw materials alone, say the Heidelberg researchers.
The transport of these raw materials to Germany and around the country to factories produces a further for EACH car:

425 million cubic metres of polluted air
12 litres of crude oil in the oceans of the world
???? polluted water

The production of the car itself adds a
further per car:
1,5000 kg of waste
75 million cubic metres of polluted air
???? polluted water
Calculations of the impact of a car in use make the generous assumption that the car has a three-way catalytic converter and uses 10 litres of lead-free petrol for every 100 km. Over 10 years, the Heidelberg researchers believe that one car will produce:
44.3 tonnes of carbon dioxide
4.8 kg of sulphur dioxide
46.8 kg of nitrogen dioxide
325 kg of carbon monoxide
36 kg of hydrocarbons, 40 of them known carcinogens
???? liters of polluted water w/ oil, hc's, ethylene glycol

Each car is moreover responsible for 1,016 million cubic metres of polluted air and a number of abrasion products from tires, brakes and road surfaces:

17,500 grams of road surface abrasion products
750 grams of tire abrasion products
150 grams of brake abrasion products
???? poluted water (it rains in Germany)

The above numbers look very low, because in the US (us) alone we discard 250,000,000, that's 250 MILLION tires each year, year after year, that's average tire tread width times rubber thickness times wheel diameter times 250 million divided by 160 million cars. Go figure. Each car also pollutes soils and groundwater and this calculated for oil, cadmium, chrome, lead, copper and zinc and whatever else comes in the gas in ppm, multiply by 160 million cars times 10,000 miles average times gas consumption, and yes Senator, suddenly we are talking real money.
The environmental impact continues beyond the end of the car's useful life. Disposal of the vehicle produces a further:
102 million cubic metres of polluted air
quantities of PCBs and hydrocarbons
The sum of these different life cycle stages produces some insights into the penalties societies must face if they become car dependent. In total, each car produces:
59.7 tonnes of carbon dioxide
2,040 million cubic metres of polluted air
160,000 liters of polluted water in mfg
???? liters of polluted rainwater from roads

Each car, say the Germans, produces 26.5 tonnes of rubbish to add to the enormous problems of disposal and landfill management faced by most local authorities.
While this detail is impressive (and wholly absent from the environmental claims of motor vehicle manufacturers and motoring organisations), it is still not complete. Some of the more startling revelations are in the researchers' wider analysis of social and environmental costs. Germany suffers from extensive forest damage attributed to acid rain and vehicle exhaust emissions. The Heidelberg researchers calculate that each car in its lifetime is responsible for three dead trees and 30 "sick" trees.
The Heidelberg researchers say that over its lifetime, each car is responsible for:

820 hours of life lost through a road traffic accident fatality
2,800 hours of life damaged by a road
traffic accident.

Statistically, they suggest, one individual in every 100 will be killed in a road traffic accident and two out of every three injured. Translated into vehicle numbers, this means:
Every 450 cars are responsible for one fatality
Every 100 cars are responsible for one handicapped person
Every 7 cars are responsible for one injured person

And into production data:
Every 50 minutes a new car is produced that will kill someone
Every 50 seconds a new car is produced that will injure
Land use data are also brought into the equation to show that Germany's cars, if one includes driving and parking requirements, commandeer 3,700 sq km of land, 60% more than what is allocated to
housing. Every German car is responsible for 200 sq metres of tarmac and concrete.
The total impact of the car over all the stages of its life cycle also produces a quantifiable financial cost. The Heidelberg researchers estimate this to be 6,000 DM per annum per car (about $5,000) and covers the external costs of all forms of pollution,
accidents and noise after income taxation are taken into account.
This is a state subsidy equivalent to giving each car user a free pass for the whole year for all public transport, a new bike every five years and 15,000 km of first class rail travel.
The car is thus revealed as an environmental, fiscal and social disaster that would not pass any value-for-money test. More importantly, the car can now be seen as a disaster in itself. It is ownership as well as use that is the problem of the car and a car used sensitively (if that is possible) is still a problem for
energy, pollution, space and waste. The balance sheet's bottom line is enormous societal deficits and penalties and an assumption that we will all continue to pay the bill.
Reference: Oeko-bilanz eines autolebens. Umwelt-und Prognose- Institut Heidelberg. Landstrasse 118a, D69121, Heidelberg,
Germany. John Whitelegg is head of the Geography Department at Lancaster University and director of the Environmental Research Unit, Lancaster University

Chris (from MN)

I have a car. It makes it possible for me to visit my girlfriend, who lives 31 miles away (~50 km). Suburban sprawl would be impossible without personal automobiles. I enjoy living in a large, family home with a nice, green lawn and near a lake and a small forest. This would be impossible without the personal automobile. I live in Minnesota (northern America), where motorcycles are impractical for almost half of the year. Also, it always takes less time for me to take my car to somewhere than to wait for a bus or a train that makes lots of stops to pick up other people. Not only that, but I ENJOY driving my car.

I suppose that you're right, Mr. N.M.W., but I see the automobile as indispensable to my life. And the public transportation system here is good (relies on buses), but I don't think that buses really save that much fossil fuels, since they are much, much larger than cars and they must drive around picking people up, even if there are very few passengers. (also, buses do not regularly service near where I live or where I work) Trains are much less convenient than even buses.

America relies on personal transportation systems, whether that be horses or buggies or gasoline cars or electric cars or ethanol cars.

The environmental/fiscal cost of the automobile is worth it to me. I do think it's better to have ethanol fuel (cheaper, makes my car go faster, makes for cleaner water & air, and is produced by local Minnesotan farmers) than gasoline, but you'll take my car keys from my cold dead hands. Maybe I've been taken in by the consumer-driven, materialistic culture, but I believe that mankind takes care of the environment for mankind's sake, not for the environment's sake.

So, if a cute baby seal dies because I drive a car, then so be it. I mean, I want a clean environment as much as the next guy, but I don't think I should have to give up a modern way of life in order to have a clean environment.



You say "suburban sprawl would be impossible without personal automobiles." Certainly, substantial sprawl developed after the automobile became popular. In other words, your life-style... ah, screw it: you're a selfish, short-sighted jerk, and nothing anyone says here will change that! You say as much yourself.

Saeed Yomi

Im university student
I need information Variable Compression Ratio Engine

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