Primary:
Austin, Michael. "Honda Finally Adds Direct Injection to Its V6 and Four Cylinder Engines."
Car and Driver. N.p., 29 Nov. 2011. Web. 03 Feb. 2013.
<http://blog.caranddriver.com/honda-finally-adds-direct-injection-to-its-v6-and-fourcylinder-engines/>.
The source is direct from the Tokyo auto show, where Honda showcased their new line of
direct injection engines and its internals. Direct injection increases power and efficiency, but by
exactly how much varies greatly. In the case of Honda’s new 3.5L V6 with DI, it makes roughly
10 more horsepower, and yields a 10% fuel improvement over the port-injection 3.7L V6. Aside
from the most obvious technology, the new engines will also have stop/start technology,
cylinders deactivation, and 2-stage oil pump. Honda is also introducing CVT, or continuously
variable transmission, into their lineup; hoping to increase their corporate average fuel economy.
"Direct Injection Gasoline Engine." Mazda. N.p., n.d. Web. 24 Mar. 2013.
<http://www.mazda.com/mazdaspirit/env/engine/disi2.html>.
This is an article directly on Mazda’s website, explaining their groundbreaking 2.3L
MZR DISI engine. Mazda’s 2.3 DISI turbocharged engine produces similar power to a 3.54.0L naturally aspirated V6 engine with port injection. Cleaner emission is made possible
by direct injection, by injecting fuel directly into the cylinders. The result is a faster heat up
of the catalyst to its thermal activation point during engine startup, by delaying ignition
timing. Power is not sacrificed with the increased efficiency of direct injection. Over port
injection, the engine’s peak torque increased 10%, due to in-cylinder cooling effect.
Papa, Joey. "The Dark Side of the Hybrid." 1800RECYCLING RSS. N.p., 15 Mar. 2010.
Web. 27 Mar. 2013. <http://1800recycling.com/2010/03/dark-side-hybrid/>.
“The hybrid has its many environmental and economic advantages, but there is one
aspect that needs to be evaluated: its battery.” Lead is considered to be highly toxic and
even more of a concern if it seeps into the water systems, yet it is one of the main
components found in hybrid batteries. The good news is that lead is easily recycled if it
makes it into the appropriate hands. The bad news? Many people throw away their old
hybrid car batteries.
"Variable Valve Timing & Lift Electronic Control (VTEC)." Honda. Honda New Zealand, n.d.
Web. 03 Feb. 2013. <http://m.honda.co.nz/technology/engine/VTEC/>.
The source is a trustworthy primary source because it is published by Honda, the
developer of VTEC, essentially their own advanced VVT system. In earlier engines without
VVT the lift of the intake and exhaust valves were fixed, which essentially means there is always
a compromise between everyday drivability (good road manner, low fuel consumption, and
lower emissions output) and performance. And the compromise between the two results in
inefficient fuel consumption and excess emissions. Honda’s VTEC integrates two cam profiles
and two rocker arms per cylinder to vary valves lift (2 stages), affected by different hydraulic
pressures at varying engine speed. This allows the cam timing to change, which results in greater
efficiency and power (horsepower and torque), over a wider range of engine speed. Honda’s
VTEC is a huge milestone in fuel efficiency technologies, but newer Continuous Variable Valve
Timing of a few recent modern engines are now able to vary valves lift independently, yielding
an almost infinite number of of valve timing scenarios. Although the application of CVVT is not
yet widely used, it is growing continuously and is something to look forward to in the near
future.
Webster, Larry. "2010 Toyota Prius Hybrid Electric Car Technology Exposed." Popular
Mechanics. N.p., 2 Mar. 2009. Web. 27 Mar. 2013.
<http://www.popularmechanics.com/cars/alternative-fuel/news/4306961>.
Prior to the release of the 2010 Toyota Prius, the best selling hybrid arguably in its
own segment, Toyota released technical details to the editors of Popular Mechanics. The
total maximum output of the 1.8L Atkinson cycle engine with electric motor is 134 hp, or
roughly equal to that of Ford Fiesta’s 1L 3-cylinder Ecoboost direct injected turbocharged
engine. The Prius’ fuel economy is 50 mpg in the city, 49 on the highway, compared to
29/41 mpg of the Fiesta. However, the Fiesta is priced at roughly $16,000, a whole $6000
less than the Prius. At about $3/gal fuel price, it would take over 10 years to recoup the
premium!
Webster, Larry. "Top 5 Turbocharger Tech Innovations: The Truth about Fuel-Sipping
Turbos." Popular Mechanics. N.p., 1 Oct. 2009. Web. 24 Mar. 2013.
<http://www.popularmechanics.com/cars/how-to/4306310>.
Modern turbochargers and most often used for efficiency, they are smaller and are
able to withstand a considerable amount of heat. This is due to advancements in
production, employing stainless-steel housing (instead of cast iron), and advanced
computer engineering. With direct injection injecting fuel right into the combustion
chamber instead of the more conventional place--the intake stream--the fuel dramatically
cools the intake charge. This cooling effect reduces the potential for harmful preignition or
detonation and allows engineers to specify higher, more efficient compression ratios. Most
importantly the advancement of the ECU in detecting and managing engine-killing
detonation makes turbochargers well trusted by manufacturers. A safe estimate is a 8-10%
increased efficiency over larger naturally aspirated engines making comparable power.
Woydt, Edward, and Dejoe Csandy. Valve Operating Means. Edward Woydt Et Al,
assignee. Patent 1527456. 24 Feb. 1925. Print.
This is one of the very first patents of variable duration valve opening that appeared
during the 1920s. It is essentially a diagram of VVT at its very basic and early stage. It
won’t be until the appearance of helical camshaft that the invention was put to any use, the
most important evolution being Honda’s revolutionary VTEC system debuted in 1997.
Although the operation of the system is different from modern systems, the theory is the
same. Due to engines becoming more and more potent, giving rise to higher engine RPM
limits starting in the 1920s, there was desirability to vary the valve opening duration to
match an engine’s rotational speed.
Secondary:
Abuelsamid, Sam. "VIDEO: GM EcoTec Chief Engineer Talks Direct
Injection."AutoblogGreen. N.p., 10 Mar. 2009. Web. 24 Mar. 2013.
<http://green.autoblog.com/2009/03/10/video-gm-ecotec-chief-engineer-talks-directinjection/>.
The article written by Sam Abuelsamid includes an embedded video, where Chris
Meagher, chief engineer for GM’s EcoTec four cylinder engines, talks about direct
injection. In the brief interview, constructed by GM based on frequently asked questions
by the consumers, Chris covers most of the benefits of direct injection. V6 power with a 4
cylinder efficiency, the Cobalt SS with direct injection and turbocharger achieves a sub 6second 0-60 time, while achieving 30+ highway mpg.
Abuelsamid, Sam. "Why Gasoline Turbocharged Direct Injected Engines?"
AutoblogGreen. N.p., 28 May 2009. Web. 22 Feb. 2013.
<http://green.autoblog.com/2009/05/28/greenlings-why-gasoline-turbochargeddirect-injected-engines/>.
The source was published in 2009, when consumers were starting to see
turbocharging and direct injection in new cars. The source gives a brief history of
turbocharging, dating back its popularity to the 1980s. By explaining the complications in
using a turbocharger with previous fuel injection systems, it creates a very effective
transition to focus on direct injection and its perfect pairing with turbocharger. By yielding
more power when needed, manufacturers are able to downsize their engines to eliminate
the weight of additional cylinders needed to be haul around, unused most by drivers most
of the time. The result is a 15-20% improvement in fuel efficiency, compared to a
comparably powerful normally aspirated engine of larger displacement.
"Are Hybrid Cars Worth It." Are Hybrid Cars Worth It. EVsRoll.com, n.d. Web. 05 Feb. 2013.
<http://www.evsroll.com/Are_Hybrid_Cars_Worth_It.html>.
Hybrids aren’t really as efficient as many buyers think. Hybrids tend to depreciate in
value faster than their traditional gasoline engine counterparts. The maintenance cost is higher,
and most importantly, they are usually much more expensive. Assuming the average person
drives 15,000 miles a year and gasoline costs $4/gal, it would take the Honda Civic Hybrid 18
years to break even with the standard gasoline engine Civic. Granted the Hybrid model has
niceties that added cost, but it is safe to assume that the typical Hybrid owner will not be able to
recoup the added premium in their time with the vehicle. The figure would also vary according
to yearly mileage, the more driven the more fuel saved, and gasoline price, the higher the price
the more worthwhile are hybrids. The 18 years is a figure comparing the $15,995 MPFI Civic,
which averages 33 mpg, to the $24,200 Civic Hybrid, averaging 44 mpg. More impressive is that
Honda is able to produce 33 mpg without having yet adopted direct injection for the Civic; with
direct injection the mpg difference between the two models would be small enough to make
hybrids almost an illogical choice. Hybrids are no longer competing with 25 mpg competitors.
With almost all major manufacturers adopting direct injection, which are still much cheaper to
produce than hybrids, hybrids are dying.
Cunningham, Wayne. "11 Gas-Saving Technologies." CNET. N.p., 29 Sept. 2011. Web. 03 Feb.
2013. <http://reviews.cnet.com/2300-10863_7-10009562.html>.
The article has a great compilation of technologies currently implemented into engines to
save gas. Direct injection is for one. Turbocharger, more than supercharger, is one of the bigger
technologies, coupled with DI to allow engine downsizing (increasing fuel economy). Newer
cars can now stop feeding fuel to the engine when decelerating with enough momentum, whereas
before the engine would still be idling. Cylinder deactivation technology has been improved
significantly since its debut in Cadillacs of the 80s, and saving fuel no longer comes at the
expense of drivability. Start/stop technology shuts the car down whenever it comes to a stop, and
starts it back again when the driver lifts the foot off the brake. Brake regeneration reduces drag
on the engine, not needing to generate extra electricity for the battery. Lock-up clutch for
automatic transmissions and dual-clutch transmissions means comfort of an auto with the fuel
efficiency of a manual. Continuously variable transmissions does away with gears altogether in
favor of a pulley system, allowing the engine to run at optimal speed most of the time. Unlike
hydraulic power steering, which creates drag on the engine even when not steered, electric power
steering uses an electric motor for power-steering boost. These major technologies is what’s
keeping gasoline engines so well loved and still mainstream.
"Energy Efficient Technologies." FuelEconomy.gov. N.p., n.d. Web. 01 Feb. 2013.
<http://www.fueleconomy.gov/feg/tech_adv.shtml>.
The US Department of Energy have compiled a list of engine/transmission technologies
they have tested that improve fuel economy in gasoline internal combustion engines, and
organized them by average efficiency increase percentage. It is clear from the source that direct
injection plays the biggest role towards the increase fuel efficiency, but other technologies are
also significant; notably VVT, turbochargers/superchargers, cylinder deactivation, and start-stop
system. Newer transmissions, CVT and AMT, also help with fuel efficiency. The department
estimates that DI, on average, has the potential to increase fuel efficiency by 12%, and save an
estimated $3600 over the lifetime of the vehicle.
"Five Fuel-Saving Technologies." Car and Driver. N.p., Aug. 2008. Web. 06 Feb. 2013.
<http://www.caranddriver.com/features/five-fuel-saving-technologies>.
The article was published a while back, during the golden year of the automotive
industry. New technologies were just becoming available to the masses of consumers, due to
reduced cost and demand for greater efficiency vehicles. Direct Injection allows for greater
power output and fuel efficiency, compared to port-injection engines of similar displacement.
Like direct injection, which isn’t news to the automotive world, cylinder deactivation isn’t an
entirely new concept, however it has never made it to the masses until now. By cutting fuel flow
to inactive cylinders during low power consumption, the engine no longer have to unnecessarily
waste fuel. Like the other two technologies, turbochargers were scarcely used, because they were
thought of as unreliable (supplementing engines to produce more power). Today, turbochargers
are used more for fuel efficiency. Like VVT, turbochargers allow small displacement engines to
produce great power when needed, thus allowing manufacturers to downsize their engines.
Variable Valve Timing, although doesn’t directly increase fuel efficiency, allows small
displacement engines to perform like a bigger displacement engine when needed, while staying
much more efficient when driven conservatively. These 4 major engine technologies are what’s
making modern gasoline engines so fuel efficient.
Gable, Christine, and Scott Gable. "Cylinder Deactivation." About.com Hybrid Cars & Alt
Fuels. N.p., n.d. Web. 12 Feb. 2013.
<http://alternativefuels.about.com/od/researchdevelopment/a/cylinderdeact.htm>.
A variable displacement engine means access to the engine’s potential power when
needed, while getting better fuel efficiency while cruising. Cylinder Deactivation works by
keeping the intake and exhaust valves of some cylinders closed when cruising. “In typical light
load driving with large displacement engines, only about 30 percent of an engine’s potential
power is utilized. Under these circumstances, the throttle valve is only slightly open and the
engine has to work hard to draw air through it. The result is an inefficient condition known as
pumping loss.” With cylinder deactivation the remaining activated pistons are forced to opened
more fully to create constant power, thus significantly decreasing those pumping losses, and
increasing the combustion chamber pressure. The unnecessary cylinders meanwhile are cut off
from fuel. The net result in the system’s efficiency is better fuel efficiency when cruising.
"Gasoline Direct Injection." Wikipedia. Wikimedia Foundation, 27 Jan. 2013. Web. 29 Jan.
2013. <http://en.wikipedia.org/wiki/Gasoline_direct_injection>.
Gasoline Direct Injection, in internal combustion engines, is a variant of fuel injection
used in modern two-stroke and four-stroke gasoline engines. The development of fuel injection
in itself is one of the greatest turning points in automobile industry, having replaced carburetors
during the 1990s, but direct injection is truly what keeps gasoline engines alive during an era of
hybrids and electric vehicles. GDI engines are more fuel efficient, cleaner, and more powerful,
“achieved by the precise control over the amount of fuel and injection timings that are varied
according to engine load.” With DI, the engine’s EMS can choose between 3 modes of different
air/fuel ratios (stratified charge, stoichiometric, and full power mode), to maximize efficiency.
DI reduces throttling and pumping losses, which greatly improve efficiency.
Goodwin, Antuan. "What's so Great about Direct Injection? (ABCs of Car Tech)." CNET. The
Car Tech Blog, 18 July 2012. Web. 29 Jan. 2013. <http://reviews.cnet.com/830113746_7-57475368-48/whats-so-great-about-direct-injection-abcs-of-car-tech/>.
Direct injection is one of the big technologies that’s helping to keep the internal
combustion engine, an invention almost 200 year-old, well alive into the 21st century. Internal
combustion engines need 3 things for its crankshaft to spin to produce power: oxygenated air,
fuel, and a spark. Before direct injection, during the days of carburetors and single-point
injection, air and fuel mixture was imprecise, and inefficient. Multi-point injection, aka port
injection, came along, and instead of 1 injector that sprays “just about right” amount of fuel into
the intake manifold (which splits into intake runners), each intake runner now has its own
injector(s). Although the system is more efficient, being able to adjust the air/fuel mixture for
each cylinder, DI further moves the injectors inside the combustion chamber. The engine’s
computer can now accurately create a near perfect air/fuel mixture almost all the time, since the
injectors can inject more than once during a single cycle (being inside the combustion chamber).
The ability to adjust the amount of fuel injected also allows different “modes” for the engine to
run at, furthering efficiency. With these traits, DI works very well with other technologies,
specifically turbochargers, to reduce engine displacement and increase efficiency.
Howard, Bill. "Why Hybrids Are Dying: Gas Engines Are Good Enough on Mpg, Plug-ins Are
Sexier." ExtremeTech. N.p., 30 Nov. 2012. Web. 29 Jan. 2013.
<http://www.extremetech.com/extreme/141147-why-hybrids-are-dying-gas-engines-aregood-enough-on-mpg-plug-ins-are-sexier>.
Direct Injection alone probably isn’t enough to keep gasoline engines relevant, in an era
of hybrids achieving ~50 miles per gallon. The source had led me to refine my topic: “Direct
Injection & Modern Fuel Efficiency Technologies: Keeping Gasoline Engines Relevant &
Mainstream in the 21st Century.” Mazda resisted the hybrid movement that started awhile ago,
staying true to its “zoom-zoom” heritage, and instead developed Skyactiv. With direct injection,
lighter internal components, combined with other engine tweaks they are able to increase the
air/fuel ratio to 13:1, equivalent to roughly 15% improvement in fuel efficiency. Lighter chassis
and new 6-speed gearbox also allow the new Skyactiv Mazda3 sedan to achieve 40 mpg on the
highway. With turbocharger, coupled with direct injection, Ford is able to integrate a tiny 1.0L 3
cylinder engine into their new Fiesta, producing 123 hp and 40+ highway mpg. With their new
EcoBoost (turbocharged DI) line, traditional V8 are being replaced by modern V6, V6 by
modern I4, and small traditional I4 by revolutionary three-cylinder turbo. Direct injection, along
with other modern technologies keep gasoline engine very well alive into the 21st century.
Mustafa Bahattin Çelik and Bulent Ozdalyan (2010). Gasoline Direct Injection, Fuel
Injection, Daniela Siano (Ed.), ISBN: 978-953-307-116-9, InTech, Available from:
http://www.intechopen.com/books/fuelinjection/gasoline-direct-injection
The article is a section from the book Fuel Injection, by Daniela Siano, recently
published in 2010. State of the art in the research and development of modern fuel injection
systems are presented in this book. It consists of 12 chapters focused on both numerical
and experimental techniques, allowing its proper design and optimization. Particularly in
the section, the book does an amazing job of showing the operation of direct injection, as
well as all the other aspects of it. The most important piece of information is the advantages
of direct injection over the previous multi-port fuel injection, which the source describes in
detail. Furthermore, the various diagrams are helpful in understanding the operation and
output of a gasoline direct injection system.
Nice, Karim. "How Turbochargers Work." HowStuffWorks. N.p., 4 Dec. 2000. Web. 10 Feb.
2013. <http://auto.howstuffworks.com/turbo.htm>.
Turbochargers do not directly improve efficiency, but instead allows engine size to be
smaller. Turbochargers are so efficient because they effectively use the exhaust gas, which
would normally be a waste, to help the engine produce more power. The exhaust gas drives the
turbo, therefore there is no engine drag, and they are also light. Most turbo systems work
similarly, in a sequence. Exhaust flow from the combustion chamber spins a turbine, connected
to a compressor. The compressor inducts air and feeds it towards the pistons. Before the air
enters the pistons, it passes through the intercooler, which cools the air, and providing a higher
density of air molecules. The denser air molecules means more power, on top of the power gain
through adding more fuel to compensate for the pressurized air. With a turbo delivering a typical
boost of 6-8 psi, there is ~30-40% improvement in power. With a turbo, a smaller engine can
produce just as much power as a bigger engine, while being more fuel efficient.