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Honda Making Significant Progress on HCCI Engine for Hybrid Application

Hondahcci4stroke
Honda’s 4-stroke test-bed

The Wall Street Journal reported this week that Honda may introduce an HCCI-type engine in a hybrid application that could result in a new Civic hybrid achieving as much as 65 mpg—30% better than the new 2006 version.

According to the engineers who spoke to the WSJ on the condition of anonymity, the company is ready to reveal its R&D results and show a prototype four-cylinder HCCI engine as early as next year.

HCCI—Homogeneous Charge Compression Ignition—relies upon a very lean (high proportion of air to fuel) and well-mixed (Homogeneous) air-fuel mixture (Charge) that is compressed (Compression) until it autoignites (Ignition). (The HCCI approach is also called Controlled Auto-Ignition: CAI.)

The resulting spontaneous burn produces a flameless energy release in a large zone almost simultaneously—very different than the spark/gasoline burn or the compression/diesel burn. (Earlier post.)

HCCI combustion can deliver a very efficient engine, potentially providing a 20% to 30% boost in gasoline engine efficiency without the nasty NOx or PM emissions of a diesel. Theoretically it can operate using a variety of fuels: gasoline, diesel, natural gas, biofuels, or hydrogen. Used in a hybrid application, the more efficient engine would increase the overall fuel efficiency of the powertrain.

Managing the combustion for the different types of fuels, though, is extremely tricky, and is the subject of a large amount of R&D. Most recently, GM announced it is working with supplier Robert Bosch and Stanford University to accelerate development of HCCI engines with a three-year, $2.5-million research program. (Earlier post.)

To develop more efficient gasoline engines, Honda opened an Advanced Powertrain Research center in Japan to focus on improving internal-combustion technology. The goal is to deliver a gasoline engine with a thermal efficiency between 40% to 50% through a combination of different technologies such as HCCI. Reaching that level of thermal efficiency would more than double the present efficiency of a typical gasoline engine.

The company has been working on auto-ignition schemes, which it termed Activated Radical Combustion, in two-stroke engines for its motorcycles, for a number of years.

According to the engineers cited in the Journal piece, Honda has been able to clear obstacles to create a prototype four-cylinder HCCI engine that runs smoothly in a low-to-medium speed range.

That, they said, should represent about 65% of the load range necessary to run a gasoline engine properly on the highway. The main challenge left to clear is high speeds, or above 4,000 revolutions per minute, the engineers said. A typical Honda gasoline-fueled engine covers a range reaching 6,000 RPMs.

In 2004, when discussing the potential of its HCCI work, Honda CEO Takeo Fukui estimated that an HCCI Accord could get 50 mpg (double that of conventional Accords) and that a HCCI hybrid Accord could boost mileage to 70 mpg.

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Comments

jm hodges

this is really nothing new for these guys.
i remember doing valve jobs on 1300cc Honda motors
that had a precombustion chamber(with a third valve that we couldn't grind because it was too small) that the spark plug screwed into in each cylinder.that engine used a carburetor that had three barrels. a primary,a secondary
(progressively linked) and a third barrel that was about the size of a dime that fed the precombustion chambers through a separate runner cast into the aluminum intake manifold,and that was twenty years ago!

saeid hajahmadi

I want to lnow how a HCCI engine works?

danwat1234

Wow, this technology with HCCI is intriguing. A lot of the comments on here give lots of ideas on how to make an HCCI engine.

It is now over half-way through 2012, and no HCCI engines in sight. Lots of manufactures have Direct Injected OTTO cycle engines, and a lot of hybrids available that have atkinson-cycle engines. Toyota's 3rd generation Prius engine is ~38% efficient, being multi-port injected and they are aiming for the 4th generation Prius to have an engine that is 42% efficient, via Direct Injection and possible a longer stroke but smaller bore. Used Priuses are getting cheap on craigslist,Hurrah!

I hope one day a Prius or other 'regular sized' 4-wheeled hybrid car can achieve 60MPG on the USA EPA highway and city test cycle. This can only be achieved I think with HCCI engines and high-tech steel alloys to save weight, along with aluminum or carbon fiber where it makes sense.

In the coming years, engines and engine controls will become more and more complex, along with infotainment, collision avoidance and collision safety equipment. I question the long term reliability maintenance costs of future cars, and whether, despite the great fuel economy of a 2020 Hybrid Prius, would the net maintenance costs still save me money versus just keeping my 1999 Civic for another 20 years and doing the basic maintenance it requires?
Chances are I would still save money with the new hybrid, I hope so.

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