Automotive

Diesel engine concept controls heat to cut emissions

Diesel engine concept controls...
A new diesel engine concept could be cheaper and cleaner than current designs
A new diesel engine concept could be cheaper and cleaner than current designs
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The new diesel engine design uses optimization of cylinder shape and tri-injection to control engine heat
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The new diesel engine design uses optimization of cylinder shape and tri-injection to control engine heat
A new diesel engine concept could be cheaper and cleaner than current designs
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A new diesel engine concept could be cheaper and cleaner than current designs

Diesel engines are some of the simplest combustion concepts in use today, with a design that has not changed much in half a century. But what has changed is the complexity of the systems that surround the diesel engine block to overcome inherent inefficiencies in emissions. A research team at the New ACE Institute in Japan has developed a new diesel combustion engine concept using multiple fuel injectors that doesn't require waste heat reduction. With a brake thermal efficiency of greater than 50 percent, the new engine could reduce engine manufacture costs.

Waste heat recovery (WHR) is commonly used as a method of capturing the engine's heat to maintain a temperature in a particulate filter and other emissions control systems. WHR is relatively expensive, but aids the vehicle's overall efficiencies in both fuel use and emissions reductions. The automotive research team at New ACE sought a way to optimize combustion that overcomes the complex tradeoffs between emissions, brake thermal efficiency (BTE) and energy losses on conventional diesel combustion.

The team's engine utilizes three fuel injectors in a variant of the Sabathe cycle. This limited pressure, dual cycle controls heat by holding constant volume and pressure in the cylinder. The modification with this new concept is to control fuel injection to temporarily create an isolation between the premixed combustion area and diffusion combustion area of the cylinder, which enables consecutive heat release.

The new diesel engine design uses optimization of cylinder shape and tri-injection to control engine heat
The new diesel engine design uses optimization of cylinder shape and tri-injection to control engine heat

This is accomplished by fitting the cylinder with three injectors. One is vertically mounted at the center and two more are positioned at an angle on either flank at the piston cavity's circumference. The side-angled sprays are directed along the swirl direction of the airflow, improving mixing and preventing spray interference and impingement on the cavity wall. This improves air mixing at the center of the cavity, which creates a more dense combustion point. Shaping of the piston cavity (crown) helps prevent injection interference between injectors.

By controlling injection timing and duration under constant fuel pressure, heat can be controlled at a variety of compression ratios and operating temperatures. The center injector fires first followed by precision timing of the side injectors.

Experimental results for the engine concept showed that friction and heat losses were reduced. This produced lower smoke and NOx emissions when compared to conventional diesel combustion.

The New ACE Institute plans to further develop this engine concept.

Source: SAE International

3 comments
3 comments
Martin Leitner
What a waste of money! The end of the combustion engine is already on the horizon. But still so many people try to ride this dead horse. :-(
Bruce Miller
All versions of ICE(Internal Combustion Engines) have a new ultra clean 99% efficient electric powertrain with only three moving parts. Electric storage has exploded. Many alternatives and combinations of batteries, Super Capacitors, and even hydrogen fuel cell systems have made renewable energy a feasible automotive source, and Ontario, Canada uses no fossil fuels to make its electricity! Quebec is soon to follow, as the fear of cancer from hydrocarbon and benzene emissions grows.
unklmurray
Martin the end of the combustion engine may be on the horizon but that horizon is so far away you might as well learn to use the combustion engines,as the main source of power in your life,.....in other words get used to them...... they aren't going away any time soon Yes the TESLA is here but the average person still cannot afford 2 buy one!!........LOL :-)