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FEV to show 2nd generation diesel High Efficiency Combustion System at 2011 SAE World Congress

FEV, Inc., will exhibit its High Efficiency Combustion System (HECS) diesel engine at the 2011 SAE World Congress, 12-14 April at Cobo Center in Detroit. The HECS engine incorporates novel and conventional technologies to achieve low CO2 emissions and a 17% reduction in fuel consumption, while also meeting Euro 6 emission standards without aftertreatment.

HECS is designed and tailored for high EGR tolerance and combines low nitrogen oxide emissions with superior fuel efficiency, even under high part load conditions. The following aspects are the primary elements of this optimized combustion system layout:

  • Optimization of mixture formation (fuel injection and swirl);
  • Improved cylinder filling with optimized gas exchange (boosting, manifold layout and flow losses);
  • Highly capable boosting system, in conjunction with a combined high pressure and low pressure EGR system;
  • Adjustment of the combustion chamber (geometry and compression ratio) to the air and fuel system capabilities;
  • Intensified cooling (Air and EGR); and
  • Implementation of a high-performance glow plug system.

Flexible multiple injection and two-stage turbocharging improve low-end torque, in spite of the reduction in engine capacity. Improving the gas exchange and significantly lowering charge temperatures leads to a shift toward leaner air-fuel ratios. This consequently results in substantially increased EGR rates, which permit a major reduction in untreated emissions. The improved NOx / BSFC trade-off can then be targeted separately from an improvement in the NOx / PM trade-off

The second-generation HECS has been adapted to a downsized 1.6L 4-cylinder diesel engine, and is designed specifically for a high specific power output of more than 100 kW/L. To achieve this output, FEV engineers designed a 200 bar peak pressure cylinder head with variable valve lift.

The variable valve lift is accomplished through the use of a unique roller finger follower that is adjustable for two different lifts. Combined with variable valve lift is a unique seat-swirl chamfer that FEV has engineered into the system. Both modifications increase swirl, contributing to greatly improved combustion.

Also key to engine performance is thermal management, which is accomplished in a number of ways. The HECS concept incorporates split cooling, and an air gap insulated exhaust gas manifold, which generally contributes to improved aftertreatment functionality, and especially during cold start to achieve early catalyst light-off. A dual-wall exhaust also reduces heat loss in order to accelerate catalyst light-off during cold starts.

Cam phasers have been incorporated to enhance performance, as well as high and low pressure EGR.

The cylinder head has been incorporated into a demonstration vehicle that is targeted to achieve low CO2 emissions as well as the lowest possible fuel consumption. The first phase of the project was directed at development of the combustion system. Future development phases for the HECS demonstration vehicle include optimization of the engine’s mechanical components/accessories, hybridization/electrification of the powertrain, and vehicle improvements (drag/rolling resistance/weight).

Comments

TDIMeister

Interesting stuff. Hope an OEM signs-up FEV to implement HECS in a production vehicle.

Stan Peterson

I am intrigued by the statement that they met EU6 emissions standards without anything other than EGR. While meeting EU6 is far from meeting T2B5 in America, it is the first time that even moderate improvements in Diesel emissions are required.

There is no doubt that the Diesel has to improve the cost of cleanup, and the best way to accomplish that is improve the combustion itself, producing less emissions that need cleanup.

Premixed Charge Compression Ignition, PCCI, is the supposed holy grail for the Diesel cycle. That would seem to mandate both VVL air induction, and various measures of EGR to be added to the combustion charge.

Perhaps this is just such a process. If so, it has great importance.

Peter_XX

There must be a misunderstanding of lack of information here. You simply have to have a DPF to meet Euro 6 particle number emissions. I think they refer to meeting the Euro 6 limit without NOx aftertreatment. Nice, of course, since it reduces the cost...

If you can meet Euro 6 NOx limits, US T2B5 is also possible to meet, as already shown by other researchers.

The particle number limit in Euro 6 is much tougher to meet than T2B5, so this does not present a problem if you can meet the first-mentioned limit.

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