成果報告書詳細
管理番号20110000001412
タイトル*平成20年度中間年報 「エネルギー使用合理化技術戦略的開発/エネルギー有効利用基盤技術先導研究開発/ディーゼルエンジンに匹敵する燃費の自動車用HCCIガソリンエンジンの研究開発」
公開日2011/10/12
報告書年度2008 - 2008
委託先名株式会社畑村エンジン研究事務所 国立大学法人千葉大学 三菱重工業株式会社
プロジェクト番号P03033
部署名省エネルギー技術開発部
和文要約和文要約等以下本編抜粋:1. 研究開発の内容及び成果等 本研究開発は、図1に示すブローダウン過給(以下BDSC)による広い運転領域でのHCCI燃焼を実現した上で、さらに過給によるダウンサイジングを組み合わせて、ディーゼルエンジンに匹敵する実走行燃費を実現しようとするものである。 本研究は、実機による実験とシミュレーションを主体に研究活動を実施し、HCCIを実用化する研究の最初の課題である高負荷運転領域の拡大の見通しが得られ、低負荷燃焼や燃焼制御、過給との組み合わせの研究に進める基礎を確立できた。さらに、個別研究テーマ毎に以下の成果を得た。
英文要約Title: Fundamental Technology Development for Energy Conservation/ Strategic Development of Energy Conservation Technology Preparatory research phase/ A Study on HCCI Gasoline Engine Realizing the Fuel Efficiency equal to Diesel Engine (FY2007-FY2009) FY2008 Annual Report
  The objective of this research and development task is to realize a gasoline HCCI operation in a wide load range by using blow-down supercharging (BDSC) and then, to attain fuel economy as well as of a diesel engine under real usage, combined with down-sizing using a turbocharger.
  In 2008 financial year, research activities were performed by both engine bench test using a test engine and numerical simulation. As a result, the first issue of high load operation in HCCI was cleared. Moreover, basic study of low load operation, engine control and combination with a supercharging was made. The achieved results in each research item are briefly shown in the followings.
(1) Establishment of controlled HCCI operation in high load condition
  A test engine was designed and built with an intake-exhaust system of BDSC and a combustion chamber geometry optimized by numerical simulation using Star-CD. Operations just using two-cylinder were carried out. The maximum IMEP at 610 kPa (BMEP 560 kPa) at 1500 r/min was achieved. This value is less than the prementioned target value, but the target value was eventually overestimated by IMEP estimation error. This means the target was substantially accomplished. The maximum IMEP at 590 kPa was achieved in the operation with four-cylinder, but the cylinder-to-cylinder variation was found. The exhaust gas emission cleared the target while the fuel consumption was slightly less than the target due to an exhaust-gas-throttling. This would be solved by adopting the direct fuel injection.
(2) Research on combustion timing control for individual cylinder and engine cycle
  In light load condition, stable combustion was not achieved even though the exhaust-gas-throttling was used. To solve this, an adoption of direct fuel injection was determined in an optimized design using Star-CD simulations. The engine test with direct injection will be carried out from April. An experimentally evaluated combustion analysis tool was developed by this team that can estimate the chemical reaction speed using a multi-zone model. The temporal change of pressure, dp/dθ can be reduced by 30% using an idealized direct fuel injection, leading to an extension of high load operation. A transparent cylinder engine was designed and built to evaluate the simulation results. EGR measurement has been started.
(3) Research on external boosting system for down-sized HCCI engine
Transient response tests of VG(Variable Geometry)-turbo and a combined system with a supercharger and a turbocharger were carried out using a diesel engine. The engine performance could be well predicted by using GT-Power code. So, a transient simulation of the system could be performed at some accelerating points of JC08 test mode. As a result, a system with only VG-turbo was found possible to cover the almost whole JC08 operation range with A/F 30 which simulates HCCI operation. A combination of VG-turbo and BDSC-HCCI was examined since an exhaust-gas-throttling, which VG-turbo can executes, is required for stable HCCI operation. As a result, this system has a large possibility as a production system.
(4) Structure of a new gasoline engine with low fuel consumption and exhaust emissions
The specifications of a new engine system have not been well described, while the specifications of the down-sized direct injection BDSC-HCCI with VG-turbo will be determined using the simulation tool developed in this study.
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