【導(dǎo)讀】KaoruAoki,ShigetakaKuroda,ShigemasaKajiwara,HondaR&DCo.,Ltd.EU2021.

　　

【正文】 the exhaust system to the rear of the engine (Fig. 15). In addition, the exhaust manifold was integrated with the cylinder head and a NOx adsorption catalyst which reduces NOx emissions during lean burn operation was also newly developed. Figure 15. Section view of emission system . Integrated Exhaust Manifold and Cylinder Head – Conventional cylinder heads have independent exhaust ports for each cylinder and a separate exhaust manifold acts to converge these exhaust ports into a single port is then mounted to the head. However, the new head on the Insight has a structure which converges the exhaust ports into a single port inside the head, as shown in Fig. 16. This greatly reduces the weight. In addition, the small heat radiating surface area reduces the exhaust gas heat loss, thus enabling early catalyst activation. Figure 16. View of Head . Lean NOx Catalyst – The catalyst system on the Insight bines a conventional threeway catalyst with NOx adsorbing materials. The NOx conversion mechanism of the newly developed catalyst is shown in Fig. 17. The NOx in the exhaust gas is adsorbed and separated by the NOx adsorption action of the catalyst during lean engine operating conditions. Conventional threeway catalyst operation reduces part of the NOx to nitrogen and oxidizes most of the HC and CO to CO2 and H2O during lean operation. However, since the exhaust gas contains large amounts of oxygen, there is relatively little NOx reduction with the threeway catalyst and most of the NOx is stored on the surface of the adsorbing material. When the exhaust is held at the theoretical air fuel ratio (stoichiometry) or richer airfuel ratio, the adsorbed NOx is reduced to nitrogen using HC and CO as reducing agents. The adsorbent is regenerated at the same time. Thus, NOx, HC and CO are effectively converted using the threeway catalytic action of the catalyst bined with the NOx adsorber. This type of catalyst exhibits superior conversion performance during both lean operation and stoichiometric operation by switching between lean and stoichiometry operating conditions. It is essential to create a regenerative atmosphere before the NOx adsorption capacity bees overloaded. This catalyst directly adsorbs NOx during lean burn engine operation and the adsorbed NOx is then reduced and exhausted as harmless nitrogen (N2) during stoichiometric operation. Figure 17. Exhaust gas purification mechanism This catalyst is characterized by the direct adsorption of NOx to the catalyst surface during lean operation. Adsorption on the catalyst surface, instead of absorption as a pound inside the surface, facilitates conversion during reduction and also provides superior durability at high temperatures. This adsorptive type catalyst reduces NOx emissions during lean burn operation to 1/10 the level of the conventional threeway catalyst. It should be noted that the adsorption and conversion performance of this type of catalyst is sensitive to sulfur levels in the fuel, as sulfur can pete for the active NOx adsorbing sites. As a conventional threeway catalyst has virtually no NOx reduction during leanoperation, the lean burn operating range typically has to be reduced to keep NOx emissions down. Use of an adsorptive type catalyst maintains the full lean burn range and improves fuel economy, even while reducing NOx. This vehicle can also satisfy the EU2021 standards, making this a highly efficient lean burn engine that plies with exhaust emissions standards throughout the world. 8. CONCLUSION This paper presents a general overview of the recently developed motor assist hybrid powertrain, as well as a description of its various ponents and its output and emission performance. This hybrid power train simultaneously achieves ultra low fuel consumption and low exhaust emissions. It also achieves a pact, lightweight power train layout. We believe this system advances 21st century automotive technology toward regional and global environmental goals. REFERENCES 1. Aoki, Kaoru, et al.: Development an Integrated Motor Assist Hybrid System, JSAE No. 9899 161 2. Yamaguchi, Tetsuro: CVT Control in the HONDA Hybrid 39。IMA39。, No. 9908 JSAE SYMPOSIUM, Latest Motive Power Transmission Technologies 39。99, 3. Ohno, Hiroshi, et al.: Development of a NOx Adsorptive Reaction Type ThreeWay Catalyst, HONDA Ramp。D Technical Review, Vol. 11 No. 2 (October 1999), 4. Fukuo, Koichi, et al.: Development of the Ultra Low Fuel Consumption Hybrid Car 39。Insight39。, HONDA Ramp。D Technical Review, Vol. 11 No. 2 (October 1999), 5. Hideki Tanaka, et al .: The Effect of 0W20 Low Viscosity Engine Oil on Fuel Economy”, SAE Paper ,Fuels and Lubricants meeting and Exposition, Toronto, Ontario, Canada, October 1999. 6. Aoki, Kaoru, et al.: An Integrated Motor Assist Hybrid System, SAE Paper , Government / Industry Meeting, Washington, ., USA