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A series of NVH experiments were performed for a set of single cylinder engine models made of aluminum, consisting of a cylinder head, a cylinder block and a bed-plate. Each has the same outer size of 150mm × 150mm; the different heights are 100mm, 200mm and 80mm respectively. Those dimensions were determined following the dimensions for a diesel engine in lightweight commercial vehicle with the bore size of 100mm and the crankshaft main bearing diameter of 60mm. We chose 112 of measuring points on the structure surfaces and performed a series of impact tests, for the following cases: (a) When the cylinder head and the bed-plate were fastened to the cylinder block by two sets of four ISO M10 tap-bolts, each with the lengths ℓ1 =117mm and ℓ2 =97mm. (b) When the cylinder head and the bed-plate were fastened to the cylinder block together by a set of four ISO M10 through-bolts of grip length ℓ3 =380mm.

A series of NVH experiments were performed for a set of single cylinder engine models made of aluminum, with bore sizes of 100mm. Each engine model consists of a cylinder head, a cylinder block and a bedplate. Each has the same size of 150mm × 150mm, with different heights of 100mm, 200mm and 80mm, respectively. By choosing 112 measuring points on the structure surfaces, we performed a series of impact tests for the following cases, (a) The cylinder head and the bedplate were fastened to the cylinder block by two sets of ISO M10 Tap-bolts, each with the lengths l1=117mm and l2=97mm. (b) The cylinder head and the bedplate were fastened to the cylinder block together by a set of ISO M10 Through-bolts of grip length l3=380mm.

Single cylinder engine testing was carried out to clearly understand the test results of multi-cylinder engines reported by the Diesel WG in JCAP (Japan Clean Air Program) (1), (2), (3) and (4). In this tests, engine specifications such as fuel injection pressure, nozzle hole diameter, turbo-charging pressure, EGR rate, and fuel properties such as 1-, 2-, 3-ring aromatics content, n-,i-paraffins content, and T90 were parametrically changed and their influence on the emissions were studied. PM emission generally increased in each engine condition with increased aromatic contents and T90. In particular, multi ring aromatics brought about large increases in PM regardless of the engine conditions. The influence of fuel properties on NOx emission is smaller than the influence on PM emission. Some other fuels that have various side chain structures of 1-ring aromatics, normal paraffins only and various naphthene contents were also investigated.