| 摘要 |
<p>Disclosed herein is an engine block including first wall means defining a combustion chamber, second wall means defining a bore including a first portion extending from the combustion chamber and a second portion enlarged with respect to the first portion, third wall means defining a water jacket in cooling relation to said second wall means, and an elongated duct of heat resistant material communicating through the first bore portion with the combustion chamber so as to receive exhaust gases discharged therefrom, said duct being circumferentially engaged by and supported from the second wall means at locations spaced lengthwise of the duct and extending in the enlarged bore portion in spaced relation from the second wall means intermediate the locations, whereby there is provided a stagnant air space between the duct and the block intermediate the locations so as to reduce heat transmission from the duct.</p> |
