单项选择题 The key feature of the Sulzer RT-flex system is that it gives complete freedom in the and operation of fuel injection and exhaust valve actuation（）

单项选择题 A clearly visible beneath of RT-flex engines is their operation at all ship speedsThis is achieved by the superior combustion performance（）

单项选择题 There is a support ring between the cylinder block and collar of the cylinder liner, thus carrying both the liner and the cylinder coverIt also passes to the cooling bores and to the cover（）