DIESEL ENGINE

PURPOSE:To improve burning condition so that white smoke is not emitted even if the quantity of intake air is sufficiently throttled and reduce noise and vibration by attaching an intake air throttle to an air intake pipe and providing a pintle nozzle having a sub-injection port, in a combustion chamber. CONSTITUTION:On idle running, an accelerator switch 5 is closed and an introduction pipe 35 is connected to a negative pressure tank 4 by means of an electromagnetic selector valve 3. Accordingly, negative pressure in a negative pressure chamber 24 increases, throttling an intake air throttle valve 1. Fuel is injected from a sub-injection port 9 at the initial stage of opening an injection valve and, then from a main injection port 37, and the fuel from the sub-injection port 9 collides against a connecting port 15, being atomized to become spray 11. Part of fuel 13, which collided against the connecting port 15 but is not rebounded, flows along the wall 12 of a vortex chamber 19, and is gently evaporated and burns, thereby suppressing the rate of rise in pressure. When intake air is throttled on idle running, an engine with a pintle nozzle 8 is superior to an engine with a throttle nozzle, in the reducing effect in any of the quantity of discharging white smoke, and noize and vibration on idling.