Abstract: A diesel engine intake system including a timing valve which is positioned in the intake system in engine starting and warming-up period under a cold engine condition. The timing valve is opened in the final period of the intake stroke so that a strong suction pressure is produced in the combustion chamber before the timing valve is opened. When the timing valve is opened, the intake air is rushed into the combustion chamber at a high speed whereby the intake air is compressed under the inertia of the high speed flow to thereby increase the temperature of the intake air. The timing valve is responsive to the suction pressure in the combustion chamber and opened when the suction pressure becomes stronger than a predetermined level.

Abstract: A fuel injection system for a diesel engine is provided with a needle-lift-suppressing type fuel injection nozzle such as the central plunger type pintle fuel injection nozzle which has a valve needle adapted to be lifted under fuel pressure fed from a fuel injection pump to increase the effective spray area with increase in the lift of the valve needle and a needle-lift-suppressing means which limits the lift of the valve needle to a pre-lift of a predetermined amount at low load and/or low speed, and a starting detecting means for detecting starting of the engine, said needle-lift-suppressing means being arranged to permit lift of the valve needle beyond said pre-lift irrespective of the engine load and engine speed when the engine is started.

Abstract: A diesel engine intake system including a timing valve which is positioned in the intake system in engine starting and warming-up periods under a cold engine condition. The timing valve is opened in the final period of the intake stroke so that a strong suction pressure is produced in the combustion chamber before the timing valve is opened. When the timing valve is opened, the intake air as rushes into the combustion chamber at a high speed, whereby the intake air is compressed under the inertia of the high speed flow to thereby increase the temperature of the intake air. The engine is also provided with a blow-by passage and an exhaust gas recirculation passage, both opening to the intake passage upstream of the timing valve, so that it is possible to prevent the blow-by gas and the recirculated exhaust gas from being drawn under the suction pressure when the timing valve is closed.