A method and apparatus for injecting fuel into a diesel engine combustion chamber is provided wherein a pre-pilot injection is injected sufficiently prior to critical mass conditions being achievable to permit vaporization and formation of a substantially homogenous mixture before a critical mass exists. Preferably, a pilot injection is injected after the pre-pilot injection but at or before a point wherein a critical mass based on the pre-pilot quantity. This will result in a reduced heat release rate will result in a slower, smoother and more controlled build up of pressure in a combustion chamber and thereby advantageously reduce combustion noise.