The paper describes the design and operation of a laboratory combustion chamber used to measure the ignition delay times of diesel engine fuels at atmospheric pressure in near quiescent air. The flow apparatus has the means to provide air temperatures in the range between 650 and 730°K which is the typical temperature range at the end of the compression stroke in a diesel engine. An injection pump with a trigger mechanism delivers equal amounts of fuel to an injector, which sprays it into the constantly replensihed supply of fresh, hot air for combustion. An infrared radiation detector monitors the evolution of the temperature inside the combustion chamber. Ignition delay is measured as the time interval between the beginning of the needle lift and the beginning of increase in infrared radiation detected by the sensor. Test results for two fuels are presented and compared with the results from previous studies performed under similar test conditions.