Abstract Recent results have concluded that the efficacy of compression stroke injections in enhancing natural thermal stratification are dependent on the injector’s included angle. Therefore, there is a need to further understand how different hardware affects the efficacy of thermally stratified compression ignition. In this study, three injector included angles are considered: 150°, 118°, and 60°. Compression stroke injection timing sweeps are performed with these three injectors using two distinct piston geometries: a re-entrant bowl piston geometry found in a production, light-duty diesel engine, and a custom-made open, shallow bowl piston geometry, designed to reduce surface-to-volume ratio. Using an equivalence ratio of 0.5 and a split fraction of 80%, it was found that, with the re-entrant bowl piston geometry, the 150° injector displayed high controllability over the burn duration and was able to elongate the burn duration by a factor of 1.8×. The 118° injector displayed slight controllability over the burn duration, while the 60° injector displayed no controllability. With the open bowl piston geometry, the 150° maintained high controllability over the burn duration, albeit with less efficacy. The 60° injector still had no controllability and now the 118° injector had no controllability. The low surface-to-volume ratio of the shallow bowl piston led to less natural thermal stratification than the re-entrant bowl piston geometry, which impacted the compression stroke injection’s ability to control the burn rate. Therefore, the hardware setup that achieves the highest efficacy is a re-entrant bowl-like piston geometry with a wide spray angle injector.