Individual Cylinder Pressure Based Feedback Control Is An Ideal Method To Optimize Engine Operation. In-Cylinder Pressure Is a Fundamentalcombustion Variable, Which Can Be Used To Characterize The Combustion Process For Each Combustion Event. Optimal Engine Control Can Be Maintained By Monitoring the Pressure In Each Cylinder and Using This Information Forfeedback Control In Order To Minimize The Exhaust Gas Emissions. The Availability Of Low Cost And Robust Pressure Sensors, Such As The Glow Plug Installed Pressure Sensor (Gpps) Isexpected To Lead To the Wide Adoption of Cylinder-Pressure-Based Enginecontrol Diesel Engines. In Order To Identify The Most Effective Parameters To Use When Controlling Combustion Based on Cylinder Pressure Information, a Seriesof Experiments Were Carried Out With Varying Injection Timings And Egr Levels. This Paper Presents The Results Obtained And Discusses The Potential Key Parameters That May Be Used For Closed Loop Control Using An In-Cylinder Pressure Transducer. This Paper Will Also Look At The Combustion Properties For Combined Hydrogen/Diesel Combustion. It Was Necessary To Find An Appropriate Running Point For The Engine In Purely Diesel Mode To Act As A Base Point. Once This Point Was Found, an Experimentaltest Matrix For the Combined Egr and Hydrogen Investigation Was Set Up.