A piston for balancing combustion efficiency and smoke generation with NOx production includes a combustion face forming a combustion bowl having a compound curvature increased in sharpness in a radially outward direction. An outer bowl surface defines a large radius of curvature adjacent an inner bowl surface, and a medium radius of curvature adjacent a cylindrical wall surface. The inner bowl, outer bowl, and wall surfaces together contour the combustion bowl, such that a diameter of the combustion bowl is about 124 mm so as to establish a bowl to bore ratio of about 0.71 in a direct injection compression ignition engine with a compression ratio of about 15:1 to 17:1.