The design of conventional injection systems requires the use of trial and error processes (with a high experimental load). Mathematical models, such as the one described in a previous work [Palomar et al. Energy Fuels 2005, 19, 1526-1535], helps in the design process. However, these models do not allow us to approach the inverse problem; that is to say, given a target law, the model cannot provide the system's dimensional characteristics which allow the injection system to reproduce the objective law. In this way, this study confronts a first approach to the resolution of the inverse problem, by means of an optimization algorithm over the direct problem. For this purpose, a second-order Newton's method is proposed to solve this problem. In this problem, a small number of parameters are maintained as variables to be used in the optimization algorithm. Thus, the main goal of the procedure is to generate a prearranged needle lifting law. The defined laws have been geometrically designed. They are indicative, without relation to a reference parameter, such as velocity, load, or injected fuel. As an initial approach, an unconstrained optimization has been carried out. Herein, we have demonstrated the efficiency of the proposed methodology to optimize the design of the engine fuel injection system according to the appropriate working conditions of the engine related to parameters such as combustion, performance, exhaust emissions, and noise.