Purpose: The purpose of this study was to investigate and analyze to increase the quality and intelligibility of speech in cars. The passenger dialogue inside the car, the sound of other equipment, and a wide range of interference effects are major challenges in the task of speech separation in-car environment.Methods: Speech enhancement based on the source separation algorithm has been proposed to enhance the preferred speech signals using a microphone array inside a car. The proposed approach determines the signal direction in the time domain by utilizing the time difference of arrival (TDOA). TDOA signals are processed, and an adaptive least mean square method is used to determine the enhanced preferred signal.Results: Experimental results show that the proposed approach yields an signal-to-noise ratio (SNR) of 7.4, perceptual evaluation of speech quality (PESQ) of 2.33 respectively. The proposed strategy outperforms existing methods in terms of PESQ, and SNR. The PESQ of the proposed method is 2.45%, and 5.22% better than the existing Independent Component Analyses, and Run length Source techniques.Conclusion: Finally, compared to the existing methods, the suggested speech enhancement algorithm is more reliable and flexible, and it can properly identify the exact location of the sound.