John Heywood's ICE Fundamentals, despite being written three decades ago, still remains one of the best books to get introduction and fundamentals, and is the book I recommend to start with.
I would also recommend a textbook for automotive technicians (mechanics), these are available in many languages, together with a part-time job as an engine mechanic at an auto repair shop. In my opinion, you get to understand the engine only after you have taken one completely apart and put it back together.
Once you have done this, if I am still around, ask me for more books.
The books in the picture helped me tremendously to build my knowledge. As I started my PhD, I had actually no prior knowledge on Diesel engines. I was a control engineer, who his thesis subject was to propose solutions for the detection and isolation of faults on marine Diesel engines. So at that time, I needed mainly to know
how does a diesel engine work,
what’s the difference between a Diesel engine and the other types of engines,
what are the differences between the diesel engines themselves and how to classify them,
what are the components and sub-systems of a Diesel engine and their role,
what are the faults that the Diesel engines are subjected to,
what are the symptoms of the faults,
how to detect the faults,
how to differentiate between the faults, if the symptoms are similar
Then at an advanced stage of my thesis, I had to make some simulations, to validate the hypothesis, which we could not perform on the test bench.
As already mentioned above, this selection of books helped me to build my knowledge. It doesn’t mean that there are not other good books on the subject. But if you have similar questions like those that I had, you will find in these books, all the needed answers.
More details on the book can be found on : https://www.fixdiesel.com/en/best-books-for-diesel-mechanic-technician-engineer-and-researcher/
Marine Diesel engine : maintenance, troubleshooting, and repair
by N. Calder
Troubleshooting Marine Diesels
by P. Compton
Troubleshooting & repairing Diesel engines
By P. Dempsey
Advanced automotive fault diagnosis
by T. Denton
Automotive technology, a system approach
By J. Erjavec
Automotive Engines: Diagnosis, Repair and Rebuilding
By T. Gilles
Pounder’s marine Diesel engines and gas turbines
By D. Woodyard
Light and heavy vehicle technology
By M. J. Nunney
Diesel engine reference book
by B. Challen and R. Baranescu
Internal combustion engines
By V. Ganesan
Internal combustion engine fundamental
By J. B. Heywood
Handbook of Diesel engines
By K. Mollenhauer and H. Tschöke
Diesel Engine Transient Operation : Principles of Operation and Simulation Analysis