https://www.mathworks.com/help/simulink/slref/discrete-time-integration-using-forward-euler-integration-method.html
Discrete-Time Integration Using the Forward Euler Integration Method - MATLAB & Simulink
The model sldemo_fuelsysuses a Discrete-Time Integrator block in the subsystem fuel_rate_control/airflow_calc.
forward euler methoddiscrete timeintegrationusingmatlab
https://www.wolframalpha.com/input?i=forward+euler+method+vs.+backward+euler+for+y%27%3D-x+y%2C+y%280%29%3D1
forward euler method vs. backward euler for y'=-x y, y(0)=1 - Wolfram|Alpha
forward euler method