Question How i make car engine rev limit?

Hello, I'm making car controller.
But,the engine rpm continues to rotate indefinitely. So, how can you limit the rpm of the engine so that it does not spin any more?

↓↓This is my project's script.

Code (CSharp):

1. engineRPM = Mathf.Lerp(engineRPM, Mathf.Max(idleRPM + wheelsRPM * gearRatios[currentGear] * differentialRatio), Time.deltaTime * 3f);
2.  
3.         if (0 < KPH)
4.         {
5.             currentTorque = (engineTorqueCurve.Evaluate(engineRPM / revLimitRPM) * maxEngineTorque) * gearRatios[currentGear] * differentialRatio * 0.7f / WheelColliders[3].radius * throttle;
6.         }
7.         else
8.         {
9.             if (!isBraking)
10.             {
11.                 currentTorque = engineTorqueCurve.Evaluate(engineRPM / revLimitRPM) * -reversGearRatio * differentialRatio * throttle * maxEngineTorque;
12.             }
13.         }