How to pronounce diesel:
To ignite a substance by using the heat generated by compression
For a spark-ignition internal combustion engine to continue running after the electrical current to the spark plugs has been turned off. this occurs when there's enough heat in the combustion chamber to ignite the air and fuel mixture without a spark, the same way that heat and pressure cause ignition in a diesel engine.
Example: "The only reason the vw bug has a solenoid is to prevent it from dieseling."