A Quakertown man has admitted trying to crash his car into the local police station and set it on fire. 32-year-old Timothy Swart pleaded guilty but mentally ill Tuesday in Bucks County Court.  Police say his car missed the building, located on Third Street, so he lit a container of gasoline and threw it, causing a small fire.  Damage to the brick building was minimal.  A guilty but mentally ill plea means the defendant admits committing a crime, but his illness made him unable to appreciate the wrongfulness of his behavior.  He can be imprisoned, but serve his time in a mental health treatment unit.