Frank Lampard's side stretched their lead at the top of the table to eight points with a sixth consecutive victory.
Tatsuhiro Sakamoto and Brandon Thomas-Asante gave the Sky Blues a commanding first-half lead before Matt Grimes sealed the points from the penalty spot.
Coventry spent a long spell in English football's third tier since they last experienced the Premier League in the 2000/2001 season.
But they now have a nine-point cushion over third-placed Millwall with just nine games of the campaign remaining.
Middlesbrough failed to pull clear of the chasing pack for the second automatic promotion place after a 1-0 defeat at the Riverside.
Conor Coady stabbed home the only goal as Charlton hauled themselves eight points clear of the relegation zone.
West Brom remain rooted in the bottom three after a 1-1 draw against Southampton.
Cyle Larin's stoppage-time equaliser denied the Baggies a much-needed win as the Saints closed to within three points of the top six.
Birmingham rekindled their play-off hopes as Patrick Roberts' goal beat QPR 1-0.
Oxford boosted their survival hopes with a 1-0 win over fellow strugglers Blackburn, while Norwich beat Sheffield United 2-1.