CI Status and KPI propgration

I am trying to implement custom HIs and KPIs , So I created a custom CI type called Vehicle and it's subtypes Engine and TIres.  I establised relationship between Vehicle and Engine, Tires as containment

Then I created custom CI , four tires , engine and a car in IT universe model and set up relationships. Now I created following Health Indicators and KPIs

Tire :  

 HI : TirePressure , KPI: TirePerformance ( calculated based on TirePressure) 


HI : EngineHeat  , KPI : EnginePerformance ( calculated based on EnginePressure)


KPI : CarPerformance ( Calculated based on HIs and Child KPIs , and choose Legacy System as HI ) 

All of them have worst status rule where possible


Using I generated  events that changed health indicators of Tires and Engine, they went into Red and Yellow statuses in Top View.  But my car stays in green. How do I propogate that status up to the parent CI. Please help I am learning and trying out a few things. Attached has the topview of a pattern view that I created for this.