Looks like Brunfelsia pauciflora.. https://www.google.co.uk/search?q=B...Q&biw=1920&bih=967&sei=y0VcUZXyHcfX0QXfvoH4DQ
Agree - although it could also be B. grandiflora. The common name in Colombia and Ecuador is "JasmÃn de Paraguay" - it's very popular for its fragrance.