The workflow engine or Process Execution and State Management Engine, is not BPM. It is only one component of it as shown on the diagram. More specifically, it is a runtime software application that processes the details of a workflow design. Modern workflow application suites will include graphic modeling tools, form builders and database integration. Understanding this is crucial in making a decision on how to proceed with a solution. BPM suites It is a wholly independant software application that interprets a predefined format at the core of the BPM Process.
AIT will help choose the right software applications to suite the requirements and the IT infrastructure available to support it. The workflow engine is the runtime software that will support a specific design time suite of software. There are opensource options and there are proprietary options available through vendors. AIT will do this.
The workflow engine enforces the rules set by the designer. Some rules need to be agile and edited by the business, others need to be immutable... This is why AIT will use a variety of solution and product components to complete a viable solution.
Consistency Creates Capacity.
Reuse processes, streamline the work load, manage the exceptions.