How do you promote involvement when employees are consistently asked for their opinion and feedback but never have anything to say because they are fearful of increased workload to fix the problems they might identify?

There is something bigger here, culturally, that needs some thought. Some analysis of the pattern of process improvement needs attention. Have people been successful with implementing process improvement? Have they been recognized? What is happening with how process improvement is being executed, that is causing employees to react this way? This might be an opportunity to perform a mini-PDCA (plan-do-check-act) on the process improvement initiative. If process improvement were really going to save employees time, or make customers happier, there would be more excitement. But if it’s not saving them time, or having a reverse affect, we might be putting the nail in the process improvement coffin.