Yes. As of January 1, 2015, chapter 13 plans in the Southern District of Texas (Houston, Galveston, Brownsville, Victoria, Corpus Christi, Laredo, and McAllen divisions) can contain a clause that permits you to pay extra to your chapter 13 trustee, as an emergency savings account.
The trustee will hold the money and if you need it during your plan, distribute it to you after your attorney files a 15- day notice, so long as no one objects. If you don't need the money during your plan, the trustee will give it all back to you at the end of your plan.
The Bankruptcy Court encourages you to save money for emergencies, so that your plan has a higher probability of success. You can also save money yourself, from money that you don't need to pay your living expenses or your chapter 13 plan payment.