Not really.
These heaters work by converting cheaper electricity available at night into actual heat. It is stored by heating bricks inside the unit, insulated to stop the heat getting out. These bricks have a high capacity to store heat.
The only way you can control the output is via vents on the unit. These prevent the air circulating - cooler air gets drawn in at the bottom - hotter air comes out at the top.
The vents are mechanical flaps, moved by twisting the output knob usually.
Once you understand that, I trust you will see that putting a timer on the unit is not really very practical.