Let's go back to the philosophy of external combustion engine - is required temperature difference between the hot and cold part to be able to convert heat into mechanical work. Now we heat the warm part to have a temperature difference. I suggest that the temperature difference to be a result of work done - temperature difference between the hot and cold part we can create it as a cooling cold part. And to get efficient engine has the power we need to apply to create the necessary temperature difference at any time should be less than the force that generates the working substance.
Lets to think - how much is the heat which we can turn into mechanical work of a working substance with a given temperature? To be able to work working substance must have a temperature -high from its boiling point. All the heat of a working substance which can be converted into mechanical work it is equal to the difference between the temperature to which it heats the heat source up to its boiling point. Theoretically and practically we can make all this heat into mechanical work always remained waste heat.
Let's perform work on the working substance as it cooled in the cold part to have a temperature difference and the engine running. To be an effective engine running on this principle should amount to heat is less than the amount of heat which has become into mechanical energy. This will achieve it by carrying out the process of converting heat into mechanical energy into heat - isolated environment - on the work process working substance cools. So like I can become a a large part of the heat into mechanical force balance between the useful power and strength that must apply in order to maintain the temperature difference will be in favor of the beneficial forces. I think there is a way beneficial forces are more powerful than the opposite and so we have an effective engine of which the temperature difference between hot and cold part is held as a result of work done.
We need to create conditions for the majority of the amount of heat on the working substance to turn into mechanical energy so that the waste heat to be a small part of the total heat quantity.
In my previous posts I have given some suggestions (It is better to begin consideration of the method with two working substances). I have a few more ideas that will present soon.
One primary method is to use more than one working substance. Each working substance can convert think ½ of the amount of heat into mechanical work. So the power we need to use for running the unit at any time will be measuring less than power produced by the working substances in their work.
Another method is to split the load and repeatedly perform work as the opportunity to make heat exchange between liquid and gaseous working substance in the course of his work. So I want to achieve a small amount of waste heat before closing the cycle of working substance. Less waste heat = good balance between useful and opposite force.
To draw attention once again to something important - Every start we need to have set a low temperature of the cold part. This will use external power.