Method for the operation of a steam thermal engine, in particular as a vehicle power unit

A process for operating a steam thermal engine, comprising:

• heating a liquid working medium to a low temperature at a low pressure in a first heat exchanger using external waste heat of relatively low energy, to form a wet steam;
• heating the wet steam to a relatively high temperature by feeding the wet steam to a second heat exchanger heated by external waste heat of relatively high energy;
• injecting liquid working medium or condensate of relatively low boiling temperature from the first heat exchanger into steam atmosphere of the second heat exchanger to produce a hot steam, which is used to perform work in an expansion unit of the thermal engine, with an instantaneous evaporation of the working medium of approximately boiling temperature with a significant increase in pressure;
• feeding the hot steam back into the first heat exchanger as condensate after the hot steam has performed the work;
• wherein the external waste heat of relatively low energy is hot coolant from a combustion engine;
• wherein the external waste heat of relatively high energy is the exhaust gas of the combustion engine;
• and
• after heating up the second heat exchanger, using the exhaust gas to heat the first heat exchanger.

A process for operating a steam thermal engine, comprising:

• heating a liquid working medium to a low temperature at a low pressure in a first heat exchanger using external waste heat of relatively low energy, to form a wet steam;
• heating the wet steam to a relatively high temperature by feeding the wet steam to a second heat exchanger heated by external waste heat of relatively high energy;
• injecting liquid working medium or condensate of relatively low boiling temperature from the first heat exchanger into steam atmosphere of the second heat exchanger to produce a hot steam, which is used to perform work in an expansion unit of the thermal engine, with an instantaneous evaporation of the working medium of approximately boiling temperature with a significant increase in pressure;
• and
• feeding the hot steam back into the first heat exchanger as condensate after the hot steam has performed the work, wherein the expansion unit includes a piston machine having at least first and second cylinders, whereby the first cylinder includes a first pressure vessel and a first valve unit having first to fourth valves, and the second cylinder includes a second pressure vessel and a second valve unit having first to fourth valves.

A device comprising:

• a first heat exchanger for heating a liquid working medium to a low temperature at a low pressure using external waste heat of relatively low energy to form a wet steam;
• a second heat exchanger for heating the wet steam to a relatively high temperature by feeding the wet steam using external waste heat of relatively high energy, the second heat exchanger being connected to the first heat exchanger, wherein liquid working medium or condensate of relatively low boiling temperature from the first heat exchanger can be injected into steam atmosphere of the second heat exchanger to produce a hot steam with an instantaneous evaporation of the working medium of approximately boiling temperature with a significant increase in pressure;
• and
• an expansion unit of a thermal engine, where the hot steam can be used to perform work, wherein the expansion unit is connected to the first heat exchanger so that the hot steam can be fed back into the first heat exchanger as condensate after the hot steam has performed the work, wherein the first heat exchanger is connected with a coolant circuit of a combustion engine for feeding hot coolant from the combustion engine to the first heat exchanger and the external waste heat of relatively low energy is the hot coolant from the combustion engine and wherein the second heat exchanger is connected with an exhaust system of the combustion engine for feeding exhaust gas of the combustion engine to the second heat exchanger and the external waste heat of relatively high energy is the exhaust gas of the combustion engine.

A device comprising:

• a first heat exchanger for heating a liquid working medium to a low temperature at a low pressure using external waste heat of relatively low energy to form a wet steam;
• a second heat exchanger for heating the wet steam to a relatively high temperature by feeding the wet steam using external waste heat of relatively high energy, the second heat exchanger being connected to the first heat exchanger, wherein liquid working medium or condensate of relatively low boiling temperature from the first heat exchanger can be injected into steam atmosphere of the second heat exchanger to produce a hot steam with an instantaneous evaporation of the working medium of approximately boiling temperature with a significant increase in pressure;
• and
• an expansion unit of a thermal engine, where the hot steam can be used to perform work, wherein the expansion unit is connected to the first heat exchanger so that the hot steam can be fed back into the first heat exchanger as condensate after the hot steam has performed the work, wherein the expansion unit includes a piston machine having at least first and second cylinders, whereby the first cylinder includes a first pressure vessel and a first valve unit having first to fourth valves, and the second cylinder includes a second pressure vessel and a second valve unit having first to fourth valves.