Bob Bourque - New Steam Engine

Chapter	Title
1	Background
2	Motivations For This Engine
3	Requirements and Constraints
4	Progress
5	Prototype Development
6	Description of the Bourque Cycle
7	Features of the Cycle
8	The Complexity Issue
9	Fuel Requirements
10	First Example Engine in a Vehicle
11	Description of the Expander
12	Expander Hot Cylinder Lubrication
13	Expander Piston Structural Analysis
14	Two More Engine and Vehicle Examples
15	Other Engine Components
16	Materials
17	Safety
18	Water Freezing
19	Control System
20	Starting Time
21	Summary
	Acknowledgments
	Some Unit Conversions
	Notes and References

A Compact Pollution-Free
External Combustion Engine
with High Part-Load Efficiency

18. Water Freezing

It would be nice to find a working fluid as good as steam but does not freeze. As discussed above, that search has so far been unsuccessful. Therefore, the freezing issue must be addressed. This is done with the following steps:

At shutdown, the water is drained into a heavily insulated storage vessel (called a ‘hotwell’). The total liquid inventory is 1-2 liters.

To retard freezing, a small amount of battery power is fed to resistance heaters around the storage vessel.

Allowance is made for the 10% expansion if it freezes.

To restart after a cold shutdown, low temperature combustion gas flows between the thermal insulation and engine components to thaw ice and warm expander oil.

The Bourque Steam Engine

A Compact Pollution-Free External Combustion Engine with High Part-Load Efficiency

A Compact Pollution-Free
External Combustion Engine
with High Part-Load Efficiency