US 4,393,656 A · Waste heat recovery system for an internal combustion engine

Abstract

A method and apparatus for recovering and utilizing waste heat from the exhaust and coolant of an internal combustion engine. The waste heat recovery system uses two separate and closed circuits of working fluid with one circuit being heated by the exhaust gases and the other being heated by the engine coolant. In the preferred embodiment, two different working fluids are used and each circuit is designed to operate at temperatures and pressures most efficient for that particular working fluid and the heat available from the exhaust in one case and the coolant in the other case. A heat exchanger is provided between the two circuits for increased efficiency and a heat reservoir of melted salt is built into the exhaust heated circuit to minimize surges in the system and to provide reserve power during high performance demands. In the preferred embodiment, the work produced by the exhaust heated circuit is sequentially added to the power output of the engine and vane expanders rather than turbines are used for a more direct and efficient coupling of the available work from the recovered waste heat to the power output of the engine. A manner is also disclosed in which the basic flow pattern of the preferred embodiment can be adapted to operate with a single working fluid if desired.

Claims18

Dependent claims

A method primarily intended for recovering and utilizing waste heat from the exhaust and coolant of an internal combustion engine by using a single working fluid, said method comprising the steps of:

(a) pumping liquified working fluid to a first location along a first path,
(b) vaporizing said working fluid at said first location along said first path to a high side temperature and pressure by applying waste heat from said exhaust,
(c) expanding said vaporized working fluid in said first path to produce work,
(d) condensing said expanded working fluid to a liquid state by removing heat therefrom,
(e) repeating steps (a)-(d) while simultaneously,
(f) pumping said liquified working fluid along a second path having at least two portions thereof in parallel,
(g) vaporizing said working fluid of step (f) in said parallel portions of said second path to high side temperatures and pressures less than the high side temperature and pressure of said first path by respectively applying waste heat in parallel from said coolant and the removed heat of step (d),
(h) expanding said vaporized working fluid in said second path to produce work,
(i) condensing said expanded working fluid of step (h) to a liquid state, and
(j) repeating steps (f)-(i).

7 more elements

A waste heat recovery system primarily intended for use with a single working fluid and an internal combustion engine having a coolant system and exhaust system, said waste heat recovery system comprising:

a first path,
means for pumping said working fluid in a liquified state to a first location aong said first path,
means for vaporizing said working fluid at said first location to a high side temperature and pressure by applying waste heat from said exhaust,
means for expanding said vaporized working fluid in said first path to produce work,
means for condensing said expanded working fluid to a liquid state by removing heat therefrom wherein said liquified working fluid passes along said first path to said pumping means,
a second path having at least two portions thereof in parallel,
means for pumping said working fluid in a liquified state along said second path and through said parallel portions,
means for vaporizing said working fluid in said parallel portions of said second path to high side temperatures and pressures less than the high side temperature and pressure of said first path by respectively applying waste heat in parallel from said coolant and the removed heat of the condensing means of said first path,
means for expanding said vaporized working fluid in said second path to produce work, and,
means for condensing said expanded working fluid in said second path to a liquid state wherein said liquified working fluid passes along said second path to said pumping means.

7 more elements

Dependencies are inferred from the claim text.

Waste heat recovery system for an internal combustion engine

Life of this patent

Waste heat recovery system for an internal combustion engine

Life of this patent

Abstract

Claims18