Refrigerant expansion and combustion hybrid (REACH) engine
Patent Information
- Application Number
- AU2025202085
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-23
- Publication Date
- 2026-10-08
Smart Images
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Abstract
Description
TECHNICAL FIELD The present invention relates generally to engine technology and thermal energy recovery systems. More specifically, it pertains to a hybrid engine design that integrates functional modules—namely, internal combustion cylinders (ICCs) and refrigerant expansion cylinders (RECs)—to capture and redeploy waste heat for additional mechanical work. This invention intersects fields such as internal combustion engine design, thermodynamics, and energy conversion, and is applicable to varied engine configurations including rotary engines and reciprocating engines across 2-stroke, 4-stroke, and 6-stroke designs. The technology is suited for engines utilising a range of fuels, including, but not limited to, gasoline-oil mixtures, petrol, diesel, LPG, heavy fuel oil or hydrogen, where fuel efficiency, thermal efficiency and emission reductions are of paramount importance. BACKGROUND OF THE INVENTION Conventional internal combustion engine (ICE) technology has served as the backbone of transportation and industrial applications for over a century. In these systems, power is generated through a series of internal combustion cylinders (ICCs) that combust fuel to perform mechanical work. However, despite decades of incremental improvements, traditional engine designs suffer from significant thermodynamic inefficiencies. A substantial portion of the fuel’s energy is dissipated as waste heat, limiting both performance and fuel economy. Rotary engines, while admired for their compact size, high power-to-weight ratio, and smooth operation, present unique challenges. Their continuous rotating chamber design inherently limits heat dissipation, leading to elevated operating temperatures that can compromise reliability and reduce efficiency. Furthermore, the absence of dedicated intake, compression, power, and exhaust strokes in rotary engines makes retrofitting external heat recovery systems particularly difficult without significantly altering the engine architecture. In a multi-rotor engine, interspersed RECs can absorb and utilise engine heat, allowing rotary engines to produce as much power with less fuel and much less heat. 2025202085 23 Mar 2025 Existing methods to reclaim wasted heat energy, such as turbocharging or exhaust heat recovery systems, have had only limited success. These approaches typically capture energy from the exhaust stream and do not integrate seamlessly with the combustion process or the engine itself. As a result, there remains a clear opportunity to enhance efficiency by directly addressing the source of waste through a more effective, better integrated thermal energy recovery process. The present invention describes a novel process and method to repurpose waste heat into useful mechanical work. This innovation provides a modular approach where certain combustion cylinders are either complemented or supplanted by components designed specifically to harness waste heat. The present invention, the Refrigerant Expansion and Combustion Hybrid (REACH) engine, builds on these ideas by integrating refrigerant expansion cylinders (RECs) alongside conventional Internal Combustion Cylinders (ICCs). The key insight is that by equating the size, function and mechanical integration of RECs with those of ICCs, the engine can be reconfigured into a balanced array of modules—where the waste heat from traditional combustion is immediately redirected to drive adjacent RECs. This modular architecture addresses several previously unresolved problems in the prior art: • Thermal Utilisation: By capturing waste heat at or near its source, the REACH engine minimises thermal energy loss compared to conventional methods that rely on distinct, secondary heat exchangers. • Retrofitting: The comparable dimensions of ICCs and RECs allow for a streamlined transition, making it feasible to retrofit existing engines with minimal reconfiguration by converting a portion of the existing ICCs into RECs. • Energy Conversion: Prior solutions often recover only a small fraction of the available waste heat. Integrating RECs directly with ICCs promises to convert a far greater percentage of waste heat energy into mechanical work, enhancing both thermal efficiency and fuel efficiency while reducing emissions. 2025202085 23 Mar 2025 In summary, while conventional ICE systems and supplementary recovery methods have provided some improvements, they do not fully exploit the potential for reclaiming waste heat at the cylinder level. The REACH engine, with its integrated combination of ICCs and RECs, represents a significant advancement by offering a scalable, modular method to achieve superior energy efficiency and environmental performance. SUMMARY OF THE INVENTION The present invention introduces a novel hybrid engine system—the Refrigerant Expansion and Combustion Hybrid (REACH) engine—that elevates conventional engine performance through an integrated heat recovery approach. In this system, a standard Internal Combustion Engine (ICE) is reconceived as an assembly of discrete, yet functionally analogous, modules: Internal Combustion Cylinders (ICCs) and Refrigerant Expansion Cylinders (RECs) sharing a common water jacket. Each ICC performs traditional fuel combustion and produces waste heat, which is transferred through the water jacket to be captured and utilised by adjacent RECs to generate additional mechanical work. This innovative design emphasizes modularity by ensuring that the RECs are comparable in shape, size, connection to the crank (or eccentric) shaft and operational function to the ICCs. By strategically converting a portion of the ICCs with RECs, the REACH engine system achieves an optimized balance between energy generation and recovery. This modular configuration not only allows for efficient retrofitting of existing engines but also minimises engine design changes and manufacturing process changes required to produce new-build REACH engines. Key features of the invention include: • Modular Architecture: The engine is composed of individual units—ICCs and RECs—that maintain comparable dimensions and operational roles, thereby facilitating the direct conversion of waste heat into mechanical energy inside the engine block. 2025202085 23 Mar 2025 • Simple and Direct Thermal Energy Transfer: The water jacket of the engine is already designed to absorb the waste heat produced by the ICCs and the cylinder walls are already designed for sufficient heat transfer between cylinder walls and water jacket. The RECs inside this same water jacket are simply absorbing heat from the water jacket whereas the ICCs are rejecting heat into the water jacket. The close integration of REC modules inside the engines water jacket beside ICC modules provides a simple and direct thermal energy transfer for maximum thermal energy recovery. • Versatility and Adaptability: The system is compatible with varied engine configurations—including rotary engines and reciprocating engines with 2-stroke, 4-stroke, and 6-stroke designs—and supports multiple fuel types including, but not limited to, gasoline-oil mixtures, petrol, diesel, LPG, heavy fuel oil or hydrogen. • Optimized Performance and Emission Control: An intelligent control system synchronises the operation of the modular ICCs and RECs, maximising fuel and thermal efficiency and reducing exhaust and thermal emissions. Protection is sought for all novel methods, configurations, apparatus components, and processes described herein, including, but not limited to, the specific techniques of heat recovery and transfer, the control of the refrigerant injection and the coordinated dual-cycle operation that underpins the modular architecture of the REACH engine. BRIEF DESCRIPTION OF THE DRAWINGS Error! Reference source not found. shows a water cooled, 2-cylinder, 2-stroke REACH engine with a liquid cooled Engine Block (1) containing cooling fluid in a Water Jacket (2) absorbing combustion by-product heat from an Internal Combustion Cylinder (ICC) (3) and supplying heat into a Refrigerant Expansion Cylinder (REC) (4). An open / close Inflow High Speed Solenoid Valve (IHSSV) (8) controls refrigerant vapour flow along a Refrigerant Vapour Inflow Line (6) that provides fluid connection from the Receiver (13) to the Refrigerant Vapour Inlet Port (5) in the REC (4) through Inflow Check Valve (7) to provide Mean Effective Pressure (MEP) for the REC’s Power Stroke. 2025202085 23 Mar 2025 An open / close Return High-Speed Solenoid Valve (RHSSV) (12) controls refrigerant vapour flow along a Refrigerant Vapour Return Line (10) that provides fluid connection from the REC (4) out of the Refrigerant Vapour Return Port (9) to the Receiver (13) through Return Check Valve (11) so the refrigerant vapour in the swept volume of the REC (4) can be returned to the Receiver by the REC’s Return Stroke. If and as required to prevent the Water Jacket (2) from overheating, a Heat Rejection Water Cycle (22) may beneficially circulate cooling fluid from the Water Jacket (2) through a Radiator (21) by means of a Cooling Fluid (Water) Pump (20) to reject heat into Outside Air (24B). In a new-build REACH engine, components of the Heat Rejection Water Cycle (22) would be correctly sized for the REACH engine, whereas in a retrofit conversion the existing water pump and radiator, although larger than necessary, may be repurposed for use in a REACH engine. An optional Heat Bank (15) may beneficially be incorporated into a REACH engine to store high temperature heat scavenged from Exhaust Gas (25) by circulating a suitable fluid such as thermal oil from the Heat Bank (15) to the ICC Exhaust Line Heat Exchanger (17) and back to the Heat Bank (15) with a suitable Thermal Pump (16); while a separate Heat Recovery Cycle (27) circulates sufficient cooling fluid from the Water Jacket (2) to the Heat Bank Exchanger (19) in the Heat Bank (15) where it absorbs heat from the Heat Bank (15) then returns back to the Water Jacket (2). The Heat Bank (15), Heat Bank Scavenging Cycle (26) and Heat Recovery Water Cycle (27) may optionally be incorporated into a REACH engine to enable a higher proportion of heat consuming RECs to be supported by a lower proportion of fuel-consuming and heat producing ICCs. If these optional components are not provided, then Water Jacket (2) heat will be provided exclusively by ICCs and therefore the REACH engine will need a higher proportion of ICCs to maintain water jacket heat. Error! Reference source not found.Error! Reference source not found. shows a reciprocating 2-stroke REC with the piston at BDC and identifies the Cylinder wall (100), Piston Rings (101), Isolated Crankcase Compartment (102), Transfer Passage (105) with Transfer Passage Check Valve (104), an Inlet Port (106) that has been Closed and Sealed, Crankcase Volume (107) and Swept Volume (108). 2025202085 23 Mar 2025 In a retrofit conversion of a reciprocating 2-stroke ICC into a REC, the Inlet Port (106) of the ICC must be closed and sealed because a REC has no concept of an intake stroke. A REC designed for a new-build REACH engine would not have an inlet port. In a reciprocating embodiment of a REACH engine there must exist a fluid connection such as the Transfer Passage (105) and a Transfer Passage Check Valve (104) which together cause refrigerant vapour blow-by that has passed the Piston Rings (101) into an Isolated Crankcase Compartment (102) to be returned to the refrigerant vapour circuit and not remain trapped in, or build up in, the Isolated Crankcase Compartment (102). In every reciprocating embodiment of the REACH engine the REC must have an Isolated Crankcase Compartment (102) because REC blow-by will be refrigerant vapour whereas ICC blow-by will be a fuel / air / exhaust gas mixture and these two gases must never mix. Similarly, refrigerant vapour from a REC’s Isolated Crankcase Compartment (102) must never, under any circumstances, be ventilated to an intake manifold shared with ICCs, by any means allowed to mix with fuel / air / exhaust gas from ICCs, or by any means allowed to enter ICCs. Furthermore, refrigerant vapour from a REC’s Isolated Crankcase Compartment (102) must never be ventilated to atmosphere. Similarly, crankcase oil used in the Isolated Crankcase Compartment (102) of a REC must be oil suitable for use with the selected refrigerant. Refrigerant oil should be selected with both the refrigerant and the dynamics of the REC in mind. It must never be possible for refrigerant oil and ICC crankcase oil to mix under any circumstances. In a new-build REACH engine, a REC would have the Refrigerant Vapour Return Port (9) placed in or near the top of the REC, whereas in a retrofit conversion of a 2-stroke engine the Exhaust Port may be converted for use as a Refrigerant Vapour Return Port (9), or the Exhaust Port may be closed and sealed and a new Refrigerant Vapour Return Port may beneficially be created nearer the top of the cylinder. 2025202085 23 Mar 2025 DETAILED DESCRIPTION OF EMBODIMENTS The present invention describes a process and method for a Refrigerant Expansion and Combustion Hybrid (REACH) engine technology that integrates heat-absorbing Refrigerant Expansion Cylinders (RECs) with fuel-burning Internal Combustion Cylinders (ICCs) in a single engine. The REACH engine improves efficiency by utilising waste heat from the ICCs to perform additional work via RECs. Waste heat, typically rejected into the environment, is instead harnessed to generate mechanical energy, reducing the number of fuel-burning cylinders in the engine, reducing fuel consumption, exhaust emissions, and thermal emissions of the engine. 1. Overall System Architecture The REACH engine incorporates several integrated components: • Internal Combustion Cylinders (ICCs): In an internal combustion engine embodiment, the ICCs are conventional cylinders operating on 2-stroke, 4-stroke, or 6-stroke cycles. In a rotary engine embodiment, they are conventional rotor housings with conventional rotors. In either case they may burn a variety of fuels including, but not limited to, gasoline-oil mixtures, petrol, diesel, LPG, heavy fuel oil or hydrogen, to produce mechanical power while generating by-product heat. • Refrigerant Expansion Cylinders (RECs): The RECs utilise high-pressure refrigerant vapor to generate power strokes. This refrigerant vapour is heated via waste heat transferred from the ICCs to the RECs through an integrated water jacket. Each REC should achieve a Mean Effective Pressure (MEP) comparable to that of the engine’s ICCs to maximise engine balance. • Water Jacket Heat Transfer System: The Water Jacket is a liquid cooling system that may use water, coolant, oil, or any other liquid appropriate for the application. The Water Jacket encases both the ICCs and RECs, providing a thermal conduit for waste heat transfer from ICCs to RECs. By maintaining an appropriate temperature, the water jacket ensures optimal cooling of ICCs and heating of RECs, which is essential for refrigerant expansion. 2025202085 23 Mar 2025 • Receiver and Ambient Energy Buffer: Refrigerant is stored in a receiver exposed to ambient air. By being in thermal equilibrium with the surrounding environment, the receiver functions as an energy buffer, stabilizing refrigerant conditions. Any excess or deficit energy in the refrigerant is corrected via heat exchange with the ambient air, ensuring consistent system performance. • Engine Control Unit (ECU): The ECU governs the operation of key components, including the Inflow High-Speed Solenoid Valve (IHSSV) for refrigerant injection and, in 2-stroke embodiments, the Return High-Speed Solenoid Valve (RHSSV) for returning refrigerant to the receiver. It also monitors water jacket temperature and manages energy balances across the system. 2. Optional Heat Bank System An optional Heat Bank System can be integrated into the REACH engine to augment its thermal efficiency and expand its capabilities. • Purpose and Benefits: The Heat Bank System scavenges high-quality heat from ICC exhaust emissions, storing it in a thermal reservoir. This additional heat can be utilised to sustain the water jacket temperature, enabling the engine to support a higher proportion of RECs to ICCs. • Components: 1. Heat Bank (Thermal Reservoir): The Heat Bank stores high-temperature heat using a heat storage fluid, such as thermal oil, selected for its excellent heat retention properties. 2. Exhaust Gas Heat Scavenging Cycle: A heat exchanger installed in the ICC exhaust line captures waste heat. A suitable thermal pump circulates the heat storage fluid between the Heat Bank and the exhaust line heat exchanger, transferring the recovered heat to the thermal reservoir. 2025202085 23 Mar 2025 3. Heat Recovery Cycle: A separate loop circulates water (or another cooling fluid) between the Heat Bank and the water jacket, transferring stored heat as necessary to maintain an optimal operating temperature in the water jacket. • ECU Integration: The ECU monitors water jacket temperature and activates the Heat Recovery Cycle when needed. This automated process ensures consistent thermal conditions for the RECs, even when ICC waste heat alone is insufficient, such as during low-load operations. 3. REC Operation in a Reciprocating Engine Embodiment The REACH engine’s REC cycle adapts to harmonize with the ICC cycle: • Power Stroke: During the Power Stroke, the ECU opens the IHSSV to allow high-pressure refrigerant vapor into the REC. The timing and duration over which the IHSSV remains open are controlled by the ECU to achieve a MEP for the Power Stroke comparable to that of the engine’s ICCs. As the piston descends, waste heat from the water jacket continues to warm the refrigerant. The combination of adequate refrigerant vapour inflow and heat inflow maintaining efficient refrigerant expansion and work generation. • Return Stroke: Following the Power Stroke, the ECU closes the IHSSV and opens the RHSSV, enabling refrigerant vapor to return to the receiver. Heat transfer from the water jacket continues and the piston’s upward motion compresses the refrigerant, which together elevate the pressure of the refrigerant in the REC. As soon as refrigerant vapour pressure in the REC exceeds refrigerant vapour pressure in the Receiver, refrigerant flows out of the REC along the Refrigerant Vapour Return Line back to the Receiver. • Null Strokes for 4-Stroke and 6-Stroke Configurations: Null-Up and Null-Down strokes are introduced in 4-stroke and 6-stroke reciprocating engines to align the REC’s power stroke frequency with that of the ICCs. These strokes allow the REC to match the ICC cycle count, preventing overproduction of power strokes to maximise balance of the REACH engine. 2025202085 23 Mar 2025 4. REC Operation in a Rotary Engine Embodiment In rotary engine embodiments, RECs operate within continuously rotating chambers. In a retrofit REC rotor housing, the intake port would be blocked and sealed, and in a new build REC rotor housing there would be no intake port. With no intake port, the null phases naturally occur in place of intake and compression phases, simplifying geometry integration and synchronization with ICC cycles. The refrigerant is injected at the point where the rotor is ready to expand through Refrigerant Vapour Inlet Ports placed where the spark plug or glow plug ports would be in an ICC rotor housing, and the exhaust port is repurposed for refrigerant return. 5. System Integration and Benefits • Flexible Thermal Management with the Optional Heat Bank System: The Heat Bank System adds an auxiliary heat reservoir that ensures stable water jacket temperatures. This allows the REACH engine to operate with fewer ICCs while sustaining more RECs, maximizing its reliance on recovered thermal energy and minimizing fuel consumption. • Reduced Fuel Consumption and Emissions: By replacing fuel combustion in selected ICCs of an engine with waste heat recovery in RECs, the REACH engine achieves significant reductions in fuel consumption, greenhouse gas emissions, and thermal emissions. • Adaptive Performance: The receiver’s role as an ambient energy buffer ensures that refrigerant conditions remain stable, while the ECU dynamically adjusts refrigerant injection to maintain consistent performance across varying environmental and operational conditions. 2025202085 23 Mar 2025 Performance Examples Example #1 A conventional 5.0 litre V-8 ICE domestic pick-up truck has 4 of its 8 ICCs converted into RECs in a retrofit REACH engine conversion, but to control costs, the optional Heat Bank is not fitted. The RECs are interleaved with the ICCs properly, the water jacket is efficient and charged with an effective coolant and a suitable refrigerant has been chosen and the ECU programming has been updated properly. The V-8 produces the same power as before but now has only 4 of its 8 cylinders burning fuel, so it is using ½ as much fuel as before - it now has the fuel economy of a 2.5 litre 4-cylinder car, and because most of the engine block heat is being consumed by RECs it has the thermal emissions of a motorcycle. Example #2 A 12.0 litre 6-cylinder heavy duty truck engine is converted to a REACH engine and the optional Heat Bank system is fitted. Because of the extra heat available from the heat bank, 4 out of 6 ICCs in the engine are converted into RECs. As before, the RECs are interleaved with the ICCs properly, the water jacket is efficient and charged with an effective coolant and a suitable refrigerant has been chosen. The truck produces the same power as before but now has only two cylinders burning fuel, so it has 4.0 litres of fuel-burning cylinders, giving it the fuel economy of a smaller domestic pick-up truck and the power of a heavy-duty transport truck. Example #3 A Mazda RX-7 rotary engine with two rotors is retrofitted into a REACH engine. One rotor housing remains as an Internal Combustion Cylinder (ICC), while the second rotor housing is converted into a Refrigerant Expansion Cylinder (REC). The intake port of the REC is sealed, and the existing exhaust port is repurposed as the refrigerant vapor return port. The two spark plug ports are both converted to refrigerant vapour inlet ports. 2025202085 23 Mar 2025 The REC is placed behind the ICC, so that airflow over the ICC moves heat back towards the REC rotor, the water jacket is charged with suitable coolant, and the refrigerant is chosen to deliver comparable MEP in the REC even under the rotary engine's high-speed operation. The ECU is programmed to manage refrigerant vapour injection timing and temperature stability effectively. The retrofitted RX-7 continues to produce the same level of power as it did before, while only one of its two rotor housings burns fuel delivering fuel consumption of around 7.0 - 8.0 litres / 100 km instead of up to 15.7 litres / 100 km. The engine has the same sporty performance, with the fuel economy of a much more mundane and conservative vehicle. The cooling effect provided by the REC also improves the maintenance profile of the remaining ICC rotor. By effectively absorbing and repurposing waste heat, the REC reduces thermal stress and operating temperatures within the ICC, reducing wear and tear on heatsensitive components. This results in extended service intervals, enhanced reliability, and a longer operational lifespan for the combustion rotor. Conclusion The REACH engine represents a breakthrough in thermal efficiency and hybrid engine technology. With the optional Heat Bank System, the REACH engine maximises waste heat recovery from ICC exhaust gases, enabling the system to support even more RECs relative to ICCs, even further enhancing the REACH engine. With or without the Heat Bank option, the REACH engine delivers significantly higher overall efficiency, reduced exhaust gas emissions, and reduced thermal emissions in a wide variety of embodiments.
Claims
1) A Refrigerant Expansion Cylinder (REC): A process and method for a refrigerant expansion cylinder (REC) that consumes waste heat generated by at least one internal combustion cylinder (ICC) to perform mechanical work, wherein the REC can be embodied in a reciprocating engine cylinder or a rotary engine rotor housing.2) Refrigerant-Based Mean Effective Pressure (MEP): A process and method for producing work in a REC by creating sufficient Mean Effective Pressure (MEP) through the combined actions of: (i) injecting refrigerant vapor into the cylinder or rotor housing for a controlled period of time from at or near Top Dead Centre (TDC) until at most Bottom Dead Centre (BDC), and (ii) transferring heat from at least one ICC into the refrigerant via the cylinder or rotor housing walls.3) Conversion of ICC to REC: A process and method for converting an existing internal combustion cylinder (ICC) into a refrigerant expansion cylinder (REC), wherein the conversion includes modifying the port connections to: (i) facilitate refrigerant inflow via a converted spark plug or glow plug port, (ii) establish a fluid connection between the REC and a receiver for refrigerant return, (iii) closing and sealing the intake port, (iv) ensuring the crankcase is isolated and (v) ensuring one-way fluid transfer of refrigerant vapour blow-by back into the refrigerant cycle.4) Refrigerant Expansion and Combustion Hybrid (REACH) Engine: A hybrid engine comprising at least one internal combustion cylinder (ICC) and at least one refrigerant expansion cylinder (REC) of claim (1), wherein: (i) the ICC combusts fuel to perform work and generates waste heat, and (ii) the REC consumes the waste heat to perform work.5) Engine Embodiments: The REACH engine of claim 4, wherein the engine may be embodied in: (i) a 2-stroke, 4-stroke, or 6-stroke reciprocating engine, or (ii) a rotary engine configuration.2025202085 23 Mar 20256) Fuel Variability in ICCs: The REACH engine of claim 5, wherein the ICCs may burn a variety of fuels, including but not limited to: (i) gasoline-oil mixtures, (ii) petrol, (iii) diesel, (iv) LPG, (v) heavy fuel oil or (vi) hydrogen or any other suitable hot-burning fuel.7) Integration of Null Strokes in RECs: A process and method for incorporating null strokes in a REC to synchronize the number of REC power strokes with the ICC power strokes in a 4-stroke or 6-stroke engine configuration, wherein the null strokes include: (i) a Null-Up Stroke, during which the REC performs no expansion or return of refrigerant, and (ii) a Null-Down Stroke, during which the REC performs no expansion or return of refrigerant.8) Null Phases in Rotary RECs: A process and method for incorporating null phases in a refrigerant expansion rotor housing (REC) of a rotary engine to synchronize the number of power strokes with those of internal combustion rotor housings (ICCs), wherein: (i) the rotor housing remains idle during the intake and compression stages with no refrigerant vapor present, creating null phases that prevent active refrigerant processing, and (ii) refrigerant vapor is introduced only at or near the position corresponding to the commencement point of the expansion phase.9) Optional Heat Bank System: A process and method for integrating an optional Heat Bank System into a REACH engine, wherein: (i) the Heat Bank stores high-quality heat scavenged from ICC exhaust emissions via a heat exchanger, (ii) a Heat Recovery Cycle transfers heat from the Heat Bank into the water jacket to maintain its temperature, and (iii) the Engine Control Unit (ECU) manages heat flow to sustain optimal REC operation and enable the engine to support a higher proportion of RECs relative to ICCs.10) Cooling and Stabilization of the Receiver: A process and method for stabilizing refrigerant conditions in a receiver, wherein: (i) the receiver is brought into thermal equilibrium by ambient air flow to maintain refrigerant at a saturated vapor pressure appropriate for the operating environment, and (ii) the receiver acts as an energy buffer, absorbing or rejecting heat based on the energy of the returning refrigerant.2025202085 23 Mar 202511) Control via ECU: A process and method for managing REACH engine performance via an Engine Control Unit (ECU), wherein the ECU: (i) adjusts the timing and duration of refrigerant injection into the REC to achieve the desired Mean Effective Pressure (MEP), (ii) regulates water jacket temperature to optimize heat transfer to the RECs, and (iii) controls the optional Heat Bank System to supplement water jacket heat when ICC waste heat is insufficient.12) Retrofit Capability: A process and method for retrofitting an existing internal combustion engine to a REACH engine by: (i) converting at least one ICC into a REC as in claim 3, and (ii) optionally incorporating the Heat Bank System as in claim 8.