WO2024148433A1

WO2024148433A1 - Dual fuel injection system

Info

Publication number: WO2024148433A1
Application number: PCT/CA2024/050026
Authority: WO
Inventors: Darren Rivet; Rebecca GOLDSACK; Shane Tyler Mcassey; Behnam MONTAZERI; Kelly WRY; Jakub MCNALLY; Steven GARBUTT
Original assignee: Diesel Tech Industries Ltd.
Priority date: 2023-01-10
Filing date: 2024-01-10
Publication date: 2024-07-18

Abstract

Systems and methods are provided for reducing greenhouse gas emissions from combustion engines by using a retrofit dual fuel system. In some embodiments, the system comprises a feeder rail, at least one fuel injection assembly connected to the feeder rail and positioned to inject a first fuel into the air intake track of the engine upstream of at least one cylinder of the engine; and a first electronic control unit (ECU) electronically connected to the first fuel injection assembly and operable to control the injection of the first fuel, the first ECU also being electronically connected to at least one original equipment manufacturer (OEM) ECU and operable to overwrite injection instructions from the at least one OEM ECU to control injection of a second fuel via a second fuel injection assembly. A related method at the first ECU for controlling injection of the first and second fuel is also provided.

Description

DUAL FUEL INJECTION SYSTEM

FIELD

[0001] Embodiments taught herein relate to a system and method for reducing emissions from combustion engines by using a dual fuel injection system. More specifically, systems and methods are directed to retrofitting a single fuel injection combustion engine to a dual fuel injection combustion engine and methods for use of the dual fuel injection system to reduce emissions.

BACKGROUND

[0002] Globally there is a desire to reduce the greenhouse gas emissions produced by internal combustion engines. This problem has been approached in a number of different ways, including the use of a dual fuel injection system. Essentially, the dual fuel injection system concept involves using a first fuel that has lower greenhouse gas emission, in conjunction with a second fuel (the original fuel) that has higher greenhouse gas emissions. The first, lower emitting, fuel would be used to offset use of the second, higher emitting, which would result in an overall reduction in emissions. However, previous approaches to the use of dual fuel injection systems have challenges that have prevented substantial use in the marketplace.

[0003] In some cases, a single point injection of the first fuel is used, which results in an uneven distribution of the first fuel and can cause pre-ign ition or knocking in the engine. In other cases, multi-port injection of the first fuel is used, however, the injection site and method of injection does not allow proper mixing of the fuel and air and the cylinders are filled with a mixture of the first fuel that has an inconsistent concentration, resulting in varying gradients of the first fuel within the cylinders. Some approaches have considered extensive retrofitting of existing engines, which is expensive and time consuming, and other approaches simply suggest manufacturing completely new engines, which does not address the problem of the emissions from currently existing engines or consider the time and effort required in the industry to change engine manufacturing systems and processes. Therefore, there remains a need for an economical approach to retrofit existing combustion engines to produce dual fuel injection engines with consistent first fuel mixing.

[0004] Dual fuel injection systems also require their own, unique, methods and processes to determine injection quantity and timing for both first and second fuels. Some methods propose to use only one type of fuel at a time, with a short overlap during a transition period. Other methods have a specific set of modes of operation and at least one original equipment manufacturer electronic control unit (OEM ECU) decides which of the pre-set modes of operation to use at a particular time, based on certain engine parameters. An OEM ECU controls a set of vehicle systems. For instance, one or more OEM ECUs may control the engine operation, aftertreatment system operation, turbocharger operation, vehicle dash cluster operation, vehicle braking system, vehicle traction control system, and/or vehicle security. [0005] In addition, as low emission fuels, like hydrogen, become less expensive and more accessible to consumers, the cost consumer will pay for low emission fuels will decrease and result in a reduction in overall operating costs for vehicles using low emission fuels. This will further drive a need in the market to find ways to use low emission fuels in pre-existing engines.

[0006] Therefore, there is a second driving force for the need for an efficient dual fuel injection system that can be used to retrofit a single fuel combustion engine to become a dual fuel combustion engine and for a method to use the dual fuel injection system to reduce greenhouse gas emissions that dynamically responds to real time information. There further remains a need for a method to actively adapt in real time to changing engine conditions to reduce greenhouse gas emissions.

SUMMARY

[0007] The disclosure provides systems and methods relating to the reduction of greenhouse gas emissions from combustion engines.

[0008] In one aspect, there is provided a retrofit dual fuel injection system for a combustion engine comprising: a feeder rail having a first fuel line and at least one feeder rail segment; at least one first fuel injection assembly connected to the feeder rail, the at least one first fuel injection assembly being positioned to inject a first fuel into the air intake track of the engine upstream of at least one cylinder of the engine; and a first electronic control unit (ECU) electronically connected to the first fuel injection assembly and operable to control the injection of the first fuel, the first ECU also being electronically connected to at least one original equipment manufacturer (OEM) ECU and operable to overwrite injection instructions from the at least one OEM ECU to control injection of a second fuel via a second fuel injection assembly.

[0009] In some embodiments, the at least one first fuel injection assembly injects the first fuel within the path of the air flowing toward the at least one cylinder such that the mixture of the first fuel and the air is substantially homogenous prior to entering the cylinder.

[0010] In some embodiments, injection mass and timing of the injection of the first fuel is determined by the first ECU such that the mixture of the first fuel and the air is controllable via the first ECU.

[0011] In some embodiments, the at least one first fuel injection assembly comprises a first fuel injector, a calibrated port adapter and an injection tube.

[0012] In some embodiments, the first fuel is injected into the air intake tract between the engines manifold and at least one cylinder such that the first fuel blends with the air in the air intake tract.

[0013] In another aspect, there is provided a method at a first ECU, the first ECU being electronically connected to at least one first fuel injector, at least one second fuel injector for a combustion engine, at least one OEM ECU operatively connected to the at least one second fuel injector, and at least one sensor, the method comprising: receiving real time parameter information from the at least one OEM ECU and/or from the at least one sensor; receiving original second fuel injection timing information from the at least one OEM ECU; determining injection timing of the first and second fuel injectors based on at least the parameter information from the at least one OEM ECU and/or the at least one sensor; overriding the original second fuel injection timing information; sending the determined injection timing of the first and second fuel injectors to the first and second injectors respectively; and sending to the at least one OEM ECU information simulating the resistance and induction of the original second fuel injection timing.

[0014] In some embodiments, the method further comprises: determining positions of other actuators used for engine and aftertreatment operation based on at least the parameter information from the at least one OEM ECU and/or from the at least one sensor; overriding the original actuator position information; sending the determined actuator positions to the relevant actuator; and sending to the at least one OEM ECU information simulating the other actuators that would affect engine and aftertreatment operation.

[0015] In some embodiments, the parameter information comprises at least one of: manifold temperature, exhaust temperature, engine temperature, coolant temperature, intercooler temperature, oil temperature, fuel temperature, boost pressure, engine torque, engine speed, throttle valve position, engine fuel pressure, engine injection timing, engine injection duration, air mass flow, and fuel usage rate.

[0016] In some embodiments, the parameter information further comprises at least one of flow rate, temperature, and pressure of the first fuel.

[0017] In some embodiments, the first ECU comprises a processing unit which analyzes information received from a second fuel injector pulse reader, the first and second fuel injector timing calculators and the parameter information to determine the injection timing of the first and second fuel injectors.

[0018] In some embodiments, the processing unit further utilizes an engine system model, a manifold flow model, and a combustion model to determine the injection timing.

[0019] In some embodiments, the method further comprises dynamically adjusting the injection timing of the first and second fuel injectors and the actuator positions of the other actuators based on at least some of the real time parameter information and saved parameters.

[0020] In some embodiments, the ratio of the amount of first fuel injected to amount of the second fuel injected increases at least during one of when the engine is turned on, when the engine is warming up, when the engine is idling, when the engine is running at loads beyond idle, when the engine is running in a transient manner, and when the engine is running in a steady manner.

[0021] In some embodiments, the method further comprises sending parameter information to a remote server with a web based application for quantifiable data collection and emission measurements.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A is a side view of an embodiment of a retrofit system connected to a combustion engine;

[0023] Figure 1 B is a perspective view of an embodiment of a retrofit system connected to a combustion engine; [0024] Figure 2A is cross section view of the retrofit system of Figure 1A along the line A-A;

[0025] Figure 2B is cross section view of the retrofit system of Figure 1 B along the line B-B;

[0026] Figure 3 is perspective view of an embodiment of a feeder rail;

[0027] Figure 4 is perspective view of an embodiment of a manifold spacer;

[0028] Figure 5A is a side view of an embodiment of a port adapter;

[0029] Figure 5B is a cross section view of the port adapter of Figure 5A along the line B-B;

[0030] Figure 6 is a cross section view of an embodiment of a segment of the retrofit system of Figures 1 A and 1 B, showing the engine piston;

[0031] Figure 7 is a functional block diagram of a first engine control unit (ECU) of the retrofit system of Figures 1A and 1 B for controlling a first fuel injector and a second fuel injector, shown in communication with various other components of the retrofit system;

[0032] Figure 8 is a close up view of the injection tube shown in Figure 2A showing at least one opening adjacent the ejection end of the injection tube;

[0033] Figure 9 is a flow diagram of an example method implemented by the first ECU of Figure 7; and

[0034] Figure 10 is a flow diagram of another example method implemented by the first ECU of Figure 7. DETAILED DESCRIPTION

[0035] Traditional internal combustion engines use one type of fuel to drive pistons which are used to transfer the potential energy of the fuel into kinetic energy and generate a power output. The type of fuel used by these traditional combustion engines is a liquid fuel, for example, diesel fuel or gasoline. However, commonly used liquid fuels produce more greenhouse gas emissions than other alternative types of fuel, for example, hydrogen, natural gas or propane. In order to reduce greenhouse gas emissions from a traditional internal combustion engine, a retrofit dual fuel injection system is provided.

[0036] Referring to Figures 1A and 1 B, an embodiment of dual fuel injection retrofit system 100 is shown. The retrofit system 100 shown in Figures 1A and 1 B includes a feeder rail 102, a manifold spacer 104 and at least one first fuel injection assembly 106. The retrofit system 100 functions to inject a first fuel into the air intake tract 115 between the intake manifold 101 and the cylinders

109 of the combustion engine. In some embodiments the retrofit system 100 does not include a manifold spacer 104.

[0037] As shown in Figures 2A, 2B and 3, the feeder rail 102 comprises a first fuel line 108, and at least one feeder rail segment 103 having a first opening 110, a second opening 112 and a passageway which connects the first opening

110 and the second opening 112. In some embodiments, at least one first fuel injection assembly 106 is inserted into the passageway within the at least one feeder rail segment 103 to fluidly connect the first fuel line 108 and the air intake tract. The at least one first fuel injection assembly 106 functions to control the amount and timing of the first fuel that is injected into the air intake tract from the first fuel line 108. The manner in which the first fuel injection assembly 106 is fluidly connected to the first fuel line 108 and the air intake tract depends on the configuration and requirements of the engine being retrofitted.

[0038] In some embodiments, the first fuel injection assembly 106 comprises a first fuel injector 114, a calibrated port adapter 116 and an injection tube 122. In one embodiment, the first opening 110 of the at least one rail segment 103 is configured to receive the first fuel injector 114 and the second opening 112 of the at least one rail segment 103 is configured to receive the calibrated port adapter 116. In some embodiments the first and second openings 110, 112 can be threaded. In some embodiments the feeder rail 102 comprises four feeder rail segments 103, in other embodiments the feeder rail 102 comprises six feeder rail segments 103. In some embodiments the number of feeder rail segments 103 equals the number of cylinders in the engine.

[0039] While one embodiment of the retrofit system 100 is shown, which has a particular arrangement to work with a particular type, make and model of engine, it will be understood that different types of engines may require that the same elements are arranged in a different manner. For example, the arrangement would be different for inline engines as compared to V engines and may be different for four cylinder engines versus six cylinder engines. It is contemplated that the retrofit system 100 may be split into two separate sections, so that there are two feeder rails 102 and two sets of at least one first fuel injection assembly 106. In some embodiments an engine is designed such that additional and/or separate feeder rails 102 and at least one first fuel injection assembly 106 are needed to properly inject the first fuel into each cylinder 109 of the engine. In such cases the retrofit system 100 may comprise multiple feeder rails 102, each having its own at least one feeder rail segment 103 and at least one first fuel injection assembly 106.

[0040] In some embodiments the feeder rail 102 is positioned along the manifold spacer 104, as shown in Figures 1A and 1 B. In some embodiments the feeder rail 102 is removably connected to the manifold spacer 104 with at least one fastener 107. As shown in Figure 2B, the fastener can be a screw. In other embodiments, where there is no manifold spacer 104, the feeder rail 102 can be connected directly to the air intake manifold 101 and the first fuel injection assembly 106 can inject a first fuel directly into the air intake manifold 101 by tapping the intake manifold and inserting the at least one first fuel injection assembly 106 through the at least one tapped hole.

[0041] When present, the manifold spacer 104 is positioned between the air intake manifold and the cylinders so that each of the at least one first fuel injection assembly 106 is able to inject a first fuel into the air intake tract for each cylinder. As shown in Figures 2B and 4, the manifold spacer 104 comprises at least one manifold spacer segment 105, which each comprise a first opening 118 through which a first injection assembly 106 can pass and a second opening 120 through which air from the air intake manifold 101 can pass into the cylinder 109 of the engine. The manifold spacer 104 can be removably connected to the air intake manifold 101 on one side and the outer body of the engine on the opposite side. In a preferred embodiment, the number of manifold spacer segments 105 is the same as the number of feeder rail segments 103.

[0042] The manifold spacer 104 is one example of a mounting assembly that may be used to properly position the feeder rail 102 in relation to the engine to be retrofitted. A skilled person would understand that other mounting assemblies may be used in place of or in addition to a manifold spacer 104.

[0043] Figures 2A and 2B show different cross sections of an embodiment of the first fuel injection assembly 106. In this embodiment, the first fuel injection assembly 106 comprises a first fuel injector 114, a calibrated port adapter 116 and an injection tube 122. The first fuel injector 114 may be any fuel injector that can be used with the first fuel and operate under the required operating conditions, as would be understood by a person skilled. In some cases the first fuel injection assembly 106 can comprises a first fuel injector 114.

[0044] An embodiment of the calibrated port adapter 116 is shown in Figures 5A and 5B. The calibrated port adapter 116 functions to provide a pathway for the first fuel to travel from the first fuel injector 114 to the injection tube 122. The calibrated port adapter 116 has a first end 124, a second end 126 and a passageway 128 extending through the calibrated port adapter 116. In a preferred embodiment, the calibrated port adapter 116 is sized to fit between the end of the first fuel injector 114 and the top of the second opening 120 of the spacer manifold 104. [0045] In one embodiment, the first end 124 of the calibrated port adapter 116 is configured to engage the second opening 112 of the feeder rail 102 and the second end 126 of the calibrated port adapter 116 is configured to engage the first opening 118 of the spacer manifold 106. The passageway 128 is calibrated to allow the first fuel to travel through the passageway 128 with specified impedance of the flow of fuel from the first fuel injector 114.

[0046] When present, the injection tube 122 functions to inject the first fuel at a desired location within the air intake tract. In a preferred embodiment, when present, the injection tube 122 is integral with the calibrated port adapter 116, thereby limiting the possibility of the injection tube 122 or, any fasteners used to connect the injection tube 122 to the calibrated port adapter 116, from loosening or dislodging and entering the air intake tract, which would damage the engine during operation.

[0047] The first fuel injection assembly 106 fluidly connects the first fuel line 108 and the air intake tract. In some embodiments the first fuel injection assembly 106 injects the first fuel at, or substantially at, the point where the velocity profile of the intake air is at its maximum. In some embodiments, the first fuel injection assembly 106 does not include a bend along its length near or adjacent to its ejection end 125. In some embodiments, the first fuel injection assembly 106 has a bend along its length near or adjacent to its ejection end 125 resulting in the first fuel being injected substantially along the longitudinal axis of the air intake tract. In some embodiments, the bend is about 60 degrees to about 120 degrees. In a preferred embodiment the bend is located substantially at the center point of the air intake tract.

[0048] In some embodiments the first fuel injection assembly 106 injects the first fuel upstream of the cylinder. In a preferred embodiment, the bend in the first fuel injection assembly 106, places the first fuel within the path of the air flowing to the cylinder such that the first fuel and air traveling along the air intake tract combine to form a substantially homogenous mixture prior to entering the adjacent cylinder. Proper mixing of the first fuel and the air is important to facilitate efficient combustion and to prevent pre-ignition of the fuel in the cylinder, which would cause knocking in the engine.

[0049] In a preferred embodiment there are the same number of first fuel injection assemblies 106 as there are cylinders in the combustion engine and each first fuel injection assembly 106 injects the first fuel into the air stream entering its associated cylinder.

[0050] As can be seen in Figure 8, in some embodiments there is at least one opening 123 adjacent to the ejection end 125 of the injection tube 122. The at least one opening 123 allows the first fuel to be injected into the air flow at an angle relative the direction of travel of the air flow in order to improve mixing of the first fuel with the intake air. In some embodiments the first fuel is injected at about 90 degrees from the direction of travel of the air flow. The number and position of the at least one opening 123 in the injection tube 122 can vary based on the air flow dynamics of the particular engine. This multi-port injection system improves the distribution of the first fuel among the cylinders, as compared to using a single port injection system.

[0051] Referring to Figure 6, in operation, a first fuel is injected into the air intake tract 115 and mixes with air traveling from the air intake manifold 101 to the cylinder 109 of the engine. The first fuel and air mixture enters a cylinder 109 in the combustion engine when the air intake valve 154 opens. The first fuel and air mixture is compressed by the upward movement of a piston 152 located within the cylinder 109, which cause the temperature of the mixture to increase. A second fuel is injected directly into the cylinder 109 by a second fuel injector 156 and is ignited by the temperature of the first fuel and air mixture. The ignition of the second fuel then ignites the first fuel, which pushes the piston 109 downward. The exhaust valve 158 opens and the exhaust exits the cylinder 109 via the exhaust tract 160. The cycle continues as long as the engine is running.

[0052] Referring to Figure 7, the system 100 further comprises a first electronic control unit (first ECU) 130 for controlling the timing of the injection of the first and second fuel. The first ECU is electronically connected to at least one original equipment manufacture electronic control unit (OEM ECU) 132 and at least one second fuel injector line 134. As used herein, "electronically connected” is intended to be inclusive of direct and indirect connections as well as wired and wireless connections. In operation, the OEM ECU(s) 132 sends information to the at least one second fuel injector line 134 about when to release the second fuel into a particular cylinder. A second fuel injector pulse reader 136 within the first ECU 130 receives the release information sent by the OEM ECU(s) 132 (including the second fuel injection pulse length and period) and sends it to a processing unit 138. The processing unit 138 can also receive information regarding a number of vehicle and engine parameters from the OEM ECll(s) 132. For example, parameters from the OEM ECll(s) 132 can be sent via a CAN bus 140, to a network manager 142 within the first ECU 130.

[0053] The first ECU 130 is also electronically connected to a plurality of sensors 150 and configured to receive vehicle and engine information therefrom. In some embodiments, the processing unit 138 can receive information from the sensors 150 into an engine combustion timing capture module 144. For example, these sensors 150 could include a camshaft sensor, which provides information on engine timing, and/or crankshaft sensors, which provides information on engine rpm. The sensors 150 may also include additional sensors for measuring properties of the first fuel including mass flow, pressure, and temperature. Information received via the network manager 142 and via the engine combustion timing capture module 144 are referred to as “parameter information”.

[0054] Parameter information from the OEM ECU(s) 132 and/or sensors 150 may vary based on the specific ECU and manufacturer, but can include parameters related to temperatures, pressures and the engine. For example, parameters can include at least one of: manifold temperature, exhaust temperature, engine temperature, coolant temperature, intercooler temperature, oil temperature, fuel temperature, boost pressure, engine torque, engine speed, throttle valve position, engine fuel pressure, engine injection timing, engine injection duration, air mass flow, fuel usage rate and other parameters well known in the industry.

[0055] The processing unit 138 analyzes the information received from the second fuel injector pulse reader 136, at least one parameter of the parameter information, and the first and second fuel injector timing calculator 146, to determine an injection strategy for each first and second fuel injectors 114, 148, including desired injection timing of the first fuel and the second fuel. The injection strategy may be used to reduce greenhouse gas emissions. In some embodiments the reduction of greenhouse gas emissions can be accomplished by decreasing the amount of second fuel injected into the cylinder and replacing the lost energy by increasing the amount of first fuel injected into the air intake tract. The processor unit 138 then sends timing information to the respective fuel injectors 114, 148. In some embodiments the first fuel injection assembly 106 comprises only the first fuel injector 114. In other embodiments the first fuel injection assembly 106 comprises first fuel injector 114 as well as other elements that assist with the proper injection (at least the timing, duration and/or placement) of the first fuel.

[0056] In some embodiments the desired injection timing of the second fuel injector 148 as determined by the first ECU 130 is different than the injection timing of the second fuel into the second fuel injector lines 134 determined by the OEM ECU(s) 132. In these instances, the second fuel injection timing instructed by the OEM ECU(s) 132, referred to herein as the original second fuel injection timing, is overwritten by the first ECU 130, referred to herein as the revised fuel injection timing. For example, the OEM ECll(s) 132 may determine that the second fuel injector 148 should fire for 2 milliseconds. However, results of the analysis of the first ECU 130 determines that the second fuel injector 148 should fire for 1.5 milliseconds. The first ECU 130 sends a signal to the second fuel injector 148 to fire for 1.5 milliseconds. The first ECU 130 also simulates the second fuel injector 148 firing for 2 milliseconds by simulating the resistance and inductance of a second fuel injector 148 firing for 2 milliseconds. This simulation information is sent to the OEM ECU(s) 132 to avoid the OEM ECU(s) 132 issuing a fault and shutting down the engine.

[0057] In some embodiments, the first ECU 130 may further: determine positions of other actuators used for engine and aftertreatment operation based on at least the parameter information from the OEM ECU(s) 132 and/or from the sensors 150; override the original actuator position information; and send the determined actuator positions to the relevant actuator. The first ECU 130 may also send to the OEM ECU(s) 132 information simulating the other actuators that would affect engine and aftertreatment operation. In some embodiments, these additional steps are performed after the determined injection timing of the first and second fuel injectors is sent to the first and second injectors respectively.

[0058] In a preferred embodiment the greenhouse gas emissions produced by the internal combustion engine are reduced by an overall decrease in the amount of second fuel used and an increase in the amount of first fuel used to power the engine. The injection ratio of the first fuel to second fuel is determined by the first ECU 130. The first ECU 130 receives parameter information in real time from the OEM ECll(s) 132 and the sensors 150. The first ECU 130 uses at least one parameter (and saved parameters) to actively and dynamically adjust the injection ratio of the first fuel to second fuel. The first ECU 130 can also dynamically adjust actuator positions of other actuators used for engine and aftertreatment operation in a similar manner. In a preferred embodiment the first ECU 130 is engaged after initial ignition of the engine by the OEM ECU(s) 132 using only the second fuel. In other words, once the engine has been started in a typical manner, the first ECU 130 is engaged to modify the usage of the second fuel and begin using the first fuel. The first ECU 130 continues to be engaged until the engine is turned off in the normal course.

[0059] In one embodiment the first fuel is a gas. The gas can be hydrogen, natural gas or propane. In one embodiment the second fuel is a liquid. The liquid can be diesel fuel or gasoline. In a preferred embodiment, the first fuel is a clean burning gas, for example hydrogen or a blend of hydrogen and ammonia. In a preferred embodiment, the second fuel is diesel.

[0060] The greenhouse gas emissions produced by an internal combustion engine of a vehicle vary depending on the state of the engine. A substantial amount of emissions are produced when the engine is turned on, when the engine is warming up, when the engine is idling, when the engine is running at loads beyond idle, when the engine is running in a transient manner, and when the engine is running in a steady manner. Therefore, during at least one of these stages it is preferred to increase the amount of first fuel being used and decrease the amount of second fuel. In one example hydrogen is the first fuel and diesel is the second fuel. In this example, it is known that hydrogen burns at a faster rate than diesel and produces more energy per kilogram. When the engine is in one of the stages discussed above, the engine is under a low amount of load and so hydrogen can effectively be burned to reduce greenhouse gas emissions during these high emission and low load states.

[0061] As the engine moves to mid and full load states, the higher cylinder pressures results in more engine stress and higher cylinder temperatures while combusting the first fuel. Therefore, the ratio of the first fuel to the second fuel used to generate power can change so that more of the second fuel is injected into the engine and less of the first fuel is used without substantially increasing emissions. In some embodiments, the first fuel can be used up to about 70% engine load (around 1700 rpm). Once the engine load exceeds about 70% the system would use only the second fuel. However, only about 3% to about 5% of the total running life of a combustion engine is spent above 70% load, therefore the switch to using only the second fuel above about 70% load would not produce a substantial amount of greenhouse gas emissions. Differing ratios of the first fuel and second fuels and differing injection timings of the first fuel and second fuel are used in the low, mid and full load states depending on if said load is steady or transient (quickly changing). In some embodiments, injection of the first fuel and second fuel are changed to allow for rapid, low -temperature combustion to occur at steady load states.

[0062] In some embodiments, the first and second fuel injection information and the parameter information are collected by the first ECU 130 and transmitted to a receiver. The receiver can receive information from more than one first ECU 130. In some embodiments, the receiver provides the information from the at least one first ECU 130 to a server, which can run a program (e.g. a web-based application) to analyze the first and second fuel injection information and the parameter information collected by the first ECU 130 to identify ways to optimize the injection of the first and second fuel in order to further improve the reduction of greenhouse gas emissions. In some embodiments, the analysis can be performed by a program using an artificial intelligence algorithm (“Al algorithm”). In some embodiment the information from the first ECU 130 is connected to a cloud database through a mobile data connection. When the Al algorithm identifies first and second fuel injection timing that further optimizes the greenhouse gas emission reduction of the engine, this first and second fuel injection timing information can be sent to the first ECU to improve the reduction of greenhouse gas emissions. In some embodiments, more than one first ECU 130 can be wirelessly connected to the server and can both send and receive information relating to the first and second fuel injection timing.

[0063] Figure 9 is a flow diagram of an example method 200 implemented by the first ECU 130.

[0064] The first ECU 130 receives input data 202 from the plurality of sensors 150 (the sensors 150 themselves are not shown in Figure 9). In this embodiment, the parameter information 202 comprises engine position data 204, engine and after-treatment sensor data 206, first fuel (e.g. hydrogen) sensor data 208, vehicle system data 210, vehicle CAN bus data 212, and cylinder pressure data 214. The cylinder pressure data 214 is optional and may be enabled or not enabled.

[0065] At block 216, the processing unit 138 of the first ECU 130 preprocesses the input data 202. Preprocessing the input data 202 generates parameter information in a format usable by the various models and control loops discussed below. In some embodiments, preprocessing includes signal filtering, signal averaging, communication data decoding and cylinder pressure combustion metrics calculation.

[0066] At block 218, the preprocessed parameter information is then fed into a system model. The system model refers to the engine and vehicle parameters within which it is desirable for the engine and vehicle to run. This system model translates its input values into internal engine states, including but not limited to torque load, emissions output, engine fuel efficiency and engine knock intensity. These internal states are then used in subsequent steps of the algorithm in order to decide actuator values. It also takes the preprocessed parameter information and converts it to information about the engine and vehicle that can be displayed or otherwise used to understand the state of the various vehicle systems. The system model comprises a model of the specific engine of the vehicle in which the system 100 is installed.

[0067] At block 220, converted data from the system model can be sent to the vehicle through the CAN bus 140. This data can be displayed to the user, uploaded to a logger, and/or used by a different onboard vehicle computer as needed. When the data is displayed to the user of the vehicle, the user can refer to the displayed data as a visual indication of the various input data.

[0068] At block 222, simulated sensor data from the system model is sent to the OEM ECll(s) 132 to mimic real sensor data and prevent the OEM ECll(s) 132 issuing a fault as discussed above.

[0069] At block 224, the first ECU 130 determines a combustion mode based on preprocessed parameter information and the system model. The combustion mode comprises an optimal approach to burning fuel based on engine load, engine speed, first fuel (e.g. hydrogen) demand, etc. The optimal approach can include reducing greenhouse gas emissions, improving engine efficiency, reducing engine wear, or a combination of all three.

[0070] At block 226, the first ECU 130 determines an injection strategy. The injection strategy comprises desired injection timing and length of the first fuel as well as injection timing and length for the second fuel to overwrite the OEM ECU(s) 132.

[0071] At block 228, the injection strategy (along with preprocessed parameter information from block 216) is applied to a manifold flow model that models the amount and proportions of air and first fuel (hydrogen) that are mixed in the air intake tract 154 and the flow rate of the air/first fuel blend traveling to the cylinder of the engine.

[0072] At block 230, the injection strategy (along with preprocessed parameter information from block 216) is applied to a combustion model that models how combustion is theorized to occur in the cylinder. [0073] At block 232, the first ECU 130 reads some of the parameter information from block 216 to perform a feedback control loop. The parameter information in this case may include small variations in engine and vehicle function and the first ECU 130 may thereby change certain engine and vehicle parameters to reduce or eliminate such variations. For instance, the feedback control loop may change engine behaviour based upon changes in ambient operating conditions including, but not limited to, ambient atmospheric temperature and pressure. The feedback control loop allows for dynamic adjustment of fuel injection based on real-time data collection.

[0074] At block 234, the first ECU 130 reads some of the parameter information from block 216 to perform an adaptive control loop. The parameter information in this case may include larger systemic deviations as opposed to the smaller variations at block 232 above. For example, the parameter information may be indicative of the wearing of the injector in a certain manner and the adaptive control loop may allow the first ECU 130 to make more systemic changes to correct for such wear.

[0075] The first ECU 130 may then utilize information from the manifold flow model, the combustion flow model, the feedback control loop, and the adaptive control loop to determine (or adjust) injection mass and timing targets (block 236) and intake charge targets (block 238). The injection mass and timing targets comprise the desired mass and timing of injection of the first fuel (e.g. hydrogen) and second fuel (e.g. diesel). The intake charge targets include target turbo charger pressure, exhaust gas circulation, and first fuel (e.g. hydrogen) percentage fraction. The injection mass and timing targets and the intake charge targets are fed back into the data preprocessing steps at block 216.

[0076] At block 240, the injection mass and timing targets and the intake charge targets are applied to actuator models that model physical actuators of the engine including injectors, valves, solenoids, etc. The actuator models convert instructions from the targets to at least one actuator stimulus (e.g. electrical pulse) that causes one or more actuators to move.

[0077] At block 242, an actuator adaptive control receives the injection mass and timing targets and the intake charge targets as well as some of the parameter information from block 216. The parameter information in this case may be indicative of changes to one or more of the actuators such as wear. The actuator adaptive control may apply a correction to the actuator models of block 240 to correct for the wear or other actuator changes.

[0078] At block 244, the actuator stimulus is transmitted to the appropriate physical actuator. For example, an electrical pulse may be sent to a valve to open or close the valve as appropriate.

[0079] Figure 10 is a flow diagram of another example method 300 implemented by the first ECU 130, showing additional details over the method 200 of Figure 9.

[0080] The method 300 starts at block 302 by setting up hardware drivers and a watchdog, followed by loading the last settings, feeding the watchdog, and checking for external faults. If no external faults are found, the method 300 proceeds to block 306. If external faults are found, then the first fuel (e.g. hydrogen) tank/cylinder/solenoid/pump will be turned off at block 304 along with the first fuel injectors.

[0081] At block 306, the first ECU 130 checks if ignition is present. At this stage, the engine will initially be using the second fuel (e.g. diesel). If ignition is present, the method 300 will proceed to block 308 discussed below. If ignition is not present, the method 300 will go back to the previous step to feed the watchdog again.

[0082] At block 308, the first ECU 130 attempts to find the OEM ECU(s) 132 and establish communication therewith. If communication is established with the OEM ECU(s) 132, the method 300 proceeds to block 310. If communication is not established with OEM ECU(s) 132, the first ECU 130 attempts to find the OEM ECU(s) 132 again and, if the OEM ECU(s) 132 cannot be found, a fault code is generated and the method 300 will go back to block 304.

[0083] At block 310, the first ECU 130 reads input data including, but not limited to, engine speed, road speed, air intake and manifold pressure, coolant temperature, engine torque, second fuel rate, after treatment data, cylinder pressure, and battery voltage.

[0084] At block 312, the first ECU 130 reads data from additional sensors regarding the first fuel (e.g. hydrogen) including mass flow, pressure, and temperature. The first ECU 130 also reads the second fuel injection pulse length and period (via the second fuel injector pulse reader 136 discussed above). As discussed with respect to Figure 9 above, the various types of input data are preprocessed by the processing unit 138 of the first ECU 130. [0085] At block 314, data and fault code information from the first ECU 130 is sent to a dash-cluster in the vehicle through a communication line. The dashcluster may comprise, for example, a dashboard showing the status of the first fuel. The dashboard may be a tablet installed in the vehicle. The first ECU 130 may also receive data from the dash-cluster through the communication line.

[0086] At block 316, the first ECU 130 checks if the communication with the dash-cluster is stable. If communication is stable, the method 300 proceeds to block 318. If the communication is not stable, a fault code is generated and the method 300 will go back to block 304.

[0087] At block 318, the first ECU 130 determines if a first fuel start command is received from the dash-cluster and verifies if the start command is true at block 319. If the start command is received and verified, the method 300 proceeds to block 320. If the start command is not received and verified the method 300 will go back to block 304. The method 300 will also go back to block 304 if a stop command is received from the dash-cluster.

[0088] At block 320, the first ECU 130 confirms that the received input data from the engine and sensors (e.g. pressure and temperature data from the OEM ECU(s) 132) are all in an acceptable range. If the data is in the acceptable range, the method 300 proceeds to block 322. If not, a fault code is generated and the method 300 will go back to block 304.

[0089] At block 322, a dynamic injection strategy is determined including calculating the first fuel injection length and period and the second fuel injection length and period using lookup tables, received input data (parameter information), and engine system modeling/feedback loop/adaptive control techniques. The steps at block 322 are equivalent to the steps at blocks 218 to 238 of the method 200 of Figure 9 as described above.

[0090] At block 324, the solenoid/pump for the first fuel is turned on (e.g. via sending an actuator stimulus as described at block 244 of the method 200 of Figure 9). The first ECU 130 then confirms that the solenoid/pump is turned on at block 326. If the solenoid/pump is on, then the method 300 proceeds to block 328. If not, a fault code is generated and the method 300 will go back to block 304.

[0091] At block 328, the first ECU 130 reads output from the camshaft and crankshaft sensors, which provides information regarding engine timing and engine rpm.

[0092] At block 330, the first ECU 130 attempts to find the injection start point. The injection start point is based on the engine structure and architecture. This step involves calculating the degrees of the camshaft and determining the degree for injection of the first cylinder followed by the sequence for the remaining cylinders. If the injection start point is found, the method 300 proceeds to block 332. If the injection start point is not found, further attempts are made, and if the start point cannot be found after a certain number of attempts, a fault code is generated and the method 300 will go back to block 304.

[0093] At block 332, the first ECU 130 starts the first fuel injection sequence and, at block 334, the first ECU 130 overwrites the second fuel injection sequence of the OEM ECU(s) 132. [0094] At block 336, the first ECU 130 determines if feedback from the injectors has been received. If yes, the method 300 starts again by feeding the watchdog. If not, a fault code is generated and the method 300 will go back to block 304.

[0095] Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications can be made to those skilled in the art that various changes and modifications can be made to these embodiments without changing or departing from their scope, intent or functionality. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof.

Claims

WE CLAIM:

1. A retrofit dual fuel injection system for a combustion engine comprising: a feeder rail having a first fuel line and at least one feeder rail segment; at least one first fuel injection assembly connected to the feeder rail, the at least one first fuel injection assembly being positioned to inject a first fuel into the air intake track of the engine upstream of at least one cylinder of the engine; and a first electronic control unit (ECU) electronically connected to the first fuel injection assembly and operable to control the injection of the first fuel, the first ECU also being electronically connected to at least one original equipment manufacturer (OEM) ECU and operable to overwrite injection instructions from the at least one OEM ECU to control injection of a second fuel via a second fuel injection assembly.

2. The injection system of claim 1 wherein the at least one first fuel injection assembly injects the first fuel within the path of the air flowing toward the at least one cylinder such that the mixture of the first fuel and the air is substantially homogenous prior to entering the cylinder.

3. The injection system of claim 2, wherein injection mass and timing of the injection of the first fuel is determined by the first ECU such that the mixture of the first fuel and the air is controllable via the first ECU.

4. The injection system of any one of claims 1 to 3, wherein the at least one first fuel injection assembly comprises a first fuel injector, a calibrated port adapter and an injection tube.

5. The injection system of any one of claims 1 to 4 wherein the first fuel is injected into the air intake tract between the engines manifold and at least one cylinder such that the first fuel blends with the air in the air intake tract.

6. A method at a first ECU, the first ECU being electronically connected to at least one first fuel injector, at least one second fuel injector for a combustion engine, at least one OEM ECU operatively connected to the at least one second fuel injector, and at least one sensor, the method comprising: receiving real time parameter information from the at least one OEM ECU and/or from the at least one sensor; receiving original second fuel injection timing information from the at least one OEM ECU; determining injection timing of the first and second fuel injectors based on at least the parameter information from the at least one OEM ECU and/or the at least one sensor; overriding the original second fuel injection timing information; sending the determined injection timing of the first and second fuel injectors to the first and second injectors respectively; and sending to the at least one OEM ECU information simulating the resistance and induction of the original second fuel injection timing.

7. The method of claim 6, further comprising: determining positions of other actuators used for engine and aftertreatment operation based on at least the parameter information from the at least one OEM ECU and/or from the at least one sensor; overriding the original actuator position information; sending the determined actuator positions to the relevant actuator; and sending to the at least one OEM ECU information simulating the other actuators that would affect engine and aftertreatment operation.

8. The method of claim 6 or 7, wherein the parameter information comprises at least one of: manifold temperature, exhaust temperature, engine temperature, coolant temperature, intercooler temperature, oil temperature, fuel temperature, boost pressure, engine torque, engine speed, throttle valve position, engine fuel pressure, engine injection timing, engine injection duration, air mass flow, and fuel usage rate.

9. The method of claim 8, wherein the parameter information further comprises at least one of flow rate, temperature, and pressure of the first fuel.

10. The method of any one of claims 6 to 9, wherein the first ECU comprises a processing unit which analyzes information received from a second fuel injector pulse reader, the first and second fuel injector timing calculators and the parameter information to determine the injection timing of the first and second fuel injectors.

11 . The method of claim 10, wherein the processing unit further utilizes an engine system model, a manifold flow model, and a combustion model to determine the injection timing.

12. The method of any one of claims 6 to 1 1 further comprising dynamically adjusting the injection timing of the first and second fuel injectors and the actuator positions of the other actuators based on at least some of the real time parameter information and saved parameters.

13. The method of any one of claims 6 to 12 wherein the ratio of the amount of first fuel injected to amount of the second fuel injected increases at least during one of when the engine is turned on, when the engine is warming up, when the engine is idling, when the engine is running at loads beyond idle, when the engine is running in a transient manner, and when the engine is running in a steady manner.

14. The method of any one of claims 6 to 13, further comprising sending parameter information to a remote server with a web based application for quantifiable data collection and emission measurements.