Abstract:
A system for the delivery of ethanol or other solution additives to the intake manifold of compression ignition diesel engines comprising an electronic control module containing a microcomputer capable of monitoring SAE J1939 serial data, receive a signal from an additive monitoring sensor and have outputs to turn on a pump relay, indicator lamp and from 1 to n pulse width modulated electrical fluid injectors.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of U.S. Provisional Patent Application Nos. 61/733,894 filed Dec. 5, 2012; 61/789,327 filed Mar. 15, 2013; and 61/804,727 filed Mar. 24, 2013. The disclosures of the prior applications are incorporated herein in their entirety by reference. 
     
    
     FIELD 
       [0002]    The technology herein relates to electronic control systems of internal combustion engines of the compression ignition type. It also relates to emission control systems of compression ignition engines. 
       BACKGROUND AND SUMMARY 
       [0003]    It is known to control various unwanted pollutants that are emitted from the compression ignition diesel engine by use of injecting or fogging the intake air stream of such engines with a mixture of ethanol, water and other substances. Such a system is typically installed as additional equipment to the pre-existing diesel injection system and does not replace the diesel fuel system. Intake air fogging with an ethanol solution reduces the combustion temperature while adding new chemical reactions, thereby reducing Nitrogen Oxides (NOX) and particulate matter rates. 
         [0004]    Example non-limiting technology herein addresses the formulation and control of the electrical pulses that are used to turn on and pulse the injector(s), which disperse the ethanol additive solution, and to improved systems and methods that provide automatic injection of additives including but not limited to ethanol and the like into an internal combustion engine to reduce pollutants and for other purposes. 
         [0005]      FIG. 1  shows an example conventional ethanol additive system of the general type in which the exemplary illustrative non-limiting technology herein can be used. In the particular non-limiting example shown, electronic control module  1  is powered up by connection to the vehicle battery  2 , through the key switch  3 , and fuse  4 . The common ground connection  5  completes the module&#39;s power circuit. 
         [0006]    A method to detect and synchronize to the engine&#39;s crankshaft is installed on the crankshaft consisting of rotating indices  6 , consisting of teeth or magnets, which is equal or greater in number to at least the number of cylinders divided by 2. A sensor of either magnetic reluctance or Hall-effect type  7 , then delivers a pulse corresponding to the passing of each indicia. Sensor  7  is then wired to module  1 . 
         [0007]    Another sensor  8 , which varies in internal resistance as a function of tip temperature is installed in or near the engine&#39;s coolant jacket. This temperature sensor  8 , is wired to the module  1 , and thereby allows the modules software to determine the temperature of the engine&#39;s coolant. 
         [0008]    Another sensor  9 , is connected by way of tubes or fittings to the engines intake manifold. This sensor varies in output voltage or resistance as a function of the pressure of the intake manifold. This sensor  9 , is wired to the module  1 , and allows the software to determine the intake manifold or turbo pressure of the engine. 
         [0009]    Another sensor  10 , is inserted into the ethanol solution tank or pressure line and it determines the presence of an adequate amount of ethanol solution. This sensor is wired to the control module  1  and allows the software to determine if adequate ethanol is available for the system to operate properly. 
         [0010]    A malfunction indicator lamp  11 , is also connected to the module  1 . It shall inform the engine operator that the system is operating correctly or may turn on or flash to indicate trouble such as failed sensors, empty ethanol tank, or other malfunctions. 
         [0011]    Should the proper conditions exist of engine rotating determined by sensor  7 , warm engine coolant per sensor  8  and adequate additive determined by sensor  10 , the module  1 , shall activate relay  12 , thereby powering on the additive fuel pump  13  and applying power to the fuel injectors  15 . 
         [0012]    Should a pressure switch be used for #10, a delay may be involved between turning relay  12  on and determining if sufficient pressure is present before injection is started or malfunction is indicated. 
         [0013]    Once the proper conditions for additive injection is met, the module  1 , reads the intake manifold sensor  9  and the engine RPM via the time pulse spacing of sensor  7  and uses a 3 dimensional “look up and linear interpolation” table to determine the injector pulse width. The module  1  has low side transistor switches  15 A to  15 D, that turn on injectors  16 A to  16 D, for an experimentally determined amount of time period. The start of the injector pulse corresponds to the time point(s) at which pulse voltage transitions occur from crankshaft sensor  7 . In this way the injector pulse starting points are synchronized to specific angular positions of the crankshaft. 
         [0014]      FIG. 2  shows an example non-limiting timing relationship between the crankshaft sensor voltage waveform  20 , and the outputs  21  to  24 . The control module&#39;s microcomputer detects a voltage transition of waveform  20 , in this case the falling edge  21   b . The output voltage waveform of circuit  15   a  is  21   a . When falling edge  21   b  occurs, a timer channel in the microcomputer is turned on and the injector begins to inject the additive solution. The timer proceeds to time out period  21   c.    
         [0015]    When the timer completes its time count, the injector output turns off. This cycle is repeated on successive crankshaft sensor voltages  22   b ,  23   b  and  24   b  falling edges thereby producing a sequential injection cycle of other waveforms  22   a ,  23   a  and  24   a  as shown in  FIG. 2 . 
         [0016]    In one example non-limiting implementation, the injector period is determined by a 3 dimensional map. The microcomputer code uses a grid of RPM and manifold sensor (MAP) values in combination with linear interpolation and extrapolation routines to determine the current pulse width.  FIG. 3  shows a graphical representation of the relationship between the rotational speed of crankshaft  6  (in RPM) the signal from the manifold pressure sensor (MAP)  9  and the periods of injector pulse widths  15   a - d.    
         [0017]    In one example non-limiting implementation, a determination and subsequent calibration of the injector pulse width grid points is devised and inputted by use of a PC type or other computer  17 , which allows the user to alter the injector pulse width and then save the changes regarding coolant temperature, intake manifold pressure 3D points, engine RPM points 3D points, injector pulse widths and other required setup values. 
         [0018]    While such conventional ethanol additive systems provide useful functionality, further improvements are possible and desirable. In particular, installing a system of the type shown in  FIG. 1  can be expensive due to the many interconnects, sensors and components. 
         [0019]    One example non-limiting implementation of the technology herein provides a microcomputer equipped electronic control module that has the necessary circuits to capture data that is available on the industry standard serial communications bus which was adopted by most diesel engine manufactures after 1998. This bus is commonly called “J1939”, and refers to the Society of Automotive Engineers (SAE) practices specifications J1939. The example non-limiting technology herein uses this data and software algorithms to eliminate cost and labor of adding additional sensors, which are typically needed to obtain the necessary data to produce the desired result. 
         [0020]    The example non-limiting technology herein thus provides a system for the delivery of ethanol or other solution additives to the intake manifold of compression ignition diesel engines. The system may comprise an electronic control module containing a microcomputer capable of monitoring SAE J1939 serial data, receive a signal from an additive monitoring sensor and have outputs to turn on a pump relay, indicator lamp and from 1 to n pulse width modulated electrical fluid injectors. Such a system can retrieve various data parameters from the J1939 data stream such as engine RPM, Engine load, coolant temperature and other data. Such a system can determine if the proper level of additive is present and when the proper engine operating conditions are met, can turn on a fluid pump electrical relay. Such a system can calculate with linear interpolation and extrapolation software routines from data stored in a 3 dimensional array a desired injector pulse width. Such a system does not need to use a crankshaft sensor or other direct means to measure engine speed or crankshaft position and instead is using data from the J1939 data bus. Such a system does not use a pressure sensor or other direct means to measure engine load or fuel rate and instead is using data from the J1939 data bus. Such a system can create a start of injection pulse instants which are not exactly synchronized to the exact position of the crankshaft but occur at a rate of injection which is approximately proportional to the speed of crankshaft rotation and such injection rate is constantly adjusted to the most recently available RPM value as obtained from the J1939 data. Such a system has the ability to allow arbitrary injector output pattern firing-orders by use of a programmable table. Such a system can monitor the additive fluid level or pressure and turn on a diagnostic lamp or notify the operator in another way if the system operation is not within prescribed parameters. Such a system uses a data communications interface to a PC type computer and a graphical human interface to allow for modifications to stored calibration parameters and to see current operating conditions within the system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    These and other features and advantages will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative embodiments in conjunction with the drawings of which: 
           [0022]      FIG. 1  is block diagram of a conventional system; 
           [0023]      FIG. 2  shows the timing relationship between the crankshaft sensor voltage waveform  20 , and the outputs  21  to  24 ; 
           [0024]      FIG. 3  shows a graphical representation of the relationship between the rotational speed of crankshaft  6  (in RPM) the signal from the manifold pressure sensor (MAP)  9  and the periods of injector pulse widths  15   a - d ; 
           [0025]      FIG. 4  is an exemplary illustrative non-limiting block diagram of a system with the use of the example non-limiting embodiment; 
           [0026]      FIG. 5  shows the timing relationship between the start of injector waveforms, and the outputs  45   a  to  45   d;    
           [0027]      FIG. 6  shows a graphical representation of the relationship between the rotational speed of crankshaft RPM, the load value and the injector pulse widths; 
           [0028]      FIG. 7  is a flowchart of an exemplary illustrative main loop; 
           [0029]      FIG. 8  is a flowchart of an exemplary alternative check additive level routine if pressure switch is used; 
           [0030]      FIG. 9  is a flowchart of exemplary illustrative injection period handling; and 
           [0031]      FIGS. 10 and 11  are flowcharts of exemplary illustrative injection pulse handling; 
           [0032]      FIG. 12  shows example timing relationships between the start of injector waveforms and the outputs  45   a  to  45   d  for a concurrent operating mode; and 
           [0033]      FIG. 13  shows a block diagram of a further non-limiting embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 4  is an exemplary illustrative non-limiting block diagram of a system with the use of the example non-limiting embodiment. The example non-limiting embodiment utilizes an Electronic Control Module  31 , which is powered up by connection to the vehicle battery  32 , through the key switch  33 , and fuse  34 . The common ground connection  35 , completes the module&#39;s power circuit. 
         [0035]    The application of the example non-limiting embodiments exploits use of an existing Original Equipment Manufacture (OEM) engine control computer  35 . Such OEM computer  35  may for example use an industry standard SAE J1939 serial data bus. Such a data bus is described in a series of standards published by the Society of Automotive Engineers including core standards J1939 — 201206 (Serial Control and Communications Heavy Duty Vehicle Network—Top Level Document); J1939/1 — 2012110n-Highway Equipment Control and Communication Network; J1939/11 — 201209 Physical Layer, 250 Kbps, Twisted Shielded Pair; J1939/13 —201110  Off-Board Diagnostic Connector; J1939/14 —201110  Physical Layer, 500 Kbps; J1939/15 —200808  Reduced Physical Layer, 250K bits/sec, UN-Shielded Twisted Pair (UTP); J1939/21 —201012  Data Link Layer; J1939/3 — 200812 On Board Diagnostics Implementation Guide; J1939/31 — 201005 Network Layer; J1939/5 — 201204 Marine Stern Drive and Inboard Spark-Ignition Engine On-Board Diagnostics Implementation Guide; J1939/71 — 201205 Vehicle Application Layer (Through May 2011); J1939/73 — 201002 Application Layer—Diagnostics; J1939/74 — 201011 Application—Configurable Messaging; J1939/75 — 201105 Application Layer—Generator Sets and Industrial; J1939/81 — 201106 Network Management; J1939/82 — 200808 Compliance—Truck and Bus; and J1939/84 — 201206 OBD Communications Compliance Test Cases for Heavy Duty Components and Vehicles, each of which are incorporated herein by reference. 
         [0036]    As described in detail in the above-listed SAE specifications, such a J1939 bus will contain 3 wires  35 , called “H”, “L” and “Common”. These wires  35 , are connected to electronic control module  31 , which contains the necessary Controller Area Network (CAN) bus interface electronic circuits so that the microcontroller contained within  31 , can read the data which is presented on the serial data bus wires  35 . 
         [0037]    A sensor  38 , is inserted into the ethanol solution tank or pressure line and it determines the presence of an adequate amount or pressure of additive solution. This sensor is wired to the control module  31  and allows the software to determine if adequate additive is available for the system to operate properly. 
         [0038]    A malfunction indicator lamp  39 , is also connected to the module  31 . It shall inform the engine operator that the system is operating correctly or may turn on or flash to indicate trouble such as failed sensors, empty ethanol tank, or other malfunctions. 
         [0039]    Control module  31 , has software that can read standard J1939 data information pertaining to: 
         [0040]    1. Engine Rotational Speed (RPM) 
         [0041]    2. Engine Coolant Temperature (CLT) 
         [0042]    3. Engine Load Demand or Fuel Rate (Load) 
         [0043]    4. Throttle Position Sensor (TPS) 
         [0044]    5. Others as needed. 
         [0045]    The particular data structure, addresses and protocol information regarding each datum can be found in public specifications cited above. 
         [0046]    The microcontroller in  31  maintains a data stack of the desired current values of this CAN bus data. Should the proper conditions exist of engine rotating above a certain value, engine coolant temperature above a certain value, an adequate ethanol supply determined by sensor  38 , the module  31 , shall activate relay  42 , thereby powering on the ethanol additive fuel pump  43  and applying power to the ethanol fuel injectors  46 . 
         [0047]      FIG. 7  shows a flowchart of example non-limiting steps performed by microcomputer  31  under control of instructions stored in a non-transitory memory device such as within a read only memory, flash memory or the like included within electronic control module with microcomputer  31 . In this non-limiting example, the microcomputer  31  powers up, resets and initializes (block  202 ) and then checks the additive level (block  204 ). If the additive level is low (“low” exit to decision block  204 ), the microcomputer executes a malfunction routine M and sets a Maif flag (block  214 ). Otherwise (“okay” exit to block  204 ), the system reads various values from the J1939 bus (e.g., CAN, RPM, CLT) and loads the clear Maif flag (block  206 ). The microcomputer  31  then checks coolant temperature (block  208 ) and RPM (block  210 ). If the coolant temperature or RPM are low (“no” exits of blocks  208 ,  210 ), the microcomputer  31  turns off the fuel pump, turns all injectors off, and clears a run flag (block  216 ). If the coolant temperature is ok (block  208 ) and the RPM is high (block  210 ), the microcomputer  31  and turns the fuel pump on and also sets the run flag) (block  212 ). 
         [0048]    Should a pressure switch be used for  38 , a delay may involved between turning relay  42  on and determining if sufficient pressure is present before injection is started or malfunction is indicated. The flowchart of  FIG. 8  shows an example non-limiting implementation in which the microcomputer  31  detects whether the fuel pump is on or off (block  218 ). If on, the microcomputer  31  checks the pressure switch (block  220 ). If no pressure (block  220  “No pressure” exit), the microcomputer  31  clears a timer (block  222 ) then determines whether the timer value is equal to a delay (block  204 ). If not equal, then the timer is incremented (block  226 ) and block  224  is repeated. Once the timer=delay (“yes” exit to decision block  224 ), microcomputer  31  checks the pressure switch (block  228 ) and if no pressure, runs a malfunction routine M (block  230 ). If at block  218  the fuel pump driver is off (“off” exit), the microcomputer  31  checks the pressure switch (block  232 ) and if there is pressure (“yes pressure”) executes the malfunction routine M (block  230 ). Meanwhile, the “No pressure” exit of decision block  232 , “Yes pressure” exit of block  228  and “Yes pressure” exit of block  220  all indicate proper operation (“ok” exit at the bottom of  FIG. 8 ). 
         [0049]    When proper conditions for additive injection are met by the module  31 , the Engine Load and the engine RPM via CAN bus  37  are used in a 3 dimensional “look up and linear interpolation” table to determine the injector pulse width. The module  31  has low side transistor switches  45   a  to  45   d , that turn on injectors  46   a  to  46   d , for an experimentally determined amount of time period. The flowchart of  FIG. 9  shows an example non-limiting injection period handling wherein when the run flag is set “Run” exit to block  234 ), microcomputer  31  tests the CAN bus interrupt flag (block  236 ) and if set (meaning that new data is present), executes a 3D linearization routine (block  238 ) to find injector pulse width (PW) from RPM, load and calibration data and sets PW to a new value. Otherwise, if decision block  234  determines that the run flag is not set (“no run” exit), microcomputer  31  turns all injector outputs off (block  240 ). 
         [0050]    When the engine RPM is above a certain value and other conditions are met, the microcomputer establishes an internal start of injection pulse period. The period of repetition is determined by the equations shown in the flowchart of  FIG. 10  providing an example non-limiting implementation. In  FIG. 10 , if the run flag is set (“run” exit to block  242 ), microcomputer  31  detects whether the CAN bus interrupt flag is set (block  244 ). If it is set, then decision block  248  detects whether start of injection target (SIT) is less than the real time clock (TC) or whether it is greater than or equal to TC. If less than, then microcomputer  31  loads the pulse width (PW) into an output timer N+1, turns the injector output N+1 on, and then sets T1=TC and N=N+1 (block  250 ). Microcomputer  31  then tests whether the injector channel number N is less than the total number of injector channels (block  252 ). If less than, microcomputer  31  repeats the  FIG. 10  flow for the next injector. Otherwise, microcomputer  31  sets N=0 (block  254 ) and repeats the flow for the first injector. 
       DEFINITIONS 
       [0051]    RPM Current Engine RPM in Revolutions per Minute at any time
 
TC Free running time clock
 
K Constant scalar
 
       SIT Start of Injection Target 
       [0052]    T1 Previous start of injector time
 
PW Pulse Width of Injector on time
 
N Current injector channel
 
C Total number of injector channels
 
         [0053]    In more detail, where RPM is the current RPM read at the fastest rate which is available from the CAN bus  37 . The start of the first injection pulse from output  45   a  is arbitrary and not synchronized to the engine position. A time stamp value T1 is saved when injector  45   a  is turned on. The microcomputer determines a time in the future to the start the next output  45   b.    
         [0000]      SIT=(1/RPM* K )+ T 1 
         [0054]    During the time after the start of the injector pulse start, T1, the microcomputer compares the current free running time clock TC to the next start of injection target SIT. When the current time TC is greater than SIT the next output,  45   b , is started and the start time T1 is reset. This repeats continuously thereafter until the additive injection conditions are no longer met. The flowchart of  FIG. 10  represents this routine. 
         [0055]    The SIT value and hence the future start target is continually being updated as new RPM data emerges from the J1939 CAN bus. The refresh rate of the RPM data can be substantially faster than the injection rate. If the engine is slowing down, the target value will be over written to a later value in “mid count” to reflect a later starting point for the next injector start point. If the engine is accelerating, the period will be over written with a shorter value to start the next injection sooner. 
         [0056]    Should an earlier start target SIT, be forced into the comparison than the current time clock, the next injection event will start immediately and the next start point will be computed. 
         [0057]    In this way, the start of injection pulses are not exactly synchronized to the exact position of the crankshaft but the rate of injections is proportional to the speed of crankshaft rotation and such injection rate is constantly adjusted to the most recently available RPM value. 
         [0058]    Sequencing of injector outputs can be preset in a programmed order. For this the microcomputer maintains a sequence counter, N. The sequence counter is advanced after the start of each start of injection. Then it is compared to the current value of the sequence counter to determine actually which one of the injector outputs  45   a  to  45   d  to start. Single or multiple injector outputs can turn on at the same time and the design is not limited to 4 as shown in the figures. 
         [0059]      FIG. 5  shows the timing relationship between the start of injector waveforms, and the outputs  45   a  to  45   d . Start point T1 is arbitrary and occurs at the initiation of additive injections. Based on the engine RPM as read from the J1939 data the SIP period is calculated and added to T1. This new number SIT is placed into a match compare register. When the time clock compares its time count and exceeds the match register, the next injector output turns on. This cycle is repeated on successive match compares of the free running time clock thereby producing a sequential injection cycle of other waveforms  52   a ,  53   a  and  54   a  as shown in  FIG. 5 . 
         [0060]    The injector period PW is determined by a 3 dimensional map. The microcomputer code uses a grid of RPM and manifold sensor values in combination with linear interpolation and extrapolation routines to determine the current pulse width.  FIG. 6  shows a graphical representation of the relationship between the rotational speed of crankshaft RPM, the load value and the injector pulse widths. 
         [0061]    An example non-limiting determination and subsequent calibration of the injector pulse width grid points is devised and inputted by use of a PC type computer  40 , which allows the user to alter the injector pulse width and then save the changes regarding coolant temperature, intake manifold pressure 3D points, engine RPM points 3D points, injector pulse widths and other required setup values. 
         [0062]    An alternative model that simplifies the implementation of the injection pulse calculation uses a fixed time period between injection pulses rather than varying the injection pulse frequency with engine RPM (see  FIG. 12 ). 
         [0063]    This method eliminates a repeated calculation and allows the use of commonly available hardware peripherals available in most micro-controllers. The only change between this method and the previously described method is that the calculation for SIT (shown in flowchart  FIG. 4 ) is replaced with a predefined constant and all of the injector channels are pulsed simultaneously, eliminating the injector channel number increment and the final two (2) steps shown in flowchart  FIG. 4 . This change is shown in Flowchart  FIG. 11  block  250 ′. 
         [0064]    Using a fixed time between injection pulses completely eliminates all synchronization between the injection pulses and may have undesirable effects resulting from beat frequencies resulting from the difference between the injection pulse event frequency and the cylinder air intake event frequency. 
         [0065]    Although  FIG. 12  shows all available injector channels turning on and pulse with the same pulse width, it is possible to sequence individual injector channels at the fixed pulse frequency. In this case the final counters “N” as shown in figure the last decision and state boxes of  FIG. 10  shall be concatenated on the end of  FIG. 11 . 
         [0066]    Another alternative non-limiting embodiment shown in  FIG. 13  takes the features of  FIG. 1  and removes some but not all of the external sensors stated in previous models. While it simplifies the implementation slightly by removing sensors MAP  9 , and CLT  8  of  FIG. 1 , it allows the use of parameter values that are only generated within OEM engine computer  35 .  FIG. 13  shows that this implementation still uses either external crankshaft sensor  7 , or OEM computer generated tachometer pulse  104 . Typically OEM computers generate this pulse to drive instrument cluster tachometers  105 . The subject computer would, if a crankshaft sensor were not used, splice into this wire in a “T” fashion to utilize this alternate signal. Typically 3 pulses per engine revolution for a 6-cylinder engine or 4 pulses for an 8 cylinder. While the edges of this pulse signal are not known to be exactly coordinated at a given angular position of the crankshaft, this signal&#39;s frequency is directly proportional to the engine RPM. 
         [0067]    This method retains the synchronous injector pattern as shown in  FIG. 2 . The crankshaft pulse signal from sensor  7 , or tach signal  104  is shown as waveform line  20  of  FIG. 2 . Injector pulse widths  21   c  to  24   c  would be calculated in the same manner as the above methods. 
         [0068]    To simplify wiring of J1939 CAN bus of ECU  35 , the model uses a “T” shaped connection wire harness  106  of  FIG. 13  to existing J1939 standard connectors. In this case, a 9 pin round connector per the J1939 SAE specification. It also may be a 2 pin or 3 pin connector. One connector is a male type and the other is a female type. The “T” harness would be inserted between the existing connector on the truck and other downstream equipment. 
         [0069]    While the technology herein has been described in connection with exemplary and illustrative non-limiting embodiments, the invention is not to be limited by the disclosure. The invention is intended to be defined by claims and to cover all corresponding and equivalent arrangements whether or not specifically disclosed herein.