Patent Publication Number: US-6981480-B2

Title: Reducing pre-cycle warm-up for electronic components

Description:
This application is a continuation-in-part application of and claims the benefit of the filing date of U.S. patent application Ser. No. 10/317,326, filed Dec. 12, 2002, now abandoned, on behalf of the same inventor as the present application and assigned to the assignee hereof. 

   FIELD OF THE INVENTION 
   This invention relates to prevention of burn-out of electronic components, including but not limited to prevention of burn-out of electronic components due to pre-cycle in internal combustion engines. 
   BACKGROUND OF THE INVENTION 
   When internal combustion engines are cold, it is known to engage pre-cycle warm-up processes to help the engine warm up more quickly. For example, fuel injectors that are oil driven have injector coils that receive a series of short pulses to cause them to rapidly move the injector spool back and forth to loosen up the injector spool by warming it up. Similarly, a glow plug is utilized to warm up the cylinders of the engine to aid fuel ignition in a cold engine. In both situations, a significant amount of current is utilized to warm up the relevant parts of the engine and assist in making cold start-ups easier and faster. 
   Nevertheless, these pre-cycle processes are engaged whenever the engine is cranked and the temperature, such as ambient, oil, or coolant temperature, is below a predetermined temperature. If, for any reason, the engine does not turn over right away and the engine is cranked again, the pre-cycle processes are engaged again because the relevant temperature will not have changed considerably. If the engine is cranked too many times in a relatively short period of time, the repeated pre-cycle processes could cause the electronic components, such as the fuel injector coils or non-self-regulated glow plugs, to burn out. 
   Accordingly, there is a need for a method of warming up an internal combustion engine quickly without burning out the electronic components utilized to warm up the engine. 
   SUMMARY OF THE INVENTION 
   A method and apparatus for reducing pre-cycle warm-up is described. A temperature sensor arranged and constructed to determine a temperature of a driver capable of driving an electronic component. When the temperature of the driver exceeds a temperature condition, a driver controller reduces pre-cycle warm-up of the electronic component. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram illustrating driver controllers and a plurality of electronic components controlled by the driver controllers in accordance with the invention. 
       FIG. 2  is a block diagram illustrating a driver controller in accordance with the invention. 
       FIG. 3  is a flowchart illustrating a method of reducing pre-cycle warm-up for an electronic component in accordance with the invention. 
   

   DESCRIPTION OF A PREFERRED EMBODIMENT 
   The following describes an apparatus for and method of utilizing the temperature of one electronic component to reduce pre-cycle warm-up of another component. For example, a temperature sensor for a driver of an electronic component, such as a glow plug or fuel injector coil, is utilized to determine when a temperature condition is exceeded. When that temperature condition is exceeded, pre-cycle warm-up for the electronic component associated with the component is reduced. 
   A block diagram illustrating driver controllers  103  and  109  and a plurality of electronic components  107  controlled by the driver controllers  103  and  109  are shown in  FIG. 1 . The example of  FIG. 1  shows an internal combustion engine  101  with a first driver controller  103  that is an engine control module (ECM)  103  that interfaces with numerous sensors for the engine, e.g., temperature sensors and pressure sensors, and determines various control signals  105  for different engine components  107 , such as fuel injectors, glow plugs, air intake heaters, fuel heaters, electromechanical devices requiring pre-cycling, and so forth. The example shown in  FIG. 1  illustrates the path of control signals  105  utilized to control the turning on and off of glow plugs  107 , for example, during the pre-cycle warm-up process for the engine cylinders. 
   The example of  FIG. 1  shows an internal combustion engine  101  with a second driver controller  109  that is an injector driver module (IDM)  109 . The ECM  103  also sends signals to other control modules, such as the IDM  109 , for example, to control when and what signals are sent to the fuel injectors. The IDM may process and/or forward the signals from the ECM  103 , and/or may generate its own signals to control the fuel injectors. As shown in  FIG. 1 , a plurality of injector control signals  111  are utilized to energize and de-energize the fuel injector coils that are part of fuel injectors  113 . These signals  111  include fuel pulse signals that determine when fuel is delivered and how much fuel is delivered. These signals  111  also include the rapid-cycling signals sent during the pre-cycle warm-up for the fuel injectors, which rapid-cycling signals, for example, may cause the fuel injector&#39;s spool to overcome stiction force and break loose of the initial resistance to movement, for example, at low temperatures. 
   A block diagram illustrating a driver controller  103 / 109  is shown in  FIG. 2 . The driver controller  103  or  109  utilizes a microprocessor  201  to run a predetermined program to provide desired functionality based on signals received at or generated by the microprocessor  201 , as known in the art. One of the functions of the microprocessor  201  is to send signals to various drivers  203  that provide a signal  105  or  111  in the form of a voltage and current for a duration of time to the electronic component  107  or  113  that is to be controlled. 
   One or more temperature sensors  205  may be utilized in conjunction with the drivers  203 . Each temperature sensor  205  may be a stand-alone thermocouple that is disposed on one or more drivers  203  or may be a built-in temperature sensor that is integral to one or more drivers  203 . The temperature sensor  205  monitors the temperature of its associated driver  203 , and sends the temperature as a signal  207  to the microprocessor  201 . The microprocessor  201  may act on the temperature signal  207  itself or may relay the temperature signal  207  to another module. For example, the IDM  109  may process the temperature signal  207  and/or may relay the temperature signal  207  to the ECM  103 . The appropriate microprocessor  201  interprets the temperature signal  207  in light of one or more temperature conditions. The temperature signal  207  may also be utilized to determine if a specific component  107  or  113  is operating. For example, if the component  107  or  113  is not operating, it may cause the driver  203  to either overheat or provide no power, in which case the temperature would be lower than expected. When temperature signals  207  from different components either overheat or provide no power, in which case the temperature would be lower than expected. When temperature signals  207  from different components of the same type are compared, a component  107  or  113  of the same type are compared, a component  107  or  113  that is not functioning correctly is likely to have a substantially different temperature. 
   When one or more temperature conditions are exceeded, the microprocessor  201  reduces pre-cycle warm-up for the electronic component  107  or  113  associated with the driver  203  that exhibited the excessive temperature condition. When the driver  203  for a component  107  or  113  has exceeded a temperature condition, such as an absolute temperature or a temperature differential, the driver  203  is presumed to be warm enough from recently driving the electronic components  107  or  113 , which are in turn presumed to be warm enough from being electronically driven. Thus, reducing pre-cycle warm-up when the engine is cranked helps to prevent the components from premature burn-out due to excess warm-up. 
   The drivers  203  may be, for example, field effect transistors with a built-in temperature sensor  205  or drivers with a temperature sensor  205  disposed thereon, as are known in the art. By utilizing temperature sensors  205  within the controller  103  or  109 , rather than utilizing temperature sensors outside the controller  103  or  109 , e.g., on the electronic components  107  or  111 , the need for providing a return path for temperature data from the devices  107  or  111  onto the controller  103  or  109  is alleviated. When multiple devices  103  or  109  are controlled in this matter, utilizing temperature sensors  205  on-board the controller  103  or  109  alleviates the need to bring multiple lines into the controller  103  or  109 . 
   Although one temperature sensor  205  is shown for each driver  203 , fewer than one temperature sensor  205  for each driver  203  may be utilized. For example, one or more temperature sensors  205  may be utilized for each type of electronic component  107  or  113 . For example, if six glow plugs  107  are utilized in the engine  101 , one or two temperature sensors  205  may be placed on one or two of the six drivers  203  for the glow plugs  107 , instead of placing six temperature sensors  205 , one on each of the six drivers for the six glow plugs  107 . When the temperature threshold for any driver  203  is exceeded, the pre-cycle warm-up for all six glow plugs  107  is reduced. Similarly, one or more temperature sensors  205  may be utilized to determine whether to reduce the pre-cycle warm-up for one or more fuel injector coils or any other electronic components for which protection is desired. 
   A flowchart illustrating a method of reducing pre-cycle warm-up for an electronic component is shown in  FIG. 3 . At step  301 , the process attempts to detect a key-on ignition condition for the ignition key or ignition switch for an engine. When a key-on condition is detected, the process continues with step  303 . The temperature of one or more drivers  203  is determined at step  303 . The temperature is determined by one or more temperature sensors  205 , which send one or more signals to a microprocessor  201 . 
   At step  305 , it is determined whether a temperature condition is exceeded. Exceeding a temperature condition includes exceeding a temperature differential and/or exceeding an absolute temperature. For example, the driver  203  temperature from a temperature sensor  205  may be compared to a reference temperature for something other than the driver  203 , such as ambient temperature, oil temperature for the engine, or coolant temperature for the engine, and when the temperature differential (the difference between the driver  203  temperature and reference temperature) is greater than a predetermined threshold, e.g., 50 degrees C., the pre-cycle warm-up for the electronic component  107  or  113  (or component type) associated with the driver  203  for that sensor  205  is reduced. Alternatively, an absolute temperature may be compared to the temperature from the sensor  205 , and when the driver  203  temperature exceeds the absolute temperature, e.g., 100 degrees C., the pre-cycle warm-up for the electronic component  107  or  113  (or component type) associated with the driver  203  for that sensor  205  is reduced. 
   The temperature condition may be advantageously selected such that a component  107  or  113  or driver  203  is considered to be warm enough, such that further pre-cycle warm-up may be reduced or eliminated, although the component  107  or  113  may be significantly below a temperature condition that may result in damage to the component  107  or  113 . By reducing pre-cycle warm-up well before a condition where damage may result wear and tear on the component is likely to be reduced, and the life of the component may be extended. 
   Various different temperature conditions at step  305  may result in various different levels of reduced pre-cycle warm-up. Thus, each time step  305  is encountered or at various different temperature conditions, a different level of reduced pre-cycle warm-up may result. The amount of pre-cycle warm-up reduction may be based on the temperature condition. Higher temperature conditions, for example, result in greater pre-cycle warm-up reduction than lower temperature conditions. For example, a five different levels of reduced pre-cycle warm-up may take place at five different temperature conditions. For example, each level may reflect a different pre-cycle warm-up time, e.g., 10 seconds, 8 seconds, 6 seconds, 4 seconds, and 0 seconds for no pre-cycle warm-up. Alternatively, each level may include a different pre-cycle warm-up current, with the lowest current as zero for no pre-cycle warm-up. Pre-cycle warm-up current and pre-cycle warm-up time may be reduced in various combinations, where current and/or time may be reduced at various levels. 
   When a temperature condition is not exceeded, the process continues with step  307 , where the normal pre-cycle process for the relevant electronic component  107  or  113  is engaged, and the engine is cranked at step  309 . 
   When a temperature condition is exceeded at step  305 , the pre-cycle warm-up process for the relevant electronic component  107  or  113  (or component type) is reduced at step  311 . Reduction of pre-cycle warm-up includes reducing the amount of time for pre-cycle warm-up by a finite amount of time, reducing the amount of current utilized for pre-cycle warm-up by a finite amount of current, temporarily eliminating pre-cycle warm-up, i.e., temporarily completely inhibiting pre-cycle warm-up or temporarily reducing the amount of pre-cycle warm-up time to zero, and so forth. The amount of reduction in pre-cycle warm-up may also be temperature based. For example, when a temperature differential of 35 degrees C. or an absolute temperature of 75 degrees C. is reached, the pre-cycle warm-up may be cut in half, e.g., half the time or half the current, or a reduction in both. And when a temperature differential of 50 degrees C. or an absolute temperature of 100 degrees C. is reached, the pre-cycle warm-up may be eliminated, e.g., the time is reduced to zero. The temperature sensor  205  information may also be utilized to determine overheating conditions for the controller  103 / 109 . When the controller  103 / 109  exceeds a controller temperature condition, such as an absolute temperature of the temperature of one or more of the drivers  203  within the controller  103 / 109 , the power output of the drivers  203  within the controller  103 / 109  may be reduced to allow the engine  101  to continue running at reduced output. When the engine is cranked at step  309  following step  311 , the time to wait for engine crank is either reduced or eliminated. 
   Although the above description utilized the examples of fuel injector coils and glow plugs, the present invention is readily applicable to other devices, such as air intake heaters, fuel heaters, electromechanical devices requiring pre-cycling, and so forth. 
   The present invention provides a temperature sensor for a driver for an electronic component in order to reduce pre-cycle warm-up for the component when a temperature condition is exceeded, thereby preventing excess heat from building up and damaging the electronic component, reducing wear and tear on the component, extending the life of the component, and/or reducing the time before the engine cranks. The internal combustion engine is allowed to crank sooner, especially when pre-cycle warm-up is eliminated completely upon determining that the temperature of the electronic component exceeds the temperature condition. By locating the temperature sensors with the drivers and in the controller, the need for additional paths to the controller is avoided. One temperature sensor may be utilized to reduce pre-cycle warm-up for a plurality of electronic components. Multiple temperature sensors may be utilized to provide back-up in case a temperature sensor malfunctions. By using relatively inexpensive temperature sensor(s), the need for expensive self-regulating glow plugs may be avoided. The temperature sensors may also be utilizes to prevent a controller, such as an ECM or IDM, from overheating or to detect components that are not operating correctly. 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.