Patent Application
20080087250
The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
In some embodiments, fuel injection system 100 may include provisions for introducing air to engine 102. In some embodiments, engine 102 may associated with intake manifold 106. Preferably, intake manifold 106 may be disposed adjacent to compression chamber 108 of engine 102. In particular, intake manifold 106 may be disposed adjacent to intake valve 110.
Generally, fuel injection system 100 may include provisions for determining properties of the air disposed within intake manifold 106 and introduced to engine 102. In some embodiments, intake manifold 106 may include various sensors. In a preferred embodiment, intake manifold 106 may include provisions for determining the pressure within intake manifold 106. Also, intake manifold 106 preferably includes provisions for determining the temperature associated with intake manifold 106.
Preferably, intake manifold 106 includes pressure sensor 112. In some embodiments, pressure sensor 112 may be disposed within intake manifold 106. Generally, pressure sensor 112 may be any device that measures the pressure within intake manifold 106. In a preferred embodiment, pressure sensor 112 may be a manifold absolute pressure sensor (MAP-sensor).
In some embodiments, intake manifold 106 may include provisions for determining the temperature of air disposed within intake manifold 106. In some embodiments, intake manifold 106 may include temperature sensor 114. Preferably, temperature sensor 114 is disposed within intake manifold 106. In a preferred embodiment, temperature sensor 114 may be disposed across from pressure sensor 112 within intake manifold 106.
Preferably, fuel injection system 100 includes provisions for injecting fuel into engine 102. In some embodiments, engine 102 may be associated with injector 116. In some embodiments, injector 116 may be associated with intake manifold 106. In some embodiments, injector 116 may be disposed within intake manifold 106. Additionally, injector 116 may be disposed adjacent to intake valve 110.
Preferably, fuel injection system 100 may include provisions for controlling the amount of airflow into intake manifold 106. In some embodiments, fuel injection system 100 preferably includes throttle body 118. In some embodiments, throttle body 118 may be disposed adjacent to intake manifold 106. Additionally, throttle body 118 is preferably adjacent to air intake duct 122.
Generally, throttle body 118 preferably includes throttle valve 120. Throttle valve 120 preferably opens and closes in a manner that changes the airflow rate into intake manifold 106. In a preferred embodiment, throttle body 118 includes throttle valve sensor 121. Preferably, throttle valve sensor 121 may be configured to measure the angle of throttle valve 120 as measured from an initial position.
In some embodiments, fuel injection system 100 may include air entry port 124. The term air entry port refers to any mechanism for allowing air to enter fuel injection system 100 adjacent to air intake duct 122. In some embodiments, air entry port 124 preferably includes airflow meter 126. In a preferred embodiment, airflow meter 126 may be a mass airflow sensor.
Generally, fuel injection system 100 may include provisions for measuring the engine speed. In some embodiments, fuel injection system 100 may include engine speed sensor 125. Preferably, engine speed sensor 125 may be associated with engine 102. Engine speed sensor 125 may be disposed along a portion of engine 102 not shown in this schematic illustration.
Additionally, fuel injection system 100 may include provisions for measuring an ambient pressure outside of engine 102 and intake manifold 106. Preferably, fuel injection system 100 may include ambient pressure sensor 127. Generally, ambient pressure sensor 127 may be disposed away from engine 102 or intake manifold 106 and in a position suitable to measure the ambient pressure.
Preferably, fuel injection system 100 may include provisions for controlling injector 116. In some embodiments, fuel injection system 100 may include electronic control unit 130 (referred to from here on as ECU 130). In some embodiments, ECU 130 may be a computer of some type configured to control injector 100.
In some embodiments, ECU 130 may be associated with fuel injector 116, pressure sensor 112, temperature sensor 114, throttle valve sensor 121, engine speed sensor 125, airflow meter 126 and ambient pressure sensor 127. Preferably, ECU 130 may be in communication with fuel injector 116, pressure sensor 112, temperature sensor 114, throttle valve sensor 121 and airflow meter 126. In some cases, ECU 130 may communicate with various devices by using electrical connections. Specifically, ECU 130 may be connected to fuel injector 116 by first connection 132. In a similar manner, ECU 130 may be connected to pressure sensor 112 by second connection 134. In a similar manner, ECU 130 may be connected to temperature sensor 114 by third connection 136. In a similar manner, ECU 130 may be connected to throttle valve sensor 121 by fourth connection 138. Likewise, ECU 130 may be connected to airflow meter 126 by fifth connection 140. In a similar manner, ECU 130 may be connected to engine speed sensor 125 by sixth connection 142. Finally, ECU 130 may be connected to ambient pressure sensor 127 by seventh connection 144. The various connections could be electrical, optical or wireless.
Using this configuration, one embodiment of fuel injection system 100 and engine 102 operates by the following preferred steps. First, air is received at air intake port 124. Preferably, the mass of the air entering at air intake port 124 is measured by airflow meter 126. This information is relayed to ECU 130 by means of fifth electrical connection 140.
Once air has passed through airflow meter 126, the air enters air intake duct 122. For schematic purposes, air intake duct 122 is shown in
Generally, throttle valve 120 controls the amount of air that enters intake manifold 106. The larger the angle of throttle valve 120, the larger the quantity of air that is permitted to enter intake manifold 106 from air duct 122. As air moves through intake manifold 106, the pressure and temperature are determined by pressure sensor 112 and temperature sensor 114, respectively. These measured values are preferably relayed to ECU 130 through connections 134 and 136.
Finally, the air disposed within intake manifold 106 may flow through port 180 into compression chamber 108 as intake valve 110 opens. Simultaneously, injector 116 may inject a quantity of fuel as the air flows past port 180 and into compression chamber 108. Preferably, the amount of fuel injected using injector 116 may be controlled by ECU 130. Specifically, ECU 130 calculates an injection amount based on inputs received by pressure sensor 112, temperature sensor 114, throttle valve sensor 121 and airflow meter 126.
Preferably, fuel injection system 100 may include provisions for optimizing fuel injection for low airflow rate conditions and high airflow rate conditions. In some embodiments, fuel injection system 100 includes more than one method for determining the injection amount dispensed by injector 116. In a preferred embodiment, fuel injection system 100 may include a first control method and a second control method. Each control method may be used to determine an appropriate fuel injection amount. In a preferred embodiment, the first control method may be a speed density control method. Generally, the speed density control method uses information gathered by pressure sensor 112, temperature sensor 114 and ambient pressure sensor 127. Additionally, the second control method may preferably be an airflow meter (AFM) control method, where the primary sensor used is airflow meter 126. For each method, ECU 130 may calculate a fuel injection quantity based on algorithms using the input parameters from the sensors associated with each control method.
In some cases, the airflow rate may be related to the speed of the engine in terms of revolutions per minute (RPM).
In this embodiment, indicator 308 is disposed within second regime 304. Therefore, the second control method, the airflow meter control method, is used to determine the injection quantity. The system preferably uses the first control method, or speed density control method, during low airflow conditions. These lower airflow conditions generally correspond with lower RPM ranges. In the embodiment shown in
The previous embodiments are only meant to be illustrative of the ways that airflow rate regimes may be defined. In some embodiments, a fuel injection system may include provisions for distinguishing between two airflow rate regimes based on multiple criteria. In some embodiments, the transitional airflow rate may be determined by a theoretical estimate that is predetermined by the ECU. In other embodiments, the transitional airflow rate may be determined by a predetermined threshold associated with an airflow meter. In some embodiments, the transitional airflow rate may be identified as the value where the airflow meter control method becomes accurate. In a preferred embodiment, airflow rate regimes are distinguished based on information measured by an engine speed sensor, an intake manifold pressure sensor and a throttle valve sensor. These parameters are generally speed density control parameters.
Also during step 404, ECU 130 preferably determines various engine parameters as measured by various sensors. During this step, throttle angle TH is determined by information received from throttle valve sensor 121. Additionally, engine speed NE is determined by information received from engine speed sensor 125. Also, intake manifold pressure PBA is determined by information received by manifold pressure sensor 112.
During step 404, the current airflow rate is compared with a predetermined transition airflow rate. In some embodiments, this transition airflow rate may be transition airflow rate T1. Preferably, T1 is a fixed value that may be preset within ECU 130 by the manufacturer.
Generally, the current airflow rate airflow may be determined by considering various sensory information received by ECU 130 during step 404. In a preferred embodiment, the current airflow rate may be determined by considering throttle angle TH, engine speed NE, and intake manifold pressure PBA. In particular, the current airflow rate may be a function of throttle angle TH, engine speed NE and intake manifold pressure PBA. In other embodiments, other sensory information may be used to determine the current airflow rate.
If the current airflow rate is greater than transition airflow rate T1, then the first control method is selected. In this case, ECU 130 preferably proceeds to step 406. Preferably, during step 406, the quantity of fuel to be injected using injector 116 is determined based on sensory information received from airflow meter 126. Once a first fuel injection quantity Q1 is determined, ECU 130 sends a first control signal to fuel injector 116 to execute injection of quantity Q1 during step 408. Following step 408, this process is repeated as new sensory information is received by ECU 130 during step 402.
If the current airflow rate is less than transition airflow rate T1, then the second control method is selected. In the case where the second control method is selected, the speed density control method, ECU 130 preferably proceeds to step 410. Preferably, during step 410, the quantity of fuel to be injected using injector 116 is determined based on sensory information received from manifold pressure sensor 112, temperature sensor 114 and ambient pressure sensor 125. Once a second fuel injection quantity Q2 is determined, ECU 130 sends a control signal to fuel injector 116 to execute injection of quantity Q2 during step 412. Following step 412, this process is repeated as new sensory information is received by ECU 130 during step 402.
In the previous embodiment, only two airflow rate regimes were considered. Preferably, a fuel injection system may include provisions for selecting between two control methods over multiple airflow rate regimes. In other words, in some embodiments, there may be more than two airflow rate regimes. Also, in some embodiments, there may be up to five airflow rate regimes.
In this embodiment, each airflow rate regime may be associated with one of two possible fuel injection control methods: control method A and control method B. First airflow rate regime 501 may be associated with control method A, and second airflow rate regime 502 may be associated with control method B. Finally, third airflow rate regime 503 may be associated with control method A.
Generally, control method A uses input from different sensors than control method B in order to calculate a fuel injection quantity. In a preferred embodiment, control method A is used to calculate a fuel injection quantity based on speed density control. As discussed previously, speed density control determines a fuel injection quantity on the basis of information received from a manifold pressure sensor, an ambient pressure sensor, and a temperature sensor. Control method B is preferably used to calculate a fuel injection quantity based on information received from an airflow meter. In other embodiments, however, control method A and control method B may use other fuel injection control methods besides speed density control or AFM.
During step 602, a current airflow rate is calculated. The current airflow rate may be determined by a number of different parameters. In some embodiments, the parameters used to determine the current airflow rate may include the intake manifold pressure PBA, the throttle valve angle TH and the engine speed NE. Following step 602, the current airflow rate is compared with transition airflow rate T3, during step 604.
If the current airflow rate is less than transition airflow rate T3, ECU 130 proceeds to step 606. In this case, the current airflow rate has been determined to be within first regime 501. During step 606, ECU 130 preferably determines a fuel injection quantity based on fuel control method A. Control method A, as discussed here, may be any type of fuel injection control method. In a preferred embodiment, as previously discussed, control method A may be a speed density control method. In this case, the fuel injection quantity will be determined based on information received from manifold pressure sensor 112, ambient pressure sensor 127 and engine speed sensor 125.
If, during step 604, the current airflow rate is determined to be above transition airflow rate T3, ECU 130 preferably proceeds to step 608. During step 608, the current airflow rate is compared to transition airflow rate T3 and transition airflow rate T4. In cases where the current airflow rate is less than transition airflow rate T4 and greater than transition airflow rate T3, ECU 130 preferably proceeds from step 608 to step 610. In this case, the current airflow rate is determined to be within second airflow rate regime 502. During step 610, ECU 130 preferably determines the fuel injection quantity based on control method B. Generally, control method B may be any fuel injection control method. In a preferred embodiment, control method B may be associated with an airflow meter. In particular, control method B may be a method for calculating the fuel injection quantity on the basis of information received from airflow meter 126.
If, during step 608, the current airflow rate is determined to be greater than transition airflow rate T4, ECU 130 proceeds to step 609. During step 609, the current airflow rate is determined to be greater than transition airflow rate T4. At this point, ECU 130 proceeds to step 606. The details of step 606 have been previously discussed. In this case, the current airflow rate has been determined to be within third airflow rate regime 503. Third airflow rate regime 503 is also preferably associated with control method A.
Following steps 606 and 610, ECU 130 preferably sends a control signal to fuel injector 116. Following this step, the whole process may be repeated again. The amount of time it takes for ECU 130 to perform steps 602, 604, 606, 608 and 610 may vary.
In other embodiments, an airflow rate scale may include more than three airflow rate regimes. Generally, an airflow rate scale may include any number of airflow rate regimes. Furthermore, there may be more than two fuel injection control methods associated with the multiple airflow rate regimes. In this manner, a fuel injection control system may be optimized over many different airflow rate regimes.
While various embodiments of the invention have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.
