System and method for filtering engine signals

Abstract

Systems and methods for controlling an engine having selectively activated and deactivated cylinders are presented. In one example, coefficients of a finite impulse response filter are adjusted in response to changes in engine induction ratio so that undesirable frequencies output from an engine sensor can be attenuated to improve engine control.

Description

Technical Field

[0001] The present specification relates to systems and methods for improving the operation of an engine including cylinders that can be selectively activated and deactivated to save fuel while meeting engine torque requirements. The systems and methods are applicable to engines that deactivate engine cylinders by deactivating the intake and exhaust valves of the deactivated cylinders.

[0002] Background and Summary of the Invention

[0003] The engine control system can sense the engine intake manifold pressure to determine the engine operating parameters that serve as the basis for adjusting the engine actuators. For example, the engine intake manifold pressure can be sampled to determine the engine intake manifold absolute pressure (MAP). The engine intake manifold pressure, together with the engine speed, can be converted into the amount of air flowing through the engine using the ideal gas law. When the engine air flow is known, the desired amount of fuel that provides the desired engine air-fuel ratio can be determined by dividing the engine air flow rate by the desired engine air-fuel ratio. However, the engine intake manifold pressure may include frequencies that may cause the intake manifold pressure to exhibit a standard deviation greater than the desired one. If the engine fuel amount is adjusted in response to the raw (e.g., unfiltered) engine intake manifold pressure sampled at a slow and fixed crankshaft interval, the engine's air-fuel ratio may change beyond the desired amount.

[0004] One method of reducing engine air-fuel variations is to apply a first order low pass filter to the MAP signal and sample the MAP signal at a rate that is an integer multiple of the engine firing frequency. The filtered MAP can then be used to determine the amount of fuel to be injected into the engine. However, if the engine has the ability to deactivate and reactivate individual cylinders such that the actual total number of active cylinders varies between engine cycles, processing the MAP sensor signal through a first order low pass filter and a constant sampling frequency may not provide a filtered MAP sensor signal suitable for controlling engine fuel injection because the frequency within the MAP sensor signal varies dynamically while the poles of the first order filter remain constant.

[0005] The inventors herein have recognized the above-mentioned problems and have developed an engine operating method, which includes: receiving a signal to a controller; adjusting coefficients of a finite impulse response filter in response to an engine induction ratio (e.g., the actual total number of active cylinders (cylinders that burn air and fuel) in a cylinder cycle divided by the actual total number of engine cylinders); filtering the signal through the finite impulse response filter; and adjusting one or more actuators in response to the filtered signal.

[0006] By adjusting the coefficients of a finite impulse response filter or an infinite impulse response filter in response to an engine induction ratio, the following technical results can be provided: providing a filtered engine signal having a desired level of dynamic response with a desired standard deviation, even when the engine is operated at an induction ratio of less than one. When the engine signal is filtered according to the present specification, the filtered engine signal can have a desired standard deviation that allows tight control of the engine air-fuel ratio. In addition, other engine actuators, such as a camshaft and an intake throttle, can be more accurately controlled when the engine induction ratio changes or is a fractional value. The finite impulse response filter can be implemented by instructions in a controller so that the modification of the filter coefficients can be synchronized with cylinder mode changes.

[0007] The present description may provide several advantages. Specifically, the method may improve engine air-fuel control. Furthermore, the method may be applied to a variety of different engines having different cylinder configurations. Furthermore, the method may eliminate or reduce the signal strength of signal frequencies that tend to increase the standard deviation of the signal, so that an actuator adjusted in response to the signal may be smoothly controlled while providing a desired dynamic response.

[0008] The above advantages and other advantages and features of the present specification will be apparent from the following detailed description alone or in conjunction with the accompanying drawings.

[0009] It should be understood that the above summary is provided to introduce a series of concepts further described in the detailed description in a simplified form. This is not meant to identify the key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims following the detailed description. In addition, the claimed subject matter is not limited to implementations that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Advantages described herein will be more fully understood by reading the examples of embodiments herein referred to as detailed description either alone or with reference to the accompanying drawings, in which:

[0011] Figure 1 It is a schematic diagram of the engine;

[0012] Figure 2A is a schematic diagram of an eight-cylinder engine having two cylinder banks;

[0013] Figure 2B is a schematic diagram of a four-cylinder engine having a single cylinder bank;

[0014] Figure 3 shows an engine signal filtered according to the prior art and according to the present specification;

[0015] Figure 4 A flow chart showing a method for filtering an engine signal; and

[0016] Figure 5 is a graphical representation of a finite impulse response filter. DETAILED DESCRIPTION

[0017] This specification relates to filtering a signal from an engine and controlling the engine in response to the filtered signal. Figure 1 An engine including cylinders that may be selectively deactivated is shown in FIG. Figure 2A and Figure 2B Show Figure 1 An exemplary configuration of the engine is described. Figure 3 An exemplary sequence is shown in which the engine induction ratio is changed and two different types of filters are applied to signals output from engine sensors. Figure 4 An exemplary method for processing signals and controlling an engine in response to the processed signals is shown.

[0018] See also Figure 1 , including multiple cylinders ( Figure 1 Internal combustion engine 10 , one cylinder of which is shown, is controlled by electronic engine controller 12 . Engine 10 includes combustion chamber 30 and cylinder walls 32 with piston 36 positioned therein and connected to crankshaft 40 .

[0019] Combustion chamber 30 is shown communicating with intake manifold 44 and exhaust manifold 48 via respective intake valve 52 and exhaust valve 54. The exhaust valve may be operated by variable exhaust valve actuator 53,

[0020] The variable exhaust valve actuator 53 can be actuated mechanically, electrically, hydraulically or by a combination thereof. For example, the exhaust valve actuator can be the type described in U.S. Patent Publication 2014 / 0303873 and U.S. Patents 6,321,704, 6,273,039 and 7,458,345, which are fully incorporated herein for all intents and purposes. The exhaust valve 54 can be kept closed during the entire engine cycle by the variable exhaust valve actuator 53. In addition, the exhaust valve actuator can open the exhaust valve 54 synchronously or asynchronously with the crankshaft 40. The position of the exhaust valve 54 can be determined by the exhaust valve position sensor 57. The intake valve 52 is opened and closed by the intake valve actuator 51, and the intake valve actuator 51 can be the same type as the exhaust valve actuator 53. The position of the intake valve 52 can be determined by the intake valve position sensor 59. Intake valve 52 can be held closed during the entire engine cycle by variable intake valve actuator 51 to deactivate an engine cylinder (e.g., when a cylinder is deactivated, no combustion occurs in the cylinder for at least one engine cycle). In one example, intake valve 52 and exhaust valve 54 remain closed, and when cylinder 30 is deactivated, no fuel is injected into cylinder 30. When cylinder 30 is deactivated, other engine cylinders may be activated.

[0021] Fuel injector 66 is shown positioned to inject fuel directly into cylinder 30, which is known to those skilled in the art as direct injection. Alternatively, fuel may be injected into the intake port, which is known to those skilled in the art as port injection. Fuel injector 66 delivers liquid fuel in proportion to the pulse width of the signal from controller 12. Fuel is delivered to fuel injector 66 by fuel system 175. In addition, intake manifold 44 is shown to be in communication with an optional electronic throttle 62 (e.g., a butterfly valve), which adjusts the position of throttle plate 64 to control the air flow from air filter 43 and intake port 42 to intake manifold 44. Throttle 62 regulates the air flow from air filter 43 in engine intake port 42 to intake manifold 44. In one example, a high pressure, two-stage fuel system may be used to generate a higher fuel pressure. In some examples, throttle 62 and throttle plate 64 may be positioned between intake valve 52 and intake manifold 44 so that throttle 62 is a port throttle.

[0022] Distributorless ignition system 88 provides an ignition spark to combustion chamber 30 via spark plug 92 in response to controller 12. Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown coupled to exhaust manifold 48 upstream of catalytic converter 70. Alternatively, a two-state exhaust gas oxygen sensor may be used in place of UEGO sensor 126.

[0023] In one example, converter 70 may include multiple catalyst bricks. In another example, multiple emission control devices, each having multiple bricks, may be used. In one example, converter 70 may be a three-way type catalyst.

[0024] The controller 12 Figure 1 1 is a conventional microcomputer including a microprocessor unit 102, input / output ports 104, read-only memory 106 (eg, non-transitory memory), random access memory 108, keep alive memory 110, and a conventional data bus. Controller 12 is shown receiving various signals (in addition to those previously discussed) from sensors coupled to engine 10, including: engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling jacket 114; position sensor 134 coupled to accelerator pedal 130 for sensing force applied by human driver 132; measurement of engine manifold pressure (MAP) from pressure sensor 122 coupled to intake manifold 44; engine position sensor from Hall effect sensor 118 sensing position of crankshaft 40; measurement of air mass entering the engine from sensor 120; brake pedal position from brake pedal position sensor 154 when human driver 132 applies brake pedal 150; turbocharger wastegate position sensor 156 (when present), alternatively sensor 156 may be an exhaust pressure sensor, which may be located in the exhaust manifold; and measurement of throttle position from sensor 58. Barometric pressure may also be sensed (sensor not shown) for processing by controller 12. In a preferred aspect of the present description, engine position sensor 118 generates a predetermined number of equally spaced pulses for each revolution of the crankshaft from which engine speed (RPM) can be determined. User interface 155 (which may be referred to as a display or panel) allows a vehicle occupant to request a vehicle mode (e.g., economy / standard) and receive requests or diagnostic information from controller 12.

[0025] In some examples, the engine can be coupled to an electric motor / battery system in a hybrid vehicle. Additionally, in some examples, other engine configurations can be employed, such as a diesel engine.

[0026] During operation, each cylinder within engine 10 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, typically, exhaust valve 54 is closed and intake valve 52 is opened. Air is introduced into combustion chamber 30 via intake manifold 44, and piston 36 moves to the bottom of the cylinder so as to increase the volume within combustion chamber 30. The position of piston 36 near the bottom of the cylinder and at the end of its stroke (e.g., when combustion chamber 30 is at its largest volume) is typically referred to by those of skill in the art as bottom dead center (BDC). During the compression stroke, intake valve 52 and exhaust valve 54 are closed. Piston 36 moves toward the cylinder head so as to compress the air within combustion chamber 30. The point at which piston 36 is at the end of its stroke and closest to the cylinder head (e.g., when combustion chamber 30 is at its smallest volume) is typically referred to by those of skill in the art as top dead center (TDC). In a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. In a process hereinafter referred to as ignition, the injected fuel is ignited by known ignition means, such as spark plug 92, resulting in combustion. During the expansion stroke, the expanding gases push piston 36 back to BDC. Crankshaft 40 converts the piston motion into rotational torque of the rotating shaft. Finally, during the exhaust stroke, exhaust valve 54 opens to release the combusted air-fuel mixture to exhaust manifold 48, and the piston returns to TDC. It should be noted that the above is shown only as an example, and the intake and exhaust valve opening and / or closing timing can be varied, such as to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0027] See now Figure 2A , shows an exemplary multi-cylinder engine including two cylinder groups. The engine includes Figure 1 Cylinders and associated components shown. Engine 10 includes eight cylinders 30. Each of the eight cylinders is numbered, and the cylinders of the number are included in the cylinder. Fuel injector 66 selectively supplies fuel to each cylinder that is enabled (e.g., burning fuel during the cycle of the engine). When the request is less than the full torque capacity of the engine, cylinders 1-8 can be selectively deactivated to improve engine fuel economy. For example, cylinders 2, 3, 5 and 8 can be deactivated during the engine cycle (e.g., two turns of a four-stroke engine) and can be deactivated in multiple engine cycles when the engine speed and load are constant or very slightly changed. During different engine cycles, cylinders 1, 4, 6 and 7 of the second fixed mode can be deactivated. In addition, cylinders of other modes can be selectively deactivated based on vehicle operating conditions (e.g., engine speed and load). In addition, the engine cylinders can be deactivated so that the cylinders of the fixed mode are not deactivated in multiple engine cycles. On the contrary, the deactivated cylinders can change between adjacent engine cycles.

[0028] Each cylinder group 202 and 204 includes a variable valve actuator 53 for enabling and deactivating the intake valve. The variable valve actuator can be operated by a camshaft 254. The intake valve remains in a closed position when deactivated. In addition, each cylinder includes a variable exhaust valve operator 53 for selectively enabling and deactivating the exhaust valve. The engine cylinder can be deactivated by stopping the flow of fuel to the cylinder throughout the engine cycle and keeping its intake and exhaust valves closed. The engine cylinder can be activated by starting to open and close the exhaust valve and the intake valve during the engine cycle while delivering fuel to the cylinder. The engine 10 includes a first cylinder group 204, which includes four cylinders 1, 2, 3 and 4. The engine 10 also includes a second cylinder group 202, which includes four cylinders 5, 6, 7 and 8. During the engine cycle, the cylinders of each group can be active or deactivated.

[0029] See now Figure 2B , shows an exemplary multi-cylinder engine including a cylinder group. The engine includes Figure 1 Cylinders and associated components shown. The engine 10 includes four cylinders 210. Each of the four cylinders is numbered, and the number of cylinders is included in the cylinder. The fuel injector 66 selectively supplies fuel to each cylinder that is enabled (e.g., burning fuel during the cycle of the engine, wherein the intake valve and the exhaust valve are opened and closed during the cycle of the active cylinder). When the request is less than the full torque capacity of the engine, cylinders 1-4 can be selectively deactivated (e.g., not burning fuel during the cycle of the engine, wherein the intake valve and the exhaust valve remain closed throughout the cycle of the deactivated cylinder) to improve engine fuel economy. For example, cylinders 2 and 3 (e.g., fixed mode deactivated cylinders) can be deactivated during multiple engine cycles (e.g., two revolutions of a four-stroke engine). During different engine cycles, cylinders 1 and 4 of the second fixed mode can be deactivated in multiple engine cycles. In addition, cylinders of other modes can be selectively deactivated based on vehicle operating conditions. In addition, the engine cylinders can be deactivated so that the fixed mode cylinders are not deactivated in multiple engine cycles. On the contrary, the cylinder that is deactivated can change between adjacent engine cycles.In this way, the engine cylinder that is deactivated can be rotated or changed between adjacent engine cycles.

[0030] The engine 10 includes a single cylinder bank 250, which includes four cylinders 1-4. During the engine cycle, the cylinders of the single bank can be active or deactivated. The cylinder bank 250 includes a variable intake valve actuator 51 for operating the intake valve. In addition, each cylinder includes a variable exhaust valve operator 53 for selectively enabling and deactivating the exhaust valve. The variable valve actuator can be operated by a camshaft 254. The engine cylinder can be deactivated by stopping the flow of fuel to the cylinder throughout the engine cycle and keeping its intake and exhaust valves closed. The engine cylinder can be activated by starting to open and close the exhaust valve and intake valve during the engine cycle while delivering fuel to the cylinder.

[0031] Figure 1-2B The system provides an engine system, the engine system comprising: an engine including one or more cylinder valve deactivation mechanisms; a sensor coupled to the engine; an actuator coupled to the engine; a controller including: executable instructions stored in a non-transitory memory to selectively deactivate one or more engine cylinders and adjust coefficients of a finite impulse response filter applied to a signal generated by the sensor, instructions for applying a second filter to an output of the finite impulse response filter in response to a change in an engine induction ratio, and instructions for adjusting the actuator in response to the output of the finite impulse response filter and the output of the second filter. The engine system further includes additional executable instructions for adjusting the coefficients by values ​​in a table or matrix stored in a memory of the controller. The engine system includes a case where the actuator is a fuel injector. The engine system includes a case where the actuator is an engine throttle. The engine system includes a case where the second filter is a low pass filter. The engine system includes a case where the second filter includes instructions stored in the controller memory.

[0032] See now Figure 3 , shows a foreshadowing sequence showing prior art signal filtering and signal filtering according to the present specification. These figures are aligned in time and occur simultaneously. The vertical lines at t0-t4 indicate the times of interest during the sequence. Figure 4 Methods and Figure 1-2B The systems collaborate to provide the signal filtering shown in this sequence.

[0033] from Figure 3 The first graph from the top down is a graph of engine induction ratio versus time. The vertical axis represents engine induction ratio, and engine induction ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0034] from Figure 3The second graph from the top down is a graph of raw (e.g., unfiltered) engine intake manifold pressure versus time. The vertical axis represents engine intake manifold pressure, and engine intake manifold pressure increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0035] from Figure 3 The second graph from the top down is a graph of raw (e.g., unfiltered) engine intake manifold pressure versus time. The vertical axis represents engine intake manifold pressure, and engine intake manifold pressure increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0036] from Figure 3 The third graph from the top down is a graph of engine intake manifold pressure filtered according to a prior art method (e.g., a first order low pass filter) versus time. In other words, the third graph shows the output of a prior art filtering method that filters the original signal shown in the second graph. The vertical axis represents filtered engine intake manifold pressure, and filtered engine intake manifold pressure increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0037] from Figure 3 The fourth plot from the top down is a plot of engine intake manifold pressure versus time filtered in accordance with the present specification (e.g., a finite impulse response (FIR) filter with adjustable coefficients). In other words, the fourth plot shows the output of a filter in accordance with the present specification that filters the original signal shown in the second plot. The vertical axis represents filtered engine intake manifold pressure, and filtered engine intake manifold pressure increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the plot to the right side of the plot.

[0038] The scaling ratios of the engine intake manifold pressures of the second, third, and fourth graphs are equal. Therefore, the scaling ratios and ranges of the vertical axes of the second, third, and fourth graphs are equal.

[0039] At time t0, the value of the engine induction ratio is 1, which indicates that all engine cylinders are active. The engine burns air and fuel in all cylinders (not shown). The raw engine intake manifold pressure signal is at a low level, and both the prior art filtering method and the filtering according to the present specification are at a low level.

[0040] Between time t0 and time t1, the engine is operating with all of its cylinders active (e.g., burning air and fuel). The raw engine intake manifold pressure has a small standard deviation. The output of the prior art filtering method smoothes the raw engine intake manifold pressure signal and provides a filtered output with an even lower standard deviation. The output of the filter according to the present specification also provides a smoothed engine intake manifold pressure.

[0041] At time t1, in response to engine operating conditions (not shown), the engine induction ratio is reduced. When the induction ratio is reduced, the raw engine intake manifold pressure increases so that the engine can supply a nearly constant amount of torque. The engine intake manifold pressure can be increased by opening the engine throttle (not shown). In response to the raw engine intake manifold pressure increase, the magnitude of the output of the prior art filtering method increases. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the filter according to the present specification also increases. In response to the change in the engine induction ratio, the coefficients of the filter according to the present specification are adjusted.

[0042] Between time t1 and time t2, the engine is operating with less than all cylinder activity (e.g., burning air and fuel). The standard deviation of the raw engine intake manifold pressure increases significantly. The output of the prior art filtering method has a standard deviation that is almost the same as the raw engine intake manifold pressure signal. The magnitude of the prior art filter output changes, so that the engine air-fuel ratio control based on its output may change more than expected. The magnitude of the output of the filter according to the present specification provides a smooth engine intake manifold pressure, thereby more accurately controlling the engine air-fuel ratio.

[0043] At time t2, in response to engine operating conditions (not shown), the engine induction ratio is again reduced. As the induction ratio is reduced, the raw engine intake manifold pressure is further increased so that the engine can supply a nearly constant amount of torque. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the prior art filtering method increases. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the filter according to the present specification also increases. In response to the change in the engine induction ratio, the coefficients of the filter according to the present specification are adjusted a second time.

[0044] Between time t2 and time t3, the engine operates with less than all cylinder activity (e.g., burning air and fuel). The standard deviation of the original engine intake manifold pressure remains large. The standard deviation of the output of the prior art filtering method also remains large. However, the output of the filter according to the present specification provides a smooth engine intake manifold pressure, which can more accurately control the engine air-fuel ratio. In other words, the standard deviation of the intake manifold pressure output from the filter according to the present specification is less than the standard deviation of the intake manifold pressure according to the prior art method. This can allow the engine controller to provide a smoother engine air-fuel ratio that exhibits lower noise, thereby improving engine emissions.

[0045] At time t3, in response to engine operating conditions (not shown), the engine induction ratio is reduced for a third time. As the induction ratio is reduced, the raw engine intake manifold pressure is further increased so that the engine can supply a nearly constant amount of torque. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the prior art filtering method increases. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the filter according to the present specification also increases. In response to the change in the engine induction ratio, the coefficients of the filter according to the present specification are adjusted for a third time.

[0046] Between time t3 and time t4, the engine operates with less than all cylinder activity (e.g., burning air and fuel). The standard deviation of the original engine intake manifold pressure remains large. The standard deviation of the output of the prior art filtering method also remains large. However, the output of the filter according to the present specification provides a smooth engine intake manifold pressure, which can more accurately control the engine air-fuel ratio. In other words, the standard deviation of the intake manifold pressure output from the filter according to the present specification is less than the standard deviation of the intake manifold pressure according to the prior art method. This can allow the engine controller to provide a smoother engine air-fuel ratio that exhibits lower noise, thereby improving engine emissions.

[0047] At time t4, in response to engine operating conditions (not shown), the engine induction ratio is reduced for a fourth time. As the induction ratio is reduced, the raw engine intake manifold pressure is further increased so that the engine can supply a nearly constant amount of torque. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the prior art filtering method increases. In response to the raw engine intake manifold pressure increase, the magnitude of the output of the filter according to the present specification also increases. In response to the change in the engine induction ratio, the coefficients of the filter according to the present specification are adjusted for a fourth time.

[0048] After time t4, the engine is operating with even less than full cylinder activity (e.g., burning air and fuel). The standard deviation of the raw engine intake manifold pressure remains large. The standard deviation of the output of the prior art filtering method also remains large. However, the output of the filter according to the present specification provides a smoothed engine intake manifold pressure, thereby allowing for more accurate control of the engine air-fuel ratio.

[0049] In this way, the raw signal output from the engine sensor can be filtered by a finite impulse response filter, and the coefficients of the filter can be adjusted each time to customize the filter output in response to the engine induction ratio and the frequency in the output of the sensor that can be related to the engine induction ratio.

[0050] See now Figure 4 , a flow chart describing a method for operating an engine is shown. The method may include filtering the output of an engine sensor in response to an engine induction ratio, and coefficients of a filter that modifies the output of the engine sensor may be adjusted in response to the engine induction ratio. Adjusting the coefficients may improve the filter response and characteristics (e.g., standard deviation) of a signal output from the filter. Figure 4 The method can be combined with Figure 1-2B In addition, Figure 4 At least a portion of the method may be incorporated as executable instructions stored in a non-transitory memory, while other portions of the method may be performed by a controller transforming operating states of devices and actuators in the physical world. When the method 400 is active, the engine of the vehicle rotates and combusts air and fuel in at least one cylinder.

[0051] At 402, method 400 determines an engine induction ratio. In one example, the engine induction ratio may be determined by the following equation:

[0052]

[0053] where i r is the engine induction ratio, n is the actual total number of active cylinders (e.g., cylinders that burn air and fuel), and d is the actual total number of engine cylinders. For example, if the engine has eight cylinders and three cylinders are firing during an engine cycle, the engine induction ratio for that engine cycle is 0.375. The engine induction ratio may be varied in response to engine speed and load and other engine operating conditions. Method 400 proceeds to 404.

[0054] At 404, method 400 determines the order of a finite impulse response filter or an infinite impulse response (IIR) filter. The order of the filter determines the decay rate of frequencies in the filtered signal. The maximum gain of the filter is 1, and the decayed frequency is determined by the zero position of the filter. As the order of the filter increases, the decay rate of the undesired frequency transmitted to the filter increases. However, the computational load for determining the filter output increases with the order of the filter. The order of the filter can be a compromise between the filter output and the computational load for filtering the signal. In one example, the order of the filter is predetermined, and the number of filter coefficients is determined from the order of the filter. The order of the filter may depend on the characteristics of the engine and sensor output. For example, a second order FIR filter may be applied to the output of a pressure sensor coupled to an eight-cylinder engine. However, a first order FIR filter may be applied to the output of a pressure sensor coupled to a four-cylinder engine. The order of the FIR filter may be determined empirically and stored in a controller memory. The order of the filter may be retrieved from the memory by reference to the memory according to the vehicle configuration. Method 400 proceeds to 406.

[0055] At 406, method 400 retrieves FIR or IIR filter coefficients from controller memory. In one example, the FIR filter coefficients can be empirically determined based on frequencies in the raw sensor output signal that may be undesirable. The filter coefficients can be selected to attenuate undesirable frequencies, and the undesirable frequencies can change based on the current engine induction ratio. In one example, a table or matrix of FIR coefficients is stored to the controller memory. The dimensions of the table or matrix can be N rows by M columns. The value of N is the maximum order of the FIR filter obtained from the table. For example, if the maximum FIR filter order is 1 (first order filter), then the value of N = 2, where one table entry for each engine induction ratio is reserved for b 0 coefficient and one table entry for each engine induction ratio is reserved for b 1 Coefficients. M is the actual total number of available engine induction ratios. It should be noted that the order of the FIR filter can be adjusted by selecting the appropriate filter coefficients to be zero. For example, if N=8, the order of the FIR filter can be adjusted between 0 and 7.

[0056] Thus, the dimensions of the matrix or table are based on the filter order and the engine induction ratio. Filter coefficients for engine induction ratios that do not have a specific entry in the table or matrix may be interpolated or extrapolated. Empirically determined values ​​in the table or matrix may be referenced by the engine induction ratio and the order of the filter. In some examples, the order of the filter may be fixed and the table or matrix may be referenced using only the engine induction ratio. Method 400 retrieves the filter coefficients and proceeds to 408.

[0057] At 408, a sensor coupled to the engine (e.g., a MAP sensor, a MAF sensor, an engine speed sensor, a wastegate position sensor, or a cam position sensor) is sampled at a predetermined frequency, and the raw output of the sensor is input to a FIR or IIR filter. In other words, a FIR or IIR filter is applied to the output of the engine sensor. In one example, the FIR filter can be implemented according to the following equation:

[0058]

[0059] where y k is the FIR filter output, k is the time step, i is the index variable, b is the FIR filter coefficient, N is the order of the filter, and u k-i is the raw engine sensor value obtained at a defined sampling interval. The filter can be represented graphically, such as Figure 5 Method 400 proceeds to 410 after filtering inputs from engine sensors.

[0060] At 410, method 400 determines if there is currently a transition in the engine induction ratio. For example, if the engine induction ratio is currently or has just changed from a value of 0.8 to a value of 0.5, the answer is yes and method 400 proceeds to 412. Otherwise, the answer is no and method 400 proceeds to 414. Method 400 evaluates the engine induction ratio so that the output of the filter from step 408 in this execution of method 400 can be smoothed with the output of the filter from step 408 in the next execution of method 400. In some examples, method 400 may be performed once each time the engine sensor is sampled.

[0061] At 412, a second filter may be applied to the output from the FIR or IIR filter described at 408. The second filter may smooth discontinuities that may be caused by changes in filter coefficients and changes in sensor output that may be associated with a changing engine induction ratio. In one example, the second filter may be another FIR filter. In another example, the second filter may be a first order low pass filter. Method 400 applies the second filter to the output of the FIR or IIR filter, and the filtered engine intake manifold pressure may be used to calculate other variables within the controller. Method 400 proceeds to 414.

[0062] At 414, method 400 adjusts one or more engine actuators in response to the output of the FIR or IIR filter or the output of the second filter. If an engine induction ratio change is ongoing or occurs within a predetermined actual number of engine sensor samples after an engine induction ratio change, method 400 may adjust one or more engine actuators in response to the output of the second filter. For example, if an engine induction ratio change is ongoing, method 400 may adjust the engine actuators in response to the most recent value output from the second filter after each engine sensor sample and the most recent value output from the second filter in the next five executions of method 400. However, if the engine induction ratio has not changed and a predetermined actual total number of engine sensor samples have been executed since the most recent engine induction ratio change, method 400 may adjust the engine actuators in response to the output of the FIR filter.

[0063] Method 400 adjusts an actuator having a position or state based on a filtered output of an engine sensor. In one example, method 400 adjusts a fuel injector pulse width in response to a filtered engine sensor output (e.g., an output from a FIR or IIR filter or a second filter). For example, if the sensor is a MAP sensor, the amount of fuel injected through the fuel injector can be adjusted in response to an engine air amount (e.g., air flow through the engine), where the engine air amount is estimated from the filtered MAP sensor output and the ideal gas law. In another example, method 400 adjusts the position of an EGR valve and a throttle in response to the output of the filtered MAP sensor. In other examples, the engine camshaft timing can be adjusted in response to the filtered MAP sensor output. After adjusting the engine actuators in response to the output of the filtered engine sensor, method 400 proceeds to exit.

[0064] therefore, Figure 4 The method provides an engine operation method, including: receiving a signal to a controller; adjusting coefficients of a finite impulse response filter in response to an engine induction ratio; filtering a signal (MAP, engine speed, engine air flow, or cam timing signal) through a finite impulse response filter; and adjusting one or more actuators in response to the filtered signal. The method includes determining coefficients by reference to a matrix or table of predetermined coefficients in response to the engine induction ratio and the order of the finite impulse response filter. The method further includes interpolating between entries in the matrix. The method includes the case where the actuator is a fuel injector. The method includes the case where the actuator is an engine camshaft. The method includes the case where the actuator is an engine throttle. The method includes the case where the engine induction ratio is the actual total number of cylinders that combust air and fuel in a cylinder cycle divided by the actual total number of engine cylinders.

[0065] Figure 4 The method also provides an engine operation method, including: receiving a signal to a controller; retrieving coefficients of a finite impulse response filter from a table or matrix in a memory of the controller via an engine induction ratio reference table or matrix; applying the coefficients to the finite impulse response filter; filtering the signal through the finite impulse response filter; and adjusting one or more actuators in response to the filtered signal. The method includes the case where the matrix is ​​an N x M matrix. The method includes the case where N is the actual total order of the finite impulse response filter. The method includes the case where M is the engine induction ratio. The method includes the case where the engine induction ratio is adjusted in response to engine operating conditions. The method includes the case where the engine induction ratio increases with engine load. The method further includes the case where the signal is filtered through a second filter in response to a change in the engine induction ratio.

[0066] See now Figure 5 , shows a graphical example of an FIR filter with coefficients adjusted in response to the engine induction ratio. The raw unfiltered output from the engine sensor is input to the FIR filter and is indicated as U k The engine induction ratio is referenced to a lookup table or matrix 502, and the table outputs coefficients b 0 、b 1 ……b N The corresponding coefficients are multiplied by the current and past values ​​of the raw engine sensor outputs at multiplication blocks 504, 510, 514, and 520. Blocks 506, 512, and 518 each represent a delay of one sample. The outputs from the multiplication blocks are then added at summation blocks 508, 516, and 522. In addition, the output of summation block 508 is added to the outputs of multiplication block 514 and summation block 516. The output of the FIR filter is indicated as Y k And it is the output of summation block 522.

[0067] It should be noted that the exemplary control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-temporary memory and can be executed by a control system including a controller in combination with various sensors, actuators and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. In this way, the various actions, operations and / or functions shown can be performed in the sequence shown, performed in parallel, or omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations and / or functions shown can be repeatedly performed according to the specific strategy used. In addition, at least a portion of the described actions, operations and / or functions can graphically represent the code in the non-temporary memory of a computer-readable storage medium to be programmed into the control system. When the described actions are implemented by executing instructions in a system including various engine hardware components in combination with one or more controllers, the control action can also transform the operating state of one or more sensors or actuators in the physical world.

[0068] This specification ends here. A reading of this specification by one skilled in the art will enable many changes and modifications to occur without departing from the spirit and scope of this specification. For example, I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas, gasoline, diesel, or alternative fuel configurations may benefit from using this specification. In addition, the engine may be turbocharged or supercharged.

[0069] According to the present invention, there is provided an engine operating method, the method comprising: receiving a signal to a controller; adjusting coefficients of a finite impulse response filter in response to an engine induction ratio; filtering the signal through the finite impulse response filter; and adjusting one or more actuators in response to the filtered signal.

[0070] According to an embodiment, the coefficients are determined by referring to a matrix or table of predetermined coefficients in response to the engine induction ratio and the order of the finite impulse response filter.

[0071] According to an embodiment, the above invention is further characterized in that interpolation is performed between entries in the matrix.

[0072] According to an embodiment, the actuator is a fuel injector.

[0073] According to an embodiment, the actuator is an engine camshaft.

[0074] According to an embodiment, the actuator is an engine throttle and wherein the signal is provided by a manifold absolute pressure sensor, an air mass sensor, an engine speed sensor, a cam position sensor, an exhaust manifold pressure sensor or a wastegate position sensor.

[0075] According to an embodiment, the engine induction ratio is the actual total number of cylinders combusting air and fuel in a cylinder cycle divided by the actual total number of engine cylinders.

[0076] According to the present invention, there is provided an engine operating method, the method comprising: receiving a signal to a controller; retrieving coefficients of a finite impulse response filter from the table or the matrix in a memory of the controller via an engine induction ratio reference table or matrix; applying the coefficients to the finite impulse response filter; filtering the signal by the finite impulse response filter; and adjusting one or more actuators in response to the filtered signal.

[0077] According to an embodiment, the matrix is ​​an N x M matrix.

[0078] According to an embodiment, N is the order of the finite impulse response filter.

[0079] According to an embodiment, M is the number of available engine induction ratios.

[0080] According to an embodiment, the engine induction ratio is adjusted in response to engine operating conditions.

[0081] According to an embodiment, the engine induction ratio increases with engine load.

[0082] According to an embodiment, the above invention is further characterized in that the signal is further filtered by a second filter in response to a change in the engine induction ratio.

[0083] According to the present invention, an engine system is provided, the engine system having: an engine including one or more cylinder valve deactivation mechanisms; a sensor coupled to the engine; an actuator coupled to the engine; and a controller including: executable instructions stored in a non-temporary memory to selectively deactivate one or more engine cylinders and adjust coefficients of a finite impulse response filter applied to a signal generated by the sensor, instructions for applying a second filter to an output of the finite impulse response filter in response to a change in an engine induction ratio, and instructions for adjusting the actuator in response to an output of the finite impulse response filter and an output of the second filter.

[0084] According to an embodiment, the above invention is further characterized by additional executable instructions for adjusting the coefficients by values ​​in a table or matrix stored in a memory of the controller.

[0085] According to an embodiment, the actuator is a fuel injector.

[0086] According to an embodiment, the actuator is an engine throttle.

[0087] According to an embodiment, the second filter is a low pass filter.

[0088] According to an embodiment, the second filter comprises instructions stored in a controller memory.

Claims

1. An engine operating method, comprising: Receive signal to controller; adjusting coefficients of a finite impulse response filter in response to an engine induction ratio; filtering the signal through the finite impulse response filter; filtering an output of the finite impulse response filter via a low pass filter in response to a change in the engine induction ratio; and adjusting one or more actuators in response to the filtered signal, The engine induction ratio is the actual total number of cylinders that combust air and fuel in a cylinder cycle divided by the actual total number of engine cylinders. 2 . The method of claim 1 , wherein the coefficient is determined by referring to a matrix or table of predetermined coefficients in response to the engine induction ratio and the order of the finite impulse response filter.

3. The method of claim 2, further comprising interpolating between entries in the matrix.

4. The method of claim 1, wherein one of the one or more actuators is a fuel injector.

5. The method of claim 1, wherein one of the one or more actuators is an engine camshaft.

6. The method of claim 1 , wherein one of the one or more actuators is an engine throttle, and wherein the signal is provided by a manifold absolute pressure sensor, an air mass sensor, an engine speed sensor, a cam position sensor, an exhaust manifold pressure sensor, or a wastegate position sensor. 7 . The method of claim 1 , further comprising, in response to an absence of a change in the engine induction ratio, not filtering the output of the finite impulse response filter via the low pass filter.

8. An engine system, comprising: An engine including one or more cylinder valve deactivation mechanisms; a sensor coupled to the engine; an actuator coupled to the engine; a controller including executable instructions stored in a non-transitory memory to selectively deactivate one or more engine cylinders and adjust coefficients of a finite impulse response filter applied to a signal generated by the sensor, instructions for applying a second filter to an output of the finite impulse response filter in response to a change in an engine induction ratio, and instructions for adjusting the actuator in response to the output of the finite impulse response filter and the output of the second filter, The engine induction ratio is the actual total number of cylinders that combust air and fuel in a cylinder cycle divided by the actual total number of engine cylinders.

9. The engine system of claim 8, further comprising additional executable instructions for adjusting the coefficients via values ​​in a table or matrix stored in a memory of the controller and not applying the second filter to the output of the finite impulse response filter in response to an absence of a change in the engine induction ratio.

10. The engine system of claim 8, wherein the actuator is a fuel injector.

11. The engine system of claim 8, wherein the actuator is an engine throttle.

12. The engine system of claim 8, wherein the second filter is a low pass filter.

13. The engine system of claim 8 wherein said second filter comprises instructions stored in a controller memory.

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