Method and system for monitoring smoke generation

Abstract

The present application relates to a method and system for monitoring smoke generation, and provides a method and system for using an engine laser ignition system to acquire an image of a cylinder in real time during combustion and estimate cylinder smoke generation. If excessive smoke generation is determined, the cylinder fuel supply is adjusted by changing the injection pressure, injection amount, and injection ratio. The air-fuel ratio of the cylinder is also adjusted based on the exhaust temperature limit to reduce smoke generation.

Description

Technical Field

[0001] The present application relates to monitoring cylinder soot generation in an engine configured with a laser ignition system. Background Art

[0002] Raw gas soot generation can be used as a parameter indicative of engine operating efficiency. For example, elevated raw gas soot generation can indicate that the combustion air-fuel ratio is too rich, or that the fuel injector spray is being incorrectly routed onto the cylinder wall or piston. As engine components age over time, and due to variability between components, soot generation may increase compared to nominal values. Excessive soot generation may degrade exhaust emissions and require mitigation measures to be taken on fuel injection to reduce soot formation. Additionally, vehicle designs may have to update particulate filters in the exhaust passages to reduce exhaust soot levels.

[0003] Various methods can be used to determine raw gas soot generation. For example, observations from an engine dynamometer diagram can be used to model raw gas soot generation. Other methods include using exhaust soot or differential pressure sensors to estimate soot accumulation on exhaust filters (such as based on the pressure drop across the filter), and inferring raw gas soot generation based on filter soot accumulation. The inventors herein have recognized that such methods can increase cost and complexity without necessarily enhancing the accuracy of soot measurement. In addition, dust may increase the permanent pressure drop across the filter, thereby confusing the results. In view of these issues, the inventors have realized that in an engine system configured with laser ignition capability, components of the laser ignition system can be advantageously used to monitor cylinder combustion and determine raw gas soot generation in real time. In one example, the estimated soot can be performed by a method comprising: adjusting the cylinder fuel supply in response to the amount of soot generated in the cylinder, the amount being estimated at the controller based on an image generated by the laser ignition device. In this way, if elevated soot generation is determined, appropriate mitigation measures can be taken essentially immediately. Summary of the invention

[0004] As an example, the optics of a laser ignition system can be used to diagnose cylinder combustion events with excessive soot generation. The laser can be used to quickly scan the interior of each cylinder. In particular, low-power light pulses can be emitted into the cylinder by the laser ignition device and detected by a photoelectric detection system coupled to the cylinder head. Once the threshold combustion phasing is completed (such as after 50% combustion phasing), the light pulses can be started and continued until the exhaust stroke is completed. The photoelectric detection system can include a camera (such as a CCD camera) and a lens (such as a fisheye lens) for detecting the light pulses. The light pulses can illuminate the soot particles formed in the cylinder during the combustion event. In one example, the light pulses can be emitted in the infrared (IR) spectrum by the laser ignition device and detected in the IR spectrum by the camera. An image of the soot particles generated in the cylinder interior after combustion can be generated based on the detected pulses. The image can be transmitted (e.g., wirelessly) within the engine system and displayed to a service provider (e.g., a mechanic or vehicle operator) on a display on the vehicle center console. In addition, a reference image of soot generation in the cylinder under given operating conditions (e.g., under given engine speed load conditions) can be retrieved from the memory of the controller and displayed to the mechanic for comparative analysis. Optionally, if the engine is coupled in a hybrid electric vehicle, the electric motor can be operated during engine operation to maintain the engine speed load conditions while generating the in-cylinder image. In one example, based on the comparison, the generated image can indicate excessive soot formation under given conditions. If the mechanic determines that the generated image indicates excessive soot formation, the mechanic can indicate the excessive soot formation to the controller via the display device. Therefore, a diagnostic code can be set and the fuel injection parameters can be adjusted to reduce further soot formation. For example, if the cylinder is operated richly for temperature control, the degree of enrichment can be reduced. As another example, if the cylinder is operated at a stoichiometric ratio, the fuel injection pressure can be increased.

[0005] In this manner, it is possible to utilize a laser ignition system to reduce the time and cost associated with determining cylinder soot formation without reducing the accuracy of the determination. By comparing images of cylinder soot formation gathered by a photodetector during / after a cylinder combustion event to a reference image, excessive soot formation can be identified and addressed in a timely manner. A technical effect of using the laser generated images of a laser ignition system is that diagnostics can be performed utilizing hardware already present in a laser ignition configured engine, thereby reducing the need for expensive sensors and filters. Fuel injection adjustments can be accelerated by identifying excessive cylinder soot formation in real time.

[0006] It should be understood that the above summary is provided to introduce some concepts further described in the detailed description in a simplified form. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the subsequent claims. In addition, the claimed subject matter is not limited to embodiments that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 An example combustion chamber of an internal combustion engine coupled in a hybrid vehicle system is shown.

[0008] Figure 2 Show use Figure 1 An example of an image captured and displayed by the engine's laser system.

[0009] FIG. 3A to FIG. 3B An example of laser pulse transmission to an engine cylinder is shown.

[0010] Figure 4 A high level flow chart is shown of a method for diagnosing excessive soot formation based on in-cylinder images generated by a photodetector of a laser ignition system. DETAILED DESCRIPTION

[0011] Methods and systems are provided for diagnosing cylinder soot formation using a laser ignition system, such as Figure 1 As shown. Figure 2 and FIG. 3A to FIG. 3B As shown, lower intensity laser pulse emission can be used to illuminate the interior of the cylinder while the photodetector captures the in-cylinder image. Higher intensity laser pulse emission can also be used to initiate combustion. The resulting image can be used to adjust various cylinder combustion parameters. The engine controller can be configured to execute a control routine (such as Figure 4 An example routine of ) is provided to determine excessive soot formation based on an in-cylinder image generated by a photodetector using light from the laser pulse emission during a combustion event. Accordingly, the fuel injection profile may be adjusted to reduce further soot formation.

[0012] Go to Figure 1, depicting an example hybrid propulsion system 100. The hybrid propulsion system can be configured in a passenger highway vehicle 5. The hybrid propulsion system 100 includes an internal combustion engine 10. The engine can be coupled to a transmission (not shown), such as a manual transmission, an automatic transmission, or a combination thereof. In addition, various additional components, such as a torque converter and / or other gears such as a final drive unit, can be included. The hybrid propulsion system also includes an energy conversion device (not shown), which can include a motor, a generator, etc., and a combination thereof. The energy conversion device can be operated to absorb energy from vehicle motion and / or the engine, and convert the absorbed energy into an energy form suitable for storage at the energy storage device. The energy conversion device can also be operated to supply output (power, work, torque, speed, etc.) to the engine 10 in order to increase the engine output. It should be understood that in some embodiments, the energy conversion device may include a motor, a generator, or both a motor and a generator, as well as various other components for providing appropriate energy conversion between the energy storage device and the vehicle drive wheels and / or the engine.

[0013] The engine 10 may be a multi-cylinder internal combustion engine, one cylinder of which is Figure 1 Engine 10 may be controlled at least partially by a control system including controller 12 and by input from a vehicle operator 132 via an input device 130. In this example, input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP.

[0014] Combustion cylinder 30 of engine 10 may include combustion cylinder walls 32 with piston 36 positioned therein. Piston 36 may be coupled to crankshaft 40 so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 40 may be coupled to at least one drive wheel of propulsion system 10 via an intermediate transmission system. Combustion cylinder 30 may receive intake air from intake manifold 45 via intake passage 43 and may exhaust combustion gases via exhaust passage 48. Intake manifold 45 and exhaust passage 48 may selectively communicate with combustion cylinder 30 via respective intake valve 52 and exhaust valve 54. In some embodiments, combustion cylinder 30 may include two or more intake valves and / or two or more exhaust valves.

[0015] The engine 10 may optionally include cam position sensors 55 and 57. However, in the example shown, the intake valve 52 and the exhaust valve 54 may be controlled by cam actuation via respective cam actuation systems 51 and 53. The cam actuation systems 51 and 53 may each include one or more cams and may utilize one or more of a cam profile switching (CPS), a variable cam timing (VCT), a variable valve timing (VVT), and / or a variable valve lift (VVL) system, which may be operated by the controller 12 to change the valve operation. To achieve detection of the cam position, the cam actuation systems 51 and 53 may have a toothed wheel. The positions of the intake valve 52 and the exhaust valve 54 may be determined by position sensors 55 and 57, respectively. In an alternative embodiment, the intake valve 52 and / or the exhaust valve 54 may be controlled by electric valve actuation. For example, the cylinder 30 may alternatively include an intake valve controlled via electric valve actuation and an exhaust valve controlled via a cam actuation system including a CPS and / or VCT system.

[0016] Fuel injector 66 is shown coupled directly to combustion cylinder 30 for injecting fuel directly into the combustion cylinder in proportion to the pulse width of signal FPW received from controller 12 via electronic driver 68. In this manner, fuel injector 66 provides what is known as direct injection of fuel into combustion cylinder 30. For example, the fuel injector may be mounted on the side of the combustion cylinder or in the top of the combustion cylinder. Fuel may be delivered to fuel injector 66 by a fuel delivery system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some embodiments, combustion cylinder 30 may alternatively or additionally include a fuel injector arranged in intake passage 43 in a so-called port injection configuration to provide fuel into the intake port upstream of combustion cylinder 30.

[0017] Intake passage 43 may include charge motion control valve (CMCV) 74 and CMCV plate 72, and may also include throttle 62 having throttle plate 64. In this particular example, the position of throttle plate 64 may be varied by controller 12 via a signal provided to an electric motor or actuator included in throttle 62, a configuration which may be referred to as electronic throttle control (ETC). In this manner, throttle 62 may be operated to vary the intake air provided to combustion cylinder 30, as well as other engine combustion cylinders. Intake passage 43 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 for providing respective signals MAF and MAP to controller 12.

[0018] Exhaust sensor 126 is shown coupled to exhaust passage 48 upstream of catalytic converter 70. Sensor 126 may be any suitable sensor for providing an indication of exhaust air-fuel ratio, such as a linear oxygen sensor or UEGO (Universal or Wide-range Exhaust Oxygen), a two-state oxygen sensor or EGO, HEGO (Hot EGO), NOx, HC, or CO sensor. The exhaust system may include a light-off catalyst and an underbody catalyst, as well as exhaust manifold, upstream and / or downstream air-fuel ratio sensors. In one example, catalytic converter 70 may include multiple catalyst bricks. In another example, multiple emission control devices may be used, each having multiple bricks. In one example, catalytic converter 70 may be a three-way catalyst.

[0019] The controller 12 Figure 1 1 is a microcomputer shown in FIG. 1 , which includes a microprocessor unit 102, input / output ports 104, an electronic storage medium for executable programs and calibration values, shown in this particular example as a read-only memory chip 106, a random access memory 108, a fail-safe memory 109, and a data bus. In addition to those signals previously discussed, controller 12 may also receive various signals and information from sensors coupled to engine 10, including a measurement of intake mass air flow (MAF) from a mass air flow sensor 120; an engine coolant temperature (ECT) from a temperature sensor 112 coupled to a cooling sleeve 114; in some examples, a surface ignition sensing signal (PIP) from a Hall effect sensor 118 (or other type) coupled to crankshaft 40 may be optionally included; a throttle position (TP) from a throttle position sensor; and an absolute manifold pressure signal MAP from sensor 122. Hall effect sensor 118 may be optionally included in engine 10, as it functions in a similar capacity to the engine laser system described herein. Storage medium read-only memory 106 can be programmed with computer readable data representing instructions executable by processor 102 for performing the methods described below and variations thereof.

[0020] The laser system 92 includes a laser driver 88 and a laser control unit (LCU) 90. The LCU 90 causes the laser driver 88 to generate laser energy. The LCU 90 may receive operating instructions from the controller 12. The laser driver 88 includes a laser oscillating portion 86 and a light converging portion 84. The light converging portion 84 converges the laser light generated by the laser oscillating portion 86 onto the laser focus 82 of the combustion cylinder 30. In one example, the light converging portion 84 may include one or more lenses.

[0021] The photodetector 94 can be located at the top of the cylinder 30 as part of the laser system 92, and can receive return pulses from the top surface of the piston 36. The photodetector 94 can include a camera with a lens. In one example, the camera is a charge coupled device (CCD). The CCD camera can be configured to detect and read the laser pulses emitted by the LCU 90. In one example, when the LCU emits laser pulses in the infrared frequency range, the CCD camera can operate and receive pulses in the infrared frequency range. In such an embodiment, the camera can also be called an infrared camera. In other embodiments, the camera can be a full-spectrum CCD camera that can operate in the visible spectrum as well as the infrared spectrum. The camera can include a lens for focusing the detected laser pulses and generating an image of the interior of the cylinder. In one example, the lens is a fisheye lens that creates a wide-angle panoramic or hemispherical image of the interior of the cylinder. After the laser emission from the LCU 90, the laser scans within the internal area of ​​the cylinder 30 at the laser focus 82. The light energy reflected by the piston 36 can be detected by the camera in the photodetector 94. The photodetector 94 can also capture an image of the interior of the cylinder, as described below.

[0022] Laser system 92 is configured to operate in more than one capacity at the timing of each operation based on the engine position of the four-stroke combustion cycle. For example, laser energy can be used to ignite the air / fuel mixture during the power stroke of the engine (including during engine starting, engine warm-up operation, and warmed-up engine operation). Fuel injected by fuel injector 66 can form an air / fuel mixture during at least a portion of the intake stroke, wherein the air / fuel mixture is ignited using laser energy generated by laser exciter 88 to initiate combustion of the otherwise non-combustible air / fuel mixture and drive piston 36 downward. In addition, light generated during the cylinder combustion event can be used by photodetector 94 to capture images of the interior of the cylinder. As shown in FIG. Figure 4 As described in detail, the generated images can then be used to diagnose cylinder combustion.

[0023] In a second operating capability, the LCU 90 can deliver low power pulses to the cylinders. The low power pulses can be used to determine piston and valve position during a four-stroke combustion cycle. Additionally, upon reactivating the engine from an idle stop condition, laser energy can be utilized to monitor the engine's position, speed, etc., to synchronize fuel delivery and valve timing. Furthermore, the light generated by the lower power laser pulse emission can be used to capture images of the cylinder interior before a cylinder combustion event occurs, such as during an intake stroke.

[0024] The images generated at the photodetector 94 can be displayed to a mechanic or service technician on the vehicle center console so that they can perform a visual inspection and identify exhaust soot formation. For example, a laser ignition device coupled to the photodetector 94 can transmit light pulses into the cylinder 30, and the photodetector 94, which includes an infrared camera equipped with a fisheye lens, generates images that are wirelessly transmitted to the engine controller and viewed on a display of the vehicle. In some examples, such as reference Figure 2 As discussed, while operating the laser ignition device, an operator controlled knob on the center console can adjust the engine position. These adjustments include adjusting the engine forward or backward from the initial engine position, allowing further inspection of the cylinder for analysis of the location of most smoke deposition or generation.

[0025] The LCU 90 can direct the laser exciter 88 to focus the laser energy at different locations depending on the operating conditions. For example, the laser energy can be focused at a first location away from the cylinder wall 32 within the interior area of ​​the cylinder 30 to ignite the air / fuel mixture. In one embodiment, the first location can be close to the top dead center (TDC) of the power stroke. In addition, the LCU 90 can direct the laser exciter 88 to generate a first plurality of laser pulses directed to the first location, and the first combustion from rest can receive laser energy from the laser exciter 88 that is greater than the laser energy delivered to the first location for later combustion. As another example, the laser energy can be focused at a second location to scan across the cylinder cavity to illuminate any soot particles present in order to diagnose excessive soot formation.

[0026] The controller 12 controls the LCU 90 and has a non-transitory computer-readable storage medium that includes code for adjusting the location of laser energy delivery based on temperature (e.g., ECT). The laser energy can be directed at different locations within the cylinder 30. The controller 12 may also include additional or alternative sensors for determining the operating mode of the engine 10, including additional temperature sensors, pressure sensors, torque sensors, and sensors that detect engine rotational speed, air volume, and fuel injection volume. Additionally or alternatively, the LCU 90 may communicate directly with various sensors (such as a temperature sensor for detecting ECT) for determining the operating mode of the engine 10.

[0027] As mentioned above, Figure 1 One cylinder of multi-cylinder engine 10 is shown, and each cylinder may similarly include its own set of intake / exhaust valves, fuel injectors, laser ignition system, etc.

[0028] The controller 12 receives the Figure 1 The signals of various sensors are used Figure 1The controller may control various actuators to adjust engine operation based on the received signals and instructions stored on the memory of the controller. For example, based on the inputs from the sensors and the images generated by the photodetector, the controller may infer excessive soot formation and mitigate further soot generation by adjusting the pulse width commanded to the direct fuel injector. For example, the controller may reduce the pulse width to reduce the degree of richness applied during fuel injection for cylinder temperature control.

[0029] In some examples, the vehicle 5 may be a hybrid vehicle with multiple torque sources available for one or more wheels 55. In other examples, the vehicle 5 is a conventional vehicle with only an engine, or an electric vehicle with only (one or more) motors. In the example shown, the vehicle 5 includes an engine 10 and a motor 52. The motor 52 may be a motor or a motor / generator. When one or more clutches 56 are engaged, the crankshaft 140 of the engine 10 and the motor 52 are connected to the wheels 55 via a transmission 54. In the depicted example, the first clutch 56 is disposed between the crankshaft 140 and the motor 52, and the second clutch 56 is disposed between the motor 52 and the transmission 54. The controller 12 may send a signal to the actuator of each clutch 56 to engage or disengage the clutch so as to connect or disconnect the crankshaft 140 with the motor 52 and its connected components, and / or connect or disconnect the motor 52 with the transmission 54 and its connected components. The transmission 54 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain may be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle.

[0030] The electric machine 52 receives electrical power from the traction battery 58 to provide torque to the wheels 55. The electric machine 52 may also operate as a generator to provide power to charge the battery 58, such as during braking operations.

[0031] Figure 2 It shows ( Figure 1 An exemplary embodiment 200 of how a laser system 92 may emit laser pulses into a cylinder 30 so that a photodetector of the laser system may capture an image of the interior of the cylinder. The image may be displayed to a vehicle operator to enable visual inspection of the cylinder for excessive soot generation. Thus, Figure 1 Components that have been introduced in Figure 2 Re-introduction in.

[0032] Figure 2A laser system 92 is shown, which includes a laser exciter 88, a photodetector 94, and an LCU 90. The LCU 90 causes the laser exciter 88 to generate laser energy. High-frequency laser pulses are directed toward various locations of the cylinder to scan as much of the cylinder as possible. For example, the laser pulses 202 can be directed toward the cylinder wall 215, the interior of the cylinder 30, the piston top surface 213, and the inner surface of the valves 52 and 54 (i.e., the surface facing the cylinder). By scanning as many cylinders as possible as quickly as possible, the laser pulses 202 act as a wide beam light source or bulb, enabling the photodetector 94 (particularly a CCD camera) to capture an image 220 of the interior of the cylinder. Therefore, when operating as a light source for image capture during diagnosis, it can be considered that the laser ignition system (or laser device) operates in a projector or illuminator mode, and the LCU 90 can receive operating instructions, such as a power mode, from the controller 12. When operating in a diagnostic mode, the laser system 92 can emit a series of low-power pulses at a high frequency. In contrast, during ignition, the laser can be pulsed quickly at a high energy intensity to ignite the air / fuel mixture. In one example, during diagnostic mode, the laser can be pulsed at a low energy level using frequency modulation with a repetitive linear frequency ramp. Low-power frequent laser pulses can be emitted in the infrared spectrum. A photoelectric detection system including a CCD camera (e.g., an infrared CCD camera) operating in the infrared spectrum with a fisheye lens can be located at the top of the cylinder as part of the laser and can capture a cylinder image 320 using light energy reflected from the inside of the cylinder. The captured image can include images of the cylinder wall 215, the cylinder-facing surfaces of the intake valve 52 and the exhaust valve 54, the piston top surface 213, and the inside of the cylinder 30. The captured image 220 is wirelessly transmitted to the controller 12 by the photodetector 94 for viewing on the display 135 in the center console 140 of the vehicle.

[0033] The center console 140 may include Figure 1 The center console 140 may be a control support surface located in a central portion of the vehicle cabin, particularly in the front portion of the vehicle cabin. The center console 140 may include various controls, such as a knob 138, a dial 142, and buttons 136. The various controls may be actuated by a vehicle operator to adjust cabin conditions. The various controls may include, for example, a volume control knob 138 coupled to the vehicle's music system for adjusting the volume of music in the cabin; a tuning button 136 coupled to the vehicle's radio system for adjusting radio channel selection; and a temperature control dial 142 coupled to the vehicle's HVAC system for adjusting cabin heating and cooling temperatures.

[0034] The center console 140 may also include a display 135. The display may be a touch-sensitive display that enables the vehicle operator to select settings for the vehicle via touch interaction. The display may also be used to display current vehicle settings. In addition, the display may be used to display a navigation system (such as GPS), phone functions, or web applications to be accessed during driving. During conditions where the laser ignition device is operated to capture images for diagnostic purposes, the display 135 may be used to depict an image of the interior of the cylinder 30 taken by the photodetector 94 coupled to the laser detection system 92. Specifically, an image of the interior of the cylinder taken by the CCD camera of the laser detection system is transmitted (e.g., wirelessly) to the engine control system and displayed to the vehicle operator (e.g., a mechanic) on the display 135. Based on operator display preferences selected via touch interaction on the display, images of the interior of the cylinder of any or all cylinders may be displayed.

[0035] In some examples, during diagnostic mode, one or more of knobs 138 may be activated for engine position control (and deactivated for cabin control). For example, when operating in a diagnostic mode for evaluating cylinder soot generation, a volume control knob may be activated for engine position control and a volume control knob may be deactivated for volume control. Thus, adjustment of the volume control knob 138 may be used to adjust the engine position from an initial engine position to assist in visual inspection of the cylinder. For example, it may be determined that the piston of a cylinder is located at or near the top of the cylinder currently displayed on display 135, thereby obstructing a full view of the interior of the cylinder. To improve the view, the vehicle operator may slowly turn the volume control knob (e.g., clockwise or counterclockwise), which in turn moves the engine position (e.g., backward or forward) so that the piston slowly moves toward the bottom of the cylinder via adjusting the power distribution generator / motor of the engine system. In embodiments where the engine includes a planetary gear transmission, the motor can hold the outer ring stationary (which keeps the tire wheel stationary) while the generator (or sun gear) rotates the engine using feedback from a rotary transformer for generator position or using a 60-2 crank wheel with a Hall Effect sensor position system for actual engine position feedback. This movement of the pistons can allow the operator to receive an image representing a more complete view of the interior of the cylinder and enable him to more accurately examine locations where smoke particles may accumulate. Additionally, during diagnostic mode, the same volume control knob or an alternative center console knob, dial, or button can be activated to enable the image of the cylinder displayed on display 135 to be magnified (e.g., zoomed in or out).

[0036] In one example, low-power light pulses may be emitted by the laser ignition device in the infrared (IR) spectrum, and the CCD camera may be configured to operate in the IR spectrum. In an alternative embodiment, the photodetector 94 may have a full-spectrum CCD camera that may be tuned to coordinate with the frequency of the laser; thus, the camera may operate in the IR and other spectrums (e.g., sunlight or light bulbs), and have the ability to disable the laser if non-IR light is detected. While viewing the image, a vehicle operator (e.g., a maintenance technician or mechanic) may actively adjust the position of the piston to better view the cylinder. For example, during a condition where the image 220 indicates that the piston is near the top of the cylinder (e.g., at the TCD), additional adjustments allow the engine to be slowly and precisely adjusted to move the piston down to the bottom of the cylinder. In the depicted example, when the piston is near the top of the cylinder in view, the operator may adjust the volume control knob 138 located on the center console 140 of the vehicle to turn the engine forward or backward from the initial engine position. If the engine is rotated backward from the initial engine position to move the piston downward, the controller may simultaneously open the engine's intake throttle to reduce expansion of the intake manifold.

[0037] like Figure 4 As described in detail, an image of the interior of the cylinder can be analyzed to assess carbon accumulation in the cylinder. For example, the amount of soot generated and the location of soot accumulation can be assessed. Therefore, based on the image, it can be determined whether there is excessive soot generation. In response to excessive soot generation, a diagnostic code can be set. The controller can also direct the engine to reduce the richness of the fuel injection to reduce further soot generation. As another example, the controller can cause the engine to operate leaner than the stoichiometric ratio for a period of time, or direct a laser to a combustion area with excessive carbon accumulation to address elevated cylinder soot levels.

[0038] FIG. 3A to FIG. 3BAn example operation of the laser system 92 is shown. The LCU 90 causes the laser exciter 88 to generate a low power laser pulse shown at 302, which can be directed toward the top surface 313 of the piston 36. After emission, the light energy can be reflected by the piston and detected by the photodetector 94. The LCU 90 can receive operating instructions, such as a power mode, from the controller 12. For example, during ignition, the laser pulses used can be pulsed quickly with high energy intensity to ignite the air / fuel mixture. Conversely, to determine the engine position, the controller can direct the laser system to a scanning frequency of low energy intensity to determine the piston position and identify one or more valve positions. For example, frequency modulation of a laser with a repetitive linear frequency ramp can allow one or more piston positions in the engine to be determined. The detection sensor 94 can be located at the top of the cylinder as part of the laser system and can be calibrated to receive the return pulse 304 reflected from the top surface 313 of the piston 36.

[0039] FIG. 3A to FIG. 3B shows how the laser system 92 can be referenced above Figure 1 The laser system 92 emits pulses in the direction of the piston 36 in the cylinder 30. The pulses emitted by the laser system 92 (e.g. Figure 3A Pulse 302 shown in FIG. 30A can be directed toward top surface 313 of piston 36. Pulse 302 can be reflected from the top surface of the piston, and a return pulse (e.g., pulse 304) can be received by laser system 92, which can be used to determine the position of piston 36 within cylinder 30.

[0040] In some examples, the position of the piston can be determined by a frequency modulation method using a frequency modulated laser beam with a repetitive linear frequency ramp. Alternatively, a phase shift method can be used to determine the distance. By observing the Doppler shift or by comparing the sample positions at two different times, the piston position, speed and engine speed information (RPM measurements) can be inferred. The position of the intake valve 352 and / or the exhaust valve 354 can also be determined using a laser system. When the cylinder identification is combined with the piston position, the position of the engine can be determined and used to synchronize fuel delivery and valve timing. Such a position state of the engine can be based on the piston position and the CID determined via the laser.

[0041] The controller 12 may further control the LCU 90 and include a non-transitory computer readable storage medium including code for adjusting the location of laser energy delivery based on operating conditions (e.g., based on the position of the piston 36 relative to TDC). The controller 12 may also include additional or alternative sensors for determining the operating mode of the engine 10, including additional temperature sensors, pressure sensors, torque sensors, and sensors that detect engine rotational speed, air volume, and fuel injection volume, as described above with respect to Figure 1 Additionally or alternatively, LCU 90 may communicate directly with various sensors, such as Hall Effect sensor 118 , the inclusion of which is optional, for determining an operating or diagnostic mode of engine 10 .

[0042] The laser system can also be used to measure cam position by, for example, blocking the emitted pulses during certain strokes of the engine cycle. In one embodiment, the laser system 92 can be located near the intake valve 352, thereby preventing the measurement of the piston position in the cylinder during the intake stroke of the drive cycle. During the intake stroke, the valve 352 opens to the chamber and blocks the emitted laser pulses from being reflected by the top surface of the piston 313. For example, during the Figure 3B , because laser system 92 is placed in close proximity to intake valve 352, when cylinder 30 is in its intake stroke, valve 352 opens to the chamber and blocks laser pulses (e.g., laser pulse 306) from reaching the top surface of piston 313. Controller 12 may still be programmed to interpret the detected signals in order to determine the position of the cam. For example, in this example, the controller may process the absence of a signal received by sensor 94 to indicate that intake valve 352 is in an open position. The controller may further process this information and the geometry of the engine to determine the position of the engine within its drive cycle. Although Figure 3B Illustrated is how the emission pulse can be blocked by the intake valve 352, but other configurations are possible. For example, the laser system can be positioned very close to the exhaust valve rather than the intake valve. When placed in this position, the emitted pulse can be blocked during the exhaust stroke of the drive cycle instead. The controller can be calibrated to account for such differences. As described in detail below, the controller 12 can process the data collected during the drive cycle to determine the engine position.

[0043] The time difference between the emission of light pulse 302 and the detection of reflected light pulse 304 by photodetector 94 can be further compared to a time threshold as a means of determining whether degradation of the laser device has occurred. For example, in an internal combustion engine, the length of the combustion chamber may be three inches to four inches. Based on this estimate and the speed of light in a vacuum (c = 3.0×10 8 m / s), a light pulse emitted by the laser system 92 reflected from the top surface of the piston 313 can be detected in the picosecond time range. Therefore, a time threshold far beyond the expected picosecond time range (e.g., 1 nanosecond) can be used as a reference to indicate laser system degradation. For example, a detection of a pulse emitted by the laser system 92 by the sensor 94 taking longer than 1 nanosecond can indicate that the laser system is misaligned.

[0044] In some examples, the engine system 20 can be included in a vehicle that is developed to perform an idle stop when an idle stop condition is met and automatically restart the engine when a restart condition is met. Such an idle stop system can increase fuel savings, reduce exhaust emissions, noise, etc. In such an engine, engine operation can be terminated at a random position within a drive cycle. When starting the process of reactivating the engine, a laser system can be used to determine a specific position of the engine. Based on this evaluation, the laser system can determine which cylinder will first supply fuel so as to start the engine reactivation process from rest. In a vehicle configured to perform an idle stop operation, where the engine stop and restart are repeated multiple times during the driving operation, stopping the engine at a desired position can provide more repeatable starts, and therefore a laser system can be used to measure the engine position during the shutdown period (after deactivating fuel injection, spark ignition, etc.) when the engine decelerates to rest, so that in response to the measured piston / engine position, the motor torque or other traction torque can be variably applied to the engine so as to control the engine stop position to the desired stop position. The piston position information of each cylinder can also be used to estimate the crankshaft position.

[0045] In another example, when the vehicle shuts down its engine, because the motor is turned off or because the vehicle decides to operate in electric mode, the cylinders of the engine may eventually stop in an uncontrolled manner relative to the position of piston 36 in combustion cylinder 30 and the positions of intake valve 352 and exhaust valve 354. For an engine with four or more cylinders, there may always be a cylinder between exhaust valve closing (EVC) and intake valve closing (IVC) when the crankshaft is stationary.

[0046] As mentioned above, laser systems can be used to measure valve position and the position of the piston within the cylinder chamber. Figure 3BIn the engine position shown, the light from the laser system 92 can be at least partially blocked from reaching the top of the piston 313 in the cylinder 30. Since the amount of light reflected is reduced compared to the amount of light reflected by the top surface of the piston when the emitted pulse is not blocked, the controller 12 can be programmed to resolve such differences and use this information to determine that the intake valve 352 is open. Based on the sequence of valve operation within the drive cycle, the controller 12 also determines that the exhaust valve 354 is closed. Because the example given is based on a four-cylinder engine, there will always be one cylinder in the intake stroke. In this way, the controller can be programmed to process data from all laser systems in order to identify the cylinder that is in its intake stroke. Based on this determination, and using the geometry of the engine, the laser system can be used to identify the position of the engine. Alternatively, as will be described in further detail below, the controller can also be programmed to process a series of measurements from a single laser detector coupled to the cylinder as a means of identifying the position of the engine.

[0047] The position of the piston in the cylinder may be measured relative to any suitable reference point, and any suitable scaling factor may be used. For example, the position of the cylinder may be measured relative to the TDC position of the cylinder and / or the BDC position of the cylinder.

[0048] In this way, Figure 1 to Figure 2The components enable a hybrid vehicle system to include: an engine including a cylinder; a direct injector for supplying fuel to the cylinder; an electric motor; a display device within a cabin of the vehicle; a laser ignition system coupled to the cylinder head and configured to direct light pulses into the cylinder; a photodetection system coupled to the laser ignition system and the cylinder for generating an image of the interior of the cylinder using the light pulses from the laser ignition system, the photodetection system including a camera and a lens; and a controller. The controller may be configured with non-transitory memory and computer-readable instructions for the following operations: operating the laser ignition system during a compression stroke to initiate cylinder combustion; capturing an image of the interior of the cylinder at the photodetection system during a power stroke and an exhaust stroke of the cylinder; comparing the generated image with a reference image retrieved from a memory of the controller; estimating an amount of soot generated during cylinder combustion based on the comparison; and in response to the estimated amount of soot exceeding a threshold, adjusting a pulse width commanded to the direct injector, the adjustment being based on exhaust temperature and combustion air-fuel ratio. The controller may include further instructions for: adjusting the output of the electric motor when operating the laser ignition system to maintain a defined engine speed and load while generating the in-cylinder image, and wherein the reference image is selected based on the defined engine speed and load. In one example, adjusting the pulse width includes: when the exhaust temperature is below a threshold temperature and the combustion air-fuel ratio is richer than the stoichiometric ratio, in response to the estimated soot amount exceeding a threshold, reducing the commanded pulse width; when the exhaust temperature is above a threshold temperature and the combustion air-fuel ratio is richer than the stoichiometric ratio, in response to the estimated soot amount exceeding the threshold, increasing the commanded pulse width; and when the exhaust temperature is below a threshold temperature and the combustion air-fuel ratio is at the stoichiometric ratio, in response to the estimated soot amount exceeding the threshold, increasing the fuel pressure and reducing the commanded pulse width. The controller may include further instructions for: after adjusting the pulse width commanded to the direct injector, in response to the estimated soot amount exceeding the threshold, setting a diagnostic code and limiting the engine torque output.

[0049] Now go to Figure 4 , shows an example method 400 for using an engine laser ignition system (such as Figure 1 The method enables adjustment of the cylinder fuel supply in response to the amount of soot generated in the cylinder, which amount is estimated at the controller based on the image generated by the laser ignition device. Instructions for executing method 400 may be generated by the controller based on instructions stored on a memory of the controller and in combination with sensors of the engine system (such as those described above). Figure 1 The controller may use an engine actuator of the engine system to adjust the engine operation according to the method described below.

[0050] At 402, it is determined whether a combustion event is expected in the cylinder. For example, it may be confirmed that the engine is running, fuel is supplied, and one or more cylinder combustion events are expected. If a cylinder combustion event is not expected, at 404, laser ignition may be disabled.

[0051] If a cylinder combustion event is desired, then at 406, the method includes operating a laser ignition device (e.g., Figure 1 A laser ignition device may be operated with a laser system (of a laser ignition system) to initiate cylinder combustion. This may include initially operating the laser ignition device at a higher power level (such as at a power level above a threshold power required to illuminate only the interior of the cylinder). Then, once cylinder combustion is initiated, in order to visualize smoke generation, the laser ignition device may be operated at a lower power level (such as at a power level below a threshold power level required to initiate cylinder combustion). In one example, the controller may operate the laser ignition device at a higher power level during the compression stroke of the cylinder to initiate cylinder combustion, and then switch to operating the laser ignition device at a lower power level during the power stroke and exhaust stroke of the cylinder (where the combustion event occurs) to visualize smoke formed by the combustion event. In addition, the laser ignition device may be operated to direct laser pulses into the cylinder to scan the cylinder in a plane. Directing the laser pulses (and switching to a lower power level) may be initiated after a threshold percentage of combustion phasing is completed. For example, scanning may begin during the power stroke of the cylinder (such as once 50% of the combustion phasing is completed) and continue until the exhaust stroke of the cylinder is completed. In one example, a laser pulse can be directed into the cylinder to scan the cylinder in a plane during each of the power stroke and exhaust stroke of the cylinder. For example, a laser pulse can be directed to the center of the cylinder to give a smooth, uniform, and complete combustion pattern throughout the cylinder, starting from a point or line in the center and moving radially outward to the wall, ending at the same moment. In addition, the gap space may receive an additional blow. In this way, the light from the ignition flame can be used to analyze the interior of the cylinder. By quickly scanning the inside of the cylinder with the help of the laser through the power stroke, the cylinder combustion can be started, and the light generated by the cylinder combustion (as if through a light bulb) can be used to illuminate the cylinder. Illumination can be used to capture an image of the inside of the cylinder, allowing the operator to observe and evaluate the inside of the cylinder. Therefore, since the flame can block the view of the inside of the cylinder during combustion, a light bulb effect is provided only when the flame is completed by a low-energy laser scan.

[0052] In some embodiments, where the engine is coupled in a hybrid electric vehicle, the routine may include maintaining a reference engine speed and load via regulating the electric motor during operation of the laser ignition device. This allows the engine speed and load to be precisely controlled to predetermined conditions, thereby improving the accuracy and reliability of the results. It also reduces the variability of the test results due to changes in engine conditions.

[0053] At 408, the routine includes receiving an in-cylinder image from a photodetector. Specifically, the photodetector can capture an image of the interior of the cylinder using light generated from cylinder combustion (after laser ignition). The generated image is generated at a photodetector coupled to a laser ignition device. In one example, at 410, images are received beginning during a power stroke of the cylinder (such as once 50% of combustion phasing is completed) and continuing to receive images until the exhaust stroke of the cylinder is complete. The captured image is then transmitted, for example, wirelessly to a display device.

[0054] At 412, the routine includes displaying the in-cylinder image(s) captured by the photodetector to a vehicle operator on a vehicle display device. Here, the vehicle operator may be, for example, a mechanic or service technician diagnosing an engine. For example, after each combustion event, the captured images may be automatically presented to the service technician for analysis. Alternatively, after each combustion event, an image of each laser scan of each cylinder may be sent to the operator.

[0055] At 414, the controller may display a reference image to the vehicle operator on a display device. The reference image may be stored in and retrieved from a memory of the controller. The reference image may represent that a given cylinder has a threshold amount of soot at current engine operating conditions, such as at current engine speed load conditions. In one example, the reference image may be pre-generated by a photodetector during predetermined conditions, such as in a previous iteration of a given routine when an amount of soot less than a threshold was generated in the cylinder. The reference image may be retrieved based on the engine speed load conditions at the time of a combustion event in the cylinder. Additionally, the reference image may be selected based on the generated image. Alternatively, after the captured image(s) are displayed on the display device, the reference image may be retrieved and displayed after operator input received via the display device.

[0056] At 416, the routine includes receiving input from a vehicle operator (e.g., a service technician) regarding cylinder soot generation, the operator input being based on the displayed in-cylinder image and a reference image. For example, the operator may compare the displayed image to the reference image, and based on the difference, the operator may indicate that excessive soot generation has occurred in a recent cylinder combustion event. As an example, the generated image may indicate that a particular cylinder is generating soot due to running too rich due to an inappropriate (e.g., oversized) fuel injector. As another example, the generated image may show that another cylinder has a damaged fuel injector that does not atomize the fuel spray.

[0057] If no operator input indicating excessive soot generation is received, then the engine operating parameters are maintained at 418. In one example, if the engine is operated richer than stoichiometry for engine component temperature control (e.g., exhaust temperature control), then the richness level may be maintained at 418. In another example, if the engine is operating at stoichiometry, then the engine may be maintained at stoichiometry.

[0058] If an operator input indicating excessive soot generation is received, then at 420, one or more engine operating parameters may be adjusted to reduce soot formation. In addition, the controller may set a diagnostic code to indicate excessive soot generation. Adjusting one or more engine parameters may include, at 422, reducing the degree of enrichment if the engine is running rich. In one example, the engine may have been operating richer than the stoichiometric ratio for engine component temperature control (e.g., exhaust temperature control to protect the exhaust manifold assembly from overheating). In response to an indication of excessive soot formation, the degree of enrichment may be reduced. In one example, in response to an increased cylinder soot level, the exhaust temperature may be compared to a threshold. If the soot level increases and the exhaust temperature is above a first threshold, the degree of enrichment of the rich fuel may be reduced. For example, if a particular cylinder produces more soot than other cylinders, the degree of enrichment of a given cylinder may be reduced, while the degree of enrichment of one or more other cylinders may be increased to maintain it richer than the stoichiometric air-fuel ratio. This enables the engine to provide the same level of cooling to the catalyst prior to image capture. Alternatively, if all cylinders are producing excess soot during rich engine operation, the engine load may be reduced concurrently with the overall richness to provide the same level of cooling to the catalyst.

[0059] Adjusting one or more engine parameters may alternatively include, at 424, increasing the degree of enrichment if the engine is running hot. In one example, in response to an increased cylinder soot level, the exhaust temperature may be compared to a second threshold value that is higher than the first threshold value. If the soot level increases and the exhaust temperature is higher than the first threshold value and the second threshold value, the degree of enrichment of the rich fuel may be increased to speed up exhaust temperature control. For example, if the engine is operated at a stoichiometric ratio, the engine may be switched to operate richer than the stoichiometric ratio in response to increased soot and increased temperature conditions. As another example, if the engine is operated richer than the stoichiometric ratio, the degree of enrichment of the rich fuel may be increased in response to increased soot and increased temperature conditions. For example, if the degree of enrichment is reduced to reduce soot formation and the exhaust temperature subsequently becomes too hot (e.g., higher than a threshold temperature), the degree of enrichment richer than stoichiometric operation may be temporarily restored to a desired level or, alternatively, the engine load may be reduced to reduce the exhaust temperature.

[0060] Additionally or alternatively, at 426, adjusting the parameters includes reducing compression injection of fuel to the cylinder. Compression stroke injection can result in a larger fuel droplet size, making the injection more likely to adhere to the cylinder wall and generate more soot. Therefore, by reducing compression injection of fuel, soot formation can be reduced. For example, the split ratio of fuel directly injected into the cylinder in the compression stroke relative to fuel directly injected into the cylinder in the intake stroke can be retrieved, and in response to the increased soot level, the split ratio can be adjusted to deliver a greater portion of the total fuel in the intake stroke relative to the compression stroke. Delivering more fuel in the intake stroke can include increasing the pulse width of the intake stroke direct injection while reducing the pulse width of the compression stroke direct injection. In addition, as the pulse width of the intake stroke direct injection increases, the number of intake stroke direct injections can be increased. In addition, if the pulse width limit is reached, the split ratio of the fuel directly injected into the cylinder relative to the fuel injected into the cylinder by the intake port can be adjusted. For example, a larger portion of the total fuel amount may be delivered as port injection and a smaller portion of the total fuel amount may be delivered as direct injection. As another example, the controller may adjust the split ratio of fuel injection to the cylinders to reduce compression stroke fuel injection relative to intake stroke fuel injection while maintaining the combustion air-fuel ratio.

[0061] Additionally or alternatively, at 428, adjusting the parameter includes increasing fuel pressure. By increasing the fuel pressure, fuel atomization and vaporization are improved, thereby reducing fuel droplet size and improving fuel combustion. By selectively increasing the fuel pressure in response to elevated soot levels (rather than using elevated fuel pressure during all fuel injections), costs associated with maintaining elevated fuel pressure are reduced. For example, if a cylinder is operating at a lower than normal temperature (or cooler than other cylinders), and fuel atomization is insufficient to avoid soot formation, the fuel pressure may be temporarily increased to avoid excessive soot formation while only temporarily consuming the additional energy required to increase the fuel pressure.

[0062] Therefore, the ignition energy of the laser may not have much effect on soot formation. However, the ignition timing may be advanced (if retarded from MBT) to increase the combustion temperature.

[0063] In this way, the controller can start combustion in the cylinder by operating the laser ignition device; generate an in-cylinder image after operating the laser ignition device using light generated via cylinder combustion; display the generated image and a reference image to an operator on a vehicle display device; and then estimate the amount of smoke generated in the cylinder via combustion. If the exhaust temperature is below a threshold, the controller can reduce the richness of the combustion air-fuel ratio in the cylinder. In contrast, if the exhaust temperature is above a threshold, the controller can increase the richness of the combustion air-fuel ratio in the cylinder.

[0064] It should be understood that the various adjustments listed at 422 to 428 may also be applied in various combinations to provide synergistic benefits in further reducing smoke. As an example, increasing fuel pressure may further assist enrichment. For example, reducing enrichment (at 422) may generally increase exhaust temperature, while reducing compression injection (at 426) may reduce exhaust temperature. By performing these two actions, exhaust temperature may remain constant. Alternatively, reducing enrichment while keeping compression injection active may heat the exhaust more quickly when the exhaust is below a threshold temperature.

[0065] In some engine systems, such as those configured without a particulate filter, if the soot level remains above a threshold for an extended period of time (such as even after performing the above-described adjustments), the controller may set a diagnostic code to indicate excessive particulate matter generation. In response to setting the diagnostic code, engine output may be temporarily limited to reduce exhaust emissions.

[0066] In the above routine, the amount of smoke is estimated based on input received from the operator after display. However, it should be understood that although the above routine depicts the operator's need to analyze the generated (one or more) images and indicate whether excessive smoke generation has occurred, in alternative embodiments, the analysis can be automated. For example, after image capture, the image can be automatically displayed on the display device, and the corresponding reference image can also be automatically displayed on the display device. The controller can then automatically compare the images without operator input to determine whether excessive smoke has been generated. This determination can be based on the similarity of the images (i.e., the generated image and the reference image) via a simpler, less computationally intensive pixel comparison or the similarity of the images via an advanced, more computationally intensive image analysis.

[0067] It will be further understood that while the above routine suggests using a laser system coupled to an engine for diagnostic purposes, in an alternative example, a laser system including a laser exciter, lens, and photodetector can be configured as a mobile laboratory tool. Among other things, the laser system can be configured as a portable tool that can be coupled to any engine and used to analyze the engine.

[0068] In one example, an engine controller may operate a laser ignition device to initiate combustion in a cylinder and illuminate the interior of the cylinder; transmit an in-cylinder image of soot particles formed by the combustion generated after operating the laser ignition device to a vehicle display device, the image being generated by a photodetector of the cylinder using light generated by the combustion in the cylinder; and adjusting the fuel injection amount and pressure based on input received from an operator regarding a cylinder soot level relative to a threshold. Adjustment may include, for example, when the exhaust temperature is below a threshold temperature, in response to the cylinder soot level exceeding the threshold, reducing the fuel injection amount while operating the cylinder richer than the stoichiometric ratio; when the exhaust temperature is above the threshold temperature, in response to the cylinder soot level exceeding the threshold, increasing the fuel injection amount while operating the cylinder richer than the stoichiometric ratio. Adjustment may also include increasing fuel pressure. In addition, adjustment may include increasing a first split ratio of fuel injected directly in the intake stroke of the cylinder relative to fuel injected directly in the compression stroke of the cylinder; and reducing a second split ratio of fuel injected directly into the cylinder relative to fuel injected into the cylinder by the intake port. The controller may display on the vehicle display device a reference image selected based on the generated image, the reference image retrieved from a database of images previously generated via operation of the laser ignition device, wherein the input received from the operator is based on a comparison of the reference image relative to the generated image.

[0069] In this way, excessive cylinder soot generation can be identified in real time and quickly addressed. As a result, exhaust soot levels can be accurately controlled without relying on expensive soot sensors. By relying on images captured via components of the laser ignition system, the engine controller can adapt to any level of soot generation. In addition, exhaust soot levels can be maintained within thresholds without the need for closed-loop control. By comparing images of cylinder soot formation to reference images, soot detection can be automated. By using the laser of an existing laser ignition system to generate in-cylinder images, soot generation associated with each cylinder can be distinguished, allowing cylinder-specific fuel supply adjustments to be used to reduce further soot formation. Overall, exhaust emissions and engine performance can be improved.

[0070] An example method includes: adjusting cylinder fuel supply in response to an amount of soot generated in the cylinder, the amount estimated at a controller based on an image generated by a laser ignition device. In the foregoing examples, additionally or optionally, the image is an in-cylinder image, and wherein estimating the amount by the laser ignition device includes starting combustion in the cylinder by operating the laser ignition device; generating the in-cylinder image after operating the laser ignition device using light generated via cylinder combustion; displaying the generated image and a reference image to an operator on a vehicle display device; and estimating the amount of soot. In any or all of the foregoing examples, additionally or optionally, the method also includes selecting the reference image based on engine speed load conditions when the cylinder is burned. In any or all of the foregoing examples, additionally or optionally, the amount of soot is estimated based on input received from an operator after the display. In any or all of the foregoing examples, additionally or optionally, operating the laser ignition device includes operating the laser ignition device at a power above a threshold power required to illuminate only the cylinder to start cylinder combustion, and then switching to operating the laser ignition device at a power below the threshold power required to start cylinder combustion. In any or all of the foregoing examples, additionally or optionally, operating the laser ignition device includes directing laser pulses into the cylinder to scan the cylinder in a plane during each of the power stroke and the exhaust stroke of the cylinder. In any or all of the foregoing examples, additionally or optionally, directing the laser pulses begins after a threshold percentage of combustion phasing is completed. In any or all of the foregoing examples, additionally or optionally, the generated image is generated at a photodetector coupled to the laser ignition device, and wherein the reference image includes a reference image previously generated by the photodetector. In any or all of the foregoing examples, additionally or optionally, adjusting the cylinder fuel supply includes: if the exhaust temperature is below a threshold, reducing the richness of the combustion air-fuel ratio in the cylinder; and if the exhaust temperature is above a threshold, increasing the richness of the combustion air-fuel ratio in the cylinder. In any or all of the foregoing examples, additionally or optionally, adjusting the cylinder fuel supply also includes increasing the fuel injection pressure. In any or all of the foregoing examples, additionally or optionally, adjusting cylinder fueling includes adjusting a split ratio of fuel injected to the cylinder to reduce compression stroke fuel injection relative to intake stroke fuel injection while maintaining a combustion air-fuel ratio.

[0071] Another example method for an engine includes: operating a laser ignition device to initiate combustion in a cylinder and illuminate the interior of the cylinder; transmitting an in-cylinder image of soot particles formed by combustion generated after operating the laser ignition device to a vehicle display device, the image being generated by a photodetector of the cylinder using light generated by combustion in the cylinder; and adjusting the fuel injection amount and pressure based on input received from an operator regarding a cylinder soot level relative to a threshold. In the foregoing examples, additionally or optionally, the adjustment includes: when the exhaust temperature is below a threshold temperature, in response to the cylinder soot level exceeding the threshold, reducing the fuel injection amount while operating the cylinder richer than the stoichiometric ratio; and when the exhaust temperature is above the threshold temperature, in response to the cylinder soot level exceeding the threshold, increasing the fuel injection amount while operating the cylinder richer than the stoichiometric ratio. In any or all of the foregoing examples, additionally or optionally, the adjustment also includes increasing the fuel pressure. In any or all of the foregoing examples, additionally or optionally, the adjusting further comprises: increasing a first split ratio of fuel injected directly in an intake stroke of the cylinder relative to fuel injected directly in a compression stroke of the cylinder; and decreasing a second split ratio of fuel injected directly into the cylinder relative to fuel port injected into the cylinder. In any or all of the foregoing examples, additionally or optionally, the method further comprises displaying a reference image selected based on the generated image on a vehicle display device, the reference image retrieved from a database of images pre-generated via operation of the laser ignition device, wherein the input received from the operator is based on a comparison of the reference image relative to the generated image.

[0072] Another example hybrid vehicle system includes: an engine including a cylinder; a direct injector for supplying fuel to the cylinder; an electric motor; a display device in a cabin of the vehicle; a laser ignition system coupled to the cylinder head and configured to direct light pulses into the cylinder; a photoelectric detection system coupled to the laser ignition system and the cylinder for generating an image of the interior of the cylinder using light pulses from the laser ignition system, the photoelectric detection system including a camera and a lens; and a controller having a non-transitory memory and computer-readable instructions for the following operations: operating the laser ignition system during a compression stroke to initiate cylinder combustion; capturing an image within the cylinder at the photoelectric detection system during a power stroke and an exhaust stroke of the cylinder; comparing the generated image with a reference image retrieved from a memory of the controller; estimating an amount of soot generated during cylinder combustion based on the comparison; and in response to the estimated amount of soot exceeding a threshold, adjusting a pulse width commanded to the direct injector, the adjustment being based on exhaust temperature and a combustion air-fuel ratio. In the foregoing examples, additionally or optionally, the controller includes further instructions for: adjusting the output of the electric motor when operating the laser ignition system to maintain a defined engine speed and load while generating the in-cylinder image, and wherein the reference image is selected based on the defined engine speed and load. In any or all of the foregoing examples, additionally or optionally, adjusting the pulse width includes: when the exhaust temperature is below a threshold temperature and the combustion air-fuel ratio is richer than the stoichiometric ratio, in response to the estimated soot amount exceeding a threshold, reducing the commanded pulse width; when the exhaust temperature is above a threshold temperature and the combustion air-fuel ratio is richer than the stoichiometric ratio, in response to the estimated soot amount exceeding a threshold, increasing the commanded pulse width; and when the exhaust temperature is below a threshold temperature and the combustion air-fuel ratio is at the stoichiometric ratio, in response to the estimated soot amount exceeding a threshold, increasing the fuel pressure and reducing the commanded pulse width. In any or all of the foregoing examples, additionally or optionally, the controller includes further instructions for setting a diagnostic code and limiting engine torque output in response to an estimated soot level exceeding a threshold after adjusting a pulse width commanded to the direct injector.

[0073] Note 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-transitory memory and can be implemented by a control system including a controller combined 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. Therefore, 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 order of processing is not necessary 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, the described actions, operations, and / or functions can graphically represent the code in the non-transitory memory of a computer-readable storage medium to be programmed into the engine control system, wherein the described actions are implemented by executing instructions in a system including a combination of various engine hardware components and an electronic controller.

[0074] It will be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific embodiments should not be considered in a limiting sense, as many variations are possible. For example, the above-described technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0075] The accompanying claims particularly point out certain combinations and subcombinations deemed novel and non-obvious. These claims may refer to "an" element or "a first" element or their equivalent. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presenting new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are deemed to be included in the subject matter of the present disclosure.

Claims

1. A method comprising: A cylinder fuel supply is adjusted in response to an amount of soot generated in the cylinder, the amount of soot estimated at a controller based on an image generated by a laser ignition device, wherein adjusting the cylinder fuel supply includes adjusting a split ratio of fuel injection to the cylinder to reduce compression stroke fuel injection relative to intake stroke fuel injection while maintaining a combustion air-fuel ratio, thereby reducing the amount of soot generated in the cylinder, wherein the intake stroke fuel injection is an intake stroke direct injection and the compression stroke fuel injection is a compression stroke direct injection, and wherein adjusting the split ratio includes increasing a pulse width of the intake stroke direct injection while reducing a pulse width of the compression stroke direct injection until a pulse width limit of the intake stroke direct injection is reached, and then increasing a first portion of the total amount of fuel injected to the cylinder via port injection relative to a second portion of the total amount of fuel injected to the cylinder via the compression stroke direct injection and the intake stroke direct injection.

2. The method of claim 1 , wherein the image is an in-cylinder image, and wherein estimating the amount of soot by the laser ignition device comprises: initiating combustion in the cylinder by operating the laser ignition device; generating the in-cylinder image after operating the laser ignition device using light generated via the combustion in the cylinder; displaying the generated in-cylinder image and the reference image to an operator on a vehicle display device; as well as The smoke amount is estimated. 3 . The method of claim 2 , further comprising selecting the reference image based on engine speed load conditions during combustion in the cylinder. 4 . The method of claim 2 , wherein the smoke amount is estimated based on input received from the operator subsequent to the displaying.

5. The method of claim 2, wherein operating the laser ignition device comprises operating the laser ignition device at a power higher than a threshold power required to illuminate only the cylinder to initiate the combustion, and then transitioning to operating the laser ignition device at a power lower than the threshold power required to initiate cylinder combustion to illuminate the cylinder.

6. The method of claim 2, wherein operating the laser ignition device comprises directing laser pulses into the cylinder to planarly scan the cylinder during each of a power stroke and an exhaust stroke of the cylinder.

7. The method of claim 6, wherein the directing of the laser pulses is initiated after a threshold percentage of combustion phasing is completed.

8. The method of claim 2, wherein the generated image is generated at a photodetector coupled to the laser ignition device, and wherein the reference image comprises a reference image previously generated by the photodetector.

9. The method of claim 1 , wherein adjusting cylinder fuel supply comprises: if the exhaust temperature is below a threshold, reducing the richness of the combustion air-fuel ratio in the cylinder; as well as If the exhaust temperature is above the threshold, the richness of the combustion air-fuel ratio in the cylinder is increased.

10. The method of claim 9, wherein adjusting cylinder fuel supply further comprises increasing fuel injection pressure.

11. The method of claim 1 , wherein adjusting cylinder fuel supply comprises: reducing the amount of fuel injection while operating the cylinder richer than stoichiometry in response to a cylinder soot level exceeding a threshold soot level when the exhaust temperature is below a threshold temperature; and When the exhaust temperature is above the threshold temperature, the fuel injection amount is increased while operating the cylinder richer than stoichiometry in response to the cylinder soot level exceeding the threshold soot level.

12. A hybrid vehicle system comprising: An engine including a cylinder; a direct injector for supplying fuel to the cylinder; Electric motor; a display device in a compartment of the vehicle; a laser ignition system coupled to the cylinder head and configured to direct pulses of light into the cylinder; a photoelectric detection system coupled to the laser ignition system and the cylinder for generating an image of the interior of the cylinder using the light pulses from the laser ignition system, the photoelectric detection system comprising a camera and a lens; as well as A controller having a non-transitory memory and computer-readable instructions for: operating the laser ignition system to initiate cylinder combustion during a compression stroke; capturing in-cylinder images at the photoelectric detection system during a power stroke and an exhaust stroke of the cylinder; comparing the generated image to a reference image retrieved from a memory of the controller; estimating an amount of soot generated during combustion in the cylinder based on the comparison; as well as adjusting cylinder fuel supply in response to an estimated amount of soot, the amount of soot estimated at a controller based on an image generated by the laser ignition system, wherein adjusting the cylinder fuel supply includes adjusting a split ratio of fuel injection to the cylinder to reduce compression stroke fuel injection relative to intake stroke fuel injection while maintaining a combustion air-fuel ratio to reduce the amount of soot generated in the cylinder, wherein the intake stroke fuel injection is an intake stroke direct injection and the compression stroke fuel injection is a compression stroke direct injection, and wherein adjusting the split ratio includes increasing a pulse width of the intake stroke direct injection while reducing a pulse width of the compression stroke direct injection until a pulse width limit of the intake stroke direct injection is reached, and then increasing a first portion of the total amount of fuel injected to the cylinder via port injection relative to a second portion of the total amount of fuel injected to the cylinder via the compression stroke direct injection and the intake stroke direct injection.

13. The system of claim 12, wherein the controller further comprises instructions for: The output of the electric motor is adjusted when operating the laser ignition system to maintain a defined engine speed and load while generating the in-cylinder image, and wherein the reference image is selected based on the defined engine speed and load.

14. The system of claim 12, wherein adjusting cylinder fuel supply comprises: if the exhaust temperature is below a threshold, reducing the richness of the combustion air-fuel ratio in the cylinder; as well as If the exhaust temperature is above the threshold, the richness of the combustion air-fuel ratio in the cylinder is increased.

15. The system of claim 12, wherein adjusting cylinder fuel supply comprises: reducing the amount of fuel injection while operating the cylinder richer than stoichiometry in response to a cylinder soot level exceeding a threshold soot level when the exhaust temperature is below a threshold temperature; and When the exhaust temperature is above the threshold temperature, the fuel injection amount is increased while operating the cylinder richer than stoichiometry in response to the cylinder soot level exceeding the threshold soot level.

Images