Diagnostics based on a laser ignition system

Abstract

A method for a hybrid vehicle engine (20) comprising: Rotating the engine (20) by means of an electric motor (18) in response to an input from an operator (132) during selected non-combustion engine conditions in which the vehicle has been placed in a service mode, characterized in that the input from the operator (132) is a requested engine position including a requested piston position of a particular cylinder (30) of the engine (20).

Description

Area

[0001] The present application relates to methods and systems for diagnosing an engine using a laser ignition system. Background and Summary

[0002] Vehicle engines may require periodic service by a mechanic for diagnostic purposes. Diagnosis may include a visual inspection of engine components (e.g., to identify scoring (seizure) damage, camshaft alignment issues, etc.), rotating an engine to a selected position to identify component damage (e.g., to detect water hammer), and / or rotating an engine (e.g., to perform vacuum tests).

[0003] US 2001 / 0 009 147 A1 is known from the prior art. This describes an electronic control system for a hybrid vehicle, in which diagnostics are performed when the vehicle is started.

[0004] It has been recognized that some of the diagnostics can be time-consuming, costly, and laborious. For diagnostics sensitive to the position of the prime mover, small fluctuations in the prime mover position can significantly distort the diagnostic results. Furthermore, due to the compressive forces within the prime mover, it can be difficult to maintain the prime mover in a selected position.

[0005] Considering the above problems, the inventors have developed a method for a hybrid vehicle system that allows for accurate engine positioning for diagnostic purposes. In one example, the engine may be diagnosed by a method that includes rotating the engine using an electric motor in response to an operator input during selected non-combustion engine conditions in which the vehicle has been placed in a service mode. In this way, engine positioning may be improved, allowing the mechanic to reliably complete vehicle diagnostics.

[0006] In one example, a hybrid vehicle may be placed into a service mode during conditions when the engine is not combusting and the vehicle is not being driven. A mechanic may use a service diagnostic tool coupled to the vehicle to request the service mode. Thus, in this mode, the mechanic may perform one or more diagnostic tests, some of which may require a specific engine positioning. For example, certain diagnostic tests may require the piston of a particular cylinder to be in a specific position. The mechanic may select a diagnostic test to perform and request a specific engine position. In response to the request, an electric motor of the vehicle system, coupled to the engine via the drive system, may be operated.The engine can be rotated to the requested engine position by the electric motor. Furthermore, motor torque can be used to hold the engine in the requested position until the mechanic completes the diagnostic test. Upon completion, the mechanic can request a new position to perform another diagnostic test, operating the electric motor to rotate and reposition the engine. If no further tests or engine positioning requests are received, the vehicle can be taken out of service mode and returned to operation mode, where the vehicle can be driven.

[0007] In this way, an electric motor of a hybrid vehicle system can be used during a maintenance mode to contribute to engine positioning for diagnostic purposes. By operating the electric motor to rotate and maintain the engine in a specific position, the accuracy of engine positioning is improved and the reliability of position-sensitive diagnostics is increased. By using existing vehicle hardware to position the engine, the need for costly and complex diagnostic tools is eliminated. Overall, vehicle diagnostics can be simplified and performed in a time- and cost-efficient manner.

[0008] It should be understood that the above summary is provided to introduce, in a simplified form, a selection of the concepts further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that eliminate all of the disadvantages noted above or in any part of this disclosure. Brief description of the drawings Fig. 1 shows an exemplary hybrid vehicle system. Fig. 2 shows an exemplary internal combustion engine of the hybrid vehicle system according to Fig. 1. Fig. 3 shows an example of the emission of laser light pulses to an engine cylinder to enable visual inspection of an interior of the cylinder. Fig. Figure 4 shows a high-level flow diagram of a method for diagnosing cylinder degradation based on images of the cylinder interior generated by a photodetector during non-combustion conditions. Fig. 5 shows a high-level flow diagram of a method for adjusting an engine position based on operator input to enable engine diagnostics to be performed. Detailed description

[0009] Methods and systems are provided to enable the visual inspection of an engine cylinder of a hybrid vehicle using a laser ignition system of the engine, such as the systems of the Fig. 1-3. The laser ignition system ( Fig. 3) Low-power laser pulses emitted can be used to generate images of the interior of the cylinder. The images can then be displayed on a vehicle center console. An engine controller can be configured to execute a control routine, such as the routine described in Fig. 4, to operate the laser ignition device during non-combustion conditions in a diagnostic mode. The images generated by a photodetector of the laser ignition system can be displayed to a service provider (or a mechanic) on the center console and used by the service provider to detect cylinder damage. One or more center console buttons can be activated when operating in the diagnostic mode to perform engine position adjustments that enhance a view of the interior of the cylinder. In this way, engine diagnostics can be performed more quickly and at a lower cost. An engine controller can be configured to perform a maintenance routine, such as the routine after Fig. 5, to change the engine position during non-combustion conditions. In Service Mode, the operator can select a diagnostic test from a list of diagnostic test options located on the center console display. Consequently, selecting a diagnostic test activates an engine sensor that measures an initial engine position to move the engine to the requested engine position to execute the diagnostic test.

[0010] Fig. 1 schematically illustrates a vehicle with a hybrid propulsion system 10. The hybrid propulsion system 10 includes an internal combustion engine 20 coupled to a transmission 16. The transmission 16 may be a manual transmission, an automatic transmission, or combinations thereof. Furthermore, various additional components may be included, such as a torque converter and / or other transmissions, such as a final drive unit, etc. The transmission 16 is shown coupled to a drive wheel 14, which may be in contact with a road surface.

[0011] In this example embodiment, the hybrid propulsion system further includes an energy conversion device 18, which may include, among other things, a motor, a generator, and combinations thereof. The energy conversion device 18 is further shown coupled to an energy storage device 22, which may include a battery, a capacitor, a flywheel, a pressure vessel, etc. The energy conversion device is operable to absorb energy from the vehicle's motion and / or the engine and convert the absorbed energy into a form of energy suitable for storage by the energy storage device (in other words, to provide generator operation). The energy conversion device is also operable to provide an output (power, work, torque, speed, etc.) to the drive wheel 14 and / or the engine 20 (in other words, to provide motor operation).It should be appreciated that in some embodiments, the energy conversion device may include, among various other components, a motor, a generator, or both a motor and a generator used to provide the appropriate conversion of energy between the energy storage device and the drive wheels and / or the engine of the vehicle.

[0012] The illustrated connections between the engine 20, the energy conversion device 18, the transmission 16, and the drive wheel 14 may indicate the transfer of mechanical energy from one component to another, whereas the connections between the energy conversion device 18 and the energy storage device 22 may indicate the transfer of various forms of energy, such as electrical, mechanical, etc. For example, torque may be transferred from the engine 20 via a transmission 16 to drive the drive wheel 14 of the vehicle. As described above, the energy storage device 22 may be configured to operate in a generator mode and / or a motor mode. In a generator mode, the system 10 may absorb some or all of the output from the engine 20 and / or the transmission 16, which may reduce the amount of drive output delivered to the drive wheel 14.Furthermore, the output received by the energy conversion device can be used to charge the energy storage device 22. Alternatively, the energy storage device 22 can receive electrical charge from an external energy source 24, such as a power outlet to a power grid. In motor mode, the energy conversion device can provide a mechanical output to the engine 20 and / or the transmission 16, e.g., using the electrical energy stored in an electric battery.

[0013] Hybrid propulsion embodiments may include full hybrid systems in which the vehicle can run on only the engine, only the energy conversion device (e.g., the motor), or a combination of both. Assist or mild hybrid configurations may also be used, where the engine is the primary torque source, with the hybrid propulsion system acting to selectively supply additional torque, e.g., during pedal input or other conditions. Still further, a starter / generator and / or intelligent alternator systems may also be used.

[0014] From the above, it should be appreciated that the exemplary hybrid propulsion system is capable of various operating modes. In a first mode, for example, the engine 20 is turned on, acting as the torque source that drives the drive wheel 14. In this case, the vehicle is operated in an "engine-on" mode, wherein the engine 20 (the Fig. 2) is supplied with fuel from a fuel system 28. The fuel system 28 includes a fuel vapor recovery system 29 to store fuel vapors and reduce emissions from the propulsion system 10 of the hybrid vehicle.

[0015] In another mode, the drive system may operate using the power conversion device 18 (e.g., an electric motor) as the torque source that propels the vehicle. This "engine off" mode of operation may be used during braking, during low speeds, while stopping at traffic lights, etc. In yet another mode, which may be referred to as an "auxiliary" mode, an alternative torque source may supplement the torque provided by the power engine 20 and act in cooperation with the torque provided by the power engine 20. As indicated above, the power conversion device 18 may also operate in a generator mode, absorbing torque from the power engine 20 and / or the transmission 16.Additionally, the energy conversion device 18 may act to amplify or absorb torque during transitions of the engine 20 between different combustion modes (e.g., during transitions between a spark ignition mode and a compression ignition mode).

[0016] The above with reference to Fig. 1 may be controlled by a vehicle control system 41 including a controller 12 having computer-readable instructions for executing the routines and subroutines for controlling the vehicle systems, a plurality of sensors 42, and a plurality of actuators 44.

[0017] Fig. Figure 2 shows a schematic diagram of an example cylinder of a multi-cylinder internal combustion engine 20 used in a hybrid vehicle system, such as the hybrid vehicle according to Fig. 1. The engine 20 may be controlled at least in part by a control system including the controller 12 and by input from a vehicle operator 132 via an input device 130. In this example, the input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP.

[0018] The combustion cylinder 30 of the engine 20 may include combustion cylinder walls 32 within which a piston 36 is positioned. The piston 36 may be coupled to a crankshaft 40 such that reciprocating motion of the piston is translated into rotational motion of the crankshaft. The crankshaft 40 may be coupled to at least one drive wheel of a vehicle via an intermediate gear system. The combustion cylinder 30 may receive intake air via an intake passage 43 from an intake manifold 45 and may exhaust combustion gases via an exhaust passage 48. The intake manifold 45 and the exhaust passage 48 may be selectively communicated with the combustion cylinder 30 via an intake valve 52 and an exhaust valve 54, respectively. In some embodiments, the combustion cylinder 30 may include two or more intake valves and / or two or more exhaust valves.

[0019] In this example, intake valve 52 and exhaust valve 54 may be controlled by cam actuation via cam actuation systems 51 and 53, respectively. Cam actuation systems 51 and 53 may each include one or more cams and may utilize a cam profile shift (CPS) system, a variable cam timing (VCT) system, a variable valve timing (VVT) system, and / or a variable valve lift (VVL) system, which may be operated by controller 12 to vary valve operation. To enable cam position detection, cam actuation systems 51 and 53 should include gears. The positions of intake valve 52 and exhaust valve 54 may be determined by position sensors 55 and 57, respectively. In alternative embodiments, the intake valve 52 and / or the exhaust valve 54 may be controlled by electrical valve actuation. For example, the cylinder 30 may beB. alternatively include an intake valve controlled by electric valve actuation and an exhaust valve controlled by cam actuation including CPS and / or VCT systems.

[0020] Fuel injector 66 is shown coupled directly to combustion cylinder 30 for injecting fuel directly into it in proportion to the pulse width of signal FPW received from controller 12 via an electronic driver 68. In this manner, fuel injector 66 provides what is known as direct injection of fuel into combustion cylinder 30. The fuel injector may be mounted, for example, on the side of the combustion cylinder or in the top of the combustion cylinder. Fuel may be delivered to fuel injector 66 via a fuel delivery system (not shown) including a fuel tank, a fuel pump, and a fuel rail.In some embodiments, the combustion cylinder 30 may alternatively or additionally include a fuel injector disposed in the intake passage 43 in a configuration that provides what is known as port injection of fuel into the intake port upstream of the combustion cylinder 30.

[0021] Intake passage 43 may include a charge motion control valve (CMCV) 74 and a CMCV plate 72, and may also include a throttle plate 62 having a throttle plate 64. In this particular example, the position of the throttle plate 64 may be varied by the controller 12 via a signal provided to an electric motor or actuator included in the throttle plate 62, a configuration that may be referred to as electronic throttle control (ETC). In this manner, the throttle plate 62 may be operated to vary the intake air provided to the combustion cylinder 30 among the other engine combustion cylinders. In other embodiments, the CMCV may be omitted. Intake passage 43 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 to provide the MAF and MAP signals, respectively, to the controller 12.

[0022] An exhaust gas sensor 126 is shown coupled to the exhaust passage 48 upstream of a catalyst 70. The sensor 126 may be any suitable sensor to provide an indication of the exhaust air / fuel ratio, such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen sensor), a dual-state oxygen sensor or EGO, a HEGO (a heated EGO), a NO x -, HC, or CO sensor. The exhaust system may include light-off catalysts and underbody catalysts, as well as air / fuel ratio sensors upstream and / or downstream of the exhaust manifold. In one example, the catalyst 70 may include multiple catalyst modules. In another example, multiple emission control devices, each with multiple modules, may be used. In one example, the catalyst 70 may be a three-way catalyst.

[0023] The control 12 is in Fig. 1 as a microcomputer including 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 preserve memory 109, and a data bus.The controller 12 may receive various signals and information from sensors coupled to the engine 20, in addition to those signals previously discussed, including measurements of the inducted mass air flow (MAF) from the mass air flow sensor 120; the engine coolant temperature (ECT) from a temperature sensor 112 coupled to a cooling sleeve 114; a profile ignition response (PIP) signal from a Hall effect sensor 118 (or other type) coupled to the crankshaft 40, which may be optionally included in some examples; a throttle position (TP) from a throttle position sensor; and a manifold absolute pressure (MAP) signal from a barometric pressure sensor 122. The Hall effect sensor 118 may be optionally included in the engine 20, as it functions with a capability similar to the engine laser system described herein.The read-only memory chip 106 of the storage medium may be programmed with computer-readable data representing instructions executable by the processor 102 to perform both the methods described below and variants thereof.

[0024] The engine 20 further includes a laser system 92. The laser system 92 includes a laser exciter 88 and a laser control unit (LCU) 90. The LCU 90 causes the laser exciter 88 to generate laser energy. The LCU 90 can receive operating instructions from the controller 12. The laser exciter 88 includes a laser oscillation section 86 and a light converging section 84. The light converging section 84 converges the laser light generated by the laser oscillation section 86 into a laser focal point 82 of the combustion cylinder 30.

[0025] A photodetector 94 may be located in the top of the cylinder 30 as part of the laser and may receive the return pulses from the top of the piston 36. The photodetector 94 includes a camera with a lens. In one example, the camera is a charge-coupled device (CCD). The CCD camera may be configured to detect and read the laser pulses emitted by the LCU 90. In one example, if the LCU emits the laser pulses in an infrared frequency range, the CCD camera may operate in the infrared frequency range and receive the pulses in the infrared frequency range. In such an embodiment, the camera may also be referred to as an infrared camera. In other embodiments, the camera may be a full-spectrum CCD camera capable of operating in both the visible and infrared spectrum.The camera may include a lens to focus the detected laser pulses and create an image of the interior of the cylinder. In one example, the lens is a fisheye lens that creates a wide panoramic or hemispherical image of the interior of the cylinder. After laser emission from the LCU 90, the laser sweeps the interior of the cylinder 30 at the laser focal point 82. The light energy reflected from the piston 36 may be detected by the camera in the photodetector 94.

[0026] The laser system 92 is configured to operate with more than one capability. For example, during combustion conditions, the laser energy may be used to ignite the air / fuel mixture during an engine power stroke, including engine cranking, engine warm-up operation, and warm-up operation. The fuel injected by the fuel injector 66 may form an air / fuel mixture during at least a portion of an intake stroke, wherein igniting the air / fuel mixture with the laser energy generated by the laser exciter 88 initiates combustion of the otherwise non-combustible air / fuel mixture and drives the piston 36 downward.

[0027] As another example, during non-combustion conditions when operating in a diagnostic mode, the laser ignition device may be used to generate images of the interior of the cylinder. The images may be displayed to a mechanic on a vehicle's center console so they can perform a visual inspection and identify any cylinder deterioration. Specifically, the laser ignition device, coupled to photodetector 94, sends light pulses into cylinder 30. Photodetector 94 includes an infrared camera equipped with a fisheye lens that generates images that are wirelessly transmitted to an engine controller and viewed on the vehicle's display. While the laser ignition device is operating, an operator-controlled knob on the center console may adjust the engine position.These settings include rotating the engine forward or backward from an initial engine position, which further enables inspection and detection of cylinder degradation. As yet another example, during other non-combustion conditions, when operating in a piston determination mode, the laser pulses can be used to determine the position of a piston within the engine cylinder. This allows for a more accurate determination of the engine position.

[0028] The LCU 90 can direct the laser exciter 88 to focus the laser energy at different locations and at different power levels depending on the operating conditions. For example, during combustion modes, the laser energy can be focused at a first location remote from the cylinder wall 32 within the interior of the cylinder 30 to ignite an air / fuel mixture. In one embodiment, the first location can be near top dead center (TDC) of a power stroke. Further, the laser pulses used to initiate cylinder combustion in this ignition mode can have a higher power level.Further, the LCU 90 may direct the laser exciter 88 to generate a first plurality of laser pulses directed to the first location, wherein the first combustion from rest may receive laser energy from the laser exciter 88 that is greater than the laser energy delivered to the first location for subsequent combustions. Furthermore, during ignition, the laser device may be pulsed more rapidly with high energy intensity to ignite the air / fuel mixture.

[0029] As another example, during non-combustion conditions, laser energy can be used to identify the position of a cylinder's piston and thereby derive engine position. Accurate engine position determination can be used during engine start-up or restart to select a cylinder in which to initiate a first combustion event. During piston position determination, the laser device can sweep laser pulses at low energy intensity. For example, the laser can be frequency-modulated with a repeating linear frequency ramp to determine the position of one or more pistons in an engine. Photodetector 94, located in the top of the cylinder, can detect light energy reflected from the piston.An engine controller may determine the position of the piston in the cylinder based on a time difference between the emission of the laser pulse and the detection of the light reflected from the piston by the photodetector.

[0030] As yet another example, during non-combustion conditions while operating in a diagnostic mode, laser energy may be used to visually inspect the interior of the cylinder to identify engine degradation. The laser energy may be focused at multiple locations, such as from one end of the cylinder wall 32 across the entire interior of the cylinder 30 to another end of the cylinder wall 32 to sweep the entire cylinder. The laser device may sweep the cylinder at a high frequency with low-energy laser pulses. For example, the laser may be frequency-modulated with a repeating linear frequency ramp. Furthermore, different materials within the cylinder may be detected at different frequencies. By scanning as much of the cylinder as possible very quickly, the laser acts like a wide beam of light or a light bulb.The laser pulses used when operating in the diagnostic mode and the piston determination mode may have a lower power level than the laser pulses used when operating in the ignition mode. In one example, the power level of the laser pulses used in the diagnostic mode may be significantly lower than the power level of the laser pulses used in the ignition mode, such as a level that would not damage the eyes. The photodetector 94, located in the top of the cylinder, may detect the light energy reflected from the piston and the cylinder walls, and the photodetector's CCD camera may capture images of the interior of the cylinder using the light beam generated by the laser.The images can then be transmitted to and displayed to a vehicle operator who can identify cylinder deterioration based on the images.

[0031] The vehicle system 10 may include a vehicle instrument panel within a cabin of the vehicle. The vehicle instrument panel may include a center console 140. As such, the center console may be a control-supporting surface located in a central portion of the vehicle cabin, particularly in the front of the vehicle cabin. The center console 140 may include various controls, such as knobs 138, rotary switches 142, and buttons 136. The various controls may be operated by a vehicle operator to adjust cabin conditions. The various controls may, for example,a volume control knob 138 coupled to a music system of the vehicle for adjusting a volume of the music in the cabin, a tuning knob 136 coupled to a radio system of the vehicle for adjusting the channel selection of the radio, and a temperature control rotary switch 142 coupled to an HVAC system of the vehicle for adjusting the heating and cooling temperatures of the cabin.

[0032] The center console 140 may also include a display 135. The display may be a touch-sensitive display that allows the vehicle operator to select the vehicle's settings via touch interactions. The display may also be used to display the current vehicle settings. Furthermore, the display may be used to display a navigation system, such as GPS, telephone capabilities, or web applications accessed while traveling. During non-combustion conditions, when the laser ignition device is operating in a diagnostic mode, the display 135 is used to display images of the interior of the cylinder 30 captured by the photodetector 94 coupled to the laser detection system 92. Specifically, the images of the interior of the cylinder captured by a CCD camera of the laser detection system, e.g.,transmitted wirelessly to the engine control system and displayed on the display 135 of a vehicle operator (e.g., a mechanic). Based on the operator's display preference selected via touch interactions on the display, images of the internal cylinders of any or all cylinders may be displayed. Furthermore, during diagnostic mode, one or more of the knobs 138 may be enabled for engine position control (and disabled for cab control). During non-combustion conditions, for example, when operating in diagnostic mode, the volume control knob may be enabled for engine position control and disabled for volume control.Thus, the settings on the volume control knob 138 can 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 cylinder's piston is positioned at or near a top of the cylinder currently displayed on the display 135, obstructing a full view of the cylinder's interior. To improve the view, the vehicle operator can slowly rotate the volume control knob (e.g., clockwise or counterclockwise), which in turn moves the engine position (e.g., reverse or forward) so that the piston is slowly moved toward the bottom of the cylinder via the settings on a power-split generator / motor of the engine system.In embodiments where the engine includes a planetary gear set, the motor can hold the outer race motionless (which keeps the tire wheels motionless) while the generator (or sun gear) rotates the engine using feedback from any resolver of the generator position or using the 60-2 crank gear with the Hall-effect sensor position system for feedback of the actual engine position. This movement of the piston can allow the operator to receive images representing a more complete view of the interior of the cylinder, allowing them to perform a more detailed inspection. The improved view can allow the operator, for example, to inspect the cylinder walls for scoring damage.Furthermore, during diagnostic mode, the same volume control knob or an alternative knob, rotary switch, or center console button may be enabled to allow the image of the cylinder displayed on display 135 to be enlarged (e.g., zoomed in or out).

[0033] The controller 12 controls the LCU 90 and has a non-transitory computer-readable storage medium containing code to adjust the location of laser energy delivery based on temperature, e.g., ECT. The laser energy can be directed to different locations within the cylinder 30. The controller 12 may also include additional or alternative sensors for determining the operating mode of the engine 20, including additional temperature sensors, pressure sensors, torque sensors, and sensors that detect engine speed, air flow, and fuel injection flow. Additionally or alternatively, the LCU 90 may communicate directly with various sensors, such as the temperature sensors for detecting ECT, to determine the operating mode of the engine 20.

[0034] As described above, Fig. 1 only one cylinder of a multi-cylinder engine, where each cylinder may similarly contain its own set of intake / exhaust valves, fuel injector, laser ignition system, etc.

[0035] Fig. 3 illustrates an example embodiment 300 of how the laser system 92 (of Fig. 2) Emit laser pulses into the cylinder 30 so that a photodetector of the laser system can capture images of the interior of the cylinder. The images can be displayed to a vehicle operator to allow a visual inspection of the cylinder for damage. As such, the components that are included in the Fig. 1-2 have already been introduced, in Fig. 3 was not reintroduced.

[0036] Fig. 3 shows an example operation of the laser system 92, 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. The high-frequency laser pulses are directed to various locations within the cylinder to scan as much of the cylinder as possible. For example, the pulses 302 can be directed to the cylinder walls 315, the interior of the cylinder 30, the piston surface 313, and the inner surface of the valves 52 and 54 (i.e., the surface facing the cylinder). By scanning as much of the cylinder as quickly as possible, the laser pulse 302 acts as a wide-beam light source or incandescent lamp, allowing the photodetector 94 (specifically, the CCD camera) to capture images 320 of the interior of the cylinder.When the laser ignition system (or a laser device) as such operates as a light source for image acquisition during diagnostics, it may be considered to operate in a projector or illuminator mode, where the LCU 90 may receive operating instructions, such as a power mode, from the controller 12. When the laser system 92 operates in diagnostic mode, it emits a train of low-power pulses at a high frequency. During ignition, the laser may be rapidly pulsed at a higher energy intensity to ignite the air / fuel mixture. In one example, during diagnostic mode, the laser may be pulsed at the low energy level with frequency modulation having a repeating linear frequency ramp. The frequent, low-power laser pulses may be emitted in the infrared spectrum. A photodetection system including a CCD camera operating in the infrared spectrum (e.g.,An image sensor (e.g., an infrared CCD camera) with a fisheye lens may be located in the top of the cylinder as part of the laser and may capture cylinder images 320 using light reflected from the interior of the cylinder. The captured images may include images of the cylinder walls 315, the cylinder-facing surface of the intake and exhaust valves 52 and 54, the piston surface 313, and the interior of the cylinder 30. The captured images 320 are wirelessly transmitted by the photodetector 94 to the controller 12 for viewing on the display 135 in the center console 140 of the vehicle.

[0037] As discussed above, the low-power light pulses in the infrared (IR) spectrum may be emitted by the laser ignition device, with the CCD camera configured to operate in the IR spectrum. In alternative embodiments, the photodetector 94 has a full-spectrum CCD camera that can be tuned to match the frequency of the laser; thus, the camera can operate in the IR and other spectra of light (e.g., daylight or incandescent light) and has the ability to deactivate the laser if non-IR light is detected. In some examples, the position of the piston may obscure a full view of the interior of the cylinder in the displayed images 320 of the interior of the cylinder. When observing the images, the vehicle operator (e.g.,A service technician (e.g., a service technician or mechanic) may actively make adjustments to a piston position to better view the cylinder. During conditions where images 320 indicate, for example, that the piston is near a top of the cylinder (e.g., at the TCD), additional adjustments allow the engine to be slowly and precisely tuned to move the piston down toward the bottom of the cylinder. During diagnostic mode, one or more knobs, dials, or buttons on the vehicle's center console 140 may be enabled to allow control of the engine position, with operation of the knob, dial, or button operating a power-split generator / motor of the engine system to adjust the engine position.In the illustrated example, when the piston is near the top of the cylinder in view, the operator can adjust knob 138, located on the vehicle's center console 140, to rotate the engine forward or reverse from the initial engine position. If the engine is rotated backward from the initial engine position to move the piston downward, the controller can simultaneously open an engine intake throttle to reduce intake manifold expansion.

[0038] In Fig. 4, a routine 400 illustrates a method for diagnosing cylinder degradation based on images of the cylinder interior generated by a photodetector of a laser ignition system. The system acquires the images during non-combustion conditions for cylinder degradation diagnostic purposes. The method allows the engine to be visually inspected without removing any component from the cylinder, thus enabling further expedited and simplified diagnostic testing.

[0039] At 402, the method includes determining whether the vehicle is turned on. In the depicted example, the vehicle is a hybrid electric vehicle. In one example, a vehicle turn-on state may be confirmed based on a vehicle key-on event. If the vehicle is not turned on, at 414, the laser ignition is disabled. Upon confirming that the vehicle is turned on, at 404, the method includes estimating and / or inferring vehicle and engine operating conditions. These may include, for example, a driver torque request, vehicle speed, battery state of charge (SOC), engine speed, engine temperature, catalyst temperature, boost level, MAP, MAF, ambient conditions (temperature, pressure, humidity, etc.).As such, the vehicle's operating mode may be determined based on the vehicle's operating conditions. For example, if the driver demand is less than a threshold demand and the battery SOC is higher than a threshold charge level, the vehicle may operate in an electric mode (also referred to as an engine-off mode or a no-combustion mode), where the vehicle is propelled using power derived from the system electric motor and / or the battery. As an alternative example, if the driver demand is higher than the threshold demand and / or the battery SOC is lower than the threshold charge level, the vehicle may operate in an engine-on mode, where the vehicle is propelled using power derived from cylinder combustion in the engine.

[0040] Accordingly, at 406, the routine determines whether the vehicle is operating in engine-off mode (also referred to herein as a no-combustion mode). If not, then at 408, it may be confirmed that the vehicle is operating in engine-on mode (also referred to herein as a combustion mode). If the vehicle is in combustion mode at 408, then at 410, the laser ignition device is operated to deliver laser pulses at a higher power level into the cylinder to ignite the air-fuel mixture in the cylinder.

[0041] If at 406 the vehicle is in no combustion mode, then at 412 it may be determined whether a laser diagnostic mode has been selected. In one example, a diagnostic mode may be selected if the vehicle is on, in an auxiliary mode, and the transmission park pawl is in a "Park" position. The diagnostic mode may be selected at regular intervals of vehicle operation (e.g., after a threshold distance of vehicle operation or a threshold period of vehicle operation since a last diagnostic operation). Alternatively, the diagnostic mode may be actively selected by the vehicle operator via selections on the center console. If the diagnostic mode is not selected and the vehicle is operating in engine-off mode, the routine returns to 414 to disable the laser ignition device.

[0042] If the laser diagnostic mode is selected by the vehicle operator at 412, the routine proceeds to 416, where the laser ignition system is operated to deliver laser pulses in an infrared spectrum at a low power level into an interior of the cylinder to sweep the cylinder. As such, in diagnostic mode, the laser ignition system operates at a lower power level than the power level used during combustion conditions (at 410). Specifically, the laser ignition system frequently emits low-power laser pulses throughout the cylinder, effectively acting as a beam of light. In this way, the laser may be operated in a projector or illuminator mode during diagnostics. The beam of light generated by the laser pulses may be used by a photodetector coupled to the laser ignition system to capture images of the interior of the cylinder.The photodetector contains a camera and a light-converging lens. The photodetector can be, for example, an infrared camera (e.g., a CCD) with a fisheye lens to generate images of the interior of the cylinder using the light from the laser pulses.

[0043] At 418, the routine includes receiving images of the interior of the cylinder captured by the photodetector. In one example, the captured images are wirelessly transmitted within the engine system from the photodetector to the engine controller. At 420, the received images are displayed to a vehicle operator on the vehicle's center console (e.g., on a center console display device). The images may be displayed in a cylinder-specific manner. In one example, images captured of all engine cylinders may be displayed, and the vehicle operator may use touch interactions on the display or the center console buttons to select a single cylinder to view.Additionally, the operator can use the center console's buttons, knobs, or rotary switches, or other touch interactions with the display, to magnify the cylinder view (e.g., zoom in on the cylinder image in the view). Here, the vehicle operator may be a service technician or mechanic capable of diagnosing engine deterioration (e.g., cylinder wall scoring) based on the captured images.

[0044] At 422, the routine includes activating a vehicle operator-controlled knob for controlling engine position. As such, this allows a knob, such as a center console radio volume control knob, to be disabled for volume control and enabled for making adjustments to an engine position and, thereby, a position of the piston within the cylinder. The activated operator-controlled knob may be coupled to the engine via an electric motor-generator of the hybrid vehicle system during non-combustion conditions, such that a position of the piston within the cylinder is adjusted based on the vehicle operator's adjustments to the knob position.The vehicle operator can make position adjustments based on the images captured by the photodetector and displayed on the center console display. For example, if the captured images indicate that the cylinder's piston is located near the top of the cylinder in the view, obscuring a view of the cylinder walls and valves, the vehicle operator can slowly rotate the knob to tune the position of the engine, thereby fine-tuning the position of the piston to a position that provides a better view of the cylinder's interior. Adjusting the position of the piston within the cylinder may involve turning the knob to rotate the engine backward or forward from an initial engine position. The controller can make throttle position adjustments as needed based on the engine position tuning.For example, if the engine needs to be rotated backward from the initial position to bring the piston to the bottom of the cylinder, then at 422, while the engine is rotated backward, the controller may increase the intake throttle opening to decrease the intake manifold expansion.

[0045] The vehicle operator can diagnose a condition of the engine, including the condition of the cylinder walls and valves, based on the images displayed to the operator on the center console. Using the images captured by the photodetector as such, the operator may be able to visually inspect the interior of the cylinder and identify deterioration (such as valve damage or scoring). If deterioration is determined by the vehicle operator based on the captured images, the operator can provide this indication to the vehicle control system (e.g., by selecting a button on the center console). The engine control system can then set a diagnostic code based on the operator's input to indicate the engine deterioration.

[0046] In this way, during a first combustion state, a laser ignition device is operated to ignite an air-fuel mixture in the cylinder, while during a second non-combustion state, the laser ignition device is operated to diagnose an interior of the cylinder. Here, during the first state, the laser ignition device is operated at a higher power level, while during the second state, the laser ignition device is operated at a lower power level. A photodetector is coupled to the cylinder to detect the laser pulses from the laser ignition device. During both the first and second states, the laser ignition device can be operated to emit laser pulses in an infrared spectrum, and the photodetector can also be operated in the infrared spectrum.The photodetector uses the light from the laser pulses during the second state to capture images of the interior of the cylinder. An output of the photodetector (e.g., an image of the interior of the cylinder) may be transmitted to an engine controller and displayed to a vehicle operator on a center console of the vehicle. The engine may be coupled to a hybrid electric vehicle, where during diagnostics, an engine position may be actively changed by a vehicle operator (e.g., a mechanic) based on settings on a knob controlled by the operator. Here, the active change of the engine position by the knob may be enabled via an electric motor-generator of the hybrid electric vehicle. The controller may adjust a throttle position based on the change in the engine position. The throttle may, for example,be opened when the prime mover is rotated backwards from an initial position.

[0047] It is further recognized that in a third non-combustion state, the laser ignition device may be operated at the lower power level to determine the position of a piston in the cylinder for engine position control. The photodetector coupled to the cylinder may detect the reflection of an emitted laser pulse from the top of a piston. Based on a time period elapsed from the time the laser is emitted by the laser ignition device to the time the reflected laser pulse is detected by the photodetector, a controller may determine the piston position. The precise engine position information may be used during a subsequent engine restart to identify a cylinder in which to perform a first combustion event, thereby improving engine restart times.

[0048] In this way, a laser ignition device can be operated for diagnostic purposes during non-combustion conditions, and cylinder degradation can be indicated based on the output of a photodetector coupled to the cylinder. By operating the laser ignition device to act as a light source, a camera of the laser ignition system can be advantageously used to capture images of the interior of a cylinder. This allows a mechanic to perform a visual inspection of the engine at reduced cost and time.

[0049] In Fig.5, a routine 500 illustrates a method for adjusting an engine position based on operator input to enable engine diagnostics to be performed. The system enables an electric motor of the hybrid vehicle system to rotate the engine to a requested position based on operator input, allowing an operator to perform several diagnostic tests.

[0050] At 502, the method includes confirming that a service mode has been selected. A service mode may be confirmed during selected non-combustion conditions when a service mode has been selected by an operator. The operator may be a service technician or a mechanic who can diagnose a condition of the engine by performing one or more diagnostic tests. As such, the service mode may be selectable when the vehicle is not running, such as when the vehicle is parked with the engine off. Further, the service mode may represent a vehicle mode in which the vehicle components (e.g., the engine, transmission, battery, etc.) are diagnosed. In one example, the operator may provide operator input selecting the service mode via a service diagnostic tool coupled to the vehicle.Alternatively, the operator can provide operator input via a vehicle user interface (e.g., a touch-interactive display on the vehicle's center console or a button on the center console) that selects the maintenance mode. If no maintenance mode is requested, the routine ends.

[0051] Upon confirming the service mode request, the controller may place the vehicle into a service mode. In one example, in service mode, the controller may present the operator with multiple diagnostic test options on the center console display. The operator may have the ability to select a diagnostic test to perform (e.g., a diagnostic test to be performed first in a sequence of diagnostic tests) from multiple diagnostic test options presented on the user interface displayed on the vehicle's center console. The plurality of diagnostic tests displayed on the user interface may include, for example, a water seal test, a camshaft offset test, a visual inspection of the cylinders, etc.

[0052] At 504, the routine includes receiving an engine position request from the operator. The engine position request may be received from the operator via the service diagnostic tool. Alternatively, the engine position request may be received from the operator via the center console user interface. The engine position request may include a requested piston position of a specified engine cylinder.

[0053] In one example, the engine position request may include a specific engine position (e.g., a specific piston position in a specific engine cylinder) required to perform a specific diagnostic test. For example, the operator may select both a diagnostic test to perform (from the multiple options displayed by the controller) and an engine position at which to perform the selected diagnostic test. Here, the controller may receive the operator's diagnostic selection on the display, while also receiving operator input regarding an engine position request (e.g., via the user interface or via the service diagnostic tool). In an alternative example, the controller may be pre-programmed with the engine positions desired for the selected diagnostic tests. A controller lookup table may, for example,B. be filled with the data, which can be referenced by the controller in response to the operator's diagnostic selection. Here, the controller can only receive the operator's diagnostic selection on the display and can derive the engine position request based on the operator's diagnostic selection. For example, if a water seal test is selected by the operator, the controller can derive that the requested engine position in an R-4 (I-4) engine includes a piston of engine cylinder 2 positioned at the compression TDC so that the water seal test can be performed. Alternatively, the piston can be moved to the bottom of the cylinder, and the camera or detector can be used to look for fluid in the cylinder.The cylinder can be further checked for the presence of carbon deposits, a melted piston, or foreign objects.

[0054] At 506, the routine determines the initial engine position using a vehicle sensor. For example, the controller may receive an estimate of the initial engine position (including an estimate of the position of specific pistons of the specified cylinders) from an engine position sensor of the vehicle. Based on a difference between the initial engine position and the requested engine position, the routine includes, at 508, rotating the engine via an electric motor of the vehicle system to the requested engine position. Specifically, the electric motor (coupled to the engine along a driveline) is operated to rotate the engine from the measured initial engine position to the requested engine position.In one example, the electric motor's speed, torque, and / or power setting may be based on the difference between the measured initial engine position and the requested engine position, with the engine rotating faster when the difference is higher and the engine rotating slower when the difference is smaller. Once the engine itself is in the requested position, the selected diagnostic test may be initiated.

[0055] At 510, the routine determines whether the diagnostic test has completed. As such, input regarding completion of the diagnostic test may be received from the operator via the user interface. Once the selected diagnostic has been successfully completed by the operator, the operator may, for example, press a center console button, make a selection on the center console, or uncouple the service diagnostic tool from the vehicle to indicate that the test has been completed. If the test has not been completed, then at 512, the engine is maintained in the requested engine position via engine torque until operator input indicating completion of the diagnostic test is received. Specifically, the engine position is maintained in the requested position via engine torque to counteract compression forces that may be unbalanced.

[0056] It is recognized that while the routine suggests maintaining the prime mover position via the electric motor until the diagnostic test is completed, in alternative examples, the prime mover may not need to be maintained based on the type of test. For example, some tests may require precise pre-positioning but may not require the position to be held during the test. As one example, if the selected diagnostic test is a vacuum test, the prime mover may be rotated to a selected position, at which point the prime mover may be quickly rotated (e.g., via the motor) to assess the vacuum-generating potential of the prime mover.

[0057] If an input indicating that the diagnostic test is complete is received at 510, then at 514, it may be determined whether a new engine position request has been received from the operator. In one example, upon completion of the first, initial diagnostic test, the operator may proceed to execute a second, subsequent diagnostic test. Here, as at 504, the operator may select both the diagnostic test to be performed (from the remaining options displayed by the controller) and an engine position at which to perform the selected diagnostic test. Alternatively, the controller may receive the operator's new diagnostic selection on the display and may derive a new engine position request based on the operator's most recent diagnostic selection.In another example, upon completion of the diagnostic test, the operator may have completed the engine diagnostics and no further diagnostic tests need to be performed. At this point, the operator may press a center console button or make a selection on the center console to indicate that no further engine position adjustments are required.

[0058] If there is no new position request at 514 and the operator input indicates completion of all diagnostic tests, then at 518, in response to receiving no further engine position requests from the operator, the controller transitions the vehicle from the maintenance mode to a non-maintenance mode (or an operating mode). Specifically, the engine is rotated via the electric motor to a predetermined engine position (e.g., a predetermined engine position used for engine restart), transitioning the vehicle from the maintenance mode to an operating mode (e.g., a non-maintenance mode).

[0059] If at 514 the engine receives a new engine position request and / or another diagnostic test selection for a new diagnostic test from the operator, then at 516 the engine is rotated via the electric motor to the additional requested engine position. Motor torque from the electric motor is then used to maintain the engine in the requested position until the last selected diagnostic test is completed. Steps 510-516 are then continuously repeated based on operator input until the operator indicates that all tests have been completed and no further engine position adjustments are required. When all diagnostic tests are completed and no further engine position requests are received from the operator, the vehicle is returned to an operating mode.In this way, a service technician can advantageously use an electric motor of a hybrid vehicle system to precisely position an engine to perform engine diagnostics.

[0060] In one example, a hybrid vehicle system includes an engine including a cylinder with a piston. The engine is coupled to an electric motor and the drive wheels of the vehicle via a driveline. The vehicle system may include a center console, which may include a display for receiving operator input. The system may further include a sensor for measuring engine position and a controller for executing adjustments based on a selection of diagnostic tests by the operator. During non-combustion states of the engine, a service mode may be requested by the operator, and in response, the controller, comprising computer-readable instructions, may place the vehicle into a service mode. Once the vehicle is configured in the service mode, the display in the center console of the vehicle may present the operator with a plurality of selectable diagnostic test options.The operator may select a diagnostic test on the display, allowing the controller to receive an engine position request that includes a requested piston position of a specified engine cylinder. The controller may receive an initial engine position estimate from a vehicle sensor and may operate the electric motor to rotate the engine to the requested position. Operation of the electric motor may be based on a difference between the initial engine position estimate and the engine position request. After rotating the engine to the requested engine position, the engine may be maintained in the requested engine position while an operator-selected diagnostic test is completed.If further engine position requests and further diagnostic test selection inputs are received from the operator, the engine position will be readjusted accordingly until all diagnostic tests are completed. If no further engine position request is received from the operator, the controller returns the vehicle to a non-service mode.

[0061] In this way, engine diagnostics can be performed during selected non-combustion conditions using the hardware present in a hybrid vehicle with a laser ignition system. By operating a laser ignition device to provide light pulses that allow a photodetector to capture images of the interior of the cylinder, a visual inspection of the cylinder by a service technician can be performed in a cost- and time-efficient manner. Furthermore, by using the hybrid vehicle system's electric motor to precisely position an engine at selected engine positions, position-sensitive diagnostic tests can be performed more accurately and reliably. In this way, the quality of engine diagnostics performed by a service technician can be improved.

[0062] It should be noted that the example control and estimation routines included herein may be used with various engine and / or vehicle system configurations. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. As such, the various acts, operations, and / or functions illustrated may be performed in the illustrated order, performed in parallel, or, in some cases, omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description.One or more of the illustrated acts, operations, and / or functions may be performed repeatedly depending on the particular strategy employed. Furthermore, the described acts, operations, and / or functions may graphically represent code to be programmed into non-transitory memory of the computer-readable storage medium in the engine control system.

[0063] It is understood that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, as numerous variations are possible. For example, the above technique may be applied to V-6, R-4 (I-4), R-6 (I-6), V-12, horizontally opposed four, 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 characteristics disclosed herein.

[0064] The following claims particularly set forth certain combinations and subcombinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims should be understood to include the inclusion of one or more such elements and neither require nor exclude two or more such elements. Further combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by presenting new claims in this or a related application.Such claims, whether broader in scope than, narrower than, equal to, or different in scope from the original claims, are also considered to be included within the subject matter of the present disclosure.

Claims

[1] A method for a hybrid vehicle engine (20) comprising: Rotating the engine (20) by means of an electric motor (18) in response to an input from an operator (132) during selected non-combustion engine conditions in which the vehicle has been placed in a service mode, characterized by that the operator input (132) is a requested engine position including a requested piston position of a particular cylinder (30) of the engine (20). [2] The method of claim 1, wherein the operator (132) input is provided by the operator (132) using a service diagnostic tool coupled to the vehicle. [3] The method of claim 2, wherein the operator input (132) further includes a diagnostic test selected on a vehicle user interface displaying a plurality of diagnostic test options. [4] The method of claim 3, wherein the user interface includes a display (135) on a center console (140) of the vehicle. [5] The method of claim 4, further comprising measuring an initial engine position using a vehicle sensor, and wherein rotating the engine (20) using the electric motor (18) includes adjusting the electric motor (18) based on a difference between the requested engine position and the measured initial engine position. [6] The method of claim 5, further comprising maintaining the engine (20) in the requested engine position using engine torque until an operator input (132) indicating completion of the diagnostic test is received. [7] The method of claim 6, further comprising, in response to the operator (132) input indicating completion of the diagnostic test, placing the vehicle from the service mode into an operating mode. [8] A method for a hybrid vehicle engine (20) comprising: During a service mode of vehicle operation, measuring an initial engine position using a vehicle sensor; receiving an engine position request from an operator (132) using a service diagnostic tool coupled to the vehicle; and rotating the engine (20) to the requested engine position using an electric motor (18). [9] The method of claim 8, wherein rotating includes operating the electric motor (18) based on a difference between the initial engine position and the requested engine position to rotate the engine (20) from the initial engine position to the requested engine position. [10] The method of claim 9, wherein the requested engine position includes a requested piston position of a particular cylinder (30) of the engine (20). [11] The method of claim 9, wherein receiving an engine position request from the operator (132) includes receiving a diagnostic test selection from the operator (132) using the service diagnostic tool on a user interface of the vehicle displaying a plurality of diagnostic test options, and wherein the requested engine position is based on the diagnostic test selection. [12] The method of claim 9, further comprising maintaining the engine (20) in the requested engine position using engine torque until an operator input (132) indicating completion of the diagnostic test is received. [13] The method of claim 12, wherein the method further comprises, in response to receiving a further engine position request from the operator (132), rotating the engine (20) by means of the electric motor (18) to the further requested engine position and, in response to not receiving a further engine position request from the operator (132), rotating the engine (20) by means of the electric motor (18) to a default engine position and placing the vehicle from the maintenance mode to a non-maintenance mode. [14] Hybrid vehicle system comprising: an engine (20) including a cylinder (30) with a piston (36); an electric motor (18); a drive system that couples the engine (20) and the electric motor (18) to each other and drives wheels of the vehicle; a center console (140) including a display (135) for receiving input from an operator (132); a sensor for measuring an engine position; and a controller with computer-readable instructions for placing the vehicle in a maintenance mode during selected non-combustion conditions when a maintenance mode is requested by an operator (132); during maintenance mode, displaying several diagnostic test options for the operator (132) on the display (135) of the center console (140); receiving a diagnostic test selection of the operator (132) on the display (135); further receiving an input from the operator (132) regarding an engine position request via a service diagnostic tool; and Operating the electric motor (18) to rotate the prime mover (20) based on the prime mover position request. [15] The system of claim 14, wherein operating the electric motor (18) includes receiving an initial engine position estimate from the sensor and operating the electric motor (18) based on a difference between the initial engine position estimate and the engine position request. [16] The system of claim 15, wherein the controller (12) further includes instructions for maintaining the engine (20) in the requested engine position after rotating the engine (20) to the requested engine position while completing a diagnostic test based on the diagnostic test selection of the operator (132). [17] The system of claim 16, wherein the operator's (132) diagnostic test selection includes at least one of a water hammer test, a pressure test, a camshaft misalignment test, and a visual inspection of a cylinder (30). [18] The system of claim 17, wherein the controller (12) further includes instructions for: after completion of the diagnostic test, if no further engine position request is received from the operator (132), resuming a non-service mode; and if a further engine position request and a further diagnostic test selection are received from the operator (132), further rotating the engine (20) by means of the electric motor (18) based on the further engine position request and maintaining the engine position until a diagnostic test based on the further diagnostic test selection is completed. [19] The system of claim 14, wherein the engine position request includes a requested piston position of a particular cylinder (30) of the engine (20).

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