RU152800U1 - ENGINE POSITION CONTROL SYSTEM - Google Patents

Abstract

1. An engine system comprising: an engine cylinder; a laser ignition system attached to a cylinder; a laser ignition system includes a laser emitter and a laser detector; a first lower resolution time measurement circuit having a first, fewer circuit elements; a second time measurement circuit higher resolution, having a second, larger number of circuit elements; and a controller with computer-readable instructions for, before restarting the engine, operating the emitter to emit a laser pulse of lower energy into the cylinder; in response to emitting, starting each of the first and second time measurement circuits, detecting the emitted laser pulse following reflection from the cylinder piston; in response to detecting, stopping each of the first and second time measurement circuits; the logical derivation of the position of the piston in the cylinder based on the combined output of the first and second time measurement circuits. 2. The system according to claim 1, in which the controller includes additional instructions for, during engine restart, tuning the fuel supply and setting the ignition timing of the cylinder based on the inverted position of the piston in the cylinder. 3. The system of claim 2, wherein the controller includes additional instructions for, during engine restart, igniting the air-fuel mixture in the cylinder by operating the emitter to emit a laser pulse of higher energy into the cylinder. The system of claim 1, wherein the resolution of the second time measurement circuit is based on the second number of circuit elements, the resolution is increased

Description

This application is a partial continuation of the application for the grant of a US patent under serial number 13 / 689,601, filed November 29, 2012, the full contents of which are incorporated into the materials of this application by reference in all respects.

FIELD OF TECHNOLOGY

This application relates to methods and systems for accurately determining the position of an engine using a laser ignition system.

BACKGROUND

On vehicles with an electric hybrid drive (HEV) and vehicles with start-stop in particular, the internal combustion engine (ICE) may be muffled or shut down during selected conditions, such as during idle shutdown conditions. Engine silencing offers the benefits of fuel economy and lower emissions. However, during jamming or decommissioning, the crankshaft and engine camshafts may stop at unknown positions in the engine cycle. During a subsequent restart of the engine, in order to achieve a fast set of engine revolutions, accurate and timely knowledge of the position of the engine pistons is required in order to enable coordination of the setting of the ignition moment and fuel supply to the engine.

Methods for determining the position of pistons or an engine typically rely on a crankshaft timing wheel with a finite number of teeth and gaps to provide timing in coordination with camshaft measurements. One example of such a method is shown in US 7,765,980 an internal combustion engine and a method for operating an internal combustion engine by means of a laser ignition unit (publ. August 3, 2010), where the position of the crankshaft is identified by a crankshaft angle sensor.

However, the inventors in the materials of this application have recognized the problems with such approaches. As an example, depending on engine temperature, the time required to identify the position of the crankshaft relative to the position of the camshaft may vary. This inconsistency in determining the relative position between the camshaft and the crankshaft (in order to identify the position of the engine and pistons) can lead to a reduced ability to achieve and maintain fast synchronization, reliable combustion and reduced emissions. In addition, delays incurred in identifying the position of the engine, in this case, may delay the start of the engine, impairing the responsiveness of the vehicle. As another example, the above approach for determining the position of the piston may have a limited resolution, which leads to additional variability in the position of the engine.

ESSENCE OF A USEFUL MODEL

To solve the above problems of the prior art, in a first aspect of the present application for a utility model, an engine system is provided comprising: an engine cylinder; a laser ignition system attached to the cylinder; a laser ignition system includes a laser emitter and a laser detector; a first lower resolution time measurement circuit having a first, fewer circuit elements; a second higher resolution time measurement circuit having a second, larger number of circuit elements; and a controller with computer-readable instructions for: before restarting the engine, operating the emitter to emit a laser pulse of lower energy into the cylinder; in response to emitting, triggering each of the first and second time measurement circuits, detecting the emitted laser pulse following reflection from the cylinder piston; in response to detecting, stopping each of the first and second time measurement circuits; and inferring the position of the piston in the cylinder based on the combined output of the first and second time measurement circuits.

The system controller may include additional instructions for, during engine restart, adjusting fuel supply and setting the ignition timing of the cylinder based on the inverted position of the piston in the cylinder.

In addition, the system controller includes additional instructions for, during engine restart, ignition of the fuel-air mixture in the cylinder by operating the emitter to emit a laser pulse of higher energy into the cylinder.

The resolution of the second time measurement circuit is based on the second number of circuit elements, the resolution increases as the second number increases, and the range of the second time measurement circuit is based on the resolution of the first time measurement circuit.

In a second aspect of the present application, there is provided a method for an engine, comprising: operating a laser ignition device for supplying a laser pulse to a cylinder; and the cylinder piston position is inferred based on the time required for detecting the laser pulse, the required time is based on each of the first coarser time measurement circuit and the second more accurate time measurement circuit.

The said method further comprises adjusting the fuel supply and ignition of the cylinder during engine restart based on a logically inferred position.

In said method, the second time measurement circuit includes a plurality of circuit elements, and wherein, the resolution of the second time measurement circuit is based on the number of circuit elements in the second time measurement circuit.

In said method, the range of the second time measurement circuit is essentially the same as the resolution of the first time measurement circuit.

In said method, the required time based on each of the first coarser time measurement circuit and the second more accurate time measurement circuit includes the required time based on the sum of the output of the first time measurement circuit and the output of the second time measurement circuit.

Said method further comprises that, in response to the operation of the laser ignition device, each of the first time measurement circuit and the second time measurement circuit are started.

In the aforementioned method, the second time measurement circuit is started after a delay after the start of the first time measurement circuit.

In the aforementioned method, the delay is based on the output of the first time measurement circuit.

In the aforementioned method, the operation of the laser ignition device for delivering a laser pulse is that the laser ignition device is operated during a standstill of the engine and before the first combustion event of the engine restart.

In the aforementioned method, the operation of a laser ignition device for supplying a laser pulse consists in supplying a laser pulse having a lower power than the laser pulse supplied to the cylinder for igniting the fuel-air mixture in the cylinder.

In a third aspect of the present application, there is provided another method for the engine, comprising: adjusting the engine operating parameter during engine restart based on the recognized engine position, the engine position is based on the time required to detect the laser pulse emitted by the laser ignition device into the engine cylinder , the required time is based on each of the first scheme of a rougher time measurement and the second scheme of a less coarse time measurement.

In the other method, the recognition of the position of the engine based on the required time consists in determining the position of the piston and the cylinder stroke for each cylinder of the engine.

In said other method, setting the engine operating parameter is to adjust the fuel supply and setting the ignition timing of the cylinder based on the recognized position of the engine.

In said other method, adjusting an engine operating parameter is to select a cylinder for performing a first combustion event during engine restart based on a cylinder stroke.

In the other method, recognizing the position of the engine is to find out the position of the engine during the engine idle state, after the engine has been shut down during engine shutdown, and before the first combustion event during restart.

In the other method, the recognition of the position of the engine is that: in response to the emission of a laser pulse into the cylinder by a laser ignition device, each of the first and second time measurement circuits is started; in response to detecting the emitted laser pulse, each of the first and second time measuring circuit is stopped; converting the sum of the first time output data of the first time measurement circuit and the second time output data of the second time measurement circuit into a distance; and logically inferring the position of the piston in the cylinder and the stroke of the cylinder based on the distance.

Thus, in one exemplary approach, some of the problems indicated in the Prior Art section can be solved by a method comprising: operating a laser ignition device to deliver a laser pulse to the cylinder, and inferring the position of the cylinder piston based on the time required for detecting a laser pulse, the required time is based on each of the first scheme for a rougher time measurement and the second scheme for a more accurate time measurement. Thus, the existing laser ignition system can mainly be used to determine the position of the engine and pistons accurately and reliably.

As an example, an engine system may be configured with a laser ignition system. During non-combustion conditions, the laser ignition system can be operated to emit a low-power laser pulse inside the engine cylinder. The laser pulse can be reflected from the upper surface of the piston of the cylinder, and the reflected laser pulse can be detected by a photo detector of the laser ignition system. The laser ignition system may include two time measurement circuits for estimating the elapsed time between emitting a laser pulse and detecting a reflected laser pulse. Two time measuring circuits may have different numbers of circuit elements and different resolutions. For example, a system may include a first time measurement circuit having fewer circuit elements and lower resolution (e.g., in the nanosecond range), and a second time measurement circuit having a larger number of circuit elements and higher resolution (e.g., in the picosecond range ) Both time measurement circuits can be triggered when a laser pulse is emitted, and both circuits can stop when a reflected pulse is detected. The sum of the output of the two circuits can then be used to accurately determine the elapsed time. For example, combining the coarser output of the first time measurement circuit with the more accurate output of the second time measurement circuit can be used to recognize a more accurate estimate of the time required to detect a laser pulse. The algorithm can then convert the time value to a distance value to more accurately determine the position of the piston. Information about the position of the piston (for example, cylinder cycle information) can be used during subsequent engine restart to select the cylinder in which the first combustion event should be triggered.

Thus, numerous time measuring circuits can be connected to a laser ignition system to provide faster and more accurate information about position, engine / piston speed, etc. By earlier identifying such information during cranking of the engine (or even before cranking), and with a higher degree of resolution, the position of the piston can be determined more accurately and with higher reliability. By using higher resolution piston position information to select a cylinder for an initial combustion event, engine restart can be improved.

It should be clear that the essence of the utility model given above is provided to familiarize yourself with the simplified form of the selection of concepts that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter of a utility model, the scope of which is uniquely determined by the utility model formula, which is attached to the detailed description. Moreover, the claimed subject matter of the utility model is not limited to implementations that resolve any of the drawbacks noted above or in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic illustration of an exemplary hybrid vehicle.

FIG. 2 shows a circuit diagram of an exemplary internal combustion engine.

FIG. 3 shows a circuit diagram of an example engine cylinder.

FIG. 4 shows an exemplary four-cylinder engine stopped at an arbitrary position in its driving cycle.

FIG. 5 shows an exemplary multidimensional characteristic of setting valve distribution phases and piston position relative to engine position during an exemplary engine cycle for a direct injection engine.

FIG. 6 shows an exemplary multidimensional characteristic of setting valve distribution phases and piston position relative to engine position during an exemplary engine cycle for a windowed fuel injection engine.

FIG. 7 shows an exemplary method for adjusting engine operation based on a vehicle operating mode and idle shutdown conditions.

FIG. 8 shows an example method for starting or restarting an engine during operation of an example vehicle driving cycle.

FIG. 9 shows an exemplary method for operating a laser engine ignition system to determine engine position.

FIG. 10 shows an exemplary method for inferring the position of a piston based on an output signal of multiple different resolution time measurement circuits.

FIG. 11-12 and 13 show exemplary embodiments of time measuring circuits of a time detection system that can be coupled to the laser ignition system of FIG. 2-3.

FIG. 14-15 show exemplary block diagrams of embodiments of a method for using the multiple time measuring circuits of FIG. 11-12 to determine the position of the piston.

DETAILED DESCRIPTION

Methods and systems are provided to improve the accuracy of determining the position of the piston, thereby improving the engine starting efficiency in a hybrid vehicle, such as the vehicle of FIG. 1. In particular, piston position determination can be achieved earlier and with a higher resolution in the engine start sequence using a laser ignition system, such as the system of FIG. 2-4. The controller may perform a control procedure, such as the example procedures of FIG. 7 to 10, for operating the laser ignition system in a higher power mode for igniting a fuel-air mixture when combustion in a cylinder is required, and in a lower power mode for determining the position of a cylinder piston when combustion in a cylinder is not required. The inferred piston position can be used by the controller to select the cylinder in which the first combustion event should be triggered during engine restart. FIG. 5-6 show multidimensional characteristics of the position of the piston and the installation of the valve distribution phases for engines with direct injection and window injection, respectively. FIG. 11-12 and 13 depict exemplary time resolution patterns of differing resolution that can be coupled to a laser ignition system to determine the position of the piston. The output of the time measurement circuits can be combined, and the combined output value can be converted to a distance value using appropriate algorithms to accurately and reliably determine the position of the piston in the cylinder, as shown in FIG. 10 and 14-15. By increasing the accuracy of determining the position of the piston, the ability to restart the engine is improved.

With reference to FIG. 1, the figure schematically depicts a vehicle with a hybrid power plant 10.

The hybrid propulsion system 10 includes an internal combustion engine 20 connected to a transmission 16. The transmission 16 may be a manual transmission, an automatic transmission, or a combination thereof. In addition, various optional components, such as a torque converter, and / or other gears, such as a final drive link, etc., may be included. A transmission 16 is shown attached to a drive wheel 14, which may be in contact with a road surface.

The engine 20 may be configured for laser ignition, as specified in FIG. 2. More precisely, the engine 20 may include a laser ignition system with a laser emitter configured to emit higher power laser pulses into the engine cylinder during combustion conditions, thereby igniting the fuel-air mixture in the cylinder. The laser emitter can also be used during non-combustion conditions (for example, when the engine is shut down) to emit a laser pulse of lower power inside the cylinder. A laser pulse of lower power can subsequently be detected by a laser ignition system detector. The time elapsed between the emission and detection of a laser pulse can be used to accurately determine the position (e.g., cylinder stroke) of the piston in each cylinder. The piston position information can then be used to select the engine cylinder to initiate combustion when the engine is subsequently resumed. The engine 20 may include a time detection system 14 for accurately determining the time required for a laser pulse to be detected. As specified with reference to FIG. 3 and 11-12, the time detection system 14 may include a plurality of time measuring circuits, each time measuring circuit includes a different number of circuit elements, and therefore, a different resolution. By combining the time output of the first circuit with a coarser time measurement with the time output of the second circuit with a more accurate time measurement, the time elapsed between the emission and detection of the laser pulse can be determined more accurately (for example, in the picosecond range).

In the exemplary embodiment of FIG. 1, the hybrid propulsion system also includes an energy conversion device 18, which, among other things, may include an electric motor, a generator, and combinations thereof. The energy conversion device 18 is further shown connected to an energy storage device 22, which may include a battery, a capacitor, a flywheel, a high pressure cylinder, etc. The energy conversion device may be driven to absorb energy from the movement of the vehicle and / or 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 can also be driven to supply output power (power, work torque, speed, etc.) to the drive wheel 14 and / or motor 20 (in other words, to provide electric motor operation). It will be appreciated that the energy conversion device, in some embodiments, may include an electric motor, a generator, or both, an electric motor and a generator, among various other components used to ensure proper energy conversion between the energy storage device and drive wheels, and / or vehicle engine.

The connections shown 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, while the connections between the energy conversion device 18 and the energy storage device 22 may indicate the transfer of a variety of forms of energy, such like electrical, mechanical, etc. For example, torque can be transmitted from the engine 20 to drive the drive wheel 14 of the vehicle via a transmission 16. As described above, the energy storage device 22 may be configured to operate in a generator mode and / or an electric motor mode. In generator mode, system 10 can absorb some or all of the output power from engine 20 and / or transmission 16, which can reduce the amount of drive output power supplied to drive wheel 14. In addition, the output power received by the energy conversion device can be used to charging the energy storage device 22. Alternatively, the power storage device 22 may receive an electric charge from an external power source 24, such as a plug connection for a power source. In electric motor mode, the energy conversion device can supply mechanical output to the engine 20 and / or transmission 16, for example, using electrical energy stored in an electric battery.

Embodiments with a hybrid propulsion system may include fully hybrid systems in which a vehicle can only be driven by an engine, only an energy conversion device (eg, an electric motor), or a combination of the two. Auxiliary or moderate hybrid configurations may also be used in which the engine is the main source of torque with a hybrid power plant operating to selectively provide additional torque, for example, during an increase in engine load at a constant speed or other conditions. In addition, starter / alternator and / or alternator systems with advanced logic can also be used.

From the above, it should be clear that an exemplary hybrid powerplant is capable of various modes of operation. For example, in the first mode, the engine 20 is turned on and acts as a source of torque driving the drive wheel 14. In this case, the vehicle is operated in “on engine” mode and fuel is supplied to the engine 20 (shown in more detail in FIG. 2) from the fuel system 100. The fuel system 100 includes a fuel vapor recovery system 110 for accumulating fuel vapor and reducing emissions from a hybrid vehicle power plant 10.

In another mode, the power plant may operate using an energy conversion device 18 (eg, an electric motor) as a source of torque driving the vehicle. This “engine off” mode can be applied during braking, low speeds, while stopping at traffic lights, etc. In yet another mode, which may be referred to as an “assist” mode, an alternate torque source can complement and act in conjunction with the torque provided by the engine 20. As indicated above, the energy conversion device 18 can also operate in a generator mode in which torque is absorbed from the engine 20 and / or transmission 16. Moreover, the energy conversion device 18 may act to amplify or absorb torque during the transitions of the engine 20 between different Combustion Mode (e.g., during a transition between spark ignition mode and compression ignition mode).

The various components described above with reference to FIG. 1 can be controlled by a vehicle control system 41, which includes a controller 12 with computer-readable instructions for executing programs and routines for regulating vehicle systems, a plurality of sensors 42, and a plurality of actuators 44. Various procedures and subroutines are discussed below.

FIG. 2 shows a circuit diagram of an example cylinder of a multi-cylinder internal combustion engine 20. The engine 20 may be controlled, at least in part, by a control system including a controller 12, and input signals from the vehicle driver 132 through the 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.

The combustion cylinder 30 of the engine 20 may include walls 32 of the combustion cylinder with a piston 36 located therein. The piston 36 may be coupled to the crankshaft 40 so that the reciprocating motion of the piston is converted into rotational motion of the crankshaft. The crankshaft 40 may be coupled to the at least one drive wheel of the vehicle via an intermediate transmission system. The combustion cylinder 30 may receive intake air from the intake manifold 45 through the inlet channel 43 and may release gaseous products of exhaust gas combustion through the exhaust channel 48. The intake manifold 45 and the exhaust channel 48 may selectively communicate with the combustion cylinder 30 through the respective intake valve 52 and exhaust valve 54. In some embodiments, the combustion cylinder 30 may include two or more intake valves and / or two or more exhaust valves.

In this example, the intake valve 52 and exhaust valve 54 can be controlled by actuating the cams through respective cam drive systems 51 and 53. Each of the cam drive systems 51 and 53 may include one or more cams and may use one or more of a cam profile changeover (CPS), cam phase adjustment (VCT), variable valve timing (WT) and / or adjustable valve lift (WL), which can be controlled by a controller 12 to change the operation of the valves. To enable cam position detection, cam drive systems 51 and 53 must have gears. The position of the intake valve 52 and exhaust valve 54 may be detected by position sensors 55 and 57, respectively. In alternative embodiments, the inlet valve 52 and / or the exhaust valve 54 may be controlled by driving an electromagnetic control valve. For example, cylinder 30, alternatively, may include an inlet valve controlled by actuating a solenoid valve, and an exhaust valve controlled through a cam drive including CPS and / or VCT systems.

The fuel injector 66 is shown connected directly to the combustion cylinder 30 for injecting fuel directly into it in proportion to the pulse width of the FPW signal received from the controller 12 through the electronic driver 68. Thus, the fuel injector 66 provides what is known as direct fuel injection into the cylinder 30 combustion. A fuel nozzle, for example, can be mounted on the side of the combustion cylinder or on top of the combustion chamber. Fuel may be supplied to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel dispenser rail. In some embodiments, the combustion cylinder 30, alternatively or additionally, may include a fuel nozzle arranged in the inlet channel 43 in a configuration that provides what is known as injecting fuel into the inlet upstream of the cylinder 30 combustion.

The inlet 43 may include a charge control valve (CMCV) 74 and a CMCV damper 72, and may also include a throttle 62 having a throttle valve 64. In this particular example, the position of the throttle valve 64 may be controlled by the controller 12 by means of signals issued to an electric motor or actuator included by inductor 62, a configuration that may be referred to as an electronic inductor control (ETC). Thus, the throttle 62 may be actuated to regulate the intake air discharged into the combustion cylinder 30, among other combustion cylinders of the engine. The inlet channel 43 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 for providing respective MAF and MAP signals to the controller 12.

An exhaust gas sensor 126 is shown connected to an exhaust channel 48 upstream of the exhaust gas catalyst 70. Sensor 126 may be any suitable sensor for reading the fuel / air ratio in the exhaust gas, such as a linear oxygen sensor or UEGO (universal or wide-range oxygen sensor for exhaust gases), a dual-mode oxygen sensor or EGO, HEGO (heated EGO), content sensor NO _x , HC, or WITH. The exhaust system may include ignition catalytic converters and catalytic converters of the bottom of the body, as well as an exhaust manifold located upstream and / or downstream of the fuel-air ratio sensors. The catalytic converter 7 0 of the exhaust gas may include multiple converter units in one example. In yet another example, multiple emission control devices may be used, each with multiple briquettes. The catalytic converter 70 of the exhaust gas, in one example, may be a three-way catalytic converter.

Controller 12 is shown in FIG. 2 as a microcomputer including a microprocessor unit 102, input / output ports 104, an electronic storage medium for executable programs and calibration values, shown as a read-only memory chip 106 in this particular example, random access memory 108, standby memory 109, and data bus. The controller 12 may receive various signals and information from sensors connected to the engine 20, in addition to those signals discussed previously, including the measurement of input mass air flow (MAF) from the mass air flow sensor 120; engine coolant temperature (ECT) from a temperature sensor 112 connected to the cooling pipe 114; in some examples, a Profile Ignition Reading (PIP) signal from a Hall effect sensor (or other type) 118 connected to the crankshaft 40 may optionally be included; throttle position (TP) with throttle position sensor; and an absolute manifold pressure signal, MAP, from sensor 122. The Hall effect sensor 118 can optionally be included in engine 20 because it operates in a working volume similar to the laser engine system described herein. The read-only memory device 106 of the storage medium may be programmed with computer-readable data representing instructions executed by the processor 102 to perform the methods described below, as well as their variants.

The engine 20 further includes a laser ignition system 92. The laser ignition 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 operational instructions from the controller 12. The laser driver 88 includes a laser pumping portion 86 and a radiation information portion 84. The radiation conducting part 84 reduces the laser radiation generated by the laser pumping part 86 at the focal point 82 of the laser of the combustion cylinder 30.

The laser ignition system 92 is configured to operate in more than one working volume, with the synchronization of each operation based on the position of the engine in a four-cycle combustion cycle. For example, laser radiation energy can be used to ignite the fuel / air mixture during the engine’s operating cycle, including while cranking the engine, the operation of warming up the engine and the operation of the warm engine. When used to ignite a fuel-air mixture in a cylinder, the laser ignition system can be operated in a higher power mode with the emission of laser pulses of higher energy intensity. The fuel injected by the fuel injector 66 may form a fuel / air mixture during at least a portion of the intake stroke, where the ignition of the fuel / air mixture by the laser radiation generated by the laser driver 88 causes the combustion of the otherwise non-combustible fuel / air mixture and forces piston 36 down.

As another example, the laser ignition system 92 can be used to determine the position of the piston in the cylinder during conditions when the engine is out of operation and combustion in the cylinders does not occur. When used to determine the position of the piston, the laser ignition system can be operated in a lower power mode with the emission of laser pulses of lower energy intensity. A time detection system 14 including at least a first lower resolution time measuring circuit and a second higher resolution time measuring circuit can be connected to a laser ignition system and can be used to accurately estimate the time elapsed after a laser pulse is emitted by a laser the emitter, and detecting the laser pulse accompanying the reflection from the upper surface of the piston of the cylinder by the detector 94. The output of the time measuring circuits can transform Use the distance value to accurately identify the position of the piston.

The LCU 90 may control the laser driver 88 to focus the laser energy at different locations depending on operating conditions. For example, laser energy can be focused at a first location away from the cylinder wall 32 within the interior of the cylinder 30 in order to ignite the fuel / air mixture. In one embodiment, the first location may be near the top dead center (TDC) of the work cycle. In addition, the LCU 90 may direct the laser driver 88 to generate a first plurality of laser pulses directed to the first location, and the first combustion from the rest state can receive laser energy from the laser driver 88, which is greater than the energy laser radiation emitted to a first location for later burnings.

The controller 12 controls the LCU 90 and has a non-removable computer-readable storage medium including a computer program for adjusting the location of the laser energy supply based on temperature, for example, ECT. Laser energy can be directed to different locations within the cylinder 30. The controller 12 can also include additional or alternative sensors to determine the operating mode of the engine 20, including additional temperature sensors, pressure sensors, torque sensors, as well as sensors that reveal the engine speed, the amount of air and the amount of fuel injection. Additionally or alternatively, the LCU 90 may communicate directly with various sensors, such as temperature sensors to detect ECT, to determine the operating mode of the engine 20.

As described above, FIG. 2 shows only one cylinder of a multi-cylinder engine, and each cylinder may likewise include its own set of intake / exhaust valves, fuel injector, laser ignition system, etc.

FIG. 3 illustrates how the laser system 92 can emit pulses in the direction of the piston 36 in the cylinder 30 described above with reference to FIG. 2. The pulses emitted by the laser system 92, for example, the pulse 302 shown in FIG. 3 can be directed towards the upper surface 313 of the piston 306. The pulse 302 can be reflected from the upper surface 313 of the piston, and a reverse pulse, for example, a pulse 304, can be received by a laser system 92, which can then be used to determine the position of the piston 36 inside the cylinder. The pulses emitted by the laser system 92 may have different energies, which are the result of different laser power modes. For example, laser pulses emitted when the laser device is operated in a higher power mode or ignition mode can have higher energies, while laser pulses emitted when the laser device is operated in a lower power mode or detection mode positions may have lower energies. A laser ignition system with multiple operating modes offers particular advantages since the laser can be driven in high power mode to ignite the fuel / air mixture or in low power mode to control the position, speed, etc. of the piston.

FIG. 3 shows an example operation of a laser system 92, which includes a laser driver 88, a detection system 94 and an LCU 90. The LCU 90 causes the laser driver 88 to generate laser radiation, which can then be directed to the upper surface 313 of the piston 36 as shown in 302. LCU 90 can receive operational instructions, such as power mode, from controller 12. If the fuel / air mixture is not ignited at high power, laser system 92 can emit a low power pulse and to accurately measure the distance from the top of the cylinder to the piston. For example, during ignition, the laser pulse used can undergo rapid pulsation with high energy intensity to ignite the fuel / air mixture. Conversely, during the determination of the position of the piston, the laser pulse used can swing the frequency with low energy intensity to determine the position of the piston. For example, a frequency modulated laser with a periodically repeating ramp can be used to determine the position of one or more pistons in an engine. The detection sensor 94 may be located in the upper part of the cylinder as part of the laser and may receive a return pulse 304 reflected from the upper surface 313 of the piston 36. After emitting laser radiation, the light energy that is reflected from the piston can be detected by the sensor.

The time difference between the emission of the laser pulse and the detection of the reflected pulse by the detector can be determined by the time detection system 14 connected to the LCU. A time detection system may include time measuring circuits that start when a laser pulse is emitted and stop when a laser pulse is detected. Numerous time measurement circuits can be configured with a different number of circuit elements, which thereby affect the resolution of the circuit. For example, a time measurement circuit with a large number of circuit elements and a higher resolution can give an estimate of the time in the picosecond time range, while a time measurement circuit with a smaller number of circuit elements and a lower resolution can give an estimate of the time in the nanosecond time range. By combining the output of the two circuits, more accurate time output can be obtained, which can then be converted to a more accurate distance value using one or more time to distance conversion algorithms.

In alternative examples, the location of the piston may be determined by modulating the frequency f using frequency modulated laser beams with a periodically repeating ramp. Alternatively, phase shift methods may be used to determine the distance. For example, by detecting a Doppler shift or by comparing model positions at two different points in time, information about the position, piston speed, and engine speed (RPM measurement) can be logically displayed. The position of the intake valve 52 and exhaust valve 54 can then be detected by position sensors 55 and 57, respectively, in order to identify the actual position of the engine. Once the position and / or speed of each piston in the engine has been determined, the controller, for example, controller 12, can process information to determine the positional state or operation of the engine. Such positional states of the engine, based on the positions of the pistons determined by the lasers, can further be based on the geometry of the engine. For example, the positional state of an engine may depend on whether the engine is a V-engine or an in-line engine. Signals of the relative position of the engine indicate that the engine has been synchronized. In addition, system information can also be used to determine crank angle and cam position in order to find information for TDC and bottom dead center (BDC) for each piston in the engine.

For example, the controller 12 may control the LCU 90 and may include a permanent computer-readable storage medium including a control program for adjusting the location of the laser energy supply based on operating conditions, for example, based on the position of the piston 36 relative to TDC. Laser energy can be directed to different locations within the cylinder 30, as described below with reference to FIG. 4. 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, as well as sensors that detect the engine speed, air amount and injection amount fuel as described above with reference to FIG. 2. Additionally or alternatively, the LCU 90 can directly communicate with various sensors, such as Hall effect sensors 118, to determine the operating mode of the engine 20.

In some examples, the engine system 20 may be included in a vehicle designed to perform an idle shutdown when the idle shutdown conditions are met, and automatically restart the engine when the restart condition is satisfied. Such idle shutdown systems can increase fuel economy, reduce exhaust emissions, noise, and the like. In such engines, engine operation may be stopped at an arbitrary position within the driving cycle.

At the beginning of the process to resume engine operation, the laser system can be used to determine the specific position of the engine. Based on this assessment, the laser system can determine which cylinder should be first supplied with fuel in order to start the process of restarting the engine from a standstill. In vehicles configured to perform idle shutdown operations in which engine stops and restarts are repeated many times during the driving operation, stopping the engine at the desired position may include starts with higher repeatability, and thus the laser system can be used to measure engine position during shutdown (after deactivation of fuel injection, spark ignition, etc.), while the engine stops rotation to the state of oya, so that the torque of the motor or other resistance torque can be variably applied to the motor in response to the engine stop position control to the desired stop position.

In yet another embodiment, when the vehicle shuts off its engine because the electric motor is turned off, or since the vehicle decides to operate in electric mode, the engine cylinders may ultimately stop in an uncontrolled manner with regard to the position of the piston 36 in the combustion cylinder 30 and the positions inlet valve 52 and exhaust valve 54.

For an engine with four or more cylinders, there can always be a cylinder located between closing the exhaust valve (EVC) and closing the intake valve (IVC) when the crankshaft is idle.

Next, with reference to FIG. 11-12, exemplary embodiments of the time detection system (14) of FIG. 1-3. The system uses numerous time measurement schemes, each using a chain of circuit elements. By using a pulse method for measuring time-to-distance measurement using a clock that is triggered by a trigger pulse and stopped by a reverse pulse, high-resolution time output can be achieved. In this case, by converting the time measurement into a distance measurement using an equation or algorithm that includes the speed of light, the resolution of the time measurement system is significantly improved, for example, from coarse output in the nanosecond range to accurate output in the picosecond range. In the embodiment of FIG. 11, the time detection system 1100 includes a first, crude time measurement circuit 1120 and a second, accurate time measurement circuit 1121. The first and second time measurement schemes may have different resolutions. In the illustrated example, the first time measurement circuit 1120 is a coarser time measurement circuit (having a lower resolution), while the second time measurement circuit 1121 is a more accurate time measurement circuit (having a higher resolution). A rough time measurement scheme is used to measure long periods of time (for example, longer than 1 ns), while a more accurate time measurement scheme is used to make accurate time measurements within a single clock cycle (for example, within 1 ns, such as picosecond range).

Each of the first and second time measuring circuits 1120, 1121 may communicate with a controller 12, which may be a CPU. In one example, the first time measurement circuit 1120 may be internal to the controller 12 (or CPU), while the second time measurement circuit 1121 is communicatively coupled to the controller.

Each of the first and second time measuring circuits may comprise a plurality of circuit elements. In some embodiments, the first and second time measuring circuits may have a different number of circuit elements. For example, a higher resolution time measuring circuit may have more circuit elements than a lower resolution time measuring circuit. In particular, the resolution of the second time measurement circuit may be based on the number of circuit elements in the second time measurement circuit. For example, as the number of circuit elements in the second time measurement circuit increases, the resolution of the second time measurement circuit may increase. For example, a second time measurement circuit having 10 ⁶ circuit elements may have a resolution of 0.001 ps, while a second time measurement circuit having 10 ³ circuit elements may have a resolution of 1 ps. In addition, the number of circuit elements can be adjusted so that the range (i.e., the upper threshold value or maximum

the output) of the second time measurement circuit was essentially the same as the resolution of the first time measurement circuit (i.e., lower threshold or minimum output of the first circuit). For example, the maximum output of the second time measurement circuit may have a value of 1 ns, while the minimum output of the first time measurement circuit may have a value of 1 ns.

As specified below, a plurality of circuit elements of the second time measuring circuit 1222 may be coupled to respective latch triggers. By sampling the output of the latch triggers, a high resolution position can be determined. As specified in FIG. 10 and FIG. 15, the controller may initially operate only the first time measurement circuit and use the output of the first time measurement circuit to determine when the second time measurement circuit should be started. For example, if the first time measurement circuitry gives an initial rough time output indicating a time value between 10 ns and 11 ns, then in a subsequent pass, each of the first and second time measurement circuits can be operated with a second time measurement circuit that starts with a delay corresponding to 10 ns (for example, when the first time measurement circuit reached 10 ns). The output from both circuits can then be combined to find out the high resolution time value.

FIG. 12 shows an alternative embodiment of a time detection system 1250 including a first, rough time measurement circuit 1220 and a second, accurate time measurement circuit 1222. In the materials of this application, the second higher resolution time measurement circuit includes two half-cycle accurate time measurement circuits 1224a and 1224b. Two half-cycle time measuring circuits together cover a single clock duration of the first time measuring circuit 1220. As specified below, each of the two half-cycle components of the second time measuring circuit includes a plurality of circuit elements coupled to respective latch triggers. By sampling the output of the latch triggers, a high resolution position can be determined. If the measured signal had not been measured within the time it takes to fully charge the entire chain of circuit elements of a half-cycle time measurement circuit, the circuit would need to be cleaned by resetting the capacitor charge. Since the current limiter of the restriction circuit would cause the cleaning operation to also take a substantial amount of time, a second half-cycle time measurement circuit is provided. This affords the second time-lapse clock measurement scheme the ability to be used, while the first time-lapse time measurement circuit is cleared. Thus, two half-cycle time measuring circuits are used alternately or mutually exclusive.

As with the embodiment of FIG. 11, in the embodiment of FIG. 12, the first and second time measurement circuits may have different resolutions, wherein the first time measurement circuit 1220 is configured as a coarser time measurement circuit (having lower resolution), and the second time measurement circuit 1222 (including each of the first and second half-cycle time measurement circuits) is configured as a more accurate time measurement circuit (having a higher resolution). A rough time measurement circuit is used to measure long periods of time (e.g., greater than 1 ns), while each half-cycle time measurement circuit is used to make accurate time measurements within a single clock cycle (e.g., within 1 ns).

Each of the first and second time measuring circuits 1220, 1222 may communicate with a controller 12, which may be a CPU. In one example, the first time measurement circuit 1220 may be internal to the controller 12 (or CPU), while the second time measurement circuit 1222 is communicatively coupled to the controller.

Essentially, each embodiment of the second time-measuring scheme provides high-resolution time measurements with the possibility of being performed while providing additional benefits. For example, the embodiment of FIG. 11, where the second time measurement circuit is made of a single component, can provide the advantages of reducing components and costs. In addition, an embodiment may be used when the sampling frequency of the samples is high, and when there may be a smaller step in the output of the rough time measurement circuit. In comparison, the embodiment of FIG. 12, where the second time measurement circuit is made of two half-cycle components, can be used when the sampling frequency of the samples is low, and when there may be a larger output step of the rough time measurement circuit.

Essentially, a coarser timer can be used to determine the approximate time for which a return occurs, and on a subsequent measuring pulse, the first timer starts during the clock interval in which a reverse pulse is expected. As an example, if the reverse pulse occurred in another clock interval (for example, 3 pulses earlier than expected), then this information can be used to more accurately anticipate the arrival of the next clock cycle (for example, 3 coarser clock cycles before). For objects that move slowly relative to the coarse timer (that is, the movement is such that a reverse pulse can be expected within the correct clock interval of the coarse timer), an approach that uses a single component or circuit in a fast timer is suitable. Otherwise, there is the potential for loss of high resolution readings at a high percentage of pulses. The advantage of a fast timer with two (half-cycle) circuits is that a high resolution is achieved for each measurement pulse, and there is no restriction on the amount of movement of an object between adjacent coarse clock pulses. Since a certain period of blindness can occur immediately after combustion, and the laser can switch to other tasks, such as heating cylinder walls or evaporating fuel, this can be an advantage.

As specified in FIG. 10 and FIG. 14, the controller may operate each of the first time measurement circuit and the second time measurement circuit together, alternating each 1-tick timer every 1 ns. For example, during the first nanosecond, the controller can operate the coarse timer and the first half-cycle timer, then, during the second nanosecond, while the first half-cycle timer is cleared, the controller can operate the coarse timer and the second half-cycle timer. Then, during the third nanosecond, the coarse timer can be operated with the (now cleared) first half-cycle timer, while the second half-cycle timer is cleared. When the time measurement circuits are stopped (by a reverse pulse), the output of both circuits can be combined to find out the high resolution time value.

A detailed embodiment of the high resolution time measurement circuit of FIG. 11-12 is shown in FIG. 13. Essentially, the circuit 200 of FIG. 13 depicts a second high resolution time measurement circuit 1121 of FIG. 11, as well as each half-clock timer (1224a and 1224b) of the high resolution of FIG. 12. It will be appreciated that two such circuits may be available in the embodiment of the time detection system shown in FIG. 12. As discussed with reference to FIG. 11-12, a circuit 1300, as illustrated, controls a high-resolution timer, which is part of a larger time-detection system, using a CPU and a clock-based timer.

Elements 1310a-1310n of the circuit of the second time measurement circuit include a chain of capacitors (inputs from Ca to Cn CMOS) that are charged by the leading edge of the trigger pulse. Current limiters (or Ra to Rn resistors) are placed between each capacitor with a resistance value selected to cause the last capacitor in the circuit to reach a positive threshold value of 1 ns (that is, the resolution of the first coarse time measuring circuit).

As discussed with reference to FIG. 10, the controller can determine the position of the piston based on the time elapsed between emitting a laser pulse inside the engine cylinder by the laser ignition device and detecting the laser pulse following reflection from the upper surface of the piston in the cylinder. The required time can be based on the output of each of the first coarser time measurement circuit 1120 or 1220 and the second more accurate time measurement circuit (1121 or 1222). In particular, the required time may be based on the sum of the output of the first time measurement circuit and the output of the second time measurement circuit.

A trigger signal 1302 (e.g., a laser pulse) is measured or evaluated by the controller. The trigger signal, for example, may include confirmation that a low-power laser pulse was emitted by a laser ignition device inside the cylinder. The trigger signal 1302 initiates the operation of the circuit, more precisely, causes the chain of capacitors (inputs Ca through Cn CMOS) to be charged by the leading edge of the trigger pulse. Each CMOS input of the elements 1310a through 1310n of the circuit is connected to a corresponding trigger latch 1308a through 1308n. A latch trigger is essentially a “blocking input” in a data acquisition circuit that makes the behavior of an element similar to a latch trigger. Latch triggers allow data lines to be read and processed.

Current limiters (Rl through Rn) are placed between each capacitor with the values selected to cause the last capacitor in the circuit (Cn) to reach the positive threshold voltage level in 1 ns. For example, if the chain has 1000 capacitors (where Cn = C1000), at 1 ns, the last capacitor in the chain (C1000) will reach the positive voltage level in 1 ns.

The feedback signal, also referred to as a measured signal 1303 in the materials of this application, initiates the output data (from Dl to Dn) of the CMOS trigger latch chain (1308a to 1308n) to be sampled. The measured signal, for example, may include confirmation that a low-power laser pulse was detected by a detector connected to the laser ignition device, following reflection from the surface of the cylinder piston. Essentially, if the latch triggers are actuated instantly, the chain of latch triggers would show how far the laser pulse has spread in the chain, thereby indicating the time elapsed between the trigger pulse and the measured pulse, with a resolution determined by the chain length. For example, using a 1 ns clock, a chain of 1000 elements (C1000) would give a resolution of 1 picosecond (ps). As another example, a chain of 1,000,000 elements would give a resolution of 0.001 ps. Since latch triggers require a finite time (for example, X ps) to snap their input signals, the trigger pulse is delayed (delay 1304) for the same time (for example, X ps). Essentially, a delay 1304 is set to correspond to the time required to block the input signals in the data acquisition circuits. This synchronizes the location of the charging capacitor in the chain with the operation of the corresponding trigger-latch.

If the measured signal 1303 does not appear within a 1 ns period, the chain, being fully charged, would need to be cleaned (also at 1303) by resetting the capacitors to prepare for another trigger pulse. The current limiters (resistors Rl to Rn) are tuned so that they encourage the cleaning operation to also take ~ 1 ns. More precisely, the values of the RC elements of the circuit are set to give a time difference of 1 ns between the first element in the chain and the last element in the chain passing above a positive threshold value. In view of the time required to clear a chain, a second chain (or half-cycle timer) is provided to take a time measurement while the first chain is cleared. Thus, the two chains alternate, being used every 1 ns.

It will be noted that if the resistance were set to be zero (i.e., if R = 0), the time difference would also be zero. Therefore, R is set to be very small in order to give a very small time difference between the increase in voltage of each element. Given this point, the chain of circuit elements could be expanded to 1 million to give a resolution of 0.001 ps.

As specified with reference to FIG. 10 and 14, in response to the operation of the laser ignition device, the controller may start each of the first time measurement circuit and the second time measurement circuit. The second time measurement circuit is started after a delay after the start of the first time measurement circuit, the delay is based on the output of the first time measurement circuit estimated previously. The laser ignition device is operated to deliver a low power laser pulse into the engine cylinder during the engine idle state and before the first engine restart combustion event. More specifically, the time measurement circuit is triggered by emitting a laser pulse having a lower power than the laser pulse supplied to the cylinder to ignite the fuel-air mixture in the cylinder during combustion conditions.

FIG. 4 shows an example of an in-line four-cylinder engine capable of directly injecting fuel into a chamber, stopped at an arbitrary position in its driving cycle, and how the laser ignition system can produce measurements that can be compared between cylinders to identify potential impairment. It will be appreciated that the approximate engine position shown in FIG. 4 is exemplary in nature, and that other engine positions are possible.

The inset in the figure under 412 is a diagram of an exemplary in-line engine block 402. Within the block are four separate cylinders, where cylinders 1-4 are labeled 404, 406, 408 and 410, respectively. The cross-sectional views of the cylinders are shown arranged according to their order of operation of the cylinders in the exemplary driving cycle shown at 415. In this example, the position of the engine is such that the cylinder 404 is in a stroke cycle of the driving cycle. The exhaust valve 413, therefore, is in the open position and the intake valve 414 is closed. Since the cylinder 408 is the last to operate in a cycle, it is in its working cycle and thus the exhaust valve 416 and the intake valve 418 are in the closed position. A piston in cylinder 408 is located near the BDC. The cylinder 410 is in a compression stroke and, thus, the exhaust valve 420 and the intake valve 422 are also both in the closed position. In this example, cylinder 406 is the last to operate, therefore, is in the intake stroke position. Accordingly, the exhaust valve 424 is closed while the intake valve 426 is open.

Each individual cylinder in the engine may include a laser ignition system attached to it, as shown in FIG. 2 described above, on which a laser ignition system 92 is connected to the cylinder 30. These laser systems can be used both for ignition in the cylinder and for determining the position of the piston within the cylinder, as described in the materials of this application. For example, FIG. 4 shows a laser system 451 attached to a cylinder 404, a laser system 453 attached to a cylinder 408, a laser system 457 attached to a cylinder 410, and a laser system 461 connected to a cylinder 406.

As described above, a laser system can be used to measure the position of the piston. The positions of the pistons in the cylinder can be measured relative to any suitable reference points and can use any suitable scale factors. For example, the position of the cylinder may be measured relative to the position of the TDC of the cylinder and / or the position of the BDC of the cylinder. For example, FIG. 4 shows a line 428 through the cross sections of the cylinders in the BDC position and a line 430 through the cross sections of the cylinders in the BDC position. Although many reference points and scales may be possible during the determination of the position of the piston, the examples shown here are based on the location of the piston inside the chamber. For example, the scale used at the measured offset compared to known positions within the camera can be used. In other words, the distance from the upper surface of the piston shown under 432 in FIG. 4, with respect to the TDC position shown under 428 and the BDC position shown under 430, can be used to determine the relative position of the piston in the cylinder. For simplicity's sake, an exemplary scale is shown calibrated for the distance from the laser system to the piston. On this scale, the origin 428 is represented as X (moreover, X = 0 corresponds to TDC), and the piston location 430 farthest from the laser system, corresponding to the maximum linear distance traveled by the piston, is represented as xmax (moreover, X = xmax corresponds to BDC). For example, in FIG. 4, the distance 471 from TDC 428 (which can be taken as a reference) to the piston top surface 432 in the cylinder 404 can be substantially the same as the distance 432 from TDC 428 to the piston top 432 in the cylinder 410. Distances 471 and 432 may be smaller (relative to TDC 428) than the distances 473 and 477 from TDC 428 to the upper surfaces of the pistons in cylinders 408 and 406, respectively.

Pistons can operate cyclically, and thus, their positions inside the chamber can be connected through a single indicator with respect to TDC and / or BDC. In general, this distance, 432 in the figure, can be represented as AX. The laser system can measure this variable for each piston within its cylinder, and then use the information to determine if additional action is necessary. For example, a laser system could send a signal to a controller indicating engine degradation in excess of an acceptable threshold value if the variable differs by a threshold value among two or more cylinders. In this example, the controller can interpret the control program as a diagnostic signal and generate a message indicating that a degradation has occurred. It is clear that the variable X should represent many indicators that can be measured by the system, one example of which is described above. The above example is based on the distance measured by the laser system, which can be used to identify the location of the piston inside its cylinder.

FIG. 5 shows a graph 500 of an exemplary setting of valve distribution phases and piston position as regards engine position (degrees of crank angle) within four cycles (intake, compression, working and exhaust) of the engine cycle for a four-cylinder engine with cylinder operation 1-3-4 -2. Based on the criteria for selecting the first working cylinder, the engine controller may be configured to identify areas in which the first working cylinder may be located based on the position of the engine measured by reflected laser pulses using a piston, as described herein. The piston gradually moves down from the TDC, reaching the lowest point in the BDC by the end of the intake stroke. The piston then returns up to TDC at the end of the compression stroke. The piston then again moves back down towards the BDC, during the working cycle, returning to its original upper position in the TDC by the end of the exhaust cycle. As depicted, a multidimensional characteristic illustrates the position of the engine along the x axis in degrees of the crankshaft angle of rotation (CAD).

Curves 502 and 504 depict valve lift profiles during normal engine operation for the exhaust valve and intake valve, respectively. The exhaust valve can open as soon as the piston reaches a low point at the end of the stroke. The exhaust valve may then close while the piston completes the exhaust cycle, remaining open at least until the next intake cycle of the subsequent cycle has begun. In the same way, the inlet valve may open at or before the start of the intake stroke and may remain open at least until the next compression stroke has begun.

As described above with reference to FIG. 2-4, the engine controller 12 may be configured to identify a first working cylinder in which combustion should be initiated during the resumption of engine operation from an idle shutdown condition. For example, in FIG. 4, the first working cylinder can be determined using one or more time measurement circuits connected to the laser ignition system to measure the time required to detect the reflected laser pulse, and therefore, to measure the location of the pistons in the cylinders as a means of determining the position of the engine. This specific engine position can be used to determine the position of the first working cylinder. The example shown in FIG. 5 relates to a direct injection engine (DI), wherein the first working cylinder can be selected located after the EVC, but before the subsequent EVO (as soon as the position of the engine is identified and it is identified that the position of the piston is synchronized with the camshaft). For comparison, FIG. 6 shows a first working cylinder of a windowed fuel injection engine (PFI), wherein the first working cylinder may be selected located prior to the IVC.

FIG. 5 refers to FIG. 4 to further specify how a determination is made as to which cylinder is the first to operate when the engine resumes operation, and how the laser can coordinate the temporal characteristics of different power modes within four cycles of the driving cycle. For the exemplary configuration shown in FIG. 4, the position of the engine can be detected by the laser system on line P1 shown in FIG. 5. In this example, on P1, cylinder 404 is in a release stroke. Accordingly, for this exemplary engine system, cylinder 408 is in operation, cylinder 410 is in compression, and cylinder 406 is in inlet. In general, before the engine starts the resume operation, one or more laser systems can ignite the low power pulses shown at 510 in FIG. 5 to determine the position of the engine. In addition, since a DI engine is used in this example, fuel can be injected into the cylinder chamber after IVO. The injection profile is defined by 506-509. For example, the rectangles under 506 in FIG. 5 show when fuel is injected into cylinder 404, rectangles 507 show when fuel is injected into cylinder 408, rectangles 508 show when fuel is injected into cylinder 410, and rectangle 509 shows when fuel is injected into cylinder 406, during an example engine cycle, shown in FIG. 5.

When the cylinder has been identified as the next working cylinder, after the fuel / air mixture has been introduced into the cylinder and the associated piston has been compressed, a laser attached to the identified next working cylinder can generate a high power pulse to ignite the fuel / air mixture in the cylinder to call a working cycle. For example, in FIG. 5, after fuel is injected 506 into cylinder 404, a laser system, such as laser system 451, generates a high power pulse of 512 to ignite the fuel in the cylinder. Similarly, cylinder 408, which is the next in the sequence of cylinders after cylinder 404, receives a high power pulse from a laser system, such as laser system 453, to ignite fuel injected 507 into cylinder 408. The next working cylinder after cylinder 408 is a cylinder 410, which receives a subsequent high power pulse from a laser system, for example, laser system 457, to ignite fuel injected 508 into cylinder 408, and so on.

In FIG. 1, an exemplary PFI engine profile similar to that shown in FIG. 5 for an engine with DI, provided for comparison. One of the differences between a DI engine and a PFI engine relates to whether fuel is injected directly into the chamber, or whether fuel is injected into the intake manifold for premixing with air before being injected into the chamber. In the DI system shown in FIG. 2-4, air is introduced directly into the chamber and is thus mixed with air during the engine intake stroke. Conversely, a PFI system injects fuel into the intake manifold during the exhaust stroke, therefore, air and fuel are pre-mixed before being injected into the cylinder chamber. Due to this difference, the engine controller may send a different set of instructions depending on the type of fuel injection system provided in the system.

In the PFI engine profile shown in FIG. 6, before time P1, one or more laser systems can ignite low power pulses 510 to determine the position of the engine. Since the engine is a PFI, fuel can be injected into the intake manifold up to IVO. At time P1, the controller identified the position of the engine pistons by laser measurements and identified the position of the camshaft so that a synchronized fuel supply can be planned. Based on the amount of fuel to be supplied, the controller can identify the next cylinder, which must be supplied with fuel up to IVO, so that window injection fuel can be provided with the valve closed. Injection profiles are shown under 606-608 in FIG. 6.

For example, with reference to FIG. 4, but for a PFI engine instead of a DI engine, a box under 606 indicates when fuel can be injected into the intake manifold (generally shown as 45 in FIGS. 2 and 3) of the first working cylinder after the engine resumes operation. As shown by FIG. 6, cylinder 408 is the next cylinder that can be supplied with fuel, and thus, fuel injection 606 is planned so that cylinder 408 is the first cylinder to operate from a standstill when ignited by a laser ignition pulse 618. When resuming operation, since the cylinder 410 is next in the sequence of the cylinders, fuel injection 607 can occur according to the sequence before IVO. Prior to EVO, a high power pulse 620 may be supplied from a laser system 457 to ignite the mixture. The next working cylinder in sequence is cylinder 406, which subsequently injects fuel 608 to IVO. Although not shown, a high power laser pulse from laser system 461 can be used to ignite this fuel / air mixture. The amount of fuel injection may gradually decrease based on the count of burns from the first combustion event in the cylinder.

Next, with reference to FIG. 7, an exemplary method 700 for operating a hybrid vehicle system of an engine system of a vehicle is shown during a vehicle driving cycle.

At 702, vehicle operating conditions may be evaluated and / or inferred. As described above, the control system 12 may receive sensor feedback from one or more sensors associated with the components of the vehicle power plant, for example, a measurement of the input mass air flow (MAF) from the mass air flow sensor 120, engine coolant temperature (ECT) ), throttle position (TP), etc. Evaluated operating conditions, for example, may include an indication of the power output or torque requested by the driver of the vehicle (for example, based on the position of the pedal), fuel level in the fuel tank, engine fuel consumption rate, engine temperature, charge state (SOC) of the on-board device energy storage, environmental conditions, including humidity and temperature, engine coolant temperature, request for automatic climate control (for example, air conditioning requests ation or heating air), etc.

At 704, based on the estimated vehicle operating conditions, a vehicle operating mode may be selected. For example, it can be determined whether the vehicle should be operated in electric mode (with a vehicle transported using energy from an on-board energy storage device such as a battery) or engine mode (with a vehicle transported using energy from an engine), or assistance mode (with a vehicle moving using at least some energy from the battery and at least some energy from the engine).

At 706, method 700 includes determining whether or not to operate the vehicle in electrical mode. For example, if the torque requirement is less than the threshold value, the vehicle may be operated in electrical mode, while if the torque requirement is higher than the threshold value, the vehicle may

operate in engine mode. As another example, if the engine has been idling for a long period of time, the controller can determine that the vehicle should be operated in electric mode.

If method 700 determines that the vehicle should be operated in electric mode at 706, then, at 708, it includes operating the vehicle in electric mode with a battery system used to drive the vehicle and meet driving torque requirements. In some examples, even if the electric mode is selected at 708, the program may continue to monitor the vehicle's torque requirement and other vehicle operating conditions to determine whether a quick switch to engine mode (or engine assist mode) should be performed. More specifically, while in electrical mode, at 710, the controller can determine whether switching to engine mode is requested.

If, at 706, it is determined that the vehicle should not be operated in electric mode, then method 700 proceeds to 712 to confirm operation in engine mode. According to the confirmation, the vehicle can be operated in engine mode with the engine used to propel the vehicle and meet the driving requirements of the torque. Alternatively, the vehicle may operate in a assisting mode (not shown) to drive the vehicle due to at least some energy from the battery and some energy from the engine.

More precisely, if the engine mode is requested at 712, or if switching from the electric mode to the engine mode is requested at 710, then, at 714, the procedure includes starting (or restarting) the engine. An exemplary method 800 for starting or restarting an engine during a vehicle driving cycle is discussed with reference to FIG. 8.

In some embodiments, a hybrid engine system engine may be selectively deactivated when the selected idle shutdown conditions are satisfied. For example, an engine can be taken out of service by shutting down fuel supply and spark ignition from an engine. Essentially, by shutting down the engine in response to an idle shutdown, for example when the vehicle is stopped at a traffic light, additional fuel economy gains and reduced engine emissions are achieved. Accordingly, while the engine is running at 716, it can be determined whether the idle shutdown conditions have been met. In one example, the idle shutdown conditions can be considered satisfied if one or more of the following conditions is confirmed: a state of charge (SOC) of the battery that is higher than a threshold value (for example, greater than 30%), the required vehicle speed, below a threshold (e.g. below 30 mph), there is no accepted request for air conditioning, engine temperature above a selected temperature, throttle opening degree lower than a threshold ix torque requirement, located lower than the threshold value, etc. If any of the idle shutdown conditions are satisfied, then, at 718, the engine is shut down or shut down. Otherwise, at 720, engine operation is supported.

If the engine is turned off at 718, then at 722, while the engine is idle off, it can be determined whether the conditions for restarting the engine have been met. In one example, restart conditions can be considered satisfied if one or more of the following conditions is confirmed: a state of charge (SOC) of the battery that is less than a threshold value (for example, less than 30%), the required vehicle speed above threshold value (for example, above 30 mph), received air conditioning request, engine temperature within the selected temperature range, throttle opening degree that is higher than the threshold initiation, torque requirement higher than the threshold value, etc. If any of the restart conditions are satisfied, the procedure returns to 714 to start or restart the engine. Otherwise, at 712, the engine is maintained in the idle OFF state until the restart conditions are confirmed. As specified below with reference to FIG. 8, when starting or restarting the engine, the controller can select the cylinder in which the first combustion event should be triggered, based on piston position information determined using the laser ignition system.

Next, with reference to FIG. 8, method 800 depicts a procedure for starting or restarting an engine, including selecting a cylinder in which to initiate a first combustion event. In one example, the method of FIG. 8 may be performed as part of the procedure of FIG. 7, such as in step 714.

At 802, method 800 includes confirming whether restart conditions have been met. As specified with reference to FIG. 7, this may include confirmation that one or more of the idle shutdown conditions have been met. Alternatively, this may include confirmation that the transition to engine mode has been selected in a hybrid vehicle. If the restart conditions are not confirmed, the procedure may end.

If the engine restart is confirmed at 808, the procedure includes starting the engine starter to initiate cranking of the engine crankshaft. Then, at 810, the method includes determining the position of the engine. For example, based on the selected criteria, the engine controller may be configured to determine the position of the engine in order to identify the position of the first working cylinder to initiate combustion during engine commissioning. For example, as described above, each cylinder may be coupled to a laser system capable of generating an optical signal of high or low energy. When operating in high energy mode, the laser can be used as an ignition system to ignite the fuel / air mixture. In some examples, a high energy mode can also be used to heat the cylinder in order to reduce friction in the cylinder. When operating in low energy mode, a laser system, which also includes a detection device capable of capturing reflected light, can be used to determine the position of the piston inside the cylinder. As specified with reference to FIG. 11-12, the position of the piston may be determined based on the time elapsed between the emission of the laser pulse by the laser ignition system and the detection of the reflected laser pulse by the detection device. The required time can be estimated using numerous time measuring circuits connected to the laser ignition system, including at least a rough time measuring circuit with fewer circuit elements and an accurate time measuring circuit having more circuit elements. By combining the output of time measurement circuits and converting the time value into a distance value, the position of the piston can be determined with a higher resolution. Position information can be used to determine which cylinder is the first to operate during a restart.

During some operating modes, for example, when the engine is running, the reflected light can create other useful optical signals. For example, when light from a laser system is reflected from a moving piston, it will have a different frequency relative to the original emitted light. This detectable frequency shift is known as the Doppler effect and has a known dependence on piston speed. The position and speed of the piston can be used to coordinate the timing of the ignition events and the fuel / air mixture injection.

At 812, the method includes determining a camshaft position. For example, the position of the intake valve 52 and exhaust valve 54 may be detected by position sensors 55 and 57, respectively. In some embodiments, each cylinder of the engine 20 may include at least two inlet poppet valves and at least two outlet poppet valves located in the upper region of the cylinder. The engine may further include a cam position sensor, whose data can be combined with a laser system sensor to determine the position of the engine and set the cam distribution phases.

At 814, the method includes identifying which cylinder in the cycle should work first. For example, information about the position of the engine and the position of the valves can be processed by the controller in order to determine where the engine is in its driving cycle (for example, in what cylinder stroke each piston is in the cylinder). Once the position of the engine has been determined, the controller can identify which cylinder should first ignite when resuming operation. In one example, the controller may select a cylinder having a piston in a compression stroke to be a cylinder in which to initiate a first engine restart combustion event, where the engine is configured for direct injection, and where the engine restart is not a cold start, but a hot restart engine.

At 816, the method includes scheduling fuel injection. For example, the controller may process information about the position of the engine and setting the cam distribution phases for planning so that the next cylinder is injected with fuel in a driving cycle. At 818, method 800 includes scheduling fuel ignition. For example, once a fuel injection has been planned for the next cylinder in the ignition sequence, the controller can subsequently plan the ignition of the fuel / air mixture with a laser system attached to the next working cylinder in order to start the engine.

FIG. 9 shows an exemplary method 900 for operating a laser engine ignition system in various power modes based on an operating state of an internal combustion engine. As specified in the method of FIG. 9, the laser system can be operated in high power mode to ignite the fuel-air mixture in the cylinder during combustion conditions, and operated in low power mode to measure the position of the piston during non-combustion conditions. In the embodiment shown, the controller can use multiple different resolution time measurement circuits to determine the time required for the emitted high-power laser pulse to be detected after reflection from the piston in the cylinder, and thereby determine where the engine is in its driving cycle. Information about the position of the engine can be transmitted from the time measurement circuit to the laser ignition system, and in it, to the controller by means of signals that may be electrical in nature, or which can be transmitted by optical, mechanical or some other means.

At 901, method 900 includes using at least one laser system to monitor engine position. For example, in FIG. 4, the laser system 451 can be used to determine the position of the piston in the cylinder 404. The position of the intake valve 414 and exhaust valve 412 can then be detected by cam sensors in order to identify the actual position of the engine. In one example, a low power mode of operation where the position of the engine is monitored may be the default state of the laser ignition system.

At 902, method 900 includes determining whether laser ignition should be performed. For example, the laser system 92 may receive information from the controller that the ignition conditions have been met. In one example, ignition conditions may be considered satisfied in response to a request to start or restart the engine from a driver or from a vehicle controller. If the ignition conditions are confirmed, then, at 904, the method includes applying laser pulses in high power mode to the engine cylinder. As described above, the engine controller may be configured to identify a first working cylinder in which combustion should be initiated during the resumption of engine operation from the conditions of shutdown of idling or initiation of engine operation in the engine on mode. When the ignition conditions are confirmed by the controller 12, the laser generator of the laser ignition system can generate a laser pulse of high energy or intensity to ignite the fuel-air mixture in this combustion chamber. After resuming engine operation, the laser system can resume piston detection for pistons in cylinders.

If the laser ignition conditions are not confirmed at 902, at 906, the method includes determining whether the conditions for determining the position of the piston are confirmed. For example, it can be determined whether information about the position of the piston is required, and whether the laser system should be operated to determine the position of the engine. If the conditions for determining the position of the piston are confirmed, then, at 908, a low-pressure pulse can be supplied by a laser system 451 to determine the position of the piston inside the cylinder 404. Similarly, laser systems 453, 457 and 461 can also provide low power pulses to determine the position of the pistons inside cylinders 408, 410 and 406, respectively. The laser device can be operated in a low power mode by laser pulses emitted at a lower intensity and at a given frequency. For example, a laser may swing its frequency in a low power mode. As specified with reference to FIG. 10, a time detection system including multiple time measuring circuits can be operated in coordination with laser operation. More precisely, time measuring circuits can be activated in response to the emission of a laser pulse by a laser device inside the engine cylinder, and time measuring circuits can be blocked in response to detecting a laser pulse (following reflection from the upper surface of the piston in the cylinder) by a laser system detector.

At 910, position information for the engine may be determined based on the output of multiple time measurement circuits. For example, as discussed with reference to FIG. 10, the engine controller 12 may perform a series of calculations to convert the time value output by the time measurement circuits into a distance value (more precisely, the distance between the laser device and the piston top). In further embodiments, the controller may calculate the position of the engine based on data received from both time measurement circuits and cam position sensors. Thus, the controller can operate the laser ignition device to deliver the laser pulse to the cylinder, and then logically infer the position of the cylinder piston based on the time required to detect the laser pulse. In the materials of this application, the required time can be based on each of the first scheme for a rougher time measurement and the second scheme for a more accurate time measurement.

At 912, method 900 includes using engine position information to determine other system information. For example, the collected cylinder data can be further processed to calculate the crank angle of the crankshaft 40. Alternatively, the controller can use the engine position to ensure that the fuel supply within the engine is synchronized.

At 914, method 900 includes identifying which cylinder should run first in the loop. For example, in the description of FIG. 5 and 11-12, the controller uses a laser system and time measuring circuits to measure the positions of the pistons inside their cylinders. This information can additionally be combined with the positions of the intake and exhaust valves detected by the cam position sensors in order to determine the position of the engine. Based on the identified position of the engine, the controller is able to identify and plan the next cylinder in the driving cycle for operation. Thus, the controller can logically infer the piston position of a given cylinder based on the output of the time measuring circuits and adjust the fuel supply and spark ignition of the given cylinder during engine restart based on the inferred position.

Returning to FIG. 9, at 916, the method includes determining whether laser monitoring of the engine should continue. For example, it can be determined whether the laser device should be maintained in low power mode. In one example, once the first working cylinder has been identified using a laser device in low power mode, and based on the output of the time measurement circuits, the controller can determine that further monitoring of the position of the engine is not required, and that the operation of the laser in high power mode required to ignite the fuel-air mixture in the cylinders. If the controller decides not to use laser systems to monitor the position of the engine, at 918, the controller, for example, can optionally use crankshaft position sensors to monitor the position of the engine.

Next, with reference to FIG. 10, a method for operating the time measuring system of FIG. 11-12 and 13, which is connected to a laser ignition system. The method allows the position of the engine to be recognized based on the time required to detect the laser pulse emitted by the laser ignition device into the engine cylinder, where the required time is based on the output of each of the first coarser time measurement circuit and the second less coarse time measurement circuit. In one example, the procedure of FIG. 10 may be performed as part of the procedure of FIG. 9, such as at 908-910.

At 1002, a first low power laser pulse may be emitted. In particular, a low power laser pulse is emitted for the first time. For example, a laser ignition device near an engine cylinder can be operated in a low power mode by a controller during non-combustion conditions when engine position control is required. In low power mode, the laser device may be configured to deliver a laser pulse of lower power to the cylinder than a laser pulse supplied to the cylinder during combustion conditions to ignite the fuel-air mixture in the cylinder.

At 1004, in response to the emission of a first low power laser pulse, a first coarse time measurement circuit is started. The first crude time measurement circuitry may be connected inside the motor controller or CPU. In response to the emission of a laser pulse, the controller can send a signal to start the first coarse time measurement circuit.

At 1006, the procedure includes detecting a low power laser pulse emitted into the cylinder following reflection from the upper surface of the piston of the given cylinder. A reflected laser pulse can be detected by a detection device coupled to the laser emitter in the laser ignition system. At 1008, in response to detection, the first coarse time measuring circuit is stopped, and the time value output by the chain of circuit elements in the first coarse timer is read and stored in the controller memory. The controller can also determine the value of the delay offset, which should be used when operating the first and second time measurement circuits in tandem. The delay offset may be based on the output of the first time measurement circuit. For example, when the output of the first time measurement circuit is 10 ns, the delay offset value can be set to be 10 ns. Essentially, the delay is based on the time required for the blocking input on the buffer chips to overcome the combined capacity of the buffer group. Since each input has a small capacitance, there will be a small time delay, which is much larger when measured in the picosecond range. In the time detection system of FIG. 12, the delay for cleaning requires coordination with a rough measurement of time. In the time detection system of FIG. 11, the delay is based on a rough measurement of time, and thus a delay of any magnitude can be processed.

At 1010, the method includes emitting a second low power laser pulse that may be skipped. In particular, a low-power laser pulse, similar to the pulse emitted at 1002, is emitted a second time. At 1012, as at 1004, in response to the emission of a low-power laser pulse, (re) the first circuit of a rougher time measurement is started. At 1014, a second more accurate time measurement circuit is started following the expiration of a certain delay time or delay offset after the first time measurement circuit is started. In other words, the information from the previous coarse measurement is used to trigger a high-resolution time measurement circuit to operate during the clock interval in which a reverse pulse is expected. Thus, if a high-resolution time measurement circuit requires a long time (for example, 1 ms) to force the first element to reach a threshold voltage (as would be the case with a very long chain of circuit elements in the second time measurement circuit), the trigger pulse of the second circuit time measurements can be started in advance at the appropriate time. Essentially, the time for the first element to reach a threshold voltage would be constant for a given circuit design.

At 1016, as at 1006, a low-power laser pulse emitted into the cylinder is detected following reflection from the piston of the cylinder. At 1018, in response to detection, each of the first rough time measurement circuit and the second accurate time measurement circuit is stopped. The time value output by each of the first lower resolution time measurement circuit and the second higher resolution time measurement circuit is read and combined. More specifically, the controller (or CPU) can read the line of latched data from the second time measurement circuit and add the high resolution time to the low resolution time. Essentially, after reading the output to prepare the time measurement circuits for the next pulse, the second time measurement circuit is cleared by pulling the trigger line to a low level. The clock timer of the first time measurement circuit is also reset.

In one example, steps 1002 through 1018 are repeated a number of times, and the results are statistically compared. For example, measuring pulses can be sent each from 10 to 100 milliseconds; the frequency depends on the required maximum measuring range.

At 1020, the combined time value inferred by the circuits is converted to a distance value using equations or algorithms for converting time into distance. In one example, the controller may convert the sum of the first time value output by the first time measurement circuit and the second time value output by the second time measurement circuit into a distance value using an equation that uses the speed of light as a parameter.

At 1022, the position of the engine is recognized based on the time required to detect the laser pulse emitted by the laser ignition device into the engine cylinder, the required time is based on each of the first, rougher timer or time measurement circuit, and the second, less coarse timer or time measurement circuit . In particular, recognizing the position of the engine based on the required time includes determining the position of the piston and the stroke of the cylinder for each cylinder of the engine. As specified in FIG. 9, the controller can then adjust the operating parameter of the engine during a subsequent restart of the engine based on the recognized position of the engine. For example, the controller can adjust the fuel supply and the ignition timing of the cylinder based on the recognized position of the engine. The controller may also select a cylinder to perform the first combustion event during engine restart based on the cylinder stroke. In one example, a cylinder where the piston is in a compression stroke may be selected for a first combustion event during a restart. Essentially, the position of the engine can be recognized during non-combustion conditions, such as during a standstill of the engine, after engine shutdown during engine shutdown, and before the first combustion event during restart.

Thus, in response to the emission of a laser pulse into the cylinder by a laser ignition device, the controller can start each of the first and second time measurement circuits. Then, in response to detecting the emitted laser pulse, the controller can stop each of the first and second time measurement circuits. The controller can then convert the sum of the first time output of the first time measurement circuit and the second time output of the second time measurement circuit to a distance, and logically display the position of the piston in the cylinder and the cylinder stroke based on the distance.

In one example, in the first pass, the rough time output of the first time measurement circuit may indicate a value between 10 and 11 ns. Then, in the second pass, a rough time measurement circuit and an accurate time measurement circuit can both be operated in response to the emission of a laser pulse into the cylinder, and the second time measurement circuit is triggered at 10 ns. When both time measurement circuits are stopped in response to the detection of the reflected laser pulse by a detector connected to the LCU, the first time measurement circuit can still output between 11 and 11 ns, while the second time measurement circuit can output output indicating 0.222 ns Thus, the controller can logically infer that the high-resolution time value has a value of 10 + 0.222 = 10.222 ns. The controller can then convert the value 10, 222 not to a distance value to determine the position of the piston in the cylinder with higher precision and accuracy.

FIG. 14 shows the method of FIG. 10 operated in a time detection system having the embodiment of FIG. 12 (with two half-cycle components) in a block diagram format. As shown in FIG. 10, a trigger signal 1402, which is clock-aligned, triggers a timer or low resolution counter. The rough output of the first timer, also referred to as a clock output 1406 in the materials of this application, is stored in the CPU 1412 and, moreover, is provided to the first high-resolution half-clock timer 1408. An inverted version of the clock output signal 1406 (corrected using a square wave with a period of 1 ns) is also supplied to the second high-resolution half-clock timer 1310. The output signal of the trigger-latch of the chain of trigger-latches (in the shown example, from D1 to D500) of the first high-resolution half-cycle timer 1408 is supplied to the CPU 1412. The output signal of the trigger-latch of the chain of trigger-latches (in the shown example, from D501 to D99) of the second The high-resolution half-clock timer 1310 is also provided to the CPU 1412. In the CPU, the location of the transition point of the trigger-trigger chain is converted during high resolution. The CPU then combines the output of the low-resolution timer and high-resolution timers, and executes a time to distance conversion algorithm that converts the combined high-resolution time output to a high-resolution distance value. The distance value reflects the position of the piston in the cylinder with higher precision, accuracy and reliability.

FIG. 15 shows the method of FIG. 10 operated in a time detection system having the embodiment of FIG. 11 in a block diagram format. A trigger signal 1402, which is clock-aligned, triggers a timer or low-resolution counter. The trigger signal may include a signal indicating that the laser pulse has been emitted by the laser ignition device into the corresponding cylinder. The rough output of the first timer (rough time), also referenced here as the clock output 1406, is stored in the CPU 1412. As discussed with reference to FIG. 10, the coarse timer can be operated alone in the first pass to recognize the coarse time output, and then operated in the second pass along with the accurate timer to recognize the output of the high resolution time. Therefore, the clock output signals 1406 are also used as input to the trigger signal 1402 and as input to the coarse timer 1404.

The trigger signal is transmitted to the high resolution timer 1504 via the CPU 1412. In particular, based on the rough output of the rough timer, the CPU can determine the delay or offset through which the trigger should be sent to the high resolution timer. In one example, a trigger signal is sent to the high resolution timer 1504 after a duration corresponding to the coarse time output of the coarse timer 1404 has expired.

The measured signal 1502 (referenced herein as a return signal) may provide a “stop” input to each of the low and high resolution timers. The return or measured signal may include a signal indicating that the laser pulse has been detected by the laser ignition device following reflection from the piston surface of the corresponding cylinder.

In response to the stop signal, the output of the latch trigger-latch of the latch-trigger chain (in the illustrated example, D1 to D1000) of the high-resolution timer 1504 is supplied to the CPU 1412. In the CPU, the location of the transition point of the latch-trigger chain is converted during high resolution. The CPU then combines the output of the low-resolution timer and high-resolution timers, and executes a time-to-distance conversion algorithm that converts the combined high-resolution time output to a high-resolution distance value. The distance value reflects the position of the piston in the cylinder with higher accuracy and reliability.

Following the determination of the position of the piston, the CPU can send the input signal "signal cleaning" to the timer high resolution. This causes the signal measured by the high-resolution timer to be erased. The signal may be erased, for example, by resetting the charge of the capacitors in a chain of high-resolution timer circuit elements. By erasing, the high-resolution timer is reset for another time measurement.

In one example, the engine system comprises an engine cylinder and a laser ignition system attached to the cylinder. The laser ignition system includes a laser emitter and a laser detector, a first lower resolution time measuring circuit having a first, fewer circuit elements, and a second higher resolution time measuring circuit having a second, more circuit elements. The resolution of the second time measuring circuit can be based on the second number of circuit elements, the resolution increases as the second number increases. In addition, the range (or upper threshold value) of the second time measurement circuitry may be based on the resolution (or lower threshold value) of the first time measurement circuitry.

The engine system controller may be configured with computer-readable instructions for, before restarting the engine, operating the emitter to emit a laser pulse of lower power into the cylinder. In response to emission, each of the first and second time measurement circuits may be triggered. The emitted laser pulse can essentially be detected by the detector following reflection from the piston of the cylinder. In response to detection, each of the first and second time measurement circuits may stop, and the position of the piston in the cylinder may be inferred based on the combined output of the first and second time measurement circuits. During a subsequent restart of the engine, the controller can adjust the fuel supply and the ignition timing of the cylinder based on the inverted position of the piston in the cylinder. In addition, during engine restart, the fuel-air mixture can ignite in the cylinder by operating the emitter to emit a laser pulse of higher energy into the cylinder.

Thus, a timer based on a clock with a time measuring circuit has a chain of RC elements to provide a high resolution time measuring circuit that can evaluate the position of the cylinder piston with high accuracy. By emitting a laser pulse emitted by the laser device of the laser ignition system and detecting the reflected laser pulse by the detector of the laser ignition system to start the timers, the time elapsed between the emission and detection of the laser pulse can be calculated with greater accuracy. Then, by converting the time value to the distance value, the position of the piston can be determined reliably and with a greater degree of confidence. By providing information about the position of the piston, the ability to determine with higher resolution accuracy when cranking the engine (or even before cranking the crankshaft), the choice of cylinder for the initial ignition event during engine restart can be improved. In general, engine restarts are made more consistent.

It will be appreciated that the configurations and methods disclosed herein are exemplary in nature, and that these specific embodiments should not be construed in a limiting sense, as numerous variations are possible. For example, the above technology can be applied to engine types V6, 1-4, 1-6, V-12, opposed 4-cylinder and other types of engine. The subject of this disclosure includes all the latest and not obvious combinations and subcombinations of various systems and configurations, and other features, functions and / or properties disclosed in the materials of this application.

The following formula of the utility model details some combinations and subcombinations considered as the latest and most unobvious. These claims of the utility model may indicate with reference to an element in the singular either the “first” element or its equivalent. It should be understood that such claims of a utility model include combining one or more of these elements without requiring or excluding two or more of these elements. Other combinations and subcombinations of the disclosed features, functions, elements and / or properties may be claimed by the utility model formula by modifying the present utility model formula or by introducing a new utility model formula in this or a related application. Such a utility model formula, broader, narrower, equal or different in volume with respect to the original utility model formula, is also considered to be included in the subject model of the present disclosure.

Despite the fact that one of the examples is aimed at measuring the position of the cylinder of the engine, other measuring devices can be provided in one of the examples. For example, an example method may include operating a laser ignition device for delivering a laser pulse; and inferring the position of the laser reflecting object based on the time required to detect the laser pulse, the required time is based on each of the first coarser time measurement circuit and the second more accurate time measurement circuit. Schemes may include one or more features of exemplary schemes described herein, such as that the second time measurement circuit includes a plurality of circuit elements, and wherein, the resolution of the second time measurement circuit is based on the number of circuit elements in the second measurement circuit time. In addition, the range of the second time measurement circuit may be substantially the same as the resolution of the first time measurement circuit. The required time based on each of the first coarser time measuring circuit and the second more accurate time measuring circuit may include the required time based on the sum of the output of the first time measuring circuit and the output of the second time measuring circuit. In response to the operation of the laser ignition device, each of the first time measurement circuit and the second time measurement circuit can be started. The second time measurement circuit may start delayed after the start of the first time measurement circuit. The delay may be based on the output of the first time measurement circuit. Operation of a laser ignition device for supplying a laser pulse may include supplying a laser pulse having a lower power than the laser pulse supplied during the operation mode without measuring the distance.

Claims (4)

1. An engine system comprising: engine cylinder; a laser ignition system attached to the cylinder; a laser ignition system includes a laser emitter and a laser detector; a first lower resolution time measurement circuit having a first, fewer circuit elements; a second higher resolution time measurement circuit having a second, larger number of circuit elements; and a controller with computer readable instructions for, before restarting the engine, operating an emitter to emit a laser pulse of lower energy into the cylinder; in response to emitting, starting each of the first and second time measurement circuits, detecting an emitted laser pulse following reflection from a cylinder piston; in response to detecting, stopping each of the first and second time measurement circuits; and the logical conclusion of the position of the piston in the cylinder based on the combined output of the first and second time measurement circuits. 2. The system of claim 1, wherein the controller includes additional instructions for, during engine restart, fuel supply settings and ignition timing settings at cylinder based on the inferred piston position in the cylinder. 3. The system of claim 2, wherein the controller includes additional instructions for, during engine restart, igniting the air-fuel mixture in the cylinder by operating the emitter to emit a laser pulse of higher energy into the cylinder. 4. The system of claim 1, wherein the resolution of the second time measurement circuit is based on the second number of circuit elements, the resolution increases as the second number increases, and the range of the second time measurement circuit is based on the resolution of the first time measurement circuit.

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