Method and system for starting an engine

Abstract

Engine starting procedure, which includes the following: Starting an engine (10) of a vehicle while a transmission coupled to the engine (10) is in a gear; Turning the engine (10) up to a starting speed; Setting the motor speed to a single target starting speed (302) that is greater than the starting speed and less than an idle speed; and after holding the target motor starting speed (302) at the target motor starting speed (302) for a target duration Adjusting the engine speed to the idle speed.

Description

Cross-reference to related registrations

[0001] The present application claims priority over the preliminary US patent application No. 61 / 821,110 filed on May 8, 2013, which was published under number US 2014 / 0336910A1. State of the art

[0002] DE 103 92 178 B4 describes a starting control device and a starting control method for an internal combustion engine. DE 10 2014 101 817 A1 discloses a system and a method for limiting the volumetric efficiency of a power engine during engine start-up in order to reduce emissions. DE 10 2005 021 870 A1 discloses a multi-stage starting method for an internal combustion engine with compression ignition. US 7 237 521 B2 describes an engine starting method and an engine starting device. Area

[0003] The present description relates to a method and a system for starting an engine. The method and the system can be particularly useful for improving the starting of an engine that is started automatically while a transmission coupled to the engine is in gear. Background and brief description

[0004] A vehicle's engine can be started while the transmission coupled to the engine is in gear. Starting the engine while the transmission is in gear can allow for a timely response to a demand to move the vehicle from a standstill. However, starting an engine while the transmission is in gear also introduces problems with vehicle handling. For example, if the engine starts and produces more than the target torque at the vehicle wheels, the vehicle's handling can deteriorate. One way to control engine torque through a vehicle's powertrain is to control the speed of the torque converter impeller. By limiting the speed of the torque converter impeller, it can be possible to control powertrain torque and improve the vehicle's handling.However, providing a constant increase in engine speed from the starting speed to idle speed during engine start-up can be challenging, as the cylinder air charge can be large during engine start-up with high engine intake manifold pressure.

[0005] The present inventors have recognized the problems mentioned above and have developed an inventive engine starting method comprising the following: starting the engine of a vehicle while a transmission coupled to the engine is in gear; rotating the engine to a starting speed; setting the engine speed to a single target starting speed which is greater than the starting speed and less than an idle speed; and, after holding the engine speed at the target starting speed for a target duration, setting the engine speed to the idle speed.

[0006] An alternative engine-starting method according to the invention comprises: starting the engine of a vehicle while a transmission coupled to the engine is in gear; turning the engine to a starting speed by means of a starter motor; setting an actuator to control the engine speed to a single target starting speed which is greater than the starting speed and less than an idle speed, wherein the single target starting speed does not vary over time, engine events or the engine speed during the engine start; and after holding the single target engine starting speed for a target duration, setting the engine speed to the idle speed.

[0007] A vehicle system according to the invention comprises: a motor; an actuator coupled to the motor; and a controller containing executable instructions stored in non-volatile memory, wherein the executable instructions provide for starting the motor while a transmission coupled to the motor is in gear, rotating the motor to a starting speed, and adjusting the actuator to control the motor speed to a single motor starting speed that is greater than the starting speed and less than an engine idle speed during engine start-up.

[0008] By setting the engine speed to a single starting speed during engine startup, it is possible to reduce the likelihood of exceeding a target engine speed while the engine is running down to idle speed. Specifically, an engine actuator can be used to set the engine speed to a single starting speed. After maintaining the engine speed at the target starting speed for a set duration, the actuator can be set to adjust the engine speed to an idle speed, where the idle speed is higher than both the starting speed and the engine pull-in speed.Controlling the engine speed to a single engine start-up speed, maintaining the engine speed at the target start-up speed for a target duration, and ramping the engine speed to a target idle speed can improve smooth and even vehicle acceleration compared to attempting to reduce an engine speed gradient during engine start-up.

[0009] The described approach can offer several advantages. In particular, it can improve engine starting by enhancing engine speed control during the starting process. Furthermore, it can reduce engine emissions by providing smoother engine starts. Additionally, it can improve the vehicle's handling.

[0010] The above advantages and other benefits and features of the present description are readily apparent from the following detailed description, whether considered alone or in conjunction with the accompanying drawings.

[0011] It is understood that the above summary is intended to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to reveal any key or essential features of the claimed invention, the scope of which is defined solely by the claims following the full description. Furthermore, the claimed invention is not limited to implementations that address any disadvantages mentioned above or in any other part of this disclosure. Brief description of the characters

[0012] The advantages described herein are better understood by reading an example of an embodiment, referred to here as a detailed description, either alone or with reference to the drawings; the drawings show: Fig. 1. A schematic diagram of a power machine; Fig. 2 an exemplary vehicle and vehicle powertrain configuration; Fig. 3 a prophetic engine start sequence; and Fig. 4 a method for starting an engine. Detailed description

[0013] The present description concerns the control of a vehicle powertrain. The vehicle may contain an engine and a transmission, as shown in the Fig. Shown in 1-2. The engine can be started while a transmission is in gear, as shown in Fig. 3 is shown. The engine can be modified according to the one in Fig. The procedures described in section 4 can be started.

[0014] On Fig. 1. Referring to, several cylinders, one of which is in Fig. As shown in Figure 1, a comprehensive internal combustion engine 10 is controlled by the electronic engine control unit 12. The engine 10 contains a combustion chamber 30 and cylinder walls 32 with a piston 36 positioned therein, which is connected to a crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. A starter 96 includes a pinion shaft 98 and a pinion 95. The pinion shaft 98 can selectively advance the pinion 95 to engage the ring gear 99. The starter 96 can be mounted directly at the front end or the rear end of the engine. In some examples, the starter 96 can selectively supply torque to the crankshaft 40 via a belt or chain. In one example, the starter 96 is in a resting state when it is not engaged with the engine crankshaft.

[0015] In the diagram, the combustion chamber 30 is connected to an intake manifold 44 and an exhaust manifold 48 via an intake valve 52 and an exhaust valve 54, respectively. Each intake and exhaust valve can be actuated by an intake cam 51 and an exhaust cam 53. The position of the intake cam 51 can be determined by the intake cam sensor 55. The position of the exhaust cam 53 can be determined by the exhaust cam sensor 57. In the diagram, the fuel injector 66 is positioned to inject fuel into an intake port of the cylinder 30, a process known to those skilled in the art as intake port injection. Alternatively, fuel can be injected directly into a cylinder, a process known to those skilled in the art as direct injection. The fuel injector 66 supplies liquid fuel proportional to the pulse width of the FPW signal from the controller 12.Fuel is supplied to the fuel injector 66 by a fuel system (not shown) comprising a fuel tank, fuel pump, and fuel distribution line (not shown). The fuel injector 66 receives operating current from a driver 68, which responds to the controller 12. Additionally, the intake manifold 44 is connected in the illustration to an optional electronic throttle valve 62, which sets the position of the throttle plate 64 to control airflow from the air inlet 42 to the intake manifold 44. In some examples, the throttle valve 62 and the throttle plate 64 may be positioned between the intake valve 52 and the intake manifold 44, so that the throttle valve 62 is a single throttle valve.

[0016] A distributorless ignition system 88 supplies a spark to the combustion chamber 30 via a spark plug 92 in response to the control unit 12. In the diagram, a universal lambda sensor 126 (UEGO sensor, UEGO - Universal Exhaust Gas Oxygen) is connected to the exhaust manifold 48 upstream of a catalytic converter 70. Alternatively, a dual-state lambda sensor can be used instead of the UEGO sensor 126.

[0017] The vehicle wheel brakes can be applied when the brake pedal 150 is actuated by the foot 152. The brake pedal sensor 154 sends a signal indicating the brake pedal position to the control unit 12. The foot 152 is assisted by the brake booster 140, which actuates the vehicle brakes.

[0018] The catalyst 70 can contain multiple catalyst bricks in one example. In another example, multiple exhaust gas purification systems, each with multiple bricks, can be used. The catalyst 70 can also be a three-way catalyst in one example.

[0019] In the representation of Fig. In Figure 1, the controller 12 is a conventional microcomputer containing a microprocessor unit 102, input / output ports (I / O) 104, a read-only memory (ROM) 106, a random access memory (RAM) 108, a cache memory (KAM) 110, and a conventional data bus. In addition to the signals discussed previously, the controller 12 receives various signals from sensors coupled to the motor 10, including the engine coolant temperature (ECT) from the temperature sensor 112 coupled to the cooling sleeve 114; a position sensor 134 coupled to an accelerator pedal 130 to detect the force applied by the foot 132; a measurement of the intake manifold pressure (MAP) from the pressure sensor 122 coupled to the intake manifold 44; and an engine position sensor from a Hall effect sensor 118, which detects the position of the crankshaft 40. a measurement of the mass of air entering the engine from sensor 120; and a measurement of the throttle position from sensor 58.Barometric pressure can also be detected for processing by the controller 12 (sensor not shown). The engine position sensor 118 generates a predetermined number of evenly spaced pulses with each revolution of the crankshaft, from which the engine speed (RPM) can be determined.

[0020] In operation, each cylinder in engine 10 typically undergoes a four-stroke cycle: the cycle comprises the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 54 generally closes and the intake valve 52 opens. Air is drawn into the combustion chamber 30 via the intake manifold 44, and the piston 36 moves towards the bottom of the cylinder to increase the volume in the combustion chamber 30. The position in which the piston 36 is near the bottom of the cylinder and at the end of its stroke (for example, when the combustion chamber 30 has reached its maximum volume) is generally referred to by those skilled in the art as bottom dead center (BDC). During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves towards the cylinder head to compress the air in the combustion chamber 30.The point at which the piston 36 is located at the end of its stroke and which is closest to the cylinder head (for example, when the combustion chamber 30 has its smallest volume) is generally referred to by those skilled in the art as top dead center (TDC). In a process referred to below as injection, fuel is introduced into the combustion chamber. In a process referred to below as ignition, the injected fuel is ignited by a known ignition device, such as a spark plug 92, resulting in combustion. During the power stroke, the expanding gases push the piston 36 back to bottom dead center (BDC). The crankshaft 40 converts piston movement into a torque of the crankshaft. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the burnt air-fuel mixture to the exhaust manifold 48, and the piston returns to TDC.It should be noted that the above is shown only as an example and that the timing of the opening and / or closing of the intake and exhaust valves may vary to provide positive or negative valve overlap, late closing of the intake valve, or various other examples.

[0021] Fig. Figure 2 is a block diagram of a vehicle 201 and a vehicle powertrain 200. The powertrain 200 can be driven by the motor 10. The motor 10 can be equipped with a Fig. The starter motor shown in Figure 1 can be started. Furthermore, the motor can generate or adjust torque via the torque actuator 204, such as a fuel injector, a throttle valve, etc.

[0022] Motor output torque can be transmitted via shaft 237 to the input side of the impeller 285 of the torque converter 206. The torque converter 206 contains a turbine wheel 286 for delivering torque to the transmission input shaft 270. The transmission input shaft 270 mechanically couples the torque converter 206 to the automatic transmission 208. The torque converter 206 also includes a torque converter bypass lock-up clutch (TCC) 212. Torque is transmitted directly from the impeller 285 to the turbine wheel 286 when the TCC is locked. The TCC is electrically operated by the controller 12. Alternatively, the TCC can be hydraulically locked. In this example, the torque converter can be considered a component of the transmission. The rotational speed and position of the torque converter's turbine wheel can be determined via the position sensor 239.In some examples, there may be 118 and / or 239 torque sensors, or there may be combined position and torque sensors.

[0023] When the torque converter lock-up clutch 212 is fully disengaged, the torque converter 206 transmits engine torque to the automatic transmission 208 via fluid transfer between the torque converter's turbine wheel 286 and pump wheel 285, thus providing torque amplification. However, when the torque converter lock-up clutch 212 is fully engaged, engine output torque is transmitted directly to an input shaft (not shown) of the transmission 208 via the transmission's torque converter lock-up clutch. Alternatively, the torque converter lock-up clutch 212 can be partially engaged, allowing adjustment of the amount of torque transmitted directly to the transmission.The control unit 12 can be configured to adjust the torque level transmitted by the torque converter 212 by adjusting the torque converter lock-up clutch in response to different engine operating conditions or based on a driver-based engine operating request.

[0024] The automatic transmission 208 contains gear clutches (for example, gears 1-6) 211 and a forward clutch 210. The gear clutches 211 and the forward clutch 210 can be selectively engaged to propel a vehicle. Torque output from the automatic transmission 208 can, in turn, be transmitted to the rear wheels 216 to propel the vehicle via the output shaft 260. In particular, the automatic transmission 208 can transmit an input drive torque at the input shaft 270 in response to a vehicle driving condition before transmitting an output drive torque to the rear wheels 216. Torque can also be directed to the front wheels 217 via the transfer case 261.

[0025] Furthermore, a frictional force can be applied to the wheels 216 by engaging the wheel brakes 218. For example, the wheel brakes 218 can be engaged in response to the driver placing their foot on a brake pedal (150 in Fig. 1) is pressed, engaged. In other examples, the control unit 12 or a control unit coupled to the control unit 12 can actuate the wheel brakes. In the same way, a frictional force can be reduced at the wheels 216 by disengaging the wheel brakes 218 in response to the driver removing their foot from a brake pedal. Furthermore, the vehicle brakes can apply a frictional force to the wheels 216 via the control unit 12 as part of an automated engine stop procedure.

[0026] A mechanical oil pump 114 can be in fluid connection with the automatic transmission 208 to provide hydraulic pressure for engaging various clutches, such as the forward clutch 210, the gear clutch 211, and / or the torque converter lock-up clutch 212. The mechanical oil pump 214 can be operated according to the torque converter 206 and can, for example, be driven by the rotation of the engine. Thus, the hydraulic pressure generated in the mechanical oil pump 214 can increase with increasing engine speed and decrease with decreasing engine speed.

[0027] The controller 12 can be configured to receive inputs from the motor 10, as in Fig. 1. shown in more detail, to receive and accordingly control engine torque output and / or the operation of the torque converter, transmission, clutches, and / or brakes. For example, engine torque output can be controlled by adjusting a combination of ignition timing, fuel pulse width, fuel pulse control, and / or air charge by controlling throttle opening and / or valve timing, valve lift, and boost pressure for turbocharged or mechanically supercharged engines. Engine control can be performed on a cylinder-selective basis to control engine torque output.

[0028] When idle stop conditions are met, the control unit 42 can initiate engine shutdown by cutting off the fuel supply and spark to the engine. To maintain a degree of torsion, the control unit 12 can anchor rotating elements of the transmission 208 to a housing 259 of the transmission and thereby to the vehicle frame. When engine restart conditions are met and / or a driver wishes to start the vehicle, the control unit 12 can restart the engine by resuming combustion in the engine cylinders.

[0029] Thus, the system of Fig. 1 and Fig. 2. A vehicle system comprising: a motor; an actuator coupled to the motor; and a controller containing executable instructions stored in non-volatile memory, wherein the executable instructions provide for rotating the motor to a starting speed and adjusting the actuator to control the motor speed to a single starting speed greater than the starting speed and less than the engine idle speed during engine start-up. The vehicle system includes the actuator being an ignition system and further includes additional instructions for maintaining the single starting speed for a set duration before reaching the engine idle speed during engine start-up. The vehicle system also includes additional instructions for varying the engine idle speed in response to engine operating conditions.Furthermore, the vehicle system includes additional instructions for ramping the engine speed from the single engine start-up speed to the engine idle speed after holding the target engine start-up speed for a specified duration. The vehicle system also includes additional instructions for setting a rate at which the engine speed is ramped to the engine idle speed. Finally, the vehicle system includes additional instructions for automatically restarting the engine.

[0030] Now on Fig. 3. Referring to this, an example engine start sequence is shown. The engine start sequence can be accessed via the [function / method - context needed] in the Fig. 1 and Fig. The system shown in 2 will be implemented. Fig. The sequence shown in section 3 can be achieved by executing instructions according to the procedure of Fig. 4 are provided. Vertical markers at times T1 - T7 indicate times of interest in the sequence.

[0031] The first application from above in Fig. Figure 3 shows the motor speed as a function of time. The Y-axis represents the motor speed, and the motor speed increases in the direction of the Y-axis arrow. The X-axis represents time, and time increases from the left side of the axis. Fig. 3 to the right of Fig. 3 to.

[0032] The second layer from the top of Fig. Figure 3 shows the motor temperature as a function of time. The Y-axis represents the motor temperature, and the motor temperature increases in the direction of the Y-axis arrow. The X-axis represents time, and time decreases from the left side of the axis. Fig. 3 to the right of Fig. 3 to.

[0033] The third layer from the top of Fig. Figure 3 shows the target motor speed as a function of time. The Y-axis represents the target motor speed, and the target motor speed increases in the direction of the Y-axis arrow. The X-axis represents time, and time increases from the left side of the axis. Fig. 3 to the right of Fig. 3. The target engine speed is the speed to which the engine is driven when no torque is requested by the driver (for example, a target torque entered by the driver via an accelerator pedal). The target engine speed can be based on a target engine starting speed or a target engine idle speed.

[0034] The fourth layer from the top of Fig. Figure 3 shows the engine throttle position as a function of time. The Y-axis represents the engine throttle position, and the throttle opening increases in the direction of the Y-axis arrow. The X-axis represents time, and time increases from the left side of the axis. Fig. 3 to the right of Fig. 3 to.

[0035] The fifth layer from the top of Fig. Figure 3 shows the engine ignition timing as a function of time. The Y-axis represents the engine ignition timing, and the ignition timing is advanced from TDC (Top Dead Center) compression stroke when the ignition timing curve is above the X-axis. The ignition timing is retarded from TDC compression stroke when the ignition timing curve is below the X-axis. The X-axis represents time, and time decreases from the left side of the X-axis. Fig. 3 to the right of Fig. 3 to.

[0036] At time T aThe engine speed is 0, indicating that the engine is stopped. The engine can be stopped automatically without any input from a driver or operator into a device whose sole purpose or function is to start and / or stop the engine (for example, an ignition switch). In one example, the engine may be stopped automatically in response to the torque requested by the driver being below a threshold torque. The target engine speed is set to a value described by a single target engine starting speed. For example, the single engine starting speed may be a value of 600 RPM, and the target engine starting speed does not change with the towing time, the time since the engine speed was zero, or the number of combustion events. The engine temperature is at a moderate level, and the engine throttle valve is partially open.The engine ignition timing is advanced slightly, but no spark is supplied to the engine because the engine is not turning.

[0037] At time T1, an engine start request (not shown) is received, and the engine begins to rotate, as indicated by the increasing engine speed. The engine temperature remains at a moderate level, and the target engine speed remains at the target engine start speed of 302. Engine actuators (for example, ignition timing and throttle position) are set to positions aimed at achieving the target engine start speed, as reflected in the target engine speed. The throttle valve is partially open or closed, and the ignition timing is advanced from TDC (top dead center) compression stroke.

[0038] At time T2, the engine has accelerated via combustion in the engine cylinders, so that it is within a threshold speed of the target engine start-up speed. After holding the target engine start-up speed for a target duration (for example, for a specific time period or engine combustion events), the target engine speed begins to ramp up to a first target engine idle speed 304 at an initial ramp rate of 310. The first target engine idle speed is based on engine temperature. The ramp rate from the target start-up speed 302 to the first target idle speed 304 can vary depending on the engine operating conditions (for example, engine temperature, time since engine stop, and barometric pressure). Adjusting the ramp rate based on engine operating conditions can ensure a smoother transition between the target engine start-up speed and the target engine idle speed.The engine temperature begins to rise slowly, and the throttle valve is partially closed to control the engine speed during starting and warm-up (for example, the time between when the engine exceeds the starting speed and before it reaches idle speed). The ignition timing is also retarded to control the engine speed during warm-up.

[0039] At time T3, the target engine speed reaches the target idle speed, and the engine speed is close to the target idle speed. The engine temperature continues to rise, and the target engine speed remains at the target idle speed. The throttle valve opening has increased, and the ignition timing has been advanced, so that the target idle speed can be maintained.

[0040] Between time T3 and time T4, the target engine speed is reduced in response to the engine temperature. Specifically, the target engine speed is reduced because the target idle speed decreases with increasing engine temperature. The engine throttle position, ignition timing, and engine speed vary in response to (not shown) variations in the torque requested by the driver.

[0041] At point T4, combustion in the engine is automatically stopped (for example, without a driver inputting a device whose sole function is to start and / or stop the engine, such as an ignition switch), and the engine speed begins to decrease. The throttle valve is closed, and the ignition timing is reduced to a base stage. The engine temperature remains at a higher level.

[0042] At time T5, an automatic engine start is requested in response to engine operating conditions. The engine is turned over by a starter motor, and the target engine speed is set to the target engine starting speed of 302. The engine throttle valve is partially open or closed, and the engine ignition timing is retarded (for example, the first ignition event for engine stop / start restarts may be retarded). The engine temperature remains at the same temperature as when the engine was stopped at time T4.

[0043] Between time points T5 and T6, combustion begins in the engine, and the engine speed increases in response to the torque provided by combustion. The throttle opening is reduced to decrease cylinder charge, and the ignition timing is retarded. Reducing the cylinder charge and retarding the ignition timing can be useful for controlling engine torque, ensuring the engine speed does not exceed the desired starting speed.

[0044] At time T6, the engine has accelerated via combustion in the engine cylinders, so that it is within a threshold speed of the target engine starting speed. After holding the target engine starting speed for a target duration, the target engine speed begins to ramp up to a second target engine idle speed 306 at a second ramp rate of 312. The second target engine idle speed is based on the engine temperature. The ramp rate from the target starting speed 302 to the second target idle speed 306 can vary depending on the engine operating conditions (for example, the engine temperature, the time since the engine was stopped, and the barometric pressure). The engine temperature remains at the higher level, and the throttle valve is partially closed to control the engine speed profile during starting and acceleration. The ignition timing is also retarded to control the engine speed during acceleration. The engine speed begins to increase in the same way as the torque converter impeller speed.At time T7, the target engine speed reaches the second target idle speed of 306. The engine speed stabilizes near the target engine speed. The throttle valve opening is increased, and the engine ignition timing is advanced, so that the engine speed is at the target engine speed. The engine throttle valve position and ignition timing are adjusted over time based on the torque requested by the driver.

[0045] In this way, the motor speed can be set to a single target starting speed, and after holding this target starting speed for a target duration, the motor speed is then ramped down to a target idle speed. Setting the motor speed to provide a target starting speed before reaching a target idle speed can improve the smoothness of the motor start by providing a more uniform motor speed curve during the start-up process.

[0046] Now on Fig. 4. With reference to this, a procedure for starting an engine is shown. The procedure of Fig. 4 can be found in the system of Fig. 1 and Fig. 2 will be provided. Furthermore, the procedure can be used by Fig. 4 the in Fig. Provide the sequence shown in section 3. The procedure of Fig. 4 can be stored in non-volatile memory as executable instructions.

[0047] In procedure 402, procedure 400 determines vehicle and engine operating conditions. The operating conditions may include, but are not limited to, engine speed, vehicle speed, brake pedal position, torque converter pump wheel speed, torque converter turbine wheel speed, ambient pressure, and temperature. After determining the operating conditions, procedure 400 proceeds to procedure 404.

[0048] In procedure 404, procedure 400 determines the target engine starting speed. The target engine starting speed can be determined empirically and stored in memory. In one example, the target engine starting speed assumes a single value during all engine starts. For example, a target engine starting speed for a four-cylinder engine might be 600 RPM. Furthermore, in some examples, the target engine starting speed does not change with engine temperature, time since engine stop, number of combustion events since engine stop, or other operating conditions. In other examples, the target engine starting speed may assume a single value for an engine start, but this single value may change between engine starts based on engine operating conditions, such as engine temperature, time since engine stop, and number of combustion events since engine stop.In one example, the target motor speed (for instance, the speed the motor should reach according to its control) remains at that value during the starting process and for a specified duration after reaching the target starting speed. The target starting speed is a speed that is higher than the starting speed (for example, 200-300 RPM) and lower than the target idle speed (for example, 800 RPM). After determining the target starting speed, procedure 400 transitions to procedure 406.

[0049] In procedure 406, the engine actuators are adjusted to achieve the target engine speed, which is set to the target engine start-up speed. In one example, the engine throttle position is adjusted to guide the engine speed to the target engine start-up speed. The ignition timing control, camshaft control, and injection control can also be adjusted to guide the engine speed to the target engine speed. In another example, actuator settings for engine start are determined empirically and stored in the control unit's memory. After adjusting the engine actuators, procedure 400 transitions to 408.

[0050] In procedure 408, the engine is supplied with fuel and a spark in procedure 400 and towed by a starter. The fuel control and fuel quantity are adjusted in response to the engine temperature, the ambient temperature, the cylinder air charge, and the target engine speed. The ignition timing is also adjusted in response to the target engine speed and the actual engine speed relative to the target engine speed. Specific ignition and fuel injection timings are determined empirically and stored in the control unit's memory. After initiating engine fuel supply, ignition, and towing, procedure 400 transitions to 410.

[0051] At step 410, procedure 400 assesses whether a target starting speed has been maintained for a target duration. The target duration can be a target time period or engine combustion events. In one example, the duration might be 0.5 seconds. In other examples, the target time period could be shorter or longer than 0.5 seconds. If procedure 400 determines that the engine speed is within a predetermined range of the target starting speed, the answer is yes, and procedure 400 proceeds to step 412; otherwise, procedure 400 returns to step 406.

[0052] It should be noted that the motor speed is controlled to the target motor speed using motor speed feedback to control motor speed actuators, regardless of whether the target motor speed is based on the target starting speed or a target idle speed. Although the actual motor speed is not always at the target motor speed, it is thus controlled to the target motor speed via motor speed feedback.

[0053] In procedure 400, method 412 determines a target engine idle speed. However, the target engine idle speed can also be determined in procedure 404, if desired. In one example, the target engine idle speed is determined empirically and is based on idle conditions with a warm engine. The target engine idle speed can be a compromise engine speed, taking into account engine noise, fuel economy, and vibrations.

[0054] In the 414, procedure 400 sets the target engine idle speed based on the engine operating conditions. For example, if the engine temperature is lower than the warm-up operating temperature, the target engine idle speed can be increased. Furthermore, the target engine idle speed can be increased if the catalyst temperature is low. Additionally, the target engine idle speed can be increased if the ambient temperature is low.

[0055] In some examples, procedure 400 at 414 also determines the motor speed ramp rate between the target motor starting speed and the target motor idle speed. In particular, the motor speed ramp rate can be varied according to the motor operating conditions, such as the motor temperature, the ambient temperature, and a speed difference between the target motor starting speed and the set target motor idle speed. The motor speed ramp rate can be determined empirically and stored in the controller's memory. After determining the set target motor idle speed, procedure 400 transitions to 416.

[0056] At 416, procedure 400 ramps the engine speed to the set target idle speed. The engine speed can be ramped from the target engine starting speed to the set target idle speed by opening the engine throttle valve and increasing the amount of fuel supplied to the engine cylinders. In other words, the engine torque is increased to ramp the engine speed to the set target idle speed. Once the engine speed has begun to ramp to the set target idle speed, procedure 400 transitions to 418.

[0057] At 418, procedure 400 adjusts the engine actuators to provide a target torque requested by the driver. Specifically, the engine throttle position, ignition timing, and fuel injection timing are adjusted to provide the driver-requested target torque. Procedure 400 terminates after the engine actuators have been adjusted.

[0058] Thus, the procedure of Fig. 4. A motor starting procedure is provided, comprising the following: rotating a motor to a starting speed; setting the motor speed to a single target starting speed that is greater than the starting speed and less than an idle speed; and, after holding the target starting speed for a target duration, setting the motor speed to the idle speed. The procedure includes rotating the motor by a starter that engages the motor in a controlled manner. Furthermore, the procedure includes adjusting the motor speed via an actuator.

[0059] In some examples, the method includes the actuator being an ignition system and further includes adjusting the ignition timing in response to the engine speed during engine start-up. The method also includes the engine start-up occurring while the engine speed is greater than the starting speed and less than the idle speed. Furthermore, the method includes adjusting the idle speed in response to engine operating conditions. The method includes the automatic restart of the engine.

[0060] Furthermore, the procedure of Fig. 4. A motor starting procedure is provided, comprising the following: turning a motor to a starting speed by means of a starter motor; setting an actuator to control the motor speed to a single target starting speed greater than the starting speed and less than an idle speed, wherein the single target starting speed does not vary over time, motor events, or the motor speed during the motor start; and, after holding the single target starting speed for a target duration, adjusting the motor speed to the idle speed. The procedure includes ramping the motor speed to the idle speed when adjusting the motor speed to the idle speed.

[0061] In some examples, the method involves varying the rate at which the engine speed is ramped to idle speed according to the engine operating conditions. Furthermore, the method involves varying the idle speed according to the engine operating conditions. The method involves turning the engine using a starter motor that is selectively coupled to the engine. The method further involves closing a throttle valve during engine start-up to reduce cylinder air charge. The method also involves injecting fuel into an engine cylinder during start-up.

[0062] As would be obvious to the average expert, in Fig.The four described procedures represent one or more of a number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Thus, various steps or functions shown can be performed in the sequence presented, in parallel, or, in some cases, omitted. Likewise, the processing sequence does not necessarily achieve the tasks, features, and advantages described here, but is provided for better illustration and description. Although not explicitly stated, it is obvious to the average expert that one or more of the presented steps or functions can be performed repeatedly, depending on the specific strategy used.

[0063] This concludes the description. A reading of it by a person skilled in the art would reveal many changes and modifications without departing from the intent and scope of protection of the description. For example, I3, I4, I5, V6, V8, V10, and V12 engines running on natural gas, gasoline, diesel, or alternative fuel configurations could make advantageous use of the present description.

Claims

[1] Engine starting procedure, which includes the following: Starting an engine (10) of a vehicle while a transmission coupled to the engine (10) is in a gear; Turning the engine (10) up to a starting speed; Setting the motor speed to a single target starting speed (302) that is greater than the starting speed and less than an idle speed; and after holding the target motor starting speed (302) at the target motor starting speed (302) for a target duration Adjusting the engine speed to the idle speed. [2] Method according to claim 1, wherein the motor (10) is rotated by a starter (96) which engages the motor (10) in a controlled manner, wherein the target duration is a time period. [3] Method according to claim 1, wherein the motor speed is adjusted via an actuator. [4] Method according to claim 3, wherein the actuator is an ignition system, and further comprising adjusting the ignition timing in response to the engine speed during engine start-up. [5] Method according to claim 4, wherein the engine start-up takes place while the engine speed is greater than the starting speed and less than the idle speed. [6] Method according to claim 1, further comprising adjusting the idle speed in response to engine operating conditions. [7] Method according to claim 1, wherein the motor (10) is automatically restarted. [8] Engine starting procedure, which includes the following: Starting an engine (10) of a vehicle while a transmission coupled to the engine (10) is in a gear; Turning the engine (10) up to a starting speed by a starter motor; Setting an actuator to control the motor speed to a single target starting speed (302) that is greater than the pull-in speed and less than an idle speed, wherein the single target starting speed (302) does not vary over time, motor events, or the motor speed during the motor start-up; and After holding the single target motor start-up speed (302) for a target duration, adjust the motor speed to the idle speed. [9] Method according to claim 8, wherein adjusting the engine speed to the idle speed comprises ramping the engine speed to the idle speed. [10] Method according to claim 9, wherein a rate at which the engine speed is ramped to the idle speed is varied with the engine operating conditions. [11] Method according to claim 10, further comprising varying the idle speed with the engine operating conditions. [12] Method according to claim 8, wherein the motor (10) is rotated by a starter motor which is specifically coupled to the motor (10). [13] Method according to claim 8, further comprising closing a throttle valve (62) during towing of the engine (10) to reduce the cylinder air charge. [14] Method according to claim 8, further comprising injecting fuel into an engine cylinder during start-up. [15] Vehicle system comprising the following: a motor (10); an actuator coupled to the motor (10); and a controller (12) containing executable instructions stored in non-volatile memory, wherein the executable instructions provide for starting the motor (10) while a transmission coupled to the motor (10) is in gear, rotating the motor (10) to a starting speed, and adjusting the actuator to control the motor speed to a single motor starting speed that is greater than the starting speed and less than a motor idle speed during motor start-up. [16] Vehicle system according to claim 15, wherein the actuator is an ignition system (88), and further comprising additional instructions for the single engine start-up speed for a set duration before reaching the engine idle speed during engine start-up. [17] Vehicle system according to claim 15, further comprising additional instructions for varying the engine idle speed in response to engine operating conditions. [18] Vehicle system according to claim 15, further comprising additional instructions for ramping the engine speed from the single engine start-up speed to the engine idle speed. [19] Vehicle system according to claim 18, further comprising additional instructions for setting a rate at which the engine speed is ramped to the engine idle speed. [20] Vehicle system according to claim 15, further comprising additional instructions for automatically restarting the engine (10).

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