GB2560171A

GB2560171A - A method of cranking an internal combustion engine of a motor vehicle

Info

Publication number: GB2560171A
Application number: GB1703306.9A
Authority: GB
Inventors: Frevert Nicolas; Schilder Boris; Schnorpfeil Stephan-Johannes; Eggert David
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2017-03-01
Filing date: 2017-03-01
Publication date: 2018-09-05
Also published as: GB201703306D0

Abstract

A method of cranking an internal combustion engine of a motor vehicle to start the internal combustion engine, eg using a motor-generator or belted alternator starter (BAS), comprises the steps of measuring a parameter indicative of environmental conditions being outside the motor vehicle (S100, S110); determining a value Q of a cranking torque and a value of rotational speed R to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of the parameter (S120); operating a starter motor coupled to the crankshaft to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational speed reaches a predetermined value thereof, (S130). The rotational speed delivered by the starter motor may be increased as atmospheric pressure decreases; the cranking torque delivered by the starter motor may be increased as ambient air temperature decreases. Internal conditions of the engine may also be take into account.

Description

(54) Title of the Invention: A method of cranking an internal combustion engine of a motor vehicle

Abstract Title: Method of cranking an i.e. engine of a motor vehicle taking into account environmental conditions (57) A method of cranking an internal combustion engine of a motor vehicle to start the internal combustion engine, eg using a motor-generator or belted alternator starter (BAS), comprises the steps of measuring a parameter indicative of environmental conditions being outside the motor vehicle (S100, S110); determining a value Q of a cranking torque and a value of rotational speed R to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of the parameter (S120); operating a starter motor coupled to the crankshaft to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational speed reaches a predetermined value thereof, (S130). The rotational speed delivered by the starter motor may be increased as atmospheric pressure decreases; the cranking torque delivered by the starter motor may be increased as ambient air temperature decreases. Internal conditions of the engine may also be take into account.

1/2

540

520

2/2

FIG.3

A METHOD OF CRANKING AN INTERNAL COMBUSTION ENGINE OF A MOTOR VEHICLE

TECHNICAL FIELD

The present disclosure relates to a method of cranking an internal combustion engine of a motor vehicle having a motor/generator operatively connected to a crankshaft of the internal combustion engine by a belt and pulley system. The method could be applied when the motor vehicle is in a halt and the internal combustion engine has been shut down for an extended time (“key start”) or when the internal combustion engine has been temporarily shut down (“first start”).

BACKGROUND

In order to reduce fuel consumption and polluting emissions some motor vehicles have been proposed in recent years whose internal combustion engine is generally cranked by means of a starter motor, namely an electric motor that rotates the crankshaft of the internal combustion engine up to a minimum rotational speed, above which the engine is able to continue running under its own power.

Before reaching this minimum rotational speed, small quantities of fuel may be supplied and ignited into the combustion chambers of the internal combustion engine, in order to support the starter motor in rotating the crankshaft and thus speed up the cranking phase of the internal combustion engine.

The torque delivered by the electric motor and the minimum rotational speed of the internal combustion engine during the engine cranking phase are generally design parameters. However, in some particular conditions of the motor vehicle, more particularly in some particular environmental conditions, they may have an unfavourable impact on the drivability of the motor vehicle, because the torque delivered by the electric motor may lead to an energy inefficient engine start, and/or because the rotational speed needed to the internal combustion engine to start up may lead to unacceptable levels of noise and vibration (NVH).

SUMMARY

In view of the above, an object of the present disclosure is that of providing a solution that allows to obtain energy efficient engine starts of an internal combustion engine in response to some particular conditions of the motor vehicle, more particularly in response to particular environment conditions.

This and other objects are achieved by the embodiments of the solution having the features reported in the independent claims. The dependent claims delineate additional aspects of such embodiments.

In greater details, an embodiment of the present disclosure provides a method of cranking an internal combustion engine of a motor vehicle to start the internal combustion engine, said method comprising the steps of:

measuring a parameter indicative of environmental conditions being outside the motor vehicle;

- determining a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of said parameter,

- operating a starter motor coupled to the crankshaft to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational speed reaches a predetermined value thereof.

Thanks to this solution an optimal engine start may be performed appropriately adjusting the cranking torque and the rotational speed delivered by the starter motor to the crankshaft of the internal combustion engine in response to the environmental conditions.

According to an embodiment of the disclosure, the parameter indicative of the environmental conditions may be a barometric atmospheric pressure.

This embodiment provides a reliable solution for allow engine starts with a high value of energy efficiency, thereby saving money and reducing the polluting emissions (e.g. the CO2 emissions).

According to this embodiment the method may comprise the step of increasing the value of the rotational speed delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the barometric atmospheric pressure decreases.

The air per cylinder in low atmospheric pressure condition is not sufficient to keep the internal combustion engine running over a predetermined value of rotational speed. Thanks to this aspect it is possible to ensure a good startability of the motor vehicle and reduce the levels of noise and vibration.

According to an embodiment of the disclosure, the parameter indicative of the environmental conditions may be an ambient air temperature that is external to the motor vehicle.

Thank to this solution is possible to obtain energy efficient engine starts.

According to this embodiment the method may comprise the step of increasing the value of the cranking torque delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the ambient air temperature decreases. Thanks to this solution is possible to avoid any conventional pinion starter inside the motor vehicle as backup required for environmental conditions with low ambient air temperature.

An aspect of this embodiment provides that the method may comprise the steps of:

keeping the value of the cranking torque delivered by the starter motor at a value corresponding to a predetermined value thereof until the crankshaft of the internal combustion engine is moving, then increasing the value of the cranking torque delivered by the starter motor until the internal combustion engine starts.

Thanks to this aspect it is possible to avoid belt slippage between the starter motor and the crankshaft of the internal combustion engine.

According to a further aspect of this embodiment the predetermined value of the cranking torque corresponds to the calibrated breakaway torque at current condition. According to an embodiment of the disclosure the method comprises the steps of:

- measuring a parameter indicative of internal conditions of the internal combustion engine;

- determining a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of the parameter indicative of the internal conditions and the parameter indicative of the environmental conditions.

Thank to this aspect it is possible to simulate in advance values of a cranking torque and values of rotational speed to be delivered to a crankshaft of the internal combustion engine according to several environmental conditions.

According to the present disclosure, the method can be carried out with the help of a computer program comprising a program-code for carrying out all the steps of the method described above, and in the form of a computer program product comprising the computer program. The method can be also embodied as an electromagnetic signal, said signal being modulated to carry a sequence of data bits which represent a computer program to carry out all steps of the method.

Another embodiment of the solution provides a motor vehicle comprising an internal combustion engine, a starter motor coupled to a crankshaft of the internal combustion engine and an electronic control unit that, for starting the internal combustion engine, is configured to:

- measuring a parameter indicative of environmental conditions being outside the motor vehicle;

This embodiment achieves basically the same effects of the method above, in particular that allowing an appropriate adjustment of the cranking torque and the rotational speed delivered by the starter motor to the crankshaft in response to the environmental conditions.

The aspects of the solution described with reference to the method may be applied also to this embodiment. In particular, an aspect of the solution provides that the parameter indicative of the environmental conditions may be an atmospheric pressure outside the motor vehicle. The electronic control unit may be configured to increase the value of the rotational speed delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the atmospheric pressure decreases. Another aspect of the solution, provides that the parameter indicative of the environmental conditions may be an ambient air temperature that is external to the motor vehicle. The electronic control unit may be configured to increase the value of the cranking torque delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the ambient air temperature decreases. The electronic control unit may be configured to keep the value of the cranking torque delivered by the starter motor at a value corresponding to a predetermined value thereof until the crankshaft of the internal combustion engine is moving, and then to increase the value of the cranking torque delivered by the starter motor until the internal combustion engine starts. A further aspect of the solution provides that the predetermined value of the cranking torque corresponds to the calibrated breakaway torque at current condition. The electronic control unit may be configured to measure a parameter indicative of internal conditions of the internal combustion engine, and to determine a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of the parameter indicative of the internal conditions and the parameter indicative of the environmental conditions.

Still another embodiment of the solution provides an apparatus for cranking an internal combustion engine of a motor vehicle to start the internal combustion engine, said apparatus comprising:

- means for measuring a parameter indicative of environmental conditions being outside the motor vehicle,

- means for determining a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of said parameter,

- means for operating a starter motor coupled to the crankshaft to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational speed reaches a predetermined value thereof.

Also this embodiment achieves basically the same effects of the method above, in particular that allowing an appropriate adjustment of the cranking torque and the rotational speed delivered by the starter motor to the crankshaft in response to the environmental conditions.

The aspects of the solution described with reference to the method may be applied also to this embodiment. In particular, an aspect of the solution provides that the parameter indicative of the environmental conditions may be an atmospheric pressure measured outside the motor vehicle. The apparatus may comprise means for increasing the value of the rotational speed delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the atmospheric pressure decreases. An aspect of the solution provides that the parameter indicative of the environmental conditions may be an ambient air temperature outside the motor vehicle. The apparatus may comprise means for increasing the value of the cranking torque delivered by the starter motor to the crankshaft of the internal combustion engine as the measured value of the ambient air temperature decreases. The apparatus may comprise means for keeping the value of the cranking torque delivered by the starter motor at a value corresponding to a predetermined value thereof until the crankshaft of the internal combustion engine is moving, then increasing the value of the cranking torque delivered by the starter motor until the internal combustion engine starts. A further aspect of the invention provides that the predetermined value of the cranking torque corresponds to the calibrated breakaway torque at current condition. The apparatus may comprise means for measuring a parameter indicative of internal conditions of the internal combustion engine, and for determining a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft of the internal combustion engine on the basis of the measured value of the parameter indicative of the internal conditions and the parameter indicative of the environmental conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompanying drawings.

Figure 1 schematically shows a motor vehicle.

Figure 2 shows an internal combustion engine of the motor vehicle according to the section A-A of figure 1.

Figure 3 is a flowchart representing a method of cranking the internal combustion engine to start the internal combustion engine.

DETAILED DESCRIPTION

Some embodiments may include a motor vehicle 90 comprising an automotive system 100, as shown in figures 1 and 2, that includes an internal combustion engine (ICE) 110. In this example, the ICE 110 is a spark-ignition engine (e.g. a gasoline engine). In other embodiments, the ICE 110 could be a compression-ignition engine (e.g. Diesel engine). The ICE 110 has an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145. A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150. A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increase the pressure of the fuel received from a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gasses to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200. An air intake duct 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed in the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gasses from an exhaust manifold 225 that directs exhaust gasses from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gasses through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate. The exhaust gasses exit the turbine 250 and are directed into an exhaust system 270. The exhaust system 270 may include an exhaust pipe 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gasses. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gasses in the EGR system 300. An EGR valve 320 regulates a flow of exhaust gasses in the EGR system 300.

In order to move the motor vehicle 90, the crankshaft 145 of the ICE 110 is mechanically coupled to the drive wheels 500 of the motor vehicle 90 by means of a transmission 505, as shown in figure 2. The transmission 505 may be a manual transmission or an automatic transmission. The transmission 505 generally includes a gearbox 510 coupled to the drive wheels 500, for example via a driveline, and a clutch 515 coupled between the gearbox 510 and the crankshaft 145. The clutch 515 may be selectively moved in a closed position, where it actually engages the crankshaft 145 to the gearbox 510, or in an open position, where the crankshaft 145 is disengaged from the gearbox 510. The clutch 515 may be an electrically driven clutch, namely a clutch that is moved between the closed and the open position by an electric actuator.

The ICE 110 is further equipped with a starter motor 520 for cranking the engine. The starter motor 520 is coupled to the crankshaft 145 in a point comprised between the ICE 110 and the clutch 515. In particular, the starter motor 520 may part of a mild hybrid system which uses the starter motor 520 to contribute power to the crankshaft 145. For example, the starter motor 520 may be a Belt Alternator Starter (BAS) of a BAS hybrid system. The BAS is an electric machine which is coupled to the crankshaft 145 via a transmission belt 525 and which can operate as an electric motor, in order to crank the ICE 110 and provide power assist during acceleration of the motor vehicle 90, as well as an electric generator, in order to perform regenerative braking during decelerations. In other embodiments, the BAS system may be replaced by any other mild hybrid system that uses an electric motor coupled to the crankshaft 145.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110. The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, an accelerator pedal position sensor 445, and a brake pedal position sensor 446. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including, but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, the cam phaser 155, the clutch 515 and the starter motor 520. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

The automotive system 100 may include further sensors and/or devices in communication with the ECU 450. The ECU 450 may receive input signals from these further sensors which are configured to generate signals in proportion to various physical parameters of the environmental conditions outside the motor vehicle 90. The sensors include, but are not limited to a barometric air pressure (BAP) sensor 530 and an ambient air temperature sensor 540. The BAP sensor 530 determines the air pressure that is present outside the ICE 110, or the motor vehicle 90, and it may be placed in the cab of the motor vehicle 90, or in other locations known for positioning the BAP sensor 530. The ambient air temperature sensor 540 determines the air temperature outside the motor vehicle 90, and it may be placed, for example, outside the motor vehicle 90, or in other known locations known for positioning the air temperature sensor 540. BAP sensors and ambient air temperature sensor are readily available in the industry.

Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system 460, and send and receive signals to/from the interface bus. The memory system 460 may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analogue and/or digital signals to/from the various sensors and control devices. The program may embody the methods disclosed herein, allowing the CPU to carryout out the steps of such methods and control the ICE 110.

The program stored in the memory system 460 is transmitted from outside via a cable or in a wireless fashion. Outside the automotive system 100 it is normally visible as a computer program product, which is also called computer readable medium or machine readable medium in the art, and which should be understood to be a computer program code residing on a carrier, said carrier being transitory or non-transitory in nature with the consequence that the computer program product can be regarded to be transitory or non-transitory in nature.

An example of a transitory computer program product is a signal, e.g. an electromagnetic signal such as an optical signal, which is a transitory carrier for the computer program code. Carrying such computer program code can be achieved by modulating the signal by a conventional modulation technique such as QPSK for digital data, such that binary data representing said computer program code is impressed on the transitory electromagnetic signal. Such signals are e.g. made use of when transmitting computer program code in a wireless fashion via a wireless connection to a laptop.

In case of a non-transitory computer program product the computer program code is embodied in a tangible storage medium. The storage medium is then the non-transitory carrier mentioned above, such that the computer program code is permanently or nonpermanently stored in a retrievable way in or on this storage medium. The storage medium can be of conventionai type known in computer technology such as a flash memory, an Asic, a CD or the like.

Instead of an ECU 450, the automotive system 100 may have a different type of processor to provide the electronic logic, e.g. an embedded controller, an on-board computer, or any processing module that might be deployed in the motor vehicle.

The ECU 450 may be configured to implement an ICE start up strategy. While the ICE 110 is actually in a halt condition, the ICE start up strategy generally provides for the

ECU 450 to perform a cracking phase of the ICE 110. The engine cranking phase generally provides for the ECU 450 to operate the starter motor 520 to deliver a determined cranking torque value Q to the crankshaft 145, until the rotational speed R of the crankshaft 145 reaches a predetermined target value thereof. By way of example, this target value of the crankshaft rotational speed R may be a minimum value above which the ICE 110 is able to continue running under its own power (i.e. only by means of fuel injections), or it may be the current rotational speed of the driven shaft of the clutch 515, namely the shaft which is directly connected to the gearbox 510, in order to reach the synchronism.

To achieve this effect, the ECU 450 may perform the steps indicated in the flow chart of figure 3. The ECU 450 may be configured to measure a value of a parameter indicative of environmental conditions being outside the motor vehicle. The parameter indicative of the environmental conditions may be a value P of a barometric atmospheric pressure, thus the ECU 450 may be configured to measure a value P of a barometric atmospheric pressure (block S100). This value P may be measured by means of the BAP sensor 530 and may be expressed in terms of a number or of a percentage. The parameter indicative of the environmental conditions may be a value T of an ambient air temperature that is external to the motor vehicle 90 or the ICE 110, the ECU 450 may be configured to measure a value T of an ambient air temperature, (block S110). This value T may be measured by means of the ambient air temperature sensor 540 and may be expressed in terms of a number or of a percentage.

The barometric atmospheric pressure value P and the ambient air temperature value T are indicative of the positive torque (i.e. traction torque) and the rotational speed that the crankshaft 145 is demanding to the automotive system 100 to start the ICE. For example, a low ambient air temperature may affect the lubrication performance of a lubricant requiring a higher positive torque to start the engine, or a low barometric atmospheric pressure may affect the air per cylinder which may be not sufficient to keep the engine running.

Based on the barometric atmospheric pressure value P and the ambient air temperature value T, the ECU 450 may be configured to determine a corresponding value Q of a cranking torque and a corresponding value R of rotational speed to be delivered to the crankshaft 145 for performing the cranking phase of the ICE 110 (block S120), and to operate the starter motor 520 to deliver the determined cranking torque value Q and the determined rotational speed value R to the crankshaft 145, until the rotational speed of the crankshaft 145 reaches the target value thereof (block S130).

Thanks to this approach, the cranking torque value Q and the rotational speed value R provided by the starter motor 520 are not constant design parameters but becomes a parameter that depends on the environmental conditions being outside the motor vehicle 90.

In particular, in a first scenario where the environmental conditions include a low altitude above the sea level, i.e. a high barometric atmospheric pressure value P, and a warm/hot condition, i.e. a high ambient air temperature value T, the positive torque the crankshaft 145 is demanding is low and the air per cylinder is sufficient to keep the engine running, i.e. > 350 RPM, to ensure the start up of the ICE 110. Thus, the ECU 450 may be configured to operate the starter motor 520 to deliver a low cranking torque value Q and a low rotational speed value R to the crankshaft 145.

In a second scenario, where the environmental conditions include a high altitude above the sea level, i.e. a low barometric atmospheric pressure value P, and a warm/hot condition, i.e. a high ambient air temperature value T, the positive torque the crankshaft 145 is demanding is low but the air per cylinder is not sufficient to keep the engine running, i.e. > 350 RPM. Thus, Thus, the ECU 450 may be configured to operate the starter motor 520 to deliver a low cranking torque value Q to the crankshaft 145, and to deliver a high rotational speed value R, i.e. > 500 RPM, to the crankshaft 145, to ensure a smooth start up of the ICE 110.

In a third scenario, where the environmental conditions include a low altitude above the sea level, i.e. a high barometric atmospheric pressure value P, and a cold condition, i.e. a low ambient air temperature value T, the positive torque the crankshaft 145 is demanding is high but the air per cylinder is sufficient to keep the engine running, i.e. > 350 RPM to ensure the start up of the ICE 110. Thus, the ECU 450 may be configured to operate the starter motor 520 to deliver a high cranking torque value Q to the crankshaft 145, and to deliver a low rotational speed value R to the crankshaft 145.

In a fourth scenario, where the environmental conditions include a high altitude above the sea level, i.e. a low barometric atmospheric pressure value P, and a cold condition, i.e. a low ambient air temperature value T, the positive torque the crankshaft 145 is demanding is high and the air per cylinder is not sufficient to keep the engine running, i.e. > 350 RPM, to ensure the start up of the ICE 110. Thus, the ECU 450 may be configured to operate the starter motor 520 to deliver a high cranking torque value Q to the crankshaft 145 and a high rotational speed value R to the crankshaft 145 to ensure a smooth start up of the ICE 110.

According to an aspect of the present embodiment, if the motor vehicle 90 is in a cold condition, i.e. a low ambient air temperature value T, the positive torque the crankshaft 145 is demanding to the automotive system 100 to start the ICE 110 is high independently from the barometric atmospheric pressure value P. In this condition, the ECU 450 may be configured to operate the starter motor 520 to deliver a predetermined cranking torque value Q’, which may correspond to a calibrated breakaway torque at current condition, for example 65Nm, and hold it until the crankshaft 145 is moving. Afterwards, the ECU 450 may be configured to operate the starter motor 520 to increase the cranking torque value Q delivered to the crankshaft 145 until the ICE 110 start. Thanks to this approach, it is possible to avoid a transmission belt 525 slippages between the starter motor 520 and the crankshaft 145 of the ICE 110.

It should be observed that, notwithstanding the procedure described above provides for determining the cranking torque Q and/or the rotational speed R on the basis of both the barometric atmospheric pressure value P and the ambient air temperature value T, according to other embodiments, the procedure could determine the cranking torque Q and/or the rotational speed R on the basis of any other parameter indicative of the positive torque and the rotational speed that the crankshaft 145 is demanding to the automotive system 100 to start the ICE.

The ECU 450 may be configured to measure further values of parameters indicative of internal conditions of the ICE 110. The parameters indicative of the internal conditions of the ICE 110 may be a value of coolant and/or oil temperature. These values may be measured by means of the coolant and/or oil temperature sensors 380.

Based on the coolant and/or oil temperature values, the barometric atmospheric pressure value P and the ambient air temperature value T, the ECU 450 may be configured to determine a corresponding value Q of a cranking torque and a corresponding value R of rotational speed to be delivered to the crankshaft 145 for performing the cranking phase of the ICE 110, and to operate the starter motor 520 to deliver the determined cranking torque value Q and the determined rotational speed value R to the crankshaft 145, until the rotational speed of the crankshaft 145 reaches the target value thereof.

It should also be observed that, notwithstanding the procedures above have been described in connection with a start up phase of the motor vehicle 90, the same procedures could be implemented when the motor vehicle 90 is in a halt and the ICE 110 has been shut down for an extended time or when the ICE 110 has been temporarily shut down.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCES motor vehicle

100 automotive system 110 internal combustion engine 120 engine block

125 cylinder

130 cylinder head

135 camshaft

140 piston

145 crankshaft

150 combustion chamber

155 cam phaser

160 fuel injector

170 fuel rail

180 fuel pump

190 fuel source

200 intake manifold

205 air intake duct

210 intake port

215 valves

220 exhaust port

225 exhaust manifold

230 turbocharger

240 compressor

250 turbine

260 intercooler

270 exhaust system

275 exhaust pipe

280 aftertreatment devices

290 VGT actuator

300 exhaust gas recirculation system 310 EGR cooler

320 EGR valve

330 throttle body

340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor

380 coolant and oil temperature and level sensors

400 fuel rail pressure sensor

410 cam position sensor

420 crank position sensor

430 exhaust pressure and temperature sensors

440 EGR temperature sensor

445 accelerator pedal position sensor

446 brake pedal position sensor

450 ECU

460 memory system

500 drive wheels

505 transmission

510 gearbox

515 clutch

520 starter motor

525 transmission belt

530 barometric air pressure sensor

540 ambient air temperature sensor

S100 block

S110 block

S120 block

S130 block

P barometric atmospheric pressure value

T ambient air temperature value

Q cranking torque value delivered to the crankshaft

R rotational speed value delivered to the crankshaft

Claims

1. A method of cranking an internal combustion engine (110) of a motor vehicle (90) to start the internal combustion engine (110), said method comprising the steps of:

- measuring a parameter indicative of environmental conditions being outside the motor vehicle (90),

- determining a value of a cranking torque and a value of rotational speed to be delivered to a crankshaft (145) of the internal combustion engine (110) on the basis of the measured value of said parameter,

- operating a starter motor (510) coupled to the crankshaft (145) to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational speed reaches a predetermined value thereof.

2. A method according to claim 1, wherein the parameter indicative of the environmental conditions may be an atmospheric pressure measured outside the motor vehicle (90).

3. A method according to claim 2, comprising the step of increasing the value of the rotational speed delivered by the starter motor (520) to the crankshaft (145) of the internal combustion engine (110) as the measured value of the atmospheric pressure decreases.

4. A method according to claim 1, wherein the parameter indicative of the environmental conditions may be an ambient air temperature outside the motor vehicle (90).

5. A method according to claim 4, comprising the step of increasing the value of the cranking torque delivered by the starter motor (520) to the crankshaft (145) of the internal combustion engine (110) as the measured value of the ambient air temperature decreases.

6.

A method according to claim 4, comprising the steps of: keeping the value of the cranking torque delivered by the starter motor (520) at a value corresponding to a predetermined value thereof until the crankshaft (145) of the internal combustion engine (110) is moving, then increasing the value of the cranking torque delivered by the starter motor (520) until the internal combustion engine (110) starts.

7. A method according to claim 6, wherein the predetermined value of the cranking torque corresponds to the calibrated breakaway torque at current condition.

8. A method according to any of the preceding claims, comprising the steps of:

- measuring a parameter indicative of internal conditions of the internal combustion engine (110);

- determining a value of a cranking torque and a value of rotational speed to be delivered to the crankshaft (145) of the internal combustion engine (110) on the basis of the measured value of the parameter indicative of the internal conditions and the parameter indicative of the environmental conditions.

9. A computer program comprising a program-code for carrying out all the steps of the method according to any of the preceding claims.

10. A computer program product comprising the computer program of claim 9.

11. An electromagnetic signal modulated to carry a sequence of data bits which represent the computer program of claim 9.

12. A motor vehicle (90) comprising an internal combustion engine (110), a starter motor (520) coupled to a crankshaft (145) of the internal combustion engine and an electronic control unit (450) that, for, starting the internal combustion engine (110) is configured to:

- measuring a parameter indicative of environmental conditions being outside the motor vehicle (90);

- operating a starter motor (520) coupled to the crankshaft (145) to deliver the cranking torque value and the rotational speed value, until a crankshaft rotational

5 speed reaches a predetermined value thereof.

Intellectual

Property

Office

Application No: GB1703306.9