CN114922760A

CN114922760A - Method for starting IC engine of vehicle and system thereof

Info

Publication number: CN114922760A
Application number: CN202210131614.8A
Authority: CN
Inventors: M·穆鲁吉桑; P·舒穆加森达拉姆; B·瓦迪亚纳坦; P·阿伦库马尔; N·N·克里希纳库马尔
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2021-02-12
Filing date: 2022-02-14
Publication date: 2022-08-19
Also published as: WO2022172287A1; EP4291768A1

Abstract

The present invention relates to a method for starting an Internal Combustion (IC) engine (110) connected to a crankshaft (120) coupled to an ISG (130), the method comprising: receiving (304), by the ECU (140), an activation signal; transmitting (306) an initiation signal to an ISG controller (150) communicatively coupled with the ISG; starting (307) the crankshaft in a reverse direction by the ISG in response to a first signal from the ISG controller corresponding to the enable signal; monitoring (308), by the ECU, a position of the crankshaft; retarding (309), by the ECU, injection and ignition of an air-fuel mixture inside the IC engine during reverse rotation of the crankshaft; and rotating (310) the crankshaft in a forward direction by the ISG in response to a second signal from the ISG controller, thereby starting the IC engine.

Description

Method for starting IC engine of vehicle and system thereof

Technical Field

The present invention relates to a method for starting an internal combustion engine of a vehicle and a system thereof.

Background

Vehicles that generate power using a power source, such as an Internal Combustion (IC) engine, are typically equipped with a driveline to transmit the power generated by the power source to one or more wheels of the vehicle. To start the IC engine, the crankshaft of the IC engine is rotated. There are several known methods of rotating the crankshaft of an IC engine in various ways, such as using an Integrated Starter Generator (ISG) system.

Typically, an ISG system includes an ISG machine that includes a stator and a rotor connected to a crankshaft of an IC engine. The ISG system also includes an ISG controller operatively connected to the ISG machine. The ISG controller controls the ISG machine, for example, by causing the ISG machine to operate as an engine starter or a generator.

When operating as an engine starter, the ISG system first rotates the crankshaft in a reverse direction to obtain a desired momentum, and then rotates the crankshaft in a forward direction. Generally, when the crankshaft rotates, an air-fuel mixture is injected into the inside of the IC engine. However, ignition occurs only during forward rotation. Therefore, the air-fuel mixture injected during the reverse rotation will be added to the air-fuel mixture injected during the forward rotation. Therefore, combustion of the fuel does not completely occur, and thus more hydrocarbons are emitted. Therefore, it is generally desirable to trigger injection of the air-fuel mixture and ignition thereof only during forward rotation of the crankshaft.

In order to achieve the above object, an additional injection suppressing device is installed in the existing engine control system. These suppression means suppress fuel injection when the crankshaft rotates in the reverse direction. Thus, injection and ignition are disabled whenever the crankshaft is rotating in the reverse direction. Other engine control systems disable the starter switch input during reverse rotation of the crankshaft.

One of the major drawbacks associated with existing engine control systems is that the crank position sensor processes the signal corresponding to the reverse rotation and starts the engine synchronization. Once the reverse rotation is completed, the Engine Control Unit (ECU) schedules the pre-injection. Due to the process of crankshaft reverse rotation, the number of teeth (of the rotor) between the gaps do not match, resulting in an engine synchronization failure that disables subsequent injection and ignition cycles. The fuel is discharged as hydrocarbon emissions due to the absence of an ignition event that ignites the pre-injected fuel. Now, the ISG machine rotates the crankshaft in a forward direction to begin injection and ignition resynchronization and rescheduling. This resynchronization delays engine start-up, thereby increasing the hydrocarbon emissions and electrical load of the vehicle.

Accordingly, there is a need in the art for a method and system for starting an internal combustion engine in a vehicle that addresses at least the above-mentioned problems.

Disclosure of Invention

In one aspect, the present disclosure is directed to a method for starting an Internal Combustion (IC) engine connected to a crankshaft coupled with an integrated starter-generator. The method comprises the following steps: an enable signal is received by the engine control unit and communicated to an integrated starter-generator controller communicatively coupled to the integrated starter-generator. Thereafter, the crankshaft is cranked (crank) in a reverse direction by the integrated starter generator in response to a first signal from the integrated starter generator controller corresponding to the start signal, and the position of the crankshaft is subsequently monitored by the engine control unit. The engine control unit is configured to retard injection and ignition of an air-fuel mixture within the IC engine during reverse rotation of the crankshaft and to rotate the crankshaft in a forward direction by the integrated starter generator in response to a second signal from the integrated starter generator controller, thereby starting the IC engine.

In one embodiment of the invention, the engine control unit continuously transmits the start signal to the integrated starter-generator controller for a predetermined time. The predetermined time is between 1.5 seconds and 5 seconds.

In another embodiment of the present invention, a crank position sensor in the IC engine continuously monitors the position of the crankshaft, the crank position sensor being coupled to the engine control unit. The engine control unit receives a crank position signal from a crank position sensor indicating either one of a forward rotation of the crankshaft or a reverse rotation of the crankshaft. The engine control unit delays injection and ignition of an air-fuel mixture inside the IC engine upon receiving a crank position signal indicating reverse rotation of the crankshaft.

In yet another embodiment of the present invention, the integrated starter generator controller generates the second signal in response to the engine control unit transmitting a start signal to the integrated starter generator controller for a predetermined time. During rotation of the crankshaft in the forward direction, the engine control unit is configured to process a crank position signal indicative of forward rotation of the crankshaft.

In yet another embodiment of the present invention, starting the IC engine includes scheduling injection and ignition of an air-fuel mixture based on a position of the crankshaft during forward rotation, determining, by the engine control unit, whether the crankshaft is rotating at a speed greater than a threshold engine start speed, and if the crankshaft is rotating at a speed greater than the threshold engine start speed, the integrated starter generator controller enters a generator mode.

In another aspect, the present disclosure is directed to a starting system for an Internal Combustion (IC) engine. The IC engine is connected to a crankshaft, the crankshaft is coupled with an integrated starter generator ISG, and a starting system of the IC engine comprises an engine control unit ECU, an ISG controller coupled with the ISG and the ECU, and a crank position sensor coupled with the ECU. The ECU is configured to receive the activation signal and transmit the activation signal to the ISG controller. The ISG cranks in a reverse direction in response to a first signal corresponding to a start signal received from an ISG controller. The system is configured to receive a signal from a crank position sensor and monitor a position of the crankshaft, and then retard injection and ignition of an air-fuel mixture within the IC engine during reverse rotation of the crankshaft. The ISG rotates the crankshaft in the forward direction after the delay, thereby starting the IC engine.

Drawings

Reference will now be made to embodiments of the invention, examples of which may be illustrated in the accompanying drawings. The drawings are intended to be illustrative, not limiting. While the invention is generally described in the context of these embodiments, it will be understood that it is not intended to limit the scope of the invention to these particular embodiments.

FIG. 1 shows a block diagram of a system for starting an Internal Combustion (IC) engine according to an embodiment of the present invention.

Fig. 2 shows a block diagram of an Engine Management System (EMS), which shows an Engine Control Unit (ECU), according to an embodiment of the present invention.

FIG. 3 shows a schematic diagram of an Integrated Starter Generator (ISG) system according to an embodiment of the present invention.

FIG. 4 illustrates a method for starting an Internal Combustion (IC) engine according to an embodiment of the present invention.

Fig. 5 shows the delay of injection and ignition of the air-fuel mixture during reverse rotation of the crankshaft according to the method of fig. 4.

FIG. 6 shows the latest method of injecting and igniting the air-fuel mixture during reverse rotation of the crankshaft.

Detailed Description

The present invention relates to a method for starting an Internal Combustion (IC) engine and a system thereof.

Various features and embodiments of the invention herein will be apparent from the following further description, which is set forth below. In the following exemplary embodiment, the vehicle is a two-wheeled vehicle. However, it is contemplated that the disclosure herein may be applied to any vehicle capable of accommodating the present subject matter without departing from the spirit of the present invention.

FIG. 1 shows a block diagram of a system 100 for starting an Internal Combustion (IC) engine 110 according to an embodiment of the invention. IC engine 110 is connected to crankshaft 120, and crankshaft 120 is coupled to an Integrated Starter Generator (ISG) 130. System 100 has an engine control unit 140, an ISG controller 150 coupled to ISG 130 and to Engine Control Unit (ECU)140, and a crank position sensor 160 coupled to ECU 140.

FIG. 2 shows a block diagram of an Engine Management System (EMS), showing an engine control unit or ECU 140. ECU 140 is coupled to a plurality of sensors, such as, but not limited to, a throttle position sensor 170, a manifold pressure sensor 180, an intake air temperature sensor 190, an engine temperature sensor 200, a crank position sensor 160, and an oxygen sensor (lambda sensor) 210. Further, a plurality of actuators are also coupled to the ECU 140, each of which is actuated by the ECU 140 upon receiving inputs from a plurality of sensors as described below.

The throttle position sensor 170 measures the throttle opening percentage. The ECU 140 is configured to process the throttle opening percentage and detect the engine load and optimize the amount of fuel and the ignition timing.

The manifold pressure sensor 180 is configured to measure manifold absolute pressure. ECU 140 is configured to process the information and detect the engine load. The manifold pressure sensor 180 may also be used to detect changes in elevation. The ECU 140 is configured to optimize the amount of fuel and the ignition timing based on the output from the manifold pressure sensor 180.

The intake air temperature sensor 190 is configured to measure an intake air temperature. The ECU 140 is configured to optimize the amount of fuel and the ignition timing based on the input from the intake air temperature sensor 190.

The engine temperature sensor 200 measures the engine block temperature, and the ECU 140 is configured to optimize the amount of fuel and the ignition timing based on the engine block temperature.

Crank position sensor 160 is configured to measure a position and a rotational speed of crankshaft 120. ECU 140 is configured to optimize injection and ignition timing based on the output of crank position sensor 160. The crank position sensor 160 is discussed in detail in the following description.

Oxygen sensor 210 is configured to measure the residual oxygen content of the exhaust gas in the vehicle exhaust and send feedback to ECU 140 to operate IC engine 110 closer to the stoichiometric air-fuel ratio (i.e., λ ═ 1).

The plurality of actuators coupled with the ECU 140 have different functions. For example, the injector 220 is configured to inject a desired amount of fuel into the combustion chamber. Idle air control valve 230 is a bypass valve configured to provide sufficient air to idle IC engine 110. Canister purge valve 240 is configured to purge fuel vapor stored in the canister and sent to the air induction system, thereby reducing evaporative emissions. The ignition coil 250 is configured to provide a spark with sufficient energy at a desired time such that combustion of the air-fuel mixture occurs in the combustion chamber. Electronic secondary air injection valve 260 is configured to allow unburned hydrocarbons that exit the combustion chamber to be oxidized in the exhaust passage. The oxygen sensor heater 270 is configured to control the duty cycle of the lambda heater and maintain the internal resistance of the oxygen sensor 210 close to the nominal resistance.

Herein, the "pre-driving process" refers to a normal operation of the plurality of sensors and the plurality of actuators confirmed by the ECU 140. In other words, since the plurality of sensors and the plurality of actuators are coupled to the ECU 140, the pre-driving process confirms that their functions are normal, and none of them reports a malfunction or error.

Referring to fig. 3, the function of a typical ISG system is illustrated. The ISG system includes an ISG controller 150 and an ISG 130. ISG controller 150 is coupled to ISG 130, and ISG 130 is configured to crank crankshaft 120 upon receiving an input from ECU 140. An electrically actuated switch, also referred to as a user operable input switch 280, is configured to instruct ECU 140 to further instruct ISG controller 150 to crank crankshaft 120. The ISG controller 150 is configured to send the rotation direction information to the ECU 140, for example, through a Controller Area Network (CAN) or hard wiring. The ECU 140 is also configured to receive an idle stop start switch status 340 from a display screen or speedometer 310 of the vehicle based on input received from the idle stop start switch 290.

As shown in fig. 3, the ECU 140 and the ISG controller 150 are configured to communicate with each other. In one embodiment, ECU 140 is configured to communicate with ISG controller 150 regarding EMS enablement status 320. In another embodiment, the ISG controller 150 is configured to communicate with the ECU 140, for example, regarding faults or errors 330 in the ISG 130, ISG status 330, user-operable input switch 280 status 330, and the like.

Referring to fig. 4, in step 301, a user (interchangeably referred to as a rider) actuates an ignition key of a vehicle. Actuation of the ignition key powers the ECU 140.

In step 302, the ECU 140 is configured to check whether the pre-drive process has been completed. If the pre-drive process is not complete and some of the sensors and/or actuators have not reported normal operation, the ECU 140 waits until the pre-drive process ends. This is shown in step 303.

In one embodiment, if at least one of the plurality of sensors and/or the plurality of actuators malfunctions or is erroneous, the ECU 140 is configured to receive and notify the user of the corresponding input through an indication on a display screen of the vehicle or the speedometer 310. Thus, the ECU 140 does not perform any further steps described in fig. 4, and therefore the vehicle is not started.

Upon receiving a satisfactory input during the pre-drive process, the ECU 140 is configured to receive an activation signal in step 304 in response to the user-operable input switch 280 being pressed. The user operable input switches 280 are located on the vehicle, preferably on the handlebar.

In the event that the user operable input switch 280 is not yet in a depressed state, the ECU 140 is configured to wait for receipt of an activation signal, as represented by step 305.

In step 306, when the electric start switch is in a pressed state and the ECU 140 has received the start signal, the ECU 140 is configured to continuously transmit the start signal to the ISG controller 150 for a predetermined time. In one embodiment, the predetermined time range is between 1.5 seconds and 5 seconds.

In one embodiment, communication between various controllers (such as, but not limited to, ECU 140, ISG controller 150, etc.), sensors (including multiple sensors), actuators (including multiple actuators, ISG 130, crankshaft 120, etc.), and themselves, is preferably performed through CAN or hard wiring.

ISG 130 is configured to crank crankshaft 120 in a reverse direction in response to a first signal received from ISG controller 150, as represented by step 307. In one embodiment, the ISG controller 150 is configured to generate the first signal in response to the ECU 140 transmitting an activation signal to the ISG controller 150 for a predetermined time.

In step 308, the position of the crankshaft is monitored by the ECU 140. This is done by a crank position sensor 160 in the IC engine 110. Crank position sensor 160 is configured to continuously monitor a position of crankshaft 120 and generate a crank position signal, which is received by ECU 140. The crank position signal is configured to indicate a forward rotation of crankshaft 120 or a reverse rotation of crankshaft 120, as the case may be.

When the crank position signal indicates reverse rotation of crankshaft 120, injection and ignition of the air-fuel mixture in IC engine 110 is retarded by ECU 140. As shown in step 309, the injection and ignition of the air-fuel mixture is retarded because the ECU 140 does not communicate with the ISG controller 150 when receiving the crank position signal indicating the reverse rotation of the crankshaft 120.

Advantageously, the crank position signal during reverse rotation of crankshaft 120 is not processed and the synchronous activity of IC engine 110 (i.e., injection and ignition of the air-fuel mixture) is retarded. Since the ECU 140 does not process and ignore the crank position signal during reverse rotation, there is a synchronization delay, which not only results in reduced hydrocarbon emissions, but also reduces engine start-up time. Furthermore, since the ECU 140 does not have to process the crank position signal, the electrical load on the vehicle is also reduced. Therefore, the drivability of the vehicle is improved.

In one embodiment, the ISG controller 150 is configured to generate the second signal in response to the ECU 140 transmitting the activation signal to the ISG controller 150 for a predetermined time. The positive rotation of crankshaft 120 causes the start of IC engine 110, as represented by step 310. In other words, a crank position signal indicating a forward rotation of crankshaft 120 causes a start of IC engine 110.

Unlike the reverse rotation, ECU 140 is configured to process a crank position signal indicating that crankshaft 120 is rotating in the forward direction. Thus, a synchronous activity of the IC engine 110 is caused to start (see step 310 a). In other words, injection and ignition of the air-fuel mixture inside the IC engine 110 occur.

The starting of the IC engine 110, as depicted by steps 310a to 310c, includes: scheduling injection and ignition of the air-fuel mixture based on a position of crankshaft 120 during forward rotation; determining, by ECU 140, whether crankshaft 120 is rotating at a speed greater than a threshold engine start-up speed; and if crankshaft 120 is rotating at a speed greater than the threshold engine start speed, ISG controller 150 enters a generator mode.

If the rotational speed of crankshaft 120 (as determined by the engine RPM sensor) is greater than (or equal to) the threshold engine start rotational speed (or predetermined threshold engine RPM), ISG controller 150 goes to generator mode and begins charging battery 300, i.e., IC engine 110 has started, as shown in step 310 b. This is shown in step 310 c.

In one embodiment, the threshold engine start speed is 700RPM to 1000 RPM. In the event crankshaft 120 speed is less than the threshold engine start speed, step 310b continues to be repeated.

In another aspect, the system 100 of the present invention as shown in FIG. 1 is capable of performing a method as described herein. In this regard, the ECU 140 is configured to: receives the enable signal and transmits the enable signal to the ISG controller 150. The ISG 130 cranks the crankshaft 120 in a reverse direction in response to a first signal corresponding to a start signal received from the ISG controller 150. ECU 140 is configured to receive a signal from crank position sensor 160 and monitor the position of crankshaft 120, and retard injection and ignition of an air-fuel mixture within IC engine 110 during reverse rotation of crankshaft 120. The ISG 130 rotates the crankshaft 120 in the forward direction after a delay, thereby starting the IC engine 110.

Referring to fig. 5, for the present invention, the curves depicted by 401, 402, 403, 404, 405, and 406 refer to engine speed, crank position sensor (160) output, ignition, injection, engine synchronization status, and status bits indicating direction of rotation, respectively. Similarly, in fig. 6, for the current state of the art approach, the curves depicted by 501, 502, 503, 504, 505, and 506 refer to engine speed, crank position sensor 160 output, ignition, injection, engine synchronization status, and status bits indicating direction of rotation, respectively.

The advantages of the present invention are more apparent by comparing fig. 5 and 6. As shown in fig. 5, the data collected during IC engine start-up, where ECU 140 delays processing of the crank position signal. The status bit 401 indicating the rotation direction information is set to 1 during the reverse rotation. At this time, the crank position signal 402 is not processed by the ECU 140, which is also observed in the engine speed 401. Once the crankshaft is rotating in the forward direction (as evident at zero in 401), both the crank position signal 402 and the IC engine synchronization activity 405 are executed by the ECU 140.

The corresponding data representing the current state-of-the-art approach in FIG. 6 shows IC engine synchronization 505 and the processing of the crank position signal 502 by ECU 140 during reverse rotation of the crankshaft. As discussed herein, this results in increased engine start time and electrical load on the vehicle.

Although the present invention has been described with respect to particular embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

Claims

1. A method for starting an Internal Combustion (IC) engine (110), the IC engine (110) connected to a crankshaft (120), the crankshaft (120) coupled with an integrated starter-generator (130), the method comprising the steps of:

receiving (304), by an engine control unit (140), an activation signal;

communicating (306) the start signal to an integrated starter generator controller (150) communicatively coupled with the integrated starter generator (130);

cranking (307) the crankshaft (120) in a reverse direction by the integrated starter generator (130) in response to a first signal from the integrated starter generator controller (150) corresponding to the crank activation signal;

monitoring (308), by the engine control unit (140), a position of the crankshaft (120);

delaying (309), by the engine control unit (140), injection and ignition of an air-fuel mixture within the IC engine (110) during reverse rotation of the crankshaft (120); and

rotating (310) the crankshaft (120) in a forward direction by the integrated starter generator (130) in response to a second signal from the integrated starter generator controller (150) to start the IC engine (110).

2. The method of claim 1, wherein the engine control unit (140) continuously transmits the start signal to the integrated starter generator controller (150) for a predetermined time.

3. The method of claim 2, wherein the predetermined time is between 1.5 seconds and 5 seconds.

4. The method of claim 1, wherein a crank position sensor (160) in the IC engine (110) continuously monitors the position of the crankshaft (120), the crank position sensor (160) being coupled to the engine control unit (140).

5. The method of claim 4, wherein a crank position signal received by the engine control unit (140) from the crank position sensor (160) is indicative of either a forward rotation of the crankshaft (120) or a reverse rotation of the crankshaft (120).

6. The method of claim 4 or 5, wherein the engine control unit (140) delays injection and ignition of an air-fuel mixture within the IC engine (110) when the engine control unit (140) receives a crank position signal indicative of reverse rotation of the crankshaft (120).

7. The method of claim 3, wherein the integrated starter generator controller (150) generates the second signal in response to the engine control unit (140) communicating the start signal to the integrated starter generator controller (150) for a predetermined time.

8. The method of claim 4 or 5, wherein during rotation of the crankshaft (120) in a forward direction, the engine control unit (140) is configured to process a crank position signal indicative of forward rotation of the crankshaft (120).

9. The method of claim 1 or 9, wherein starting (310) the IC engine (110) comprises:

scheduling (310a) injection and ignition of an air-fuel mixture during forward rotation based on a position of the crankshaft (120);

determining (310b), by the engine control unit (140), whether the crankshaft (120) is rotating at a speed greater than a threshold engine start speed; and

if the crankshaft (120) is rotating at a speed greater than the threshold engine start speed, the integrated starter generator controller (150) enters (310c) a generator mode.

10. A system (100) for starting an Internal Combustion (IC) engine (110), the IC engine (110) connected to a crankshaft (120), the crankshaft (120) coupled with an integrated starter generator (130), the system (100) comprising:

an engine control unit (140);

an integrated starter generator controller (150) coupled with the integrated starter generator (130) and the engine control unit (140); and

a crank position sensor (160) coupled with the engine control unit (140);

wherein the engine control unit (140) is configured to:

receiving a starting signal;

communicating the start signal to the integrated starter generator controller (150), the integrated starter generator (130) cranking the crankshaft (120) in a reverse direction in response to a first signal corresponding to the start signal received from the integrated starter generator controller (150); receiving a signal from the crank position sensor (160) and monitoring a position of the crankshaft (120); and

delaying injection and ignition of an air-fuel mixture within the IC engine (110) during reverse rotation of the crankshaft (120), the integrated starter generator (130) rotating the crankshaft (120) in a forward direction after the delaying, thereby starting the IC engine (110).