# US 10,865,757 B2 · Engine starting system and starter

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- Number: US 10,865,757 B2
- Document ID: US10865757B2
- Status: Granted
- Kind: B2
- Application number: 16/308,699
- Filed: 2017-06-15
- Published: 2019-05-16
- Granted: 2020-12-15
- Earliest claimed: 2016-06-16
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Takuro Nakaoka; Akihiro Imura; Mitsuru Shibanuma; Yuki Kubo; Minoru Okamiya; Suguru Mizuno
- Web page: https://patentgrep.com/patent/US10865757B2

## CPC

- F02N 11/006: {using a plurality of electric motors}
- F02N 11/04: the motors being associated with current generators
- F02N 11/0814: {comprising means for controlling automatic idle-start-stop}
- F02N 11/0844: {with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind}
- F02N 11/0851: {characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear}
- F02N 15/022: {the starter comprising an intermediate clutch}
- F02N 15/04: the gearing including disengaging toothed gears
- F02N 15/067: {the starter comprising an electro-magnetically actuated lever}
- F02N 2200/022: Engine speed
- F02N 2300/104: Control of the starter motor torque
- F02N 2300/2002: using different starting modes, methods, or actuators depending on circumstances, e.g. engine temperature or component wear
- F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR

## Abstract

A first controller includes a start control section and a passage determination section. After activating a second starter to start cranking, the start control section stops the operation of the second starter and starts the motor operation of the first starter at a predetermined timing. The passage determination section determines whether a predetermined passage conditional expression holds after cranking is started by the second starter. The start control section stops the operation of the second starter and starts the motor operation of the first starter if the passage conditional expression holds before the engine passes the first compression top dead center, regardless of whether the engine has passed the first compression top dead center.

## Claims

### Claim 1

An engine starting system comprising:
a first starter that is connected to a crankshaft of an engine and rotatably drives the crankshaft;
a second starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft; and
a controller that controls operation of the first starter and the second starter, wherein
the first starter is a motor generator having a function of an electric generator and a function of an electric motor,
the second starter is a pinion enmeshing starter configured to include
a motor that receives electric power to cause it to rotate,
a pinion that moves axially to mesh with the ring gear,
a one-way clutch that transmits torque in only one direction from the motor to the pinion and blocks torque transmission from the pinion to the motor, and
a solenoid device having a function of moving the pinion axially and a function of starting/stopping power supply to the motor,
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where
the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the first starter, and
the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, stops operation of the second starter and starts motor operation of the first starter at a predetermined timing, and
a passage determination section that determines whether the passage conditional expression holds after cranking is started by the second starter, and
the start control section stops operation of the second starter and starts motor operation of the first starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center.

### Claim 2 (depends on 1)

The engine starting system according to claim 1, wherein
if the engine crosses the first compression top dead center without the passage conditional expression being satisfied, the start control section sets a timing of a stopping operation of the second starter and a timing of a starting motor operation of the first starter to be before an estimated timing at which the one-way clutch is reengaged.

### Claim 3 (depends on 2)

The engine starting system according to claim 2, wherein
the start control section sets the timing of the starting motor operation of the first starter to be the same as the timing of the stopping operation of the second starter, or before or after the timing of the stopping operation of the second starter.

### Claim 4 (depends on 1)

The engine starting system according to claim 1, wherein
the start control section sets a timing of a starting motor operation of the first starter to be after the power supply to the motor of the second starter is stopped.

### Claim 5 (depends on 1)

The engine starting system according to claim 1, wherein the start control section
determines an initial crank angle before the cranking is started, and
changes a timing of a stopping operation of the second starter and a timing of a starting motor operation of the first starter according to the initial crank angle, after the cranking is started.

### Claim 6 (depends on 1)

The engine starting system according to claim 1, wherein
the controller temporarily operates the first starter as an electric motor and stops the first starter before the engine passes the first compression top dead center.

### Claim 7

An engine starting system comprising:
a first starter that is connected to a crankshaft of an engine and rotatably drives the crankshaft,
a second starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft, and
a controller that controls operation of the first starter and the second starter, wherein
the first starter is a motor generator having a function of an electric generator and a function of an electric motor,
the second starter is a pinion enmeshing starter including
a motor that receives electric power to cause it to rotate,
a pinion that moves axially to mesh with the ring gear,
a one-way clutch that transmits torque in only one direction from the motor to the pinion and blocks torque transmission from the pinion to the motor, and
a solenoid device having a function of moving the pinion axially and a function of starting/stopping power supply to the motor,
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where
the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the first starter, and
the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, starts operation of the first starter and stops motor operation of the second starter at a predetermined timing, and
a passage determination unit that determines whether the passage conditional expression holds after cranking is started by the second starter,
the start control unit stops operation of the second starter and increases an output due to motor operation of the first starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center.

### Claim 8 (depends on 7)

The engine starting system according to claim 7, wherein
the start control section sets a timing of a stopping operation of the second starter and a timing of increasing an output due to motor operation of the first starter to be before an estimated timing at which the one-way clutch is reengaged, if the engine passes the first compression top dead center without the passage conditional expression being satisfied.

### Claim 9 (depends on 8)

The engine starting system according to claim 8, wherein
the start control section sets the timing of increasing an output due to motor operation of the first starter to be the same as the timing of the stopping operation of the second starter or to be before or after the timing of the stopping operation of the second starter.

### Claim 10 (depends on 7)

The engine starting system according to claim 7, wherein
the start control section sets a timing of increasing an output due to motor operation of the first starter to be after power supply to the motor of the second starter is stopped.

### Claim 11 (depends on 7)

The engine starting system according to claim 7, wherein the start control section
determines an initial crank angle before the cranking is started, and
changes a timing of a stopping operation of the second starter and a timing of increasing an output due to motor operation of the first starter according to the initial crank angle, after the cranking is started.

### Claim 12 (depends on 1)

The engine starting system according to claim 1, wherein
the solenoid device includes a first solenoid having a function of axially moving the pinion, and a second solenoid having a function of starting/stopping energization current to the motor, and
the start control section, when a stopping operation of the second starter, causes the first solenoid to disengage the pinion from the ring gear before the second solenoid stops the power supply to the motor.

### Claim 13 (depends on 1)

The engine starting system according to claim 1, wherein
if a passage determination condition is the at least one condition necessary for determining whether the passage conditional expression holds, the passage determination section sets an engine speed as the passage conditional condition.

### Claim 14 (depends on 13)

The engine starting system according to claim 13, wherein
the start control section calculates the engine speed based on a rotation angle of the crank shaft determined by the crank angle sensor.

### Claim 15 (depends on 13)

The engine starting system according to claim 13, including
a rotation angle sensor that determines a rotation angle of the first starter, wherein
the start control section estimates a crank angle based on a rotation angle of the first starter determined by the rotation angle sensor and calculates the engine speed based on the estimated crank angle.

### Claim 16 (depends on 1)

The engine starting system according to claim 1, wherein
the first starter is connected to the crank shaft via a belt.

### Claim 17

A first starter comprising a motor generator connected to a crank shaft of an engine and having a function of an electric motor that rotatably drives the crankshaft and a function of an electric generator, and
operation of the first starter being controlled by a controller together with a second starter which is a pinion enmeshing starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft, wherein
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where
the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the electric motor, and
the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, stops operation of the second starter and starts motor operation of the first starter at a predetermined timing, and
a passage determination section that determines whether the passage conditional expression is satisfied after cranking is started by the second starter,
the start control section stops operation of the second starter and transmits a start signal for a starting motor operation of the first starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center, and
the first starter has a start signal receiver that receives the start signal.

### Claim 18

A second starter, operation of the second starter being controlled by a controller together with a first starter that is connected to a crank shaft of an engine and the second starter comprising a motor generator having a function of an electric motor that rotatably drives the crank shaft and a function of an electric generator, and
the second starter being a pinion enmeshing starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft, wherein
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the first starter, and the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, stops operation of the second starter and starts motor operation of the first starter at a predetermined timing, and
a passage determination section that determines whether the passage conditional expression holds after cranking is started by the second starter,
the start control section stops motor operation of the first starter and transmits a stop signal for stopping operation of the second starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center, and
the second starter has a stop signal receive that receives the stop signal.

### Claim 19

A first starter comprising a motor generator connected to a crank shaft of an engine and having a function of an electric motor that rotatably drives the crankshaft and a function of an electric generator, and
operation of the first starter being controlled by a controller together with a second starter which is a pinion enmeshing starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft, wherein
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where
the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the electric motor, and
the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, starts motor operation of the first starter and stops operation of the second starter at a predetermined timing, and
a passage determination section that determines whether the passage conditional expression holds after cranking is started by the second starter,
the start control section stops operation of the second starter and transmits a start signal for increasing an output due to motor operation of the first starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center, and
the first starter has a start signal receiver that receives the start signal.

### Claim 20

A second starter, operation of the second starter being controlled by a controller together with a first starter that is connected to a crank shaft of an engine and the second starter comprising a motor generator having a function of an electric motor that rotatably drives the crank shaft and a function of an electric generator, and
the second starter being a pinion enmeshing starter that cranks the engine by rotatably driving a ring gear connected to the crankshaft, wherein
a magnitude relationship such that required passage torque is greater than engine starting torque is defined as a passage conditional expression, where the required passage torque is obtained by adding rotational torque obtained with kinetic energy stored in the engine from the start of cranking and driving torque which can be outputted with motor operation of the first starter, and the engine starting torque is obtained by adding compression torque and friction torque of the engine,
the controller includes
a start control section that, after activating the second starter to start cranking in response to a request for starting the engine, starts motor operation of the first starter and stops operation of the second starter at a predetermined timing, and
a passage determination unit that determines whether the passage conditional expression holds after cranking is started by the second starter,
the start control section increases an output due to motor operation of the first starter and transmits a stop signal for stopping operation of the second starter if the passage conditional expression holds before the engine passes a first compression top dead center, regardless of whether the engine has passed the first compression top dead center, and
the second starter has a stop signal receive that receives the stop signal.