Engine starting system and starter

Patent metadata

Field	Value
Publication number	US-10865757-B2
Application number	US-201716308699-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Jun 16, 2016
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

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.

First claim

The invention claimed is:

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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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 su

Assignees

• Denso Corp

Inventors

• Nakaoka Takuro
• Imura Akihiro
• Shibanuma Mitsuru
• Kubo Yuki
• Okamiya Minoru
• Mizuno Suguru

Classifications

• F02N2300/104

  Control of the starter motor torque · CPC title

• F02N15/022

  the starter comprising an intermediate clutch · CPC title

• F02N11/006 Primary

  using a plurality of electric motors · CPC title

• F02N15/04

  the gearing including disengaging toothed gears · CPC title

• F02N11/0851

  characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear · CPC title