Engine start system minimizing mechanical impact or noise

• US 8,985,080 B2
• Filed: 04/06/2010
• Issued: 03/24/2015
• Est. Priority Date: 04/07/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Murata, Mitsuhiro, Notani, Hideya, Usami, Shinji, Saito, Mikio, Yoshida, Yasuyuki
• Primary Examiner(s): Gimie, Mahmoud
• Assistant Examiner(s): VILAKAZI, SIZO BINDA
• Application Number:
  US12/754,818
• Publication Number:
  US 20100251852A1
• Time in Patent Office: 1,813 Days
• Field of Search: 123/179.25, 123/179.3, 123/179.4, 290/38.R, 290/38.C, 290/38.E, 701/112, 701/113
• US Class Current: 123/179.4
• CPC Class Codes: F02N 11/08 Circuits or control means specially adapted for starting of engines
• CPC Class Codes: F02N 11/0833 Vehicle conditions F02N11/0822, F02N11/0825 take precedence
• CPC Class Codes: F02N 11/0844 with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind
• CPC Class Codes: F02N 11/0855 during engine shutdown or after engine stop before start command, e.g. pre-engagement of pinion
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 15/04 the gearing including disengaging toothed gears
• CPC Class Codes: F02N 15/067 the starter comprising an electro-magnetically actuated lever
• CPC Class Codes: F02N 2011/0892 Two coils being used in the starting circuit, e.g. in two windings in the starting relay or two field windings in the starter
• CPC Class Codes: F02N 2300/2011 Control involving a delay; Control involving a waiting period before engine stop or engine start
• CPC Class Codes: H01H 51/065 Relays having a pair of normally open contacts rigidly fixed to a magnetic core movable along the axis of a solenoid, e.g. relays for starting automobiles details H01H50/20
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y10T 74/132 Separate power mesher

Abstract

An engine start system which may be employed in automotive idle stop systems. To start an engine, the system brings a pinion gear into engagement with a ring gear coupled to the engine and turns on an electric motor to rotate the ring gear through the pinion gear to crank the engine. When it is requested to start the engine during deceleration of the engine before stop thereof, the system thrusts the pinion into engagement with the ring gear and then turns on the motor to rotate the pinion gear, in other words, delays the activation of the motor until after the pinion gear has engaged the ring gear. This minimizes mechanical impact or noise arising from the engagement of the pinion gear with the ring gear and improves the reliability in engagement with the ring gear during the deceleration of the engine and durability of the system.

Claims

1. An engine start system comprising:

a motor which is energized by supply of electric power from a battery through a motor circuit to produce torque;

an output shaft which rotates when subjected to the torque, as produced by said motor;

a pinion gear through which the torque, as produced by said motor, is transmitted to a ring gear coupled to an engine;

a pinion movable body which is movable along said output shaft together with said pinion gear;

a solenoid switch which works to produce a magnetic attraction to attract a plunger to thrust said pinion gear toward the ring gear and has a first and a second terminal bolt connectable with the motor circuit;

a motor on-off relay which has relay contacts disposed in the motor circuit and opens or closes the relay contacts electrically;

a controller which electrically controls an operation of said solenoid switch and an operation of said motor on-off relay when the engine is restarted during deceleration of the engine prior to stop of the engine; and

delay means for delaying a second operation time that is a time when said motor on-off relay is to be energized until after a first operation time that is a time when said solenoid switch is to be energized on when the engine is restarted,

wherein said solenoid switch does not work to establish or block flow of the electric power to said motor and has the first and second terminal bolts disconnected from the motor circuit,

wherein said motor on-off relay works to open or close the relay contacts to block or establish flow of the electric power from the battery to said motor, and

wherein said delay means produces a time lag between the first and second operation times so as to turn on said motor on-off relay to establish the flow of the electric power to said motor after said pinion gear is moved by said solenoid switch to the ring gear and then engages the ring gear at least partially or to a maximum movable position where engagement of said pinion gear with the ring gear is to be established and then engages the ring gear.

2. An engine start system as set forth in claim 1, wherein said motor on-off relay has the relay contacts disposed upstream of the main contacts of the motor circuit.

3. An engine start system as set forth in claim 1, wherein said motor on-off relay is installed on a housing of a starter in which said motor is installed.

4. An engine start system as set forth in claim 1, wherein the engine start system is installed in a vehicle equipped with an idle stop system working to stop and restart the engine automatically.

5. An engine start system comprising:

a motor which is energized by supply of electric power from a battery through a motor circuit to produce torque;

an output shaft which rotates when subjected to the torque, as produced by said motor;

a pinion gear through which the torque, as produced by said motor, is transmitted to a ring gear coupled to an engine;

a pinion movable body which is movable along said output shaft together with said pinion gear;

an assembly configured to move the pinion movable body to the ring gear and open or close main contacts installed in the motor circuit to cut or supply the electric power from the battery to the motor;

a controller which controls operations of said assembly when the engine is restarted during deceleration of the engine prior to stop of the engine; and

delay means for delaying a second operation time that is a time when said assembly is to be activated to close the main contacts until after a first operation time that is a time when said assembly is to be activated to move said pinion movable body when the engine is restarted, said delay means producing a time lag between the first and second operation times so as to close the main contacts through said assembly to supply the electric power to said motor after said pinion movable body is moved by said assembly to shift the pinion gear from a rest position to a gear engageble position where said pinion gear is engageble with the ring gear, and then said pinion gear engages the ring gear.

6. An engine start system as set forth in claim 5, further comprising a magnetic coil producing an electromagnet when energized, a plunger which is movable along an inner periphery of said magnetic coil in an axial direction thereof, and a single electromagnetic switch designed to perform an operation of the assembly following movement of said plunger, and wherein the time lag is provided by a plunger stroke that is a distance which said plunger moves from a time when said plunger starts to be moved by attraction, as produced by the electromagnetic, until the main contacts are closed.

7. An engine start system as set forth in claim 5, wherein the assembly includes a pinion actuator operable to move the pinion movable body to the ring gear and a switching mechanism operable to open or close the main contacts installed in the motor circuit to cut or supply the electric power from the battery to the motor.

8. An engine start system as set forth in claim 7, further comprising a magnetic coil producing an electromagnet when energized, a plunger which is movable along an inner periphery of said magnetic coil in an axial direction thereof, and a single electromagnetic switch designed to perform both an operation of said pinion actuator and an operation of the switching mechanism following movement of said plunger, and wherein the time lag is provided by a plunger stroke that is a distance which said plunger moves from a time when said plunger starts to be moved by attraction, as produced by the electromagnetic, until the main contacts are closed.

9. An engine start system comprising:

a motor which is energized by supply of electric power from a battery through a motor circuit to produce torque;

an output shaft which rotates when subjected to the torque, as produced by said motor;

a pinion gear through which the torque, as produced by said motor, is transmitted to a ring gear coupled to an engine;

a pinion movable body which is movable along said output shaft together with said pinion gear;

an assembly configured to move the pinion movable body to the ring gear and open or close main contacts installed in the motor circuit to cut or supply the electric power from the battery to the motor;

a controller which controls operations of said assembly when the engine is restarted during deceleration of the engine prior to stop of the engine; and

delay means for delaying a second operation time that is a time when said assembly is to be activated to close the main contacts until after a first operation time that is a time when said assembly is to be activated to move said pinion movable body when the engine is restarted, said delay means producing a time lag between the first and second operation times so as to close the main contacts through said assembly to supply the electric power to said motor after said pinion movable body is moved by said assembly to advance the pinion gear from a rest position to a maximum movable position where engagement of said pinion gear with the ring gear is to be achieved, and then said pinion gear has engaged the ring gear.

10. An engine start system as set forth in claim 9, further comprising a magnetic coil producing an electromagnet when energized, a plunger which is movable along an inner periphery of said magnetic coil in an axial direction thereof, and a single electromagnetic switch designed to perform an operation of the assembly following movement of said plunger, and wherein the time lag is provided by a plunger stroke that is a distance which said plunger moves from a time when said plunger starts to be moved by attraction, as produced by the electromagnetic, until the main contacts are closed.

11. An engine start system as set forth in claim 9, wherein the assembly includes a pinion actuator operable to move the pinion movable body to the ring gear and a switching mechanism operable to open or close the main contacts installed in the motor circuit to cut or supply the electric power from the battery to the motor.

12. An engine start system as set forth in claim 11, further comprising a magnetic coil producing an electromagnet when energized, a plunger which is movable along an inner periphery of said magnetic coil in an axial direction thereof, and a single electromagnetic switch designed to perform both an operation of said pinion actuator and an operation of the switching mechanism following movement of said plunger, and wherein the time lag is provided by a plunger stroke that is a distance which said plunger moves from a time when said plunger starts to be moved by attraction, as produced by the electromagnetic, until the main contacts are closed.