Patent Application
20150285204
Exemplary embodiments pertain to the art of motor vehicles and, more particularly, to an internal combustion engine for a motor vehicle having a change of mind (COM) starter system.
Internal combustion engines generally include a starter motor. The starter motor is electrically energized to initiate operation of the internal combustion engine. A typical starter includes a starter motor that generates torque that is passed to a pinion gear and a solenoid. The solenoid shifts the pinion gear into engagement with a ring gear on the internal combustion engine. Once engaged, the starter motor rotates the pinion to spin the ring gear and initiate operation of the internal combustion engine.
In a standard starter motor a generally stationary pinion is shifted into engagement with a stationary ring gear. The pinion is shifted such that pinion teeth enter a gap between ring gear teeth for engagement. A standard starter motor is not typically, intentionally, energized to engage a rotating pinion. Such an engagement typically results in clashing gears and potential gear damage. In a change of mind (COM) starter, a pinion may be shifted into a rotating ring gear spinning within a speed band. Generally, the pinion is rotated to a particular speed prior to engagement with the rotating ring gear. Thus, a typical COM starter includes a ring gear speed sensor and a pinion speed sensor. In operation, if ignition is re-initiated while the ring gear is moving, a first coil of the solenoid initiates rotation of the pinion. When the pinion and ring gear are within a predetermined rotational range, as detected by the pinion speed sensor and ring gear speed sensor, a second coil of the solenoid shifts the pinion into the ring gear to re-establish operation of the internal combustion engine.
Disclosed is an internal combustion engine including a ring gear, a speed sensor operatively associated with the ring gear, and a change of mind (COM) starter motor mechanically linked to the internal combustion engine. The COM starter motor includes an armature and a pinion operatively connected to the armature. A solenoid is operatively connected to the COM starter motor. The solenoid selectively moves the pinion into engagement with the ring gear. An electronic control unit (ECU) is operatively connected to the speed sensor and the solenoid. The ECU is configured and disposed to indirectly detect a rotational speed of the pinion and selectively energize the solenoid to axially shift the pinion into engagement with the ring gear when the pinion reaches a particular rotational speed relative to a rotational speed of the ring gear.
Also disclosed is a change of mind (COM) starter system including an armature, a pinion operatively connected to the armature, and a solenoid operatively connected to the COM starter motor. An electronic control unit (ECU) is operatively connected to the solenoid. The ECU is configured and disposed to indirectly detect a rotational speed of the pinion and selectively energize the solenoid to axially shift the pinion when the pinion reaches a particular rotational speed relative to a rotational speed of the ring gear.
Still further disclosed is a system including an armature, a pinion operatively connected to the armature, an energy source electrically coupled to the armature, and an electronic control unit (ECU) electrically coupled to the energy source. The ECU is configured and disposed to indirectly detect a rotational speed of the pinion.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
With initial reference to
As shown in
Solenoid 20 is mounted to housing 30 of COM starter motor 14. Solenoid 20 includes a solenoid housing 60 surrounding an interior section 62. Interior section 62 houses a first coil 65 and a second coil 67. Solenoid 20 is also shown to include a plurality of terminals 70 including a first or battery terminal 72 and a second or armature terminal 74. Battery terminal 72 is electrically connected to an energy source such as a battery 77. Solenoid 20 is further shown to include a plunger 80 operatively associated with first coil 65. Plunger 80 selectively acts upon a lever 84 to axially shift pinion 41 into meshing engagement with ring gear 8. As will be detailed more fully below, ECU 24 activates a first relay 90 to energize first coil 65 to axially shift pinion 41 and a second relay 92 to energize second coil 67 closing a circuit (not separately labeled) allowing electrical current to flow from battery 77 to armature 36 causing pinion 41 to rotate.
As will be discussed more fully below, first coil 65 is energized when pinion 41 is rotating at a predetermined speed relative to ring gear 8. If ring gear 8 is stationary, first coil 65 may be energized before pinion 41 is rotating. If ring gear 8 is rotating, as sensed by sensor 10, second coil 67 is energized to begin rotating pinion 41. Only after pinion 41 reaches a predetermined speed, does ECU 24 energize first coil 65. In accordance with an exemplary embodiment, ECU 24 indirectly determines at what speed pinion 41 is rotating. The term “indirectly determines” should be understood to mean that ECU 24 determines pinion 41 speed without the use of a pinion speed sensor and without a sense wire to transmit an electrical signal from COM starter motor 14 to ECU 24. Instead, ECU 24 determines pinion speed by analyzing changes in an electrical parameter of battery 77. The change of electrical parameter may be a change in voltage, a change in current or combinations thereof The change of the electrical parameter may be measured at battery 77, at solenoid 20 or at armature 36.
ECU 24 may determine a speed of armature 36 by measuring a voltage V(n) and comparing the value V(n) to a previously measured voltage V(n−1). ECU stores the lower of value V(n) and V(n−1) in V(0). V(0) will eventually be equal to low point V(lp) 320 of battery voltage (300). Of course, other methods may be used to determine the low point 320. ECU 24 determines a speed S(a) of armature 36 by measuring battery voltage (300). Speed S(a) of armature 36 may be determined by the formula
S(a)={[V(n)−V(lp)]*K1}+K10
This equation for S(a) above may be a linear equation or a first order polynomial equation. It should of course be understood that a second order polynomial, third order polynomial or any order polynomial equation may also be used. It should also be understood that constant K10 may be equal to zero.
ECU 24 may calculate a speed S(p1) of pinion 41 based on
S(p1)=S(a)*K2
where K2 equals a constant equal to a gear ratio between pinion 41 and armature 36.
A gear (not shown), that establishes the gear ratio, between pinion 41 and armature 36 is well known in the art and is typically a planetary or offset gear system. ECU 24 may then convert the speed S(p1) of pinion 41 to a pinion speed S(p) that is considered correlated to the engine speed based on
S(p)=S(p1)*K4
where K4 is a constant equal to the gear ratio between ring gear 8 and pinion 41.
Similarly, a current graph 400, shown in
S(a)={[C(p)−C(n)]*K3}+K11
where K3 and K11 are constants
K3 and K11 may be determined empirically
ECU 24 calculates speed S(p) of pinion 41 based on
S(p)=S(a)*K2
where K2 equals a constant equal to the gear ratio between the pinion 41 and the armature 36. This equation for S(a) above may be a linear equation or a first order polynomial equation. Of course, it should be understood, that a second order polynomial, third order polynomial or any order polynomial equation may also be used. It should also be understood that constant K11 may be equal to zero.
ECU 24 converts speed S(p1) of pinion 41 to a pinion speed S(p) that is considered correlated to the engine speed by the equation:
S(p)=S(p1)*K4
where K4 is a constant equal to the gear ratio between ring gear 8 and the pinion 41.
After determining pinion speed in block 206, ECU 24 receives data from speed senor 10 regarding ring gear speed in block 600. At this point, ECU 24 determines, in block 610, whether pinion 41 is rotating within a predetermined speed range relative to ring gear 8. If pinion 41 and ring gear 8 are generally synchronized, first relay 90 energizes first coil 65 in block 620. When first coil 65 is energized, pinion 41 is axially shifted into meshing engagement with ring gear 8 to re-initiate operation of internal combustion engine 2. The term “generally synchronized” should be understood to mean that pinion 41 is rotating within the predetermined speed range relative to a speed of ring gear 8. If, in block 610, pinion 41 and ring gear 8 are not synchronized, ECU 24 determines whether second relay 92 has closed to energize second coil 67 in block 630. If second relay 92 is closed, method 200 returns to block 204. If, however, second relay 92 is open, a signal is sent to close second relay 92 in block 650 and method 200 returns to block 204.
At this point, it should be understood that the change of mind (COM) starter system, in accordance with an exemplary embodiment, determines whether the pinion and the ring gear are synchronized by indirectly determining pinion speed. More specifically, ECU determines pinion speed without the use of a pinion speed sensor. ECU determines pinion speed based on changes in electrical parameters of a vehicle battery connected to operate the COM starter motor. In this manner, the exemplary embodiments reduce the need for additional sensors, wiring, and connections as well as simplifies vehicle manufacturing and vehicle maintenance of and reduces the cost of replacement parts.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.
