Interrelated power delivery controls – including engine control – Transmission control – With brake control
Reexamination Certificate
2002-04-10
2003-09-23
Bonck, Rodney H. (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
With brake control
C192S218000, C251S129150, C477S906000
Reexamination Certificate
active
06623402
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for detecting abnormalities of a linear solenoid valve for regulating a control oil pressure that is supplied to a hydraulic device based on a control signal (an electric signal). The invention relates more particularly to an apparatus and a method for detecting abnormalities of a hydraulic device having a frictional engagement element such as a hydraulically actuated clutch or brake adapted to be brought into engagement upon receipt of an oil pressure force and a linear solenoid valve for regulating an actuation control oil pressure that is supplied to the frictional engagement element.
2. Description of the Related Art
A hydraulic device is used as, for example, a transmission in an automotive automatic transmission or the like, and in general, the transmission is constructed so as to automatically control speed changes according to the opening of an accelerator and the vehicle speed. The transmission for performing such automatic speed changes is constructed to have gear trains constituting a plurality of power transmission paths, and the gear trains are automatically changed over to select any of the power transmission paths by controlling the engagement of frictional engagement elements (a hydraulic clutch, brakes and the like), whereby the speed change control is implemented. In a known engagement control of a frictional engagement element, the control is performed by controlling the supply of working oil pressure (engagement control oil pressure), and in many cases a solenoid valve is used to control the supply of working oil pressure in an electric fashion. In this case, since the malfunction of the solenoid valve results in a failure of change-speed control, it is important to detect abnormalities of the solenoid valve. For example, JP-A-2000-266176 discloses an apparatus for detecting abnormalities of a solenoid valve.
In recent automatic transmissions, in many cases, controlling the regulation of engagement control oil pressure is implemented by a linear solenoid valve. In a case where a linear solenoid valve is used to implement controlling the engagement of a frictional engagement element to thereby perform change-speed controlling, it is possible to freely regulate an engagement control oil pressure which is supplied to the frictional engagement element by controlling energizing of the linear solenoid valve, and this provides an advantage that the degree of freedom in setting an engagement control oil pressure at the time of changing speeds becomes large. However, in case there occurs an abnormality in the linear solenoid valve, it becomes impossible to control the regulation of change-speed control oil pressure, this causing a problem that the change-speed control becomes imprecise. Owing to this, conventionally, an oil pressure sensor for measuring an engagement control oil pressure outputted from the linear solenoid valve is mounted on a change-speed control device externally, and an engagement control oil pressure outputted from the linear solenoid valve relative to a control signal inputted into the linear solenoid valve is detected with the hydraulic sensor to thereby detect the existence of abnormalities of the linear solenoid valve.
Incidentally, in an automatic transmission, there is no need to use an oil pressure sensor, and in general there is mounted no oil pressure sensor, and therefore, every time an abnormality detection is implemented, an oil pressure sensor is mounted externally on the automatic transmission to detect abnormalities of the linear solenoid valves, this causing a problem that abnormality detection can be carried out only at limited places such as plants and dealerships. In addition, oil pressure sensors are expensive, and this causes a problem that there is provided an expensive abnormality detector. Furthermore, there is caused a problem that there is a risk of dust or foreign matters entering the hydraulic device when the oil pressure sensor is attached to and detached from the same device.
SUMMARY OF THE INVENTION
The invention was made in view of the above problems and an object thereof is to provide an apparatus and a method for detecting abnormalities of a linear solenoid valve and a hydraulic device using the linear solenoid valve with ease. In particular, an object of the invention is to provide an apparatus and a method for detecting abnormalities of a linear solenoid valve and a hydraulic device using the linear solenoid valve by having a hydraulic switch which is inexpensive and is equipped within an oil pressure controller of an automatic transmission in many cases.
With a view to attaining the objects, according to an aspect of the invention, there is provided an apparatus for detecting abnormalities of a linear solenoid valve comprising a linear solenoid valve (for example, first to third linear solenoid valves
51
,
52
,
53
in an embodiment) for regulating a control oil pressure that is supplied to a hydraulic device (for example, a second clutch
12
, a third clutch
13
in the embodiment) based on a control signal, a hydraulic switch (for example, first and second hydraulic switches
61
,
62
in the embodiment) set to be switched on and off when an oil pressure variation is applied thereto which overpasses a predetermined switching oil pressure, and a valve actuating controller (for example, an electronic control unit
60
, an external diagnosis unit
70
or the line in the embodiment) for sending out the control signal to the linear solenoid valve, wherein the hydraulic switch is disposed in such a manner as to receive the control oil pressure that has been regulated by the linear solenoid valve. A control signal is sent from the valve actuating controller to the linear solenoid valve to increase the control oil pressure from a predetermined lower pressure which is lower than the switching oil pressure to a predetermined higher pressure which is higher than the switching oil pressure to thereby cause the linear solenoid valve to regulate the control oil pressure, during which, when the hydraulic switch is switched on and off a pressure-increased side signal oil pressure is detected which corresponds to the control signal outputted from the valve actuating controller. And, a control signal is sent from the valve actuating controller to the linear solenoid valve to decrease the control oil pressure from the predetermined higher pressure to the predetermined lower pressure to thereby cause the linear solenoid valve to regulate the working oil pressure, during which, when the hydraulic switch is switched on and off a pressure-decreased side signal oil pressure is detected which corresponds to the control signal outputted from the valve actuating controller. Further, the linear solenoid valve is diagnosed as being abnormal when a difference between the pressure-increased side signal oil pressure and the pressure-decreased side signal oil pressure exceeds an abnormality determination value.
In addition, according to another aspect of the invention, there is provided a method for detecting the existence of an abnormality of a linear solenoid valve for regulating a control oil pressure that is supplied to a hydraulic device based on a control signal using a hydraulic switch disposed at a position to receive the control oil pressure which has been regulated by the linear solenoid valve and set to be switched on and off when an oil pressure variation is applied thereto which overpasses a predetermined switching oil pressure, and the method comprises the steps of, firstly, sending a control signal to the linear solenoid valve to increase the control oil pressure from a predetermined lower pressure which is lower than the switching oil pressure to a predetermined higher pressure which is higher than the switching oil pressure, while the above step is being implemented, detecting a pressure-increased side signal oil pressure which corresponds to the control signal resulting when the hydraulic switch is switched
Matsubara Chihiro
Nishina Masatoshi
Tsuura Akio
Armstrong Westerman & Hattori, LLP
Bonck Rodney H.
Honda Giken Kogyo Kabushiki Kaisha
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