1. An internal combustion engine control apparatus comprising:
a hydraulically operated variable valve operating mechanism configured to vary a valve timing of air intake valves; and
a valve timing control section configured to control the hydraulically operated variable valve operating mechanism to set the valve timing to a warm-up idle valve timing with a high idling speed when engine temperature is determined to be cold and to set the valve timing to a post-warm-up idle valve timing with a post-warm-up idling speed when the engine temperature is determined to be equal to or above a warm-up temperature threshold, the high idling speed being higher than the post-warm-up idling speed,
the valve timing control section being further configured to switch the valve timing from the warm-up idle valve timing to the post-warm-up idle valve timing as the engine temperature approaches the warm-up temperature threshold such that the switch starts before an engine rotational speed falls below a rotational speed threshold lying between the high idling speed during the warm-up idle valve timing and the post-warm-up idling speed during the post-warm-up idle valve timing such that a sufficient hydraulic pressure switches the valve timing with a specific degree of responsiveness being attained when the engine rotational speed is at or above the rotational speed threshold.
2. The internal combustion engine control apparatus according to claim 1, wherein
the valve timing control section is further configured to set a lift center angle phase of the air intake valves such that a the warm-up lift center angle phase for the warm-up idle valve timing is more retarded than a post-warm-up lift center angle phase for the post-warm-up idle valve timing; and
the valve timing control section is further configured to advance the lift center angle phase of the air intake valves such that the post-warm-up lift center angle phase is reached before the post-warm-up idling speed is reached, when switching from the warm-up idle valve timing to the post-warm-up idle valve timing.
3. The internal combustion engine control apparatus according to claim 2, wherein
the valve timing control section is further configured to advance the lift center angle phase of the air intake valves such that the post-warm-up lift center angle phase is reached before the rotational speed threshold is reached, when switching from the warm-up idle valve timing to the post-warm-up idle valve timing.
4. The internal combustion engine control apparatus according to claim 2, wherein
the variable valve operating mechanism comprises a hydraulically operated liftoperating angle varying mechanism configured to continuous control a valve lift and a valve operating angle of the air intake valves to selectively increase or decrease the valve lift and the valve operating angle of the air intake valves.
5. The internal combustion engine control apparatus according to claim 4, wherein
the valve timing control section is further configured to switch the valve lift and the valve operating angle of the air intake valves such that the valve lift and the valve operating angle used for the post-warm-up idle valve timing phase is reached before the post-warm-up idling speed is reached, when switching from the warm-up idle valve timing to the post-warm-up idle valve timing.
6. The internal combustion engine control apparatus according to claim 4, wherein
the valve timing control section is further configured to switch the valve lift and the valve operating angle of the air intake valves such that the valve lift and the valve operating angle used for the post-warm-up idle valve timing phase is reached before the rotational speed threshold is reached, when switching from the warm-up idle valve timing to the post-warm-up idle valve timing.
7. The internal combustion engine control apparatus according to claim 1, wherein
the valve timing control section is further configured to control the switch from the warm-up idle valve timing to the post-warm-up idle valve timing such that the switching to the post-warm-up idle valve timing finishes at or before the rotational speed threshold.
8. An engine comprising the internal combustion engine control apparatus according to claim 1.
9. An internal combustion engine control apparatus comprising:
hydraulically operated variable valve operating means for varying a valve timing of air intake valves; and
valve timing control means for controlling the hydraulically operated variable valve operating means to set the valve timing to a warm-up idle valve timing with a high idling speed when engine temperature is determined to be cold and to set the valve timing to a post-warm-up idle valve timing with a post-warm-up idling speed when the engine temperature is determined to be equal to or above a warm-up temperature threshold, the high idling speed being higher than the post-warm-up idling speed,
the valve timing control means further performing switching of the valve timing from the warm-up idle valve timing to the post-warm-up idle valve timing as the engine temperature approaches the warm-up temperature threshold such that the switch starts before an engine rotational speed falls below a rotational speed threshold lying between the high idling speed during the warm-up idle valve timing and the post-warm-up idling speed during the post-warm-up idle valve timing such that a sufficient hydraulic pressure switches the valve timing with a specific degree of responsiveness being attained when the engine rotational speed is at or above the rotational speed threshold.
10. A method for controlling an intake air for an internal combustion engine comprising:
varying a valve timing of air intake valves;
setting the valve timing to a warm-up idle valve timing with a high idling speed when engine temperature is determined to be cold;
setting the valve timing to a post-warm-up idle valve timing with a post-warm-up idling speed when the engine temperature is determined to be equal to or above a warm-up temperature threshold, the high idling speed being higher than the post-warm-up idling speed and
switching of the valve timing from the warm-up idle valve timing to the post-warm-up idle valve timing as the engine temperature approaches the warm-up temperature threshold such that the switch starts before an engine rotational speed falls below a rotational speed threshold lying between the high idling speed during the warm-up idle valve timing and the post-warm-up idling speed during the post-warm-up idle valve timing such that a sufficient hydraulic pressure switches the valve timing with a specific degree of responsiveness being attained when the engine rotational speed is at or above the rotational speed threshold.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A current detection circuit comprising:
a first semiconductor device having a first terminal, a second terminal, and a first current control terminal, a current flowing between the first and second terminals being controlled by a control voltage applied to the first current control terminal;
a second semiconductor device having a third terminal connected to the first terminal, a fourth terminal, and a second current control terminal the second semiconductor device having a structure substantially the same as a structure of the first semiconductor device, a current flowing between the third and fourth terminals being controlled by the control voltage applied to the second current control terminal;
a MOS field-effect transistor having a drain connected to the second terminal of the first semiconductor device, a source, and a gate, a current flowing between the drain and the source being controlled by a voltage applied to the gate;
an electrostatic capacitor having one end connected to the source of the MOS field-effect transistor, and another end connected to the gate of the MOS field-effect transistor;
a rectifying element having a cathode connected to the gate of the MOS field-effect transistor and an anode connected to a first voltage source for outputting a predetermined first power voltage;
a voltage clamp circuit connected to the gate of the MOS field-effect transistor, the voltage clamp circuit clamping a maximum voltage of the gate of the MOS field-effect transistor to a predetermined clamp voltage;
a voltage control circuit for controlling a voltage at the fourth terminal of the second semiconductor device so as to substantially coincides with a source voltage of the MOS field-effect transistor; and
a detector circuit for detecting a current flowing through the fourth terminal of the second semiconductor device.
2. The current detection circuit as claimed in claim 1, further comprising a load connected to the second terminal of the first semiconductor device,
wherein the first terminal of the first semiconductor device and the third terminal of the second semiconductor device are grounded.
3. The current detection circuit as claimed in claim 1, further comprising a load connected to the first terminal of the first semiconductor device,
wherein the second terminal of the first semiconductor device and the drain of the MOS field-effect transistor are connected to a second voltage source for outputting a predetermined second power voltage.
4. The current detection circuit as claimed in claim 1, further comprising a driver circuit for applying the control voltage to the first and second current control terminals.
5. The current detection circuit as claimed in claim 2, further comprising a driver circuit for applying the control voltage to the first and second current control terminals.
6. The current detection circuit as claimed in claim 3, further comprising a driver circuit for applying the control voltage to the first and second current control terminals.
7. The current detection circuit as claimed in claim 1,
wherein the voltage control circuit comprises:
an operational amplifier having a non-inverted input terminal connected to the source of the MOS field-effect transistor, an inverted input terminal connected to the fourth terminal of the second semiconductor device, and an output terminal; and
an output transistor having a fifth terminal connected to the fourth terminal of the second semiconductor device, a sixth terminal connected to the detector circuit, and a third current control terminal connected to the output terminal of the operational amplifier, a current flowing between the fifth and sixth terminals being controlled by a voltage applied from the operational amplifier to the third current control terminal.