Patent Description:
Known is a hybrid vehicle including a first transmitting route through which rotational power is transmitted from an engine through a first one-way clutch to an oil pump and a second transmitting route through which rotational power is transmitted from an electric motor through a second one-way clutch to the oil pump (see PTL <NUM>, for example). According to this, even when any one of the engine and the electric motor stops, the oil pump is mechanically driven, and lubricating oil is supplied to the engine and a transmission.

PTL <NUM>, which forms the basis for the preamble of claim <NUM>, discloses an oil feeding system of an engine equipped with a transmission configured to change a rotational speed of rotation of a crankshaft and to output the rotation, including an oil pump configured to be driven in cooperation with the rotation of the crankshaft, an oil passage through which the oil outflowing from the oil pump flows, in which the oil passage includes a transmission oil passage through which the oil outflowing from the oil pump is guided to the transmission, and an engine body oil passage through which the oil outflowing from the oil pump is guided to portions other than the transmission, and an oil control portion configured to change a ratio between a pressure of the oil flowing through the transmission oil passage and a pressure of the oil flowing through the engine body oil passage.

However, even when the hybrid vehicle stops the engine and travels by driving power of the electric motor, the lubricating oil is supplied from the oil pump to the engine and the transmission. When supplying the lubricating oil to the engine, high hydraulic pressure is necessary for a piston jet and the like. Therefore, the oil pump has to do needless work, and energy loss occurs.

An object of one aspect of the present invention is to reduce energy loss of a hybrid vehicle when the hybrid vehicle stops an engine and travels by driving power of an electric motor.

A hybrid vehicle according to claim <NUM> includes: an engine including an engine internal space; an electric motor; a transmission that includes an input shaft, an output shaft, a gear train located at the input shaft and the output shaft, and a transmission internal space in which the gear train is located, and changes speed of rotational power transmitted from the engine and the electric motor to the input shaft and outputs the rotational power to a driving wheel; an oil pump driven by the rotational power from the engine and the electric motor; an oil passage including a common oil passage through which lubricating oil discharged from the oil pump flows, an engine lubricating oil passage extending from the common oil passage toward the engine internal space, and a transmission lubricating oil passage extending from the common oil passage toward the transmission internal space; and a variable throttle valve that changes a flow rate in the transmission lubricating oil passage and increases an opening degree of the variable throttle valve in a mode transition in which a first traveling mode in which the hybrid vehicle travels by driving power of the engine transitions to a second traveling mode in which the hybrid vehicle stops the engine and travels by the driving power of the electric motor.

According to the above configuration, when the first traveling mode transitions to the second traveling mode, the opening degree of the variable throttle valve increases. With this, while supplying the lubricating oil to the transmission internal space that is lower in the degree of sealing than the engine internal space, the pressure of the common oil passage is lowered. Thus, the amount of work of the oil pump can be reduced. Moreover, when the second traveling mode transitions to the first traveling mode, the opening degree of the variable throttle valve decreases. With this, while supplying the lubricating oil to the transmission internal space, the lubricating oil can be supplied to the engine internal space having a high sealing property. Therefore, the energy loss of the hybrid vehicle when the hybrid vehicle stops the engine and travels by the driving power of the electric motor can be reduced.

The present invention can reduce the energy loss of the hybrid vehicle when the hybrid vehicle stops the engine and travels by the driving power of the electric motor.

<FIG> is a side view of a motorcycle <NUM> according to Embodiment <NUM>. As shown in <FIG>, the motorcycle <NUM> is one example of a straddle vehicle straddled by a rider, and is a hybrid vehicle. The motorcycle <NUM> includes a front wheel <NUM>, a rear wheel <NUM> (driving wheel), and a vehicle body frame <NUM>. The front wheel <NUM> is steered in association with the manipulation of a handle <NUM> that is supported by the vehicle body frame <NUM> so as to be turnable. A fuel tank <NUM> is located behind the handle <NUM>. A seat <NUM> on which the rider is seated is located behind the fuel tank <NUM>. A power unit <NUM> as a driving power source is mounted on the vehicle body frame <NUM> so as to be located between the front wheel <NUM> and the rear wheel <NUM>.

The power unit <NUM> includes an engine E and a driving motor M as prime movers. The engine E is an internal combustion engine, and the driving motor M is an electric motor. A piston <NUM> (see <FIG>) is in a cylinder of the engine E. An internal space of the cylinder of the engine E is an engine internal space S <NUM>. A crank case <NUM> extending rearward is located at a lower portion of the engine E. The crank case <NUM> houses a transmission TM. An internal space of the crank case <NUM> is a transmission internal space S2. Driving power output from the transmission TM is transmitted to the rear wheel <NUM> through an output transmitting structure <NUM> (for example, a chain, a belt, a drive shaft, or the like).

<FIG> is a schematic diagram of a power system of the motorcycle <NUM> shown in <FIG>. As shown in <FIG>, the engine E includes the piston <NUM> and a crank shaft <NUM> that rotates in association with reciprocation of the piston <NUM>. The crank shaft <NUM> is one example of a power transmitting shaft. A throttle <NUM>, a fuel supplier <NUM>, and an ignitor <NUM> are located at the engine E. The throttle <NUM> adjusts the amount of intake air. The fuel supplier <NUM> mixes the intake air with fuel. The ignitor <NUM> ignites the fuel-air mixture in a combustion chamber of the engine E.

The transmission TM includes an input shaft <NUM>, an output shaft <NUM>, and plural pairs of transmission gear trains <NUM> whose reduction ratios are different from each other. The transmission TM can transmit power from the input shaft <NUM> through the transmission gear trains <NUM> to the output shaft <NUM>. The transmission TM performs speed change by selecting any one of the transmission gear trains <NUM>. For example, the transmission TM is a dog clutch transmission. The driving power of the output shaft <NUM> is transmitted through the output transmitting structure <NUM> to the rear wheel <NUM>.

One end portion of the crank shaft <NUM> of the engine E is connected to a primary reduction gear <NUM> such that the crank shaft <NUM> can transmit power to the primary reduction gear <NUM>. The other end portion of the crank shaft <NUM> is connected to an integrated starter generator <NUM> (hereinafter referred to as an "ISG <NUM>") such that the crank shaft <NUM> can transmit power to the ISG <NUM>. The ISG <NUM> serves as a below-described phase adjuster. The driving power of the crank shaft <NUM> is transmitted to the input shaft <NUM> through the primary reduction gear <NUM> and a clutch C.

The clutch C is located at one end portion of the input shaft <NUM> and cuts or establishes a power route extending from the crank shaft <NUM> to the input shaft <NUM>. The clutch C is a friction clutch. The clutch C operates by hydraulic pressure but may operate by electric power. The driving power of the driving motor M is transmitted to the input shaft <NUM> through a power transmitting structure <NUM> (for example, a chain-sprocket structure, a gear structure, a pulley-belt structure, or the like). A clutch pump P1 and a lubricating oil pump P2 are located in the vicinity of the input shaft <NUM> and are mechanically driven in association with the rotation of the input shaft <NUM>.

Specifically, the driving power of the engine E is transmitted to a first one-way clutch <NUM>. The driving power of the driving motor M is transmitted to a second one-way clutch <NUM>. The first one-way clutch <NUM> and the second one-way clutch <NUM> are connected to the clutch pump P1 and the lubricating oil pump P2 through a power transmitting structure <NUM> such that the first one-way clutch <NUM> and the second one-way clutch <NUM> can transmit power to the clutch pump P1 and the lubricating oil pump P2. The first one-way clutch <NUM> and the second one-way clutch <NUM> are located in parallel with each other. The first one-way clutch <NUM> and the second one-way clutch <NUM> are connected to the power transmitting structure <NUM> so as to meet at the power transmitting structure <NUM>.

To be specific, the driving power of the engine E is transmitted to the clutch pump P1 and the lubricating oil pump P2 through the first one-way clutch <NUM> and the power transmitting structure <NUM>, and the driving power of the driving motor M is transmitted to the clutch pump P1 and the lubricating oil pump P2 through the second one-way clutch <NUM> and the power transmitting structure <NUM>. When both the engine E and the electric motor M are driving, the driving power of the prime mover that is higher in rotational frequency between the engine E and the electric motor M is transmitted to the clutch pump P1 and the lubricating oil pump P2 through the power transmitting structure <NUM> by the actions of the first one-way clutch <NUM> and the second one-way clutch <NUM>.

Oil discharged from the clutch pump P1 is supplied through an oil control valve unit <NUM> to the clutch C as operating oil. The oil control valve unit <NUM> operates the clutch C by opening or closing a passage of oil flowing from the clutch pump P1 toward the clutch C. To be specific, the oil control valve unit <NUM> is one example of a clutch actuator. The oil discharged from the lubricating oil pump P2 is supplied through an oil passage <NUM> to the engine internal space S1 and the transmission internal space S2 as lubricating oil. A filter that removes foreign matters may be located at the oil passage <NUM>.

The oil passage <NUM> includes a common oil passage <NUM>, an engine lubricating oil passage <NUM>, and a transmission lubricating oil passage <NUM>. The lubricating oil discharged from the lubricating oil pump P2 flows through the common oil passage <NUM>. The engine lubricating oil passage <NUM> extends from the common oil passage <NUM> toward the engine internal space S <NUM>. To be specific, the oil flowing out from the engine lubricating oil passage <NUM> is discharged into the engine internal space S1 and lubricates the engine E. The transmission lubricating oil passage <NUM> extends from the common oil passage <NUM> toward the transmission internal space S2.

To be specific, the oil flowing out from the transmission lubricating oil passage <NUM> is discharged into the transmission internal space S2 and lubricates the transmission TM. The degree of sealing of the engine internal space S1 is higher than the degree of sealing of the transmission internal space S2. Therefore, oil pressure necessary to discharge the oil from the engine lubricating oil passage <NUM> to the engine internal space S1 is higher than oil pressure necessary to discharge the oil from the transmission lubricating oil passage <NUM> to the transmission internal space S2. A variable throttle valve <NUM> is located at the transmission lubricating oil passage <NUM> and can change a flow rate in the transmission lubricating oil passage <NUM>. The configuration of the variable throttle valve <NUM> will be described later.

An ECU <NUM> (electronic control unit) controls the engine E. Specifically, the ECU <NUM> controls the throttle <NUM>, the fuel supplier <NUM>, and the ignitor <NUM>. The ECU <NUM> controls the electric motor M. The ECU <NUM> controls engagement and disengagement of the clutch C by controlling the oil control valve unit <NUM>. The ECU <NUM> switches among an engine traveling mode (first mode), an EV mode (second mode), and an HEV mode (first mode).

The engine traveling mode is a mode in which: the clutch C is in an engaged state; the electric motor M is in a stop state; and the motorcycle <NUM> travels by the driving power of the engine E. The EV traveling mode is a mode in which: the clutch C is in a disengaged state; the engine E is in a stop state; and the motorcycle <NUM> travels by the driving power of the electric motor M. The HEV mode is a mode in which: the clutch C is in the engaged state; and the motorcycle <NUM> travels by both of the driving power of the engine E and the driving power of the electric motor M.

<FIG> is a sectional view of the variable throttle valve <NUM> of the power system shown in <FIG>. <FIG> is a sectional view taken along line IV-IV of <FIG>. <FIG> is a sectional view showing the variable throttle valve <NUM> of <FIG> in an engine stop state. As shown in <FIG>, the crank case <NUM> includes a lower case <NUM> and an upper case <NUM>. The upper case <NUM> is assembled to the lower case <NUM> in an upper-lower direction such that an axial portion of the crank shaft <NUM> is sandwiched between the lower case <NUM> and the upper case <NUM>. With this, an outer peripheral surface of the axial portion of the crank shaft <NUM> is covered with the crank case <NUM>.

An annular gap <NUM> is between the crank shaft <NUM> and the crank case <NUM>. A pair of annular oil seals <NUM> sandwiched between the crank case <NUM> and the crank shaft <NUM> are located at both sides of the annular gap <NUM> in the axial direction of the crank shaft <NUM>.

The lower case <NUM> includes an inflow passage <NUM> that communicates with the common oil passage <NUM> (see <FIG>) and faces the annular gap <NUM>. The upper case <NUM> includes an outflow passage <NUM> that communicates with the transmission internal space S2 (see <FIG>) and faces the annular gap <NUM>. The crank shaft <NUM> includes a through hole <NUM> that extends in a radial direction of the crank shaft <NUM> and faces the annular gap <NUM>. The inflow passage <NUM>, the annular gap <NUM>, the through hole <NUM>, and the outflow passage <NUM> are included in the transmission lubricating oil passage <NUM>. The annular gap <NUM> and the crank shaft <NUM> are included in the variable throttle valve <NUM>. The crank shaft <NUM> is an association body that operates in association with the power transmitting shaft (for example, the input shaft <NUM>) that rotates when the engine E drives.

When the engine E drives in the engine traveling mode or the HEV mode, the crank shaft <NUM> rotates at high speed. Therefore, the oil flowing from the inflow passage <NUM> toward the outflow passage <NUM> cannot flow through the through hole <NUM> of the crank shaft <NUM> but flows through only the annular gap <NUM>. Therefore, the opening degree of the variable throttle valve <NUM> depends only on the size of the annular gap <NUM>. Thus, the opening degree of the variable throttle valve <NUM> is small.

As a result, by a restriction effect of the variable throttle valve <NUM>, the oil hardly flows through the transmission lubricating oil passage <NUM>, and the oil pressure of the engine lubricating oil passage <NUM> increases. Thus, the oil is adequately supplied to the engine internal space S1 while supplying the oil to the transmission internal space S2.

On the other hand, as shown in <FIG>, when the engine E stops in the EV mode, the crank shaft <NUM> stops. When stopping the engine E, the ISG <NUM> is controlled by the ECU <NUM> such that the crank shaft <NUM> stops in a phase in which the through hole <NUM> coincides with the inflow passage <NUM> and the outflow passage <NUM>. To be specific, the ISG <NUM> is one example of a phase adjuster that adjusts the phase of the crank shaft <NUM>.

In this state, the oil flowing from the inflow passage <NUM> toward the outflow passage <NUM> flows through not only the annular gap <NUM> but also the through hole <NUM> of the crank shaft <NUM>. Therefore, the opening degree of the variable throttle valve <NUM> when the engine E is in a stop state is larger than the opening degree of the variable throttle valve <NUM> when the engine E drives. In other words, the variable throttle valve <NUM> decreases the opening degree when the crank shaft <NUM> rotates, and increases the opening degree when the crank shaft <NUM> stops. Therefore, the opening degree of the variable throttle valve <NUM> increases by a state change of the crank shaft <NUM>, the state change being caused by a mode transition in which the engine traveling mode or the HEV mode transitions to the EV traveling mode.

As a result, the oil easily flows through the transmission lubricating oil passage <NUM>, and the oil pressure of the engine lubricating oil passage <NUM> decreases. Thus, the supply of the oil to the engine internal space S1 is suppressed. To be specific, the oil discharged by the lubricating oil pump P2 and flowing through the oil passage <NUM> is hardly supplied to the engine internal space S1 but is supplied to the transmission internal space S2. Therefore, the load of the lubricating oil pump P2 is reduced.

According to the above-described configuration, when the engine traveling mode or the HEV mode transitions to the EV traveling mode, the opening degree of the variable throttle valve <NUM> increases. With this, while supplying the lubricating oil to the transmission internal space S2 that is lower in the degree of sealing than the engine internal space S1, the pressure of the common oil passage <NUM> is lowered. Thus, the amount of work of the lubricating oil pump P2 can be reduced. Moreover, when the EV traveling mode transitions to the engine traveling mode or the HEV mode, the opening degree of the variable throttle valve <NUM> decreases. With this, while supplying the lubricating oil to the transmission internal space S2, the lubricating oil can be supplied to the engine internal space S1 having a high sealing property. Therefore, the energy loss of the motorcycle <NUM> when the motorcycle <NUM> stops the engine E and travels by the driving power of the electric motor M can be reduced.

Moreover, since the opening degree of the variable throttle valve <NUM> increases by the state change of the crank shaft <NUM> which is caused by the mode transition, the variable throttle valve <NUM> can be realized while suppressing the addition of on-vehicle parts. Specifically, the variable throttle valve <NUM> decreases the opening degree when the crank shaft <NUM> rotates, and increases the opening degree when the crank shaft <NUM> stops. Therefore, the variable throttle valve <NUM> can be realized while suppressing an increase of an occupied space of parts.

Moreover, when stopping the crank shaft <NUM>, the ISG <NUM> as the phase adjuster brings the crank shaft <NUM> into a phase in which the through hole <NUM> coincides with the inflow passage <NUM> and the outflow passage <NUM>. Therefore, when stopping the crank shaft <NUM>, the opening degree of the variable throttle valve <NUM> can be stably increased.

The power transmitting shaft included in the variable throttle valve <NUM> is not limited to the crank shaft <NUM>. For example, the power transmitting shaft included in the variable throttle valve <NUM> may be a balancer shaft that is an association body that operates in association with the power transmitting shaft (for example, the crank shaft <NUM>) that rotates when the engine E drives.

<FIG> is a sectional view showing a variable throttle valve <NUM> and its vicinity in the motorcycle according to Embodiment <NUM>. The same reference signs are used for the same components as in Embodiment <NUM>, and the repetition of the same explanation is avoided. As shown in <FIG>, the input shaft <NUM> of the transmission TM is a hollow pipe, and a rod portion 160a of a rod <NUM> is inserted into the input shaft <NUM>. One end of the rod portion 160a is connected to a piston of the clutch C, and a piston portion 160c is located at the other end portion of the rod 160b.

The piston portion 160c is housed in a cylinder <NUM>. The piston portion 160c moves in the cylinder <NUM> by the hydraulic pressure supplied from the oil control valve unit <NUM>. The clutch C operates by the movement of the rod <NUM> that moves in the axial direction by the hydraulic pressure supplied from the oil control valve unit <NUM>. To be specific, the rod <NUM> is an association body that moves in the axial direction in association with the clutch C.

The rod <NUM> includes a valve element portion 160b that projects from the rod portion 160a in a radial direction. The valve element portion 160b is housed in a valve housing <NUM> connected to the crank case <NUM>. The valve housing <NUM> includes an inflow opening 161a and an outflow opening 161b. The inflow opening 161a communicates with the common oil passage <NUM> (see <FIG>) and faces an oil space <NUM> inside the valve housing <NUM>. The outflow opening 161b communicates with the transmission internal space S2 (see <FIG>) and faces the oil space <NUM> inside the valve housing <NUM>. In the present embodiment, the rod <NUM> and the valve housing <NUM> are included in the variable throttle valve <NUM>. The variable throttle valve <NUM> is located at the transmission lubricating oil passage <NUM> (see <FIG>).

When the engine E drives in the engine traveling mode or the HEV mode, the rod <NUM> is moved (leftward in <FIG>) by the oil control valve unit <NUM> controlled by the ECU <NUM> such that the clutch C becomes the engaged state. When the clutch C is in the engaged state, the valve element portion 160b is located at such a position as to partially close at least one of the inflow opening 161a or the outflow opening 161b. Thus, the opening degree of the variable throttle valve <NUM> decreases.

As a result, by the restriction effect of the variable throttle valve <NUM>, the oil hardly flows through the transmission lubricating oil passage <NUM> (see <FIG>), and the oil pressure of the engine lubricating oil passage <NUM> (see <FIG>) increases. Thus, the oil is adequately supplied to the engine internal space S <NUM> while supplying the oil to the transmission internal space S2 (see <FIG>).

On the other hand, when the engine E stops in the EV mode, the rod <NUM> is moved (rightward in <FIG>) by the oil control valve unit <NUM> controlled by the ECU <NUM> such that the clutch C becomes the disengaged state. When the clutch C is in the disengaged state, the valve element portion 160b is located at such a position as to fully open the inflow opening 161a and the outflow opening 161b. Thus, the opening degree of the variable throttle valve <NUM> increases.

As a result, the oil easily flows through the transmission lubricating oil passage <NUM> (see <FIG>), and the oil pressure of the engine lubricating oil passage <NUM> (see <FIG>) decreases. Thus, the supply of the oil to the engine internal space S1 (see <FIG>) is suppressed. To be specific, the oil discharged by the lubricating oil pump P2 (see <FIG>) and flowing through the oil passage <NUM> (see <FIG>) is hardly supplied to the engine internal space S1 (see <FIG>) but is supplied to the transmission internal space S2 (see <FIG>). Therefore, the load of the lubricating oil pump P2 is reduced.

Claim 1:
A vehicle (<NUM>) comprising:
an engine (E) including an engine internal space (S <NUM>);
an electric motor (M);
a transmission (TM) that
includes an input shaft (<NUM>), an output shaft (<NUM>), a gear train (<NUM>) located at the input shaft (<NUM>) and the output shaft (<NUM>), and a transmission internal space (S2) in which the gear train (<NUM>) is located, and
changes speed of rotational power transmitted from the engine (E) and the electric motor (M) to the input shaft (<NUM>) and outputs the rotational power to a driving wheel (<NUM>);
an oil pump (P2) driven by the rotational power from the engine (E) and the electric motor (M);
an oil passage (<NUM>) including
a common oil passage (<NUM>) through which lubricating oil discharged from the oil pump (P2) flows,
an engine lubricating oil passage (<NUM>) extending from the common oil passage (<NUM>) toward the engine internal space (S <NUM>), and
a transmission lubricating oil passage (<NUM>) extending from the common oil passage (<NUM>) toward the transmission internal space (S2); and
a variable throttle valve (<NUM>) that changes a flow rate in the transmission lubricating oil passage (<NUM>),
characterized in that:
the vehicle (<NUM>) is a hybrid vehicle; and
the variable throttle valve (<NUM>) increases an opening degree of the variable throttle valve (<NUM>) in a mode transition in which a first traveling mode in which the hybrid vehicle (<NUM>) travels by driving power of the engine (E) transitions to a second traveling mode in which the hybrid vehicle (<NUM>) stops the engine (E) and travels by the driving power of the electric motor (M).