JP2016175477A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle that can improve a regeneration efficiency at the time of a high speed travel, that can be easily converted from an existing vehicle, and that can improve a fuel consumption by enabling an engine stop without stopping a steering assist during a travel.SOLUTION: The hybrid vehicle is configured by connecting a propeller shaft 25 and a rotation shaft of a motor generator 33 via a speed reduction mechanism 30 where the rotation shaft of the motor generator is provided as an input shaft and the propeller shaft is provided as an output shaft, and also configured by including a second power steering pump 45 for supplying power steering fluid 48 to a steering unit 53 and including a power transmission path 110 for transmitting power of the propeller shaft 25 to the second power steering pump 45 even when stopping a diesel engine 10 during a travel of the hybrid vehicle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle that can improve regeneration efficiency during high-speed traveling and can be easily converted from an existing vehicle.

  In recent years, a hybrid vehicle (hereinafter referred to as “HEV”) including a hybrid system having an engine and a motor generator that are controlled in combination according to the driving state of the vehicle has attracted attention from the viewpoint of improving fuel efficiency and environmental measures. Yes. In the HEV, when the vehicle is accelerated or started, the driving force is assisted by the motor generator, while regenerative power generation is performed by the motor generator during inertia traveling or braking (see, for example, Patent Document 1).

  In such a so-called parallel HEV, the motor generator is normally connected to the drive system of the vehicle from the engine side of the transmission for shifting the rotational power of the engine. For this reason, when the HEV is traveling at high speed (for example, 50 to 90 km / h), the transmission is shifted to a high speed, so that the regenerative braking torque in the motor generator is reduced and the power generation is increased. There is a problem that it is difficult to improve the efficiency of regenerative power generation because it is out of the efficiency point.

  Moreover, since it is necessary to change the layout of the powertrain components of the existing vehicle in order to arrange the motor generator, there is a problem that it is not easy to convert the existing vehicle to HEV. .

  Further, in the conventional HEV, steering assist is performed using a power steering fluid supplied from a power steering pump driven by an engine. By the way, in recent years, further improvement in fuel efficiency of HEV has been demanded, and as a technology to meet this demand, for example, development of a technology for stopping the engine during HEV traveling, such as a technology for stopping idling during execution of auto cruise. Has been done. However, in the prior art, when the engine is stopped while the HEV is running as described above, the power steering pump driven by the engine is also stopped, so that it is difficult to assist the steering.

JP 2002-238105 A

  An object of the present invention is to improve the regenerative efficiency during high-speed driving compared to the prior art, to facilitate conversion from existing vehicles, and to stop the engine without stopping the steering assist during driving, thereby improving fuel efficiency. It is to provide a hybrid vehicle that can be improved.

In order to achieve the above object, a hybrid vehicle of the present invention includes a propeller shaft that connects a transmission connected to a diesel engine and a differential that drives wheels, a hybrid system including the diesel engine and a motor generator, and a power steering fluid. A hybrid vehicle comprising: a steering unit that assists the steering of the hybrid vehicle using a power source; and a first power steering pump that is driven by the diesel engine and supplies power steering fluid to the steering unit. The motor generator is connected to a rotation shaft via a speed reduction mechanism having the rotation shaft of the motor generator as an input shaft and the propeller shaft as an output shaft. A second power steering pump for supplying power steering fluid to the steering unit, and power transmission for transmitting the power of the propeller shaft to the second power steering pump even when the diesel engine is stopped while the hybrid vehicle is running. It is characterized by comprising a route.

  According to the hybrid vehicle of the present invention, since the propeller shaft and the rotation shaft of the motor generator are connected via the speed reduction mechanism, the regenerative braking torque of the motor generator is increased during inertia traveling during high speed traveling. Regeneration efficiency can be improved. Moreover, since the regeneration efficiency at the time of high-speed driving can be improved simply by newly attaching a speed reduction mechanism to the propeller shaft of an existing vehicle, conversion from the existing vehicle can be performed more easily than in the past.

  Also, when the power transmission between the diesel engine and the propeller shaft is cut off and the diesel engine is stopped during traveling, the power transmission path formed by the gear of the speed reduction mechanism that is rotating with the rotational force of the propeller shaft Power steering fluid can be supplied to the steering unit by the second power steering pump driven by the steering assist to assist steering. Thereby, the diesel engine can be stopped without stopping the steering assist during traveling, and the fuel efficiency can be improved.

  The above configuration may further include an accumulator that accumulates the power steering fluid supplied from at least one of the first power steering pump and the second power steering pump and supplies the accumulated power steering fluid to the steering unit.

  According to this configuration, when the state in which power steering fluid is supplied from the first power steering pump to the steering unit and the state in which power steering fluid is supplied from the second power steering pump to the steering unit are switched, the steering power is supplied to the steering unit. It is possible to prevent the power steering fluid pressure from fluctuating greatly.

  In the above configuration, the set discharge pressure of the power steering fluid of the second power steering pump is set to be smaller than the set discharge pressure of the power steering fluid of the first power steering pump, and the configuration includes the first power steering pump, The second power steering pump is disposed in a hydraulic circuit communicating with the steering unit, and the flow of power steering fluid from the first power steering pump to the second power steering pump and from the second power steering pump to the first power steering pump. It may further comprise a valve that suppresses the flow of the power steering fluid and that preferentially guides the higher pressure of the power steering fluid supplied from the first power steering pump and the second power steering pump to the steering unit. .

  According to this configuration, the flow of power steering fluid from the first power steering pump to the second power steering pump can be suppressed, and the flow of power steering fluid from the second power steering pump to the first power steering pump can also be suppressed. . Further, while the first power steering pump supplies power steering fluid to the steering unit, the power steering fluid from the second power steering pump to the steering unit can be stopped, and the power steering fluid from the first power steering pump to the steering unit can be stopped. When the supply of fluid stops, the supply of power steering fluid from the second power steering pump to the steering unit can be started.

  According to the hybrid vehicle of the present invention, it is possible to improve the regenerative efficiency at the time of high-speed traveling, and it is easy to divert from an existing vehicle, and it is possible to stop the engine without stopping the steering assist during traveling. Can improve fuel efficiency.

It is a block diagram of the hybrid vehicle which consists of embodiment of this invention. It is the schematic diagram which expanded the deceleration mechanism vicinity of a hybrid vehicle.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hybrid vehicle according to an embodiment of the present invention. This hybrid vehicle (hereinafter referred to as “HEV”) is a large vehicle such as a bus or a truck, and includes a hybrid system having a diesel engine 10 and a motor generator 33 that are controlled in combination according to the driving state of the vehicle. Yes.

  In the diesel engine 10, the crankshaft 13 is rotationally driven by thermal energy generated by the combustion of fuel in a plurality (six in this example) of cylinders 12 formed in the engine body 11. The rotational power of the crankshaft 13 is transmitted to the transmission 20 through the fluid coupling 14 and the wet multi-plate clutch 15. A dry clutch may be used instead of the fluid coupling 14 and the wet multi-plate clutch 15.

  The transmission 20 uses an AMT that automatically shifts gears to a target gear determined based on the HEV operating state and preset map data. The transmission 20 includes a main transmission mechanism 21 capable of shifting input rotational power in a plurality of stages, and a sub-transmission mechanism capable of shifting rotational power transmitted from the main transmission mechanism 21 into two stages, a low speed stage and a high speed stage. 22.

  The rotational power changed by the transmission 20 is transmitted to the differential 26 through the propeller shaft 25 connected to the output shaft 23, and is distributed as a driving force to a pair of driving wheels 27 made of double tires.

  The motor generator 33 is electrically connected to the battery 35 through the inverter 34.

  The diesel engine 10 and the motor generator 33 are controlled by a control device 80. Specifically, at the time of HEV start or acceleration, the motor generator 33 assists at least a part of the driving force, while at the time of inertial running or braking, the motor generator 33 performs regenerative power generation, and surplus The battery 35 is charged by converting kinetic energy into electric power.

  Further, the control device 80 executes auto-cruise when the user turns on the auto-cruise operation switch during HEV traveling. In this auto-cruise, the control device 80 performs high-efficiency operation control for operating the diesel engine 10 in a predetermined high-efficiency region, and idling stop control for stopping operation of the diesel engine 10 by stopping fuel supply to the diesel engine 10. Are alternately executed, so that the HEV speed is controlled to be within a predetermined range without an accelerator operation.

In such HEV, the propeller shaft 25 and the rotating shaft 32 of the motor generator 33 are connected via a speed reduction mechanism 30. The speed reduction mechanism 30 uses the rotating shaft 32 of the motor generator 33 as an input shaft and the propeller shaft 25 as an output shaft. That is, in the speed reduction mechanism 30, the speed reduction ratio (Nm / Np), which is the ratio of the rotation speed Np of the propeller shaft 25 to the rotation speed Nm of the motor generator 33, is greater than 1.0. Note that this reduction ratio may be set to either fixed or variable.

  Next, the HEV power soaring system will be described. The power steering system is a system that assists HEV steering. Specifically, the power steering system includes various hydraulic circuits (first hydraulic circuit 43, second hydraulic circuit) through which the first power steering pump 40, the second power steering pump 45, the double check valve 49, and the power steering fluids 44, 48, 51 flow. 47, a main hydraulic circuit 50), an accumulator 52, and a steering unit 53.

  The first hydraulic circuit 43 communicates the first power steering pump 40 and the double check valve 49. The second hydraulic circuit 47 communicates the second power steering pump 45 and the double check valve 49. Note that the upstream end of the first hydraulic circuit 43 upstream of the first power steering pump 40 and the upstream end of the second hydraulic circuit 47 upstream of the second power steering pump 45 are reservoirs for storing the power steering fluids 44 and 48. It is connected to a tank (not shown). The main hydraulic circuit 50 communicates the double check valve 49 and the steering unit 53. Further, the passage of the main hydraulic circuit 50 is branched and connected to the accumulator 52.

  The first power steering pump 40 is connected to the diesel engine 10 and is driven by the diesel engine 10 to pump the power steering fluid 44. Specifically, the drive shaft 41 of the first power steering pump 40 is connected to the crankshaft 13 of the diesel engine 10 via a V-belt 42 or a gear. The rotational power of the crankshaft 13 is transmitted to the drive shaft 41 via the V-belt 42 or a gear to rotate the drive shaft 41. In this way, the first power steering pump 40 is driven by the diesel engine 10.

  FIG. 2 is an enlarged schematic view of the vicinity of the HEV speed reduction mechanism 30. The speed reduction mechanism 30 has a gear 110 that rotates by receiving the power 115 of the rotating propeller shaft 25 even when the diesel engine 10 is stopped during HEV traveling.

  Specifically, even when the diesel engine 10 is stopped during the execution of the auto-cruise mode, the propeller shaft 25 connected to the drive wheels 27 via the differential 26 rotates while the drive wheels 27 are rotating. doing. Of the plurality of gears of the speed reduction mechanism 30, at least some of the gears 110 have other gears so that they can rotate when the power 115 (specifically, rotational power) of the propeller shaft 25 is transmitted. And connected to the propeller shaft 25.

  The drive shaft 46 of the second power steering pump 45 is connected to the gear 110 and is driven by the gear 110 to pump the power steering fluid 48. The gear 110 is a power transmission path for transmitting the power 115 of the propeller shaft 25 to the second power steering pump 45 even when the diesel engine 10 is stopped during HEV traveling.

  The set discharge pressure of the power steering fluid 48 of the second power steering pump 45 is set to be smaller than the setting discharge pressure of the power steering fluid 44 of the first power steering pump 40. Specifically, the second power steering pump 45 is provided with a relief valve. By adjusting the relief valve, the set discharge pressure of the second power steering pump 45 is smaller than the set discharge pressure of the first power steering pump 40. The value has been adjusted.

As shown in FIG. 1, the double check valve 49 allows the power steering fluids 44 and 48 to flow from the first power steering pump 40 and the second power steering pump 45 to the steering unit 53, and from the first power steering pump 40 to the second power steering pump 40. This is a valve that suppresses the flow of the power steering fluid 44 to the pump 45 and the flow of the power steering fluid 48 from the second power steering pump 45 to the first power steering pump 40. Further, the double check valve 49 preferentially passes the higher pressure of the power steering fluids 44 and 48 supplied from the first power steering pump 40 and the second power steering pump 45 to the steering unit 53 via the main hydraulic circuit 50. It is also a valve to derive.

  The accumulator 52 accumulates the power steering fluid 51 (= 44, 48) via the double check valve 49, that is, the power steering fluid 51 supplied from the first power steering pump 40 and the second power steering pump 45, and the accumulated power steering. Fluid 51 is supplied to steering unit 53 via main hydraulic circuit 50. The configuration of the accumulator 52 is not limited to this. For example, the accumulator 52 has a power steering fluid 51 (= 44 or 44) supplied from only one of the first power steering pump 40 and the second power steering pump 45. 48) may be configured to accumulate.

  The steering unit 53 is an apparatus that assists the steering of the steering 54 by using the supplied power steering fluid 51. If it has such a function, the specific structure of the steering unit 53 will not be specifically limited, A well-known steering unit can be applied. In the present embodiment, a steering unit including a hydraulic power cylinder is used as an example of the steering unit 53.

  The operation of the HEV power steering system described above is as follows. First, when the diesel engine 10 is operating while the HEV is running, the first power steering pump 40 is driven by the diesel engine 10 to pump the power steering fluid 44. Further, the second power steering pump 45 also feeds the power steering fluid 48 by being driven by the gear 110 of the speed reduction mechanism 30 rotating by being connected to the propeller shaft 25 while the HEV is running.

  In this case, as described above, the set discharge pressure of the second power steering pump 45 is set smaller than the set discharge pressure of the first power steering pump 40, and the double check valve 49 has the first power steering pump 40 and the second power steering pump. Since the higher pressure of the power steering fluids 44, 48 supplied from 45 is preferentially led to the steering unit 53, the power steering fluid 48 pumped by the second power steering pump 45 is not supplied to the steering unit 53. Then, the power steering fluid 44, 51 in which the power steering fluid 44 pumped by the first power steering pump 40 and the power steering fluid 51 accumulated in the accumulator 52 merge is supplied.

  When the diesel engine 10 is stopped during inertia traveling or braking during traveling in the HEV auto cruise mode, the pumping of the power steering fluid 44 by the first power steering pump 40 is stopped. On the other hand, even if the diesel engine 10 is stopped during HEV traveling, the propeller shaft 25 continues to rotate as the drive wheels 27 rotate, so the gear 110 of the speed reduction mechanism 30 connected to the propeller shaft 25 rotates. ing. Therefore, the second power steering pump 45 driven by the rotating gear 110 of the speed reduction mechanism 30 can pump the power steering fluid 48 even when the diesel engine 10 is stopped during HEV traveling. . As a result, the power steering fluid 48, 51 in which the power steering fluid 48 pumped by the second power steering pump 45 and the power steering fluid 51 accumulated in the accumulator 52 merge is supplied to the steering unit 53.

According to the HEV described above, the propeller shaft 25 and the rotating shaft 32 of the motor generator 33 are connected via the speed reduction mechanism 30 as described above in the description of the hybrid system. Regardless, since the regenerative braking torque of the motor generator 33 can be increased by the speed reduction mechanism 30, the regenerative efficiency can be improved. In addition, this configuration can be realized simply by newly installing the speed reduction mechanism 30 on the propeller shaft 25 of the existing vehicle. Therefore, the change of the layout of the powertrain component can be very small. More easily.

  Further, according to HEV, as described above in the description of the power steering unit, when the diesel engine 10 is stopped during traveling, the first driven by the gear 110 (power transmission path) of the rotating reduction mechanism 30 is driven. The power steering fluid 48 pumped from the two power steering pumps 45 can be supplied to the steering unit 53 to assist the steering. Thereby, the diesel engine 10 can be stopped without stopping the steering assist during traveling, and the fuel consumption can be improved.

  Further, since the diesel engine 10 can be stopped without stopping the steering assist during the HEV traveling as described above, for example, when the diesel engine 10 is operated at a low speed and a low load in order to perform the steering assist during the traveling. In comparison, PM (particulate matter) in exhaust is effectively deposited on exhaust purification devices such as DPD (Diesel Particulate Diffuser) and DPF (Diesel Particulate Filter). Can be suppressed. Thereby, the fuel consumption required for regeneration of the exhaust emission control device can be suppressed. Also in this point, according to this HEV, a fuel consumption can be improved effectively.

  Since the HEV includes an accumulator 52, the power steering fluid 44 of the first power steering pump 40 is supplied to the steering unit 53, and the power steering fluid 48 of the second power steering pump 45 is supplied to the steering unit 53. When the state is switched, the pressure of the power steering fluids 44, 48, 51 supplied to the steering unit 53 can be prevented from greatly fluctuating. Thereby, steering assist can be performed effectively.

  Further, since the HEV includes the double check valve 49, the flow of the power steering fluid 44 from the first power steering pump 40 to the second power steering pump 45 can be suppressed, and the first power steering pump 45 to the first power steering pump 45 The flow of the power steering fluid 48 to the power steering pump 40 can also be suppressed.

  Further, the double check valve 49 is configured to preferentially lead out the higher pressure of the power steering fluids 44 and 48 supplied from the first power steering pump 40 and the second power steering pump 45 to the steering unit 53, Further, since the set discharge pressure of the second power steering pump 45 is set lower than the set discharge pressure of the first power steering pump 40, while the first power steering pump 40 supplies the power steering fluid 44 to the steering unit 53. The supply of the power steering fluid 48 from the second power steering pump 45 to the steering unit 53 can be stopped. When the supply of the power steering fluid 44 from the first power steering pump 40 to the steering unit 53 stops, the second power steering pump Power steering from 45 to steering unit 53 It is possible to start supplying the Rude 48.

DESCRIPTION OF SYMBOLS 10 Diesel engine 20 Transmission 25 Propeller shaft 26 Differential 27 Drive wheel 30 Reduction mechanism 32 Rotating shaft 33 Motor generator 40 1st power steering pump 44, 48, 51 Power steering fluid 45 2nd power steering pump 49 Double check valve 52 Accumulator 53 Steering unit 110 Gear (power transmission path)

Claims (3)

A propeller shaft for connecting a transmission connected to a diesel engine and a differential for driving wheels; a hybrid system having the diesel engine and a motor generator; and a steering unit for assisting steering of the hybrid vehicle using power steering fluid A first power steering pump that is driven by the diesel engine and supplies power steering fluid to the steering unit;
The propeller shaft and the rotation shaft of the motor generator are connected to each other via a speed reduction mechanism having the rotation shaft of the motor generator as an input shaft and the propeller shaft as an output shaft.
A second power steering pump for supplying power steering fluid to the steering unit, and power transmission for transmitting the power of the propeller shaft to the second power steering pump even when the diesel engine is stopped while the hybrid vehicle is running. A hybrid vehicle comprising a route.   2. The hybrid vehicle according to claim 1, further comprising an accumulator that accumulates power steering fluid supplied from at least one of the first power steering pump and the second power steering pump and supplies the accumulated power steering fluid to the steering unit. The set discharge pressure of the power steering fluid of the second power steering pump is set to be smaller than the set discharge pressure of the power steering fluid of the first power steering pump,
The first power steering pump and the second power steering pump are arranged in hydraulic circuits respectively communicating with the steering unit, and the flow of power steering fluid from the first power steering pump to the second power steering pump and the second power steering pump from the second power steering pump A valve that suppresses the flow of the power steering fluid to the first power steering pump and preferentially leads the higher pressure of the power steering fluid supplied from the first power steering pump and the second power steering pump to the steering unit; The hybrid vehicle according to claim 1, further comprising:

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