DE102013209572A1 - Method for controlling power train of hybrid diesel-electric car, involves commanding electromotor to produce output torque, which is equal to difference between smoothed rider rotational torque and engine output torque - Google Patents

Abstract

The method involves obtaining a rider rotational torque requirement (60). The rider rotational torque requirement is smoothed. A diesel combustion engine (12) is commanded to produce output torque, which is smaller than one smoke bordering torque. A multiphase asynchronous alternative current electromotor (14) of a vehicle power train (10) is commanded to produce an output torque, which is equal to difference between the smoothed rider rotational torque and the output torque of the engine. The torque demanded by the engine and the electromotor is optimized. An independent claim is also included for a hybrid diesel-electric power train.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61 / 655,723, filed Jun. 5, 2012, which is hereby incorporated by reference in its entirety.

TECHNICAL AREA

The present invention relates to a hybrid diesel powertrain control.

BACKGROUND

Automotive vehicles include a powertrain that serves to power the vehicle and power the on-board electronics. The powertrain or drive generally includes an internal combustion engine that drives the axle drive system through multi-stage power transmission. Many vehicles are powered by an internal combustion engine (ICE, short of the English Internal Combustion Engine) in Hubkolbenausführung. The internal combustion engine converts chemical energy stored in fuel (gasoline, diesel, biofuels, natural gas or other fuels) into kinetic energy by combustion of the air mixed fuel.

Hybrid vehicles use several alternative drive sources to drive the vehicle, which minimizes the engine's dependence on engine power. For example, a hybrid electric vehicle (HEV) incorporates both electrical energy and chemical energy and converts it to mechanical propulsion power to propel the vehicle and power the vehicle systems. The HEV generally uses one or more electrical machines (motor / generators) that operate individually or in conjunction with the internal combustion engine to power the vehicle. The electric machines convert kinetic energy into electrical energy that can be stored in an energy storage device. The electrical energy from the energy storage device may also be converted back to kinetic energy for driving the vehicle.

In a diesel engine, combustion of an excessively rich fuel mixture may result in the production of carbon-based smoke. This smoke generation often sets a torque-load limit (i.e., the smoke limit) above which the fuel can not be completely burned. While it is possible to obtain more additional engine torque by exceeding the smoke limit (since it is considerably more than stoichiometric), the resulting combustion is very inefficient and any additional power results in reduced combustion efficiency, high fuel consumption and exhaust smoke.

SUMMARY

A hybrid diesel / electric powertrain includes a diesel engine that is in power flow communication with an electric motor and a controller. The diesel engine and the electric motor are each configured to generate a respective torque in response to an intended torque command. The controller communicates with the electric motor, the diesel engine, and an accelerator pedal and is configured to receive a driver torque request from the accelerator pedal. The controller may be further configured to smooth the driver torque request to eliminate any high frequency noise in the signal. The controller may include a hybrid control module in communication with the electric motor and an engine control module in communication with the diesel engine.

The controller may be configured to request, in response to the driver torque demand from the diesel engine, to generate an output torque that is less than a smoke limit torque and to request the electric motor to output torque equal to the difference between the driver torque request and the output torque To produce diesel engine. The smoke limit torque may be a function of available air flow to the diesel engine.

The controller may be further configured to optimize the torque required by the diesel engine and the electric motor such that the torque required by the diesel engine is less than an efficiency limit torque when the torque required by the electric motor is less than a maximum torque limit. As will be understood, the efficiency limit torque is smaller by a predetermined amount than the smoke limit torque. If the torque required by the electric motor is equal to a maximum torque limit for the engine, then the controller may determine a torque output of the diesel engine that is greater than the efficiency limit torque but still less than the smoke limit torque.

Similarly, a method of controlling a vehicle powertrain having an electric motor in power flow communication with a diesel engine comprises: obtaining a driver torque request; Smoothing the driver torque demand; Requesting the diesel engine to produce an output torque that is less than a smoke limit torque; and requesting the electric motor to produce an output torque that is equal to the difference between the smoothed driver torque request and the output torque of the diesel engine.

The above features and advantages as well as other features and advantages of the present invention will be readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 12 is a schematic diagram of a hybrid diesel / electric powertrain associated with an engine control module, a transmission control module, and a hybrid control module.

2A FIG. 12 is a schematic graph of a driver acceleration demand as a function of time. FIG.

2 B FIG. 12 is a schematic graph of desired powertrain torque and diesel engine output torque versus time. FIG.

2C FIG. 12 is a schematic graph of required electric motor output torque as a function of time. FIG.

DETAILED DESCRIPTION

Referring now to the drawings, wherein like reference numerals are used to identify similar or identical components throughout the several views, there is illustrated 1 schematically a hybrid powertrain 10 for a hybrid diesel / electric vehicle. The hybrid powertrain 10 can an internal combustion engine 12 include that with an electric traction motor 14 (Electric motor 14 ) is in mechanical communication. The internal combustion engine 12 may generally be of an engine control module 16 (ECM 16 ) are controlled while the electric motor 14 generally from a hybrid control module 18 (HCM 18 ) can be controlled. The ECM 16 and the HCM 18 may be embodied as one or more digital computers or data processing devices including one or more microcontrollers or central processing units (CPU), read only memory (ROM), random access memory (RAM), electrically erasable programmable read only memory (EEPROM) High-speed clock, analog-to-digital (A / D) circuitry, digital-to-analog (D / A) circuitry, input / output (I / O) circuitry, and / or signal conditioning and buffer electronics. Every module 16 . 18 may be configured to automatically perform one or more control / processing routines that are considered to be the module 16 . 18 associated software or firmware can be embodied.

While 1 In general, illustrating a particular configuration of a hybrid diesel / electric vehicle, other arrangements may be analogously useful in the presently described technology. Likewise, additional electric motors in various arrangements in the drive train 10 be included to serve as a prime mover for the hybrid vehicle. Thus, the internal combustion engine 12 and the electric motor (s) 14 with each other and with a gearbox 20 in power flow connection to ultimately a drive shaft 22 and one or more drive wheels 24 drive.

The electric motor 14 can by means of an engine output shaft 26 provide a torque source. Analogously, the internal combustion engine 12 by means of a crankshaft 28 passing through a clutch 30 and / or one or more (not shown) planetary gear sets selectively with the engine output shaft 26 can be coupled to generate a torque. A torque from the crankshaft 28 Can be used to the vehicle 10 drive directly and / or to the electric motor 14 as a generator for charging a traction battery 32 drive.

The electric motor 14 can be embodied as a polyphase, permanent magnet / polyphase asynchronous machine designed to be in about 60 volts to about 300 volts or more, depending on the vehicle design. The electric motor 14 can be done by means of an inverter module (PIM) 34 and a high voltage busbar 36 with the traction battery 32 be electrically connected. The PIM 34 Generally, it may be configured as needed to convert DC power to AC power and vice versa. The battery 32 can from one to the electric motor 14 with active working of this engine 14 as a generator applied torque can be loaded selectively, for. B. by gaining energy during a regenerative braking process or when driven by the internal combustion engine 12 , As can be understood, the electric motor 14 an electric motor, a Power generator, a motor / generator or any combination thereof. In some embodiments, such as a plug-in HEV (PHEV), the battery may 32 also be charged by means of a (not shown) power supply outside the vehicle when the vehicle 10 idle.

The internal combustion engine 12 can with an air intake 40 and one or more fuel injectors 41 in fluid communication. The air intake 40 may be configured to supply a supply of fresh air to the internal combustion engine, where the air with the fuel from the fuel injector 41 can mix. An adjustable throttle 42 can the flow of air from the inlet 40 to the internal combustion engine 12 under the direction of the ECM 16 modulate controllable. Analogously, the ECM 16 by means of the one or more fuel injectors 41 the flow of fuel into the internal combustion engine 12 Taxes. In one configuration, an intake manifold 44 between the throttle 42 and the internal combustion engine 12 be arranged to even the intake air into the internal combustion engine 12 to flow.

During a vehicle drive, the ECM 16 that of the internal combustion engine 12 generated torque by selectively modifying the behavior of one or more "torque actuators" change. In general, a torque actuator is a controllable aspect of the internal combustion engine that is attached to the crankshaft 28 increase or decrease output torque. Torque actuators generally fall into two categories: slow-acting actuators and fast-acting actuators. Fast acting actuators can effect an almost instantaneous change (eg, 20-50 ms) in engine output torque, such as injecting more or less fuel into a cylinder, retarding ignition (in a gasoline engine), changing variable phaser and / or boosting exhaust gas recirculation (EGR) to dilute the air / fuel mixture. Conversely, slowly responding actuators may require many revolutions of the engine (eg, 100-500 milliseconds) to effect a torque change, and may often involve cranking the engine from a lower speed to a higher speed. Slow-acting actuators can, for example, control the throttle 42 to the in the internal combustion engine 12 increasing / decreasing the amount of air entering and / or changing the boost pressure by means of one or more compressors (eg turbocharger (not shown)).

In very general terms, and with many other variables fixed or ignored, more torque is generated as more oxygen-rich air and fuel enters the internal combustion engine 12 to be delivered. By opening the throttle to its widest and least restrictive position, the engine can 12 working at their highest long-term torque output (ie their maximum capacity).

The ECM 16 can utilize inputs from various sensors (eg, intake sensors, manifold air pressure sensors, fuel sensors, and / or air mass sensors) to increase the torque capacity and performance of the internal combustion engine 12 to estimate or calculate. The ECM 16 For example, the determined torque capacity along with other measured or determined information about the HCM 18 which can determine the most efficient way to increase the torque generating capacity of the internal combustion engine 12 and the engine 14 to use. In one embodiment, the HCM 18 use a torque-optimizing routine to cope with various torque demands in a manner that operates the engine as frequently as possible at its most efficient condition. The HCM 18 can then determine the torque amount that the internal combustion engine 12 should generate / deliver, and how much torque (positive or negative) the electric motor 14 should deliver. The engine torque request may then be returned to the ECM 16 be delivered, so the ECM 16 can intelligently control the various engine torque actuators to track torque demand as closely as possible. Analogously, the HCM 18 the motor torque request directly to the PIM 34 deliver to the engine 14 to control. In general, more accurate estimates allow the torque capacity of the engine 12 a more precise optimization of the hybrid powertrain 10 through the HCM 18 ,

In addition to the ECM 16 and the HCM 18 can the powertrain 10 furthermore a transmission control module 50 (TCM 50 ), which includes the operation of the transmission 20 can monitor. The TCM 50 can work with both the ECM 16 as well as the HCM 18 in an automatic transmission configuration, coordinating gear changing operations in the transmission 20 support. During a gearshift, for example, through the gearbox 20 Described net torque may desirably be at a predetermined value, which is lower than the torque requested by the driver. That way, the ECM 16 and / or the HCM 18 Temporarily override torque commands requested by a driver to engage in a gear change cooperative with the TCM 50 to facilitate.

In one operating mode, the ECM 16 / HCM 18 cooperate to the one or more torque actuators of the internal combustion engine 12 in response to an immediate driver torque request 60 on an accelerator pedal 62 (It should be noted that in practice, such a torque demand may be more gradual and / or louder at the time of its ascent from no actuation to full actuation). In a configuration where the internal combustion engine 12 a diesel engine 12 (ie, compression ignited) may be the driver torque demand 60 from the ECM 16 received and first filtered / smoothed to eliminate any high-frequency noise. The smoothed demand can then be used to control the torque output of the engine 12 by changing the amount of fuel that the engine 12 through the fuel injectors 41 is delivered to control. The ECM 16 may then, in response to the fuel command, adjust the amount of airflow through the throttle 42 (along with an EGR) so that it maintains a desired fuel / air mixture to provide efficient, clean combustion. While fueling is generally a fast response torque actuator to maintain generally efficient combustion, the fuel response during normal acceleration may be artificially limited as a function of throttle / airflow dynamics. The type of powertrain control is typically different than in a spark-ignited gasoline internal combustion engine where the driver torque demand 60 is used to the throttle 42 and fuel delivery depends on available airflow.

2A . 2 B and 2C generally illustrate a scenario in which a driver gas pedal demand 60 at a time 80 raised or raised by pedal action. The graph 82 in 2A schematically shows such a demand over time 84 while the second and third graph 86 . 88 (in 2 B and 2C each shown) schematically a torque 90 as a function of time 84 represent. Each of the three figures / each of the three graphs 82 . 86 . 88 is coordinated in time, but the size of the various curves is not necessarily to scale.

2 B and 2C generally illustrates four different torque curves 100 . 102 . 104 and 106 , The curve 100 provides the desired torque demand 100 from the drive train 10 dar. This desired torque demand 100 puts the accelerator pedal demand 60 of the driver who has been converted to an acceleration torque request. The curve 106 is the required torque 106 that's from the desired torque demand 100 has been smoothed / filtered, and is generally the input to the engine / engine optimization provided by the HCM 18 is carried out. The curve 102 is the required engine torque 102 that the ECM 14 from the HCM 18 is delivered, the curve 104 is the required motor torque 104 that to the PIM 34 is delivered. As it should be understood, the required engine torque should be 104 and the required engine torque 102 in a configuration in which the engine and the internal combustion engine are on the same crankshaft, to the curve 106 sum up.

As generally noted above, with diesel engines, combustion must be properly handled to provide clean, efficient combustion. Thus, the ECM 16 the fuel reaction of the internal combustion engine 12 as a function of available fresh air flow at any given moment. Such a constraint can then be translated directly into a maximum amount of torque available at any moment. This upper torque limit is commonly referred to as the "smoke limit 108 '' designated. As in 2 shown is the smoke limit 108 over time 82 increase, albeit typically at a rate consistent with the slow-response torque actuators.

For non-hybrid powertrains, the ECM 16 the engine torque 102 up to the smoke limit 108 let rise. However, this may result in a reduction in fuel economy / efficiency while also reducing the life of an exhaust aftertreatment particulate filter.

In the present system, the ECM 16 try the engine torque 102 at least by a predetermined amount 110 below the smoke threshold 108 to keep (ie at an efficiency limit 112 that is lower than the smoke limit 108 is). Unfortunately, the powertrain under engine power alone can provide the desired torque demand 106 not precise track. Therefore, the HCM 18 the electric motor 14 (using the PIM 34 ) instruct the torque delivered by the internal combustion engine 102 if necessary with a positive torque from the engine 14 to complete. Should the engine 12 a maximum torque limit 114 can reach the engine torque 104 be saturated in one configuration and the HCM 18 can (generally at 116 ) command the engine, the engine torque 102 above the efficiency limit (generally at 118 ). In such a configuration, the engine torque 102 still on exceeding the smoke limit 108 be prevented. In another configuration, instead of exceeding the efficiency limit, the HCM 18 only the desired shaped trajectory of torque 106 Re-tune so that the engine does not reach its maximum torque limit 112 reached.

Therefore, as generally in 2A . 2 B and 2C shown the required engine torque 102 starting from an initial time 120 a desired one desired output torque 100 exceed. This positive difference 122 can be due to a negative engine torque 104 on the electric motor 12 be balanced, which can generate electricity to the traction battery 32 replenish.

If at the time 80 the torque required by the driver 60 can use the ECM 16 an increased desired torque demand 100 to the HCM 18 send. The HCM 18 can the ECM 16 instruct the engine torque 102 at the efficiency limit 112 while simultaneously starting the engine torque 104 to increase. At the time 124 can the engine torque 104 become positive when the electric motor 14 starts, energy from the battery 32 to consume the internal combustion engine 12 to support. When the engine torque 102 towards the stationary value 126 the desired output torque 100 can increase, the required engine torque 104 sink (generally at 128 ).

By the time 130 can the engine torque 102 the stationary value 126 the desired output torque 100 exceed, with the HCM 18 the electric motor 14 can begin to start generating electricity to the resulting torque 106 at the desired value 126 to keep. In this way, the battery can recover any energy expended during acceleration assistance.

In another configuration, the efficiency limit 112 be a variable limit, thereby corresponding to the proximity of the engine torque to the smoke limit 108 Losses can be assigned. The HCM 18 can take into account such losses in the implementation of its engine / engine optimization and the smoke limit 108 approach only to the extent necessary to compensate for a driveline reaction with fuel economy. In other words, any use of an engine torque would 104 above a certain efficiency limit 112 cost calculation to see that additional fuel consumption would be required to achieve this.

Although the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative constructions and embodiments for practicing the invention within the scope of the appended claims. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not as limiting.

Claims (10)

A method of controlling a vehicle driveline having an electric motor in power flow communication with a diesel engine, the method comprising: Obtaining a driver torque demand; Smoothing the driver torque demand; Requesting the diesel engine to produce an output torque that is less than a smoke limit torque; and Requesting the electric motor to produce an output torque equal to the difference between the smoothed driver torque demand and the output torque of the diesel engine. The method of claim 1, further comprising optimizing the torque required by the diesel engine and the electric motor so that the torque required by the diesel engine is less than an efficiency limit torque when the torque required by the electric motor is less than a maximum torque limit; and wherein the efficiency limit torque is less than the smoke limit torque by a predetermined amount. The method of claim 2, wherein the torque required by the diesel engine is greater than the efficiency limit torque and less than the smoke limit torque when the torque required by the electric motor is equal to a maximum torque limit. The method of claim 1, wherein the driver torque request is provided by means of the operation of an accelerator pedal. The method of claim 1, wherein the smoke limit torque is a function of available airflow to the diesel engine. A hybrid diesel / electric powertrain, comprising: a diesel engine in power flow communication with an electric motor, the diesel engine and the electric motor, each configured to generate a respective torque in response to an intended torque command; a controller in communication with the electric motor, the diesel engine, and an accelerator pedal, the controller configured to: obtain a driver torque request from the accelerator pedal; to require the diesel engine to produce an output torque that is less than a smoke limit torque; requesting the electric motor to produce an output torque equal to the difference between the driver torque demand and the output torque of the diesel engine. The hybrid diesel / electric powertrain of claim 6, wherein the controller is further configured to smooth the driver torque request prior to issuing the command of the electric motor to generate output torque. The hybrid diesel / electric powertrain of claim 6, wherein the controller is further configured to optimize the torque required by the diesel engine and the electric motor such that the torque required by the diesel engine is less than an efficiency limit torque when that of the electric motor required torque is less than a maximum torque limit; and wherein the efficiency limit torque is less than the smoke limit torque by a predetermined amount. The hybrid diesel / electric powertrain of claim 8, wherein the torque required by the diesel engine is greater than the efficiency limit torque and less than the smoke limit torque when the torque required by the electric motor equals a maximum torque limit. The hybrid diesel / electric powertrain of claim 6, wherein the smoke limit torque is a function of available air flow to the diesel engine.

Images