Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Electric vehicle
Reexamination Certificate
2001-03-19
2001-11-27
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Electric vehicle
C701S087000, C701S051000, C180S165000, C290S04000F, C290S04000F
Reexamination Certificate
active
06324449
ABSTRACT:
FIELD OF AND BACKGROUND OF THE INVENTION
The invention relates to a control device for a vehicle that is propelled by an electric engine. Such control devices are provided both for vehicles driven solely by an electric engine as well as for vehicles with a hybrid drive.
Vehicles driven by internal combustion engines are usually distinguished by a retarding action exerted on the vehicle due to an engine drag torque during coasting when the accelerator or brake pedal is released and the internal combustion engine is not de-coupled from the transmission by a clutch.
OBJECTS OF THE INVENTION
One object of the present invention is to offer the driver this type of familiar vehicle behavior even if the vehicle is partially or solely propelled by an electric engine. A related object is to provide the driver with increased driving comfort even while limiting or minimizing the amount of energy consumed from the energy storage device of the vehicle. Related control devices for vehicles propelled by an electric engine are known from, e.g., German Patent DE 43 24 010 C2 and European Laid-Open Publication EP-A 0 846 590 (which has a counterpart U.S. Pat. No. 5,954,779). The disclosures of these three related art references are incorporated into the present application by reference.
SUMMARY OF THE INVENTION
According to one formulation of the invention, this and other objects are attained by a control device for a vehicle driven by an electric engine:
with a simulated engine drag torque achieved by controlling the electric engine upon release of the previously actuated accelerator pedal or the previously actuated brake pedal of the vehicle,
wherein the electric engine is controlled through an engine brake current (I
B
=f(n;v)) or analogous parameter, such that the current or analogous parameter varies in accordance with a respective engine speed (n) or vehicle speed (v), and
wherein onset of the current or analogous parameter is dependent on reaching a minimum value of an increase in engine speed or vehicle speed (or a minimum acceleration value of the engine speed or vehicle speed) after release of the accelerator pedal or the brake pedal.
It is possible to simulate an engine drag torque familiar to the driver of a vehicle that is driven solely by an internal combustion engine. This is done by providing an engine brake current (or analogous parameter) upon release of the accelerator pedal or brake pedal, and making this engine brake current a function of the vehicle speed or the engine rpm in accordance with a predefinable characteristic. Further, in order to increase the driving comfort and in addition particularly to save the energy carried on board in the energy storage device, the onset of the simulated engine drag torque is set to commence upon a parameter reaching a predefined minimum threshold above the parameter value that exists after release of the accelerator pedal or release of the brake pedal. The parameter and the minimum threshold value thereof can be, e.g., of any of the following: a required increase in engine rpm or in vehicle speed, or a required engine speed acceleration or vehicle speed acceleration, compared to the engine speed or vehicle speed that is present after release of the accelerator pedal or brake pedal. Due to this engine brake characteristic being re-definable in adaptation to the minimum differential threshold values, or the onset of the engine drag torque being thus redefinable, these control values are a function of the actual engine speed or vehicle speed that is present after the accelerator pedal or brake pedal has been released. This occurs in such a way that external acceleration or deceleration forces acting on the vehicle (e.g., an upward or downward slope of the roadway or special wind conditions, or the nature of the road surface), which also affect the vehicle's acceleration or deceleration after the release of the accelerator pedal or brake pedal, are advantageously taken into account.
In such situations, the invention thus avoids, on the one hands additional deceleration by a simulated engine drag torque, which in itself is not necessary or desirable. This prevents impairment of the driving comfort, since the driver may, depending on the situation, attempt to compensate for the unintended excessive deceleration by renewed actuation of the accelerator pedal. It further avoids, in particular, the unnecessary usage of the energy carried on board in the vehicle's energy storage device that would arise from the undesirably strong deceleration or the subsequent acceleration of the vehicle. It is preferable to have the utilization of the kinetic energy of the vehicle be as exact as possible, without resort to regenerative braking, More specifically, the vehicle's energy consumption is optimized by advantageously expanding the vehicle's electric range, rather than recuperating the braking energy, regardless of the specific recuperation method employed, since the recuperation process is always connected with electric losses due to inefficiencies in the recovery processes. According to the invention, any such undesirable excessive braking or re-acceleration is advantageously avoided, however, because the onset of the simulated engine drag torque is made to depend on reaching a minimum threshold value of (i) an engine rpm increase, (ii) a vehicle speed increase, (iii) an engine acceleration or (iv) vehicle acceleration. Reaching the minimum threshold value is factored from the speed of the engine or the speed of the vehicle at the time of or subsequent to the release of the accelerator pedal or brake pedal.
On the other hand, the invention provides a simulated engine drag torque that prevents the vehicle from accelerating due to external forces after the accelerator pedal or brake pedal is released. This makes it possible generally to counteract any external acceleration or deceleration forces acting on the vehicle after the release of the accelerator pedal or brake pedal.
Advantageously, the engine brake characteristic is selected so that the engine drag torque sets in only at engine speeds or vehicle speeds above a certain minimum engine speed or minimum vehicle speed. This has the advantage in particular of avoiding unchecked control fluctuations. According to a preferred embodiment of the invention, the brake current characteristic as a function of the electric engine speed or the vehicle speed is selected such that the brake current initially increases and, after reaching a predefined maximum engine brake current, remains essentially constant. The rate of the increase in the brake current in the first speed range is preferably constant. However, this rate of increase in the brake current in the first speed range and/or the absolute value of the maximum brake current can instead be variable, i.e. a function of additional parameters.
REFERENCES:
patent: 5676111 (1997-10-01), Zhang
patent: 5954779 (1999-09-01), Dietzel
patent: 6188945 (2001-02-01), Graf et al.
patent: 6216067 (2001-04-01), Baeuerle et al.
patent: 43 24 010 C2 (1995-01-01), None
patent: 0 846 590 A2 (1998-06-01), None
Albert Michael
Reckhorn Thomas
Cuchlinski Jr. William A.
Hernandez Olga
Siemens Aktiengesellschaft
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Control device for an electric engine driven vehicle does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control device for an electric engine driven vehicle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control device for an electric engine driven vehicle will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2583641