Digital tachograph system with digital memory system

A digital tachograph system includes a vehicle unit operative to detect vehicle performance characteristics such as vehicle speed, elapsed trip distance, engine rpm, total engine revolutions, total fuel consumption, rate of fuel consumption and the like as a function of time. The forgoing vehicle performance characteristic data is displayed in the vehicle unit and is stored in a data memory located therein. A fixed base unit includes a central computer system for processing vehicle performance data, storing the data in a memory file and for reading out the vehicle performance data in the form of a printout, graph plot, CRT display or the like. The vehicle performance data may be transferred from the vehicle unit to a field terminal which connects to the central computer system either by means of a cable connection by directly interconnecting said portable memory unit or by radio transmission means.

The present invention relates to vehicle performance and control systems 
and more particularly to a digital tachograph system. 
In my U.S. Pat. No. 3,835,382 there is described an electronic multi-mode 
vehicle performance indicator system for providing a digital display of 
odometer, tachometer and speedometer readings. In my copending application 
Ser. No. 449,708, filed Mar. 11, 1974 (U.S. Pat. No 3,950,700), the system 
of U.S. Pat. No. 3,835,382 is further provided with means digitally 
displaying the preselected maximum vehicle velocity or engine rpm. Neither 
of the systems disclosed in U.S. Pat. No. 3,835,382 or U.S. Pat. No. 
3,950,700, however, is provided with means for recording the vehicle 
performance data which is being generated during the course of operation 
of the vehicle. 
Presently known tachograph systems for recording vehicle performance 
graphically record the performance data by means of a scribe on paper 
having a pressure sensitive thin plastic coating. Such paper charts are 
susceptible to marking or defacement by abrasion and dirt by repeated 
handling thereof. Such marks, although they consist of fine scratches may 
obscure or make it very difficult to read whole sections of recorded data. 
Furthermore, inherent variations in the chart dimensions due to 
temperature, humidity, atmospheric pressure and manufacturing defects 
cause distortions in the recorded graphic data which may seriously 
compromise the accuracy and/or interpretation of such recorded data. 
Furthermore, since the stylus in such conventional tachographs receives its 
modulation pressure via mechanical coupling devices, the resulting record 
suffers a further deterioration in fidelity. 
The conventional method of converting such recorded chart data into digital 
form is by visual reading thereof with the aid of a microscope or the 
like. This method is obviously time consuming, costly and subject to 
substantial human error. Thus, data collected during a very short time 
period requires a very high measure of resolution such as in the case of 
the time period just preceding an accident. 
Semiautomatic optoelectronic pattern recognition systems have to a very 
limited extent overcome some of the above-mentioned deficiencies. However, 
they still require the manual handling of charts and the presence of an 
operator to feed such charts into the analysis system. Additionally, the 
inaccuracies in graphic form appear in the printed report. Additionally 
such analysis apparatus is sensitive to chart dimension variations, 
marring and scratches. These variations, marring and scratches frequently 
cause the semiautomatic apparatus to introduce gross errors of its own 
making. 
Additionally, the resolution of such optoelectronic analysis apparatus is 
too coarse to provide an accident analysis, and accordingly, the 
microscopic technique must still be used to obtain high resolution data. 
Frequently, an effort is made to erase scratches and mars on the charts, 
thus, requiring further human operator attention. In such conventional 
systems data such as gas consumption must be visually collected from 
manually recorded data such as gaspump readings and manually typed into 
the semiautomatic optoelectronic analysis apparatus via its interconnected 
keyboard, in addition to vehicle identification. 
The tachograph data processing system of the present invention overcomes 
the deficiencies of known tachographs and methods of converting their 
graphic data into reports having numerical data. The present invention 
which incorporates the tachograph display of my U.S. Pat. No. 3,835,382 
includes an automatic method of transferring data from the tachograph to a 
central terminal computer system via radio transmission. Since the data 
exists in digital form in said tachograph, no conversion to digital format 
is necessary. The fuel consumption is measured by vehicle sensors 
connected to the tachograph thus overcoming the need for manual transfer 
of such fuel data into the computer system in addition to avoiding the 
need for conventional plastic coated paper charts. Furthermore, vehicle 
identification may be encoded in the tachograph system of the present 
invention thus making identification by manual typing necessary. The 
resolution and accuracy of data collected in the tachograph of the present 
invention is such that accident reports may be easily prepared. 
Furthermore, a graph plotter connected to the central computer 
automatically creates a magnified graphic representation of the vehicle 
speed just prior to an accident without the use of microscopes. In 
addition, a digital report printout and displays are available via 
peripherals connected to the central computer. 
SUMMARY OF THE INVENTION 
In accordance with the principles of the present invention, there is 
provided a digital tachograph system comprising vehicle detection means 
operative to detect vehicle performance characteristics and to produce 
vehicle characteristic data signals corresponding to said detected 
characteristics and vehicle data memory means operative to receive and 
store said vehicle characteristic data. There is further provided field 
computer terminal means and data transmission means operative to 
selectively transmit the vehicle characteristic data from said vehicle 
data memory means to said field computer terminal means. The field 
computer terminal means is operative upon receipt thereof to selectively 
read out said vehicle characteristic data. 
Further objects, features and advantages of this invention will become 
apparent from a consideration of the following description, the appended 
claims and the accompanying drawings in which:

DETAILED DESCRIPTION OF THE INVENTION 
In my U.S. Pat. No. 3,835,382 there is described an electronic multi-mode 
vehicle performance indicator system for providing a digital display of 
odometer, tachometer and speedometer readings. In my U.S. Pat. No. 
3,950,700, the system of U.S. Pat. No. 3,835,382 is further provided with 
means digitally displaying the preselected maximum vehicle velocity or 
engine rpm. Neither of the systems disclosed in U.S. Pat. No. 3,835,382 or 
my, is provided with means for recording the vehicle performance data 
which is being generated during the course of operation of the vehicle. 
Thus, although not necessarily limited thereto, the tachograph system of 
the present invention is particularly suitable for incorporation into the 
vehicle performance indicator system disclosed in U.S. Pat. No. 3,950,700. 
Accordingly, the structure and principles of operation of the tachograph 
system of the present invention will be described in conjunction with the 
vehicle performance indicator system of my U.S. Pat. No. 3,950,700. For 
reasons of clarity, the elements shown in the drawings which are common to 
the system shown and described in U.S. Pat. No. 3,950,700 carry the same 
identifying numerals in the present application as they do in said U.S. 
Pat. No. 3,950,700. 
Furthermore, the specification and drawings of my U.S. Pat. No. 3,950,700 
are hereby incorporated by reference into the present application in order 
to facilitate a complete and clear understanding of the present invention. 
Referring to FIG. 1, the portion of the tachograph system of the present 
invention which is located in the vehicle, is referred to as vehicle 
tachograph unit 500. Vehicle speed takeoff 10a which may, for example 
comprise an electromagnetic generator, is mechanically linked to speed 
sensor 12a which produces an electric signal which represents the vehicle 
speed. This vehicle speed is applied to input port 502 of the display 
sector 504 of microprocessor 506. 
Generally speaking, microprocessor 506 is operative to receive signals from 
sensors and controls and to process said signals to suitably drive display 
devices which indicate vehicle operation parameters. The display signal 
processing functions are carried out in the display sector 504 of 
microprocessor 506, while temporary data storage control functions are 
carried out in storage control sector 508. In the following description, 
the operation of storage control sector 508 will follow that of display 
sector 504. 
As described in my U.S. Pat. No. 3,905,700, the display system 510, in 
response to the processed vehicle speed signals at output port 512, 
displays the vehicle speed in numeric form through numeric display devices 
44, 52 and 82. Whenever the preselected excess speed limit set by code 
selector switch 110 is exceeded by the vehicle, indicator 112 is turned 
ON. 
Code selector switch 110 is connected to input port 514 of display sector 
504. Insufficient speed indicator 122 is turned ON whenever the vehicle 
speed falls below a preselected lower limit which is programmed into 
display sector 504. The pulses produced at output port 516, representing 
the mileage travelled by the vehicle, are applied to impulse counter 32 
with the stored count being displayed in this odometer configuration in 
impulse counter 32. 
The engine rpm takeoff 10b is mechanically connected to rpm sensor 12b 
which, like sensor 10b may comprise an electromagnetic generator which 
produces an output signal representing the instantaneous vehicle speed. 
The vehicle points may serve as the vehicle takeoff 10b. The rpm signal 
produced by sensor 10b which is entered into display sector 504 at input 
port 518 is then processed and may be selectively applied, by mode 
selector switch 20 to display system 510 and input counter 32 via output 
ports 512 and 516 respectively. 
Mode selector switch 20 is operative to select either the vehicle speed and 
total vehicle miles traversed mode or engine rpm and total engine 
revolutions mode. Thus, display system 510 and impulse counter 32 commonly 
display either vehicle speed-totalized miles or engine rpm--total engine 
revolutions. The vehicle battery 522 supplies power to microprocessor 
system 506 via lead 524 and ignition switch 523 through lead 525. In the 
event that rpm and speed display is desired simultaneously, an additional 
display system 510 and impulse counter 32 may be added to microprocessor 
506. 
Vehicle idle status can be determined by utilizing data jointly from 
vehicle speed takeoff 10a and vehicle rpm takeoff 10b. In the event that 
an rpm takeoff is not available, the vehicle ignition switch 523 is 
connected to microprocessor system 506 via lead 525 at input port 531. 
Thus, the state of ignition switch 523 in conjunction with zero vehicle 
speed indicates an engine idling condition. 
Fuel quantity sensor 526 is operative to provide a signal representing the 
remaining quantity of fuel in the vehicle fuel tank. Sensor 526, if the 
analog type, comprises a potentiometer, and the analog output signal is 
applied to analog-to-digital converter 528 at input A. The resulting 
digital signal at output D is applied to microprocessor 506 at its input 
port 530. An alternate fuel rate of flow sensor 532 produces a digital 
output signal which is applied to microprocessor 506 at its input port 
532. If sensors 526 and 532 are digital then their outputs may be applied 
directly to input ports 530 and 534 respectively, but if analog, their 
outputs are applied to converter 528 and the resulting digital output from 
converter 528 are then applied to input ports 530 and 532. The data 
signals applied to ports 530 and 534 relating to rates of fuel consumption 
and totalized fuel consumption comprise information which is of particular 
importance to operators of truck fleets. 
Information relating to remaining fuel quantity, rate of fuel consumption, 
or total fuel consumed may optionally be displayed by feeding such data 
from storage control sector 508 to display sector 504. As indicated by 
bidirectional arrow 536, there may be a bidirectional transfer of data 
within microprocessor system 506 and such information may be fed via port 
512 for display in display system 510, and via port 516 to impulse counter 
32. Vehicle speed and engine rpm data may be fed from display section 504 
to storage control section 508 where such data may be processed with the 
fuel data as explained in greater detail below. 
The combined data in storage control sector 508 is transferred via port 570 
to connector 538 and mating connector 540 to buffer data memory 542 
including connector 540 comprise a detachable portable memory system 544. 
The off-board system 546 comprises a field terminal 547 which may be 
located at a field station and which may typically include a plurality of 
commonly connected line terminals and a central terminal computer system 
548. Field terminal 547 includes a plug connector 550 which may be located 
at a location remote from or at the central terminal computer system 548. 
Central terminal computer system 548 comprises a computer 554 connected as 
follows. Keyboard 556 has its output connected to port PI1 of computer 
554; printer 558 has its input connected to computer output port P1; graph 
plotter 560 has its input connected to computer output port P2; CRT 
display 562 has its input connected to computer output port P3; memory 
file 564 has its input-output port connected to PIO; and lead 566 
interconnects connector plug 550 with computer input port PI2. 
In operation, when a vehicle arrives at remote location station 552, i.e. 
at a vehicle stop station or at the end of a trip, the vehicle operator 
detaches portable memory system 544 at connector 538 and connects it to 
field terminal 547 at connector 550. Now portable memory system 544 
contains stored data in buffer memory 542, the memory 542 may typically 
comprise a non-volatile electrically erasable memory such as an MNOS 
(metal nitride oxide semiconductor) type memory. When plug 540 is mated 
with connector 550 the stored data accumulated during the vehicle trip in 
portable memory system 544 is fed through conductor 566 into computer 554 
at input port PI2. Computer 554 thus processes the incoming data in 
accordance with the programming instructions selected by the fleet 
managment to provide output reports at the periphal equipment, namely, 
printer 558, graph plotter 560 and CRT display 562. Furthermore, memory 
file 564 is operative to store selected large quantities of data from 
computer 544 and to provide previously stored data to computer 554 upon 
command. Input keyboard 556 enables manually typed data to be fed into 
computer 544 in conjunction with data fed from connector 550 and memory 
file 564. 
In one embodiment of the present invention as shown in FIG. 1, display 
sector 504 may comprise random logic integrated circuitry as disclosed in 
my U.S. Pat. No. 3,835,382 and my U.S. Pat. No. 3,950,700. Thus, outline 
568 indicates those elements which are common to the systems shown and 
described in my said patent and copending patent application and such 
elements, therefore, bear the same identifying numerals. 
In another embodiment of the present invention, display sector 504 may 
comprise an "off-the shelf" microprocessor system such as Motorola type 
M6800 or RCA COSMAC type. Such microprocessors may be programmed with the 
capability of converting random logic designs into microcomputer language 
operative to perform such random logic design functions with said 
microprocessors. In practice, the random logic elements and related data 
flow as shown in my said copending application may be converted into a 
computer program operative to effect operations described hereinabove with 
respect to display sector 504. Similarly, storage control sector 508 may 
be arranged by utilizing random logic elements or microprocessor 
techniques, with display sector 504 and storage control sector 508 
comprising a single microprocessor system. 
In another embodiment of the present invention shown in FIG. 2, the buffer 
data memory 542 is integral with microprocessor system 506 and is not 
removable from the vehicle unit 500. Data transfer from buffer data memory 
542 to field terminal 547 is effected by a fixed connector 538 which is 
connected to port 570 and interconnects multiconductor 566 and buffer data 
memory 542. In operation, when the vehicle arrives at remote location 552, 
an operator mates connector 538 with connector 550, whereby the elapsed 
trip data flows from buffer data memory 542 through port 570, connector 
538, multiconductor 567, connector 550 and multiconductor 566 into 
computor 554 at input port PI2 where such data is processed as described 
hereinabove with respect to FIG. 1. After several moments, the vehicle 
operator may remove connector 550 from connector 538 as the data transfer 
has been completed. 
In further embodiment of the present invention shown in FIG. 3, data 
transfer from buffer data memory 542 to field terminal 547 is accomplished 
by radio transmission. As shown in FIG. 3, the output of buffer data 
memory 542 which is integral with microprocessor system 506 is connected 
to microprocessor port 570 which is connected to the modulator input M of 
radio transmitter 574 which is connected to digital tachograph 501 in the 
vehicle. The output T of transmitter 574 is connected to a transmitting 
antenna 576 via cable 578. Transmitting antenna 576 may be suitably 
mounted on the vehicle. 
Input port 580 of microprocessor 506 is connected to output C of proximity 
detector 582 which may typically comprise either a limit switch, photocell 
or radio receiver or the like. Proximity detector output C is also 
connected to control input I of data transmitter 574, while receiving 
antenna input A of proximity detector 582 is connected to receiving 
antenna 584 via transmission line 586 in the case where proximity detector 
582 comprises a radio receiver. Receiving antenna 584 may, alternately, 
comprise a trip lever connected to proximity detector 582 should the 
latter be a limit switch, or a lens system (not shown) if detector 582 is 
a photocell. 
Proximity actuator 588, which is located at field terminal 547, may 
typically comprise either a radio transmitter, a directional encoded light 
source or a trip mechanism designed to trip proximity detector 582 (should 
detector 582 be a limit switch) via antenna 584. Antenna 590 is connected 
to input I of data radio receiver 592, which is mounted at location 552 
while output D of receiver 592 is connected to input port PI2 of computer 
554. 
In operation, when the vehicle arrives at location 552, proximity actuator 
588 trips proximity detector 582 via radio transmission of limited range, 
(or directional light signal, or mechanical pressure, etc.) via antenna 
584 through transmission line 586. Proximity detector 582 through its 
output C and input port 580 of microprocessor 506 initiates "a read data" 
subroutine which causes the stored data to appear at port 570 and flow to 
modulator input M of data radio transmitter 574. Furthermore, the signal 
at output C of proximity detector 582 appearing at input I of transmitter 
574 causes it to transmit data appearing at the input M thereof. The 
transmitted data in the form of radio signals is received at antenna 590 
and flow to input I of data radio receiver 592 where it is detected and 
amplified. This data at output D of data radio receiver 592 in the form of 
an amplified pulse train now enters computer 554 at its input port PI2 via 
cable 566 and the data is processed as described hereinabove with respect 
to FIG. 1. 
Although the invention has been described with reference to particular 
embodiments thereof it is to be understood that such embodiments are 
merely illustrative of the application of the principles of the invention. 
Numerous modifications may be made therein and other arrangements may be 
devised without departing from the spirit and scope of the invention.