Abstract:
In a vehicular velocity controlling apparatus for an automotive vehicle, a vehicular velocity detector is provided to detect a vehicular velocity of the vehicle, a vehicular velocity controlling section is provided that controls a vehicular driving force of the vehicle to make a detected value of the vehicular velocity substantially equal to a set vehicular velocity previously set, a plurality of switches are provided which includes a first switch (SET/COAST switch) and a second switch (RESUME/ACCELERATE switch), each switch being enabled to be interlocked with a predetermined operation of at least one switching member at a position such as to match with a general vehicular occupant&#39;s sense of vehicular manipulation, and a set vehicular velocity modifying section is provided that modifies the set vehicular velocity in such a manner that the detected value of the vehicular velocity is set to the set vehicular velocity when at least one of the following conditions is established, when a time duration of the predetermined operation of the first switch is equal to or longer than a first predetermined time duration and the detected value of the vehicular velocity is lower than the set vehicular velocity and when the time duration of the predetermined operation of the second switch is equal to or longer than a second predetermined time duration and the detected value of the vehicular velocity is higher than the set vehicular velocity.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a vehicular velocity controlling apparatus for an automotive vehicle to control a vehicular driving force (or vehicular braking force but hereinafter referred to as the vehicular driving force only since the vehicular braking force is merely a negative value of the vehicular driving force) to make a present vehicular velocity of the vehicle substantially equal to a previously set target vehicular velocity (hereinafter, referred to a set vehicular velocity) and more particularly relates to the vehicular velocity controlling apparatus in which a modification technique of the set vehicular velocity is improved. 
     2. Description of the Related Art 
     A previous vehicular velocity controlling apparatus has been proposed in which three push button switches are aligned vertically along a peripheral surface of a vehicular steering wheel. 
     That is to say, a set/coast push button switch (hereinafter, referred to as a SET/COAST switch) is disposed at a lowest position of the three push button switches, a resume/accelerate push button switch (hereinafter, referred to as a RESUME/ACCELERATE switch) is disposed at an uppermost position thereof, and a cancel push button switch (hereinafter, referred to as a CANCEL switch) is disposed at a center position between the SET/COAST switch and the RESUME/ACCELERATE switch. 
     The SET/COAST switch serves as a switch enabled to set the set vehicular velocity Vset, to start such a vehicular velocity control as described above, and to decrease the set vehicular velocity value Vset. When a main switch of the previously proposed vehicular velocity controlling apparatus is turned on so that the vehicular velocity controlling apparatus falls in a vehicular velocity control wait state, the SET/COAST switch is pushed by a vehicular occupant for a short period of time (hereinafter, called a short-term push operation) so that the present vehicular velocity V is set as the set vehicular velocity Vset to start the vehicular velocity control. In addition, if the short-term push operation is carried out for the SET/COAST switch during the vehicular velocity control, the set vehicular velocity Vset is decreased by a predetermined velocity ΔV (Vset−ΔV). If the SET/COAST switch is continued to be pushed (hereinafter, referred to as a continuous push operation or continuous operation) for a relatively long period of time during the vehicular velocity control, the set vehicular velocity Vset is decreased toward a lower velocity value at a predetermined deceleration. 
     On the other hand, the RESUME/ACCELERATE switch serves as a switch enabled to resume the vehicular velocity control and to increase the set vehicular velocity Vset toward a higher velocity value. If the short-term push operation is carried out for the RESUME/ACCELERATE switch during the vehicular velocity control, the set vehicular velocity Vset is increased toward the higher velocity value by a predetermined vehicular velocity ΔV (Vset+ΔV). If the continuous push operation is carried out for the RESUME/ACCELERATE switch during the vehicular velocity control, the set vehicular velocity Vset is increased toward the higher velocity value by a predetermined acceleration. 
     In addition, if the short-term push operation is carried out therefor with the vehicular velocity control released, the vehicular velocity control is resumed to make the vehicular velocity substantially equal to the set vehicular velocity Vset which is prior to the release of the vehicular velocity control. 
     Furthermore, the CANCEL switch serves as a switch enabled to release the vehicular velocity control. 
     On the other hand, in addition to the three push button switches described above, another vehicular velocity controlling apparatus has previously been proposed in which lever type switches are attached onto the peripheral surface of the steering wheel. When a lever of the lever type switches is pivoted by the vehicular occupant in a downward direction with respect to a vehicular body, the SET/COAST switch is turned on. When the lever is pivoted by the vehicular occupant in an upward direction with respect to the vehicular body, the RESUME/ACCELERATE switch is turned on. 
     Suppose that, in each of the previously proposed vehicular velocity controlling apparatuses as described above, the vehicular occupant depresses an accelerator pedal during a vehicular run by means of the vehicular velocity control. In this case, the vehicle is accelerated in response to the depression of the vehicular occupant on the accelerator pedal while the vehicular velocity control is temporarily halted. If the vehicular occupant depresses a brake pedal during the vehicular run by means of the vehicular velocity control, the vehicular velocity control is automatically released even if the CANCEL switch is not operated. It is noted that to RESUME the vehicular velocity control in this state, the RESUME/ACCELERATE switch may be operated. 
     On the other hand, a previous inter-vehicle distance controlling apparatus has been proposed in which the vehicular velocity is controlled to make an inter-vehicle distance from the vehicle to a preceding vehicle which is running ahead of the vehicle substantially equal to a previously set target inter-vehicle distance (hereinafter, referred to as a set inter-vehicle distance). In the previously proposed inter-vehicle distance controlling apparatus, the above-described vehicular velocity control function is included so that the set vehicular velocity Vset is set in addition to the set inter-vehicle distance. If the preceding vehicle is present in a front detection zone of the vehicle, the vehicular velocity V is controlled to follow up the preceding vehicle. If the preceding vehicle disappears from the front detection zone, the inter-vehicle distance control mode is automatically switched to the vehicular velocity control mode so that the vehicular driving force is controlled to make the vehicular velocity V substantially equal to the set vehicular velocity Vset. 
     SUMMARY OF THE INVENTION 
     However, in each of the above-described previously proposed vehicular velocity controlling apparatuses (the previous inter-vehicle distance controlling apparatus is included), when the set vehicular velocity Vset is modified using either one of the SET/COAST switch and RESUME/ACCELERATE switch, the operation of these switches is complex and troublesome, an operability thereof tends to be reduced, and it needs to carry out an operation which does not match with a general vehicular occupant&#39;s sense of a vehicular manipulation. 
     It is, therefore, an object of the present invention to provide a vehicular velocity controlling apparatus for an automotive vehicle in which the modification for the set vehicular velocity Vset provides, without trouble, an operation which matches with the general vehicular occupant&#39;s sense of the vehicular manipulation and which has improved the operability. 
     According to one aspect of the present invention, there is provided a vehicular velocity controlling apparatus for an automotive vehicle, comprising: a vehicular velocity detector to detect a vehicular velocity of the vehicle; a vehicular velocity controlling section that controls a vehicular driving force of the vehicle to make a detected value of the vehicular velocity substantially equal to a set vehicular velocity previously set; a plurality of switches including a first switch and a second switch, each switch being enabled to be interlocked with a predetermined operation of at least one switching member at a position such as to match with a general vehicular occupant&#39;s sense of vehicular manipulation, the first switch being operated in response to the predetermined operation of the switching member at a first position such as to match with the general driver&#39;s sense of vehicular manipulation to decrease the vehicular velocity, and the second switch being operated in response to the predetermined operation of the switching member at a second position such as to match with the general vehicular occupant&#39;s sense of vehicular manipulation to increase the vehicular velocity; and a set vehicular velocity modifying section that modifies the set vehicular velocity in such a manner that the detected value of the vehicular velocity is set to the set vehicular velocity when at least one of the following conditions is established; when a time duration of the predetermined operation of the first switch is equal to or longer than a first predetermined time duration and the detected value of the vehicular velocity is lower than the set vehicular velocity and when the time duration of the predetermined operation of the second switch is equal to or longer than a second predetermined time duration and the detected value of the vehicular velocity is higher than the set vehicular velocity. 
     This summary of the invention does not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a schematic circuit block diagram of a preferred embodiment of a vehicular velocity controlling apparatus. 
     FIG. 1B is a schematic internal circuit block diagram of a vehicular velocity controller shown in FIG.  1 A. 
     FIG. 2 is an explanatory view for explaining a modification operation of the set vehicular velocity Vset carried out in the preferred embodiment of the vehicular velocity controlling apparatus shown in FIG. 1A in a first vehicular run situation. 
     FIG. 3 is an explanatory view for explaining the modification operation of a previously set target vehicular velocity (the set vehicular velocity Vset) carried out in the preferred embodiment of the vehicular velocity controlling apparatus shown in FIG. 1A in a second vehicular run situation. 
     FIGS. 4 and 5 are integrally an operational flowchart representing a vehicular velocity control routine executed by the vehicular velocity controller in the preferred embodiment shown in FIG.  1 B. 
     FIG. 6 is an explanatory view for explaining one modification operation of the set vehicular velocity Vset carried out in each of the previously proposed vehicular velocity controlling apparatuses described in the BACKGROUND OF THE INVENTION (hereinafter, referred to as a comparative example) in the case of the first vehicular run situation. 
     FIG. 7 is an explanatory view for explaining another modification operation of the set vehicular velocity Vset carried out in the comparative example in the case of the first vehicular run situation. 
     FIG. 8 is an explanatory view for explaining one modification operation of the set vehicular velocity Vset carried out in the comparative example in the case of the second vehicular run situation. 
     FIG. 9 is an explanatory view for explaining another modification operation of the set vehicular velocity Vset carried out in the comparative example in the case of the second vehicular run situation. 
     FIG. 10A is a schematic perspective view of three push button switches used in the vehicular velocity controlling apparatus shown in FIG.  1 A. 
     FIG. 10B is a schematic perspective view of the arrangement of the three push button switches on a vehicular steering wheel and of an arrangement of lever type switches on a steering column of the steering wheel as denoted by a phantom line. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will hereinafter be made to the drawings in order to facilitate a better understanding of the present invention. 
     Before explaining the present invention, the problems which would occur in each of the previously proposed vehicular velocity controlling apparatuses (referred to hereinafter as the comparative example) will be described with reference to FIGS. 6,  7 ,  8 , and  9 . 
     First, suppose that, as shown in FIG. 6, while the vehicle is running to follow up the preceding vehicle with the set vehicular velocity set to 50 Km/h by means of the vehicular velocity control, the vehicular occupant accelerates the vehicle through the depression of the accelerator pedal, the vehicle is, at this time, moved from the same traffic lane as the preceding vehicle to its adjacent overtake traffic lane, and, then, the vehicle is accelerated up to 80 Km/h to catch up with a new preceding vehicle running at the overtake traffic lane so that the set vehicular velocity is increased from 50 Km/h to 100 Km/h. This supposition is hereinafter called a first vehicular run situation. 
     A modification procedure is such that while the vehicle is accelerated through the accelerator pedal depression and the vehicular velocity is constantly at 80 Km/h to harmonize with a vehicular stream, the short-term push operation for the SET/COAST switch is carried out so that the present vehicular velocity V of 80 Km/h is, once, set as the set vehicular velocity Vset and, hereinafter, the continuous push operation is carried out for the RESUME/ACCELERATE switch so that the set vehicular velocity Vset is increased up to 100 Km/h. It is noted that even if, at this time, the set vehicular velocity Vset is increased, the inter-vehicle distance to the new preceding vehicle is set to be narrower than the set inter-vehicle distance since the vehicle is running to follow up the new preceding vehicle which is running at the same overtake traffic lane as the vehicle through the inter-vehicle distance control. 
     In order to increase the set vehicular velocity Vset in the case of the first vehicular run situation described above, it is necessary to carry out the short-term push operation for the SET/COAST switch and, thereafter, to carry out the continuous push operation for the other switch of the RESUME/ACCELERATE switch. Hence, the operation of these switches is complex, troublesome, and the operability is reduced. In addition, since it is necessary to once operate the SET/COAST switch placed at the lowest position of the three switches to increase the set vehicular velocity Vset, this modification procedure does not match with the general vehicular occupant&#39;s sense of the vehicular manipulation. It is noted that, in the case of the lever type switches, it is also necessary for the vehicular occupant to once pivot the lever in the downward direction to turn on the SET/COAST switch and, thereafter, in turn, to pivot the lever in the upward direction to turn on the RESUME/ACCELERATE switch. 
     In this case, as shown in FIG. 7, while the vehicular accelerator pedal is used to accelerate the vehicle and the vehicle is running at the vehicular velocity of 80 Km/h to harmonize with the vehicular stream, the continuous push operation is carried out for the RESUME/ACCELERATE switch so that the vehicular velocity is increased from 50 Km/h to 100 Km/h. However, even if the continuous push operation for the RESUME/ACCELERATE switch is carried out, the set vehicular velocity Vset is not increased in a step change manner form from 50 Km/h to the present vehicular velocity of 80 Km/h but the vehicular velocity Vset is increased at the predetermined acceleration from 50 Km/h to 100 Km/h. Hence, the problems of the operation complexity and of the mismatch with the vehicular occupant&#39;s sense of the vehicular manipulation do not occur but an operation time duration T for the increase of the set vehicular velocity Vset from 50 Km/h to reach to the actual vehicular velocity of 80 Km/h becomes wasted so that the operation time duration becomes accordingly long. 
     Next, suppose a second vehicular run situation such that, as shown in FIG. 8, while the vehicle is running to follow up the preceding vehicle by means of the inter-vehicle distance control with the set vehicular velocity Vset set at 80 Km/h, the vehicle is accelerated through the accelerator pedal depression to overtake the preceding vehicle which is running at its vehicular velocity of 50 Km/h and, thereafter, the vehicle is returned to the same traffic lane as the preceding vehicle, and the set vehicular velocity Vset is decreased to the set vehicular velocity of 60 Km/h. 
     This modification procedure of the set vehicular velocity Vset in the second vehicular run situation shown in FIG. 8 is such that when the vehicular velocity is increased to overtake the preceding vehicle through the accelerator pedal depression and, thereafter, the vehicle is returned to the same traffic lane as the preceding vehicle which is now behind the vehicle with the accelerator pedal released, the short-term push operation of the SET/COAST switch is repeated by some number of times (hereinafter, referred to as a tap down operation) so that the set vehicular velocity Vset is lowered from 80 Km/h to 60 Km/h. 
     However, when the tap down operation is started for the SET/COAST switch to decrease the set vehicular velocity Vset, the set vehicular velocity Vset is once increased and, thereafter, is decreased in accordance with the tap down operation since, at a time point at which the tap down operation is started, the actual vehicular velocity V is higher than the set vehicular velocity of 80 Km/h. In other words, whereas the SET/COAST switch disposed at the lowest position is operated, the set vehicular velocity Vset is once increased so as to give the mismatch with the vehicular occupant&#39;s sense of the vehicular manipulation. 
     In addition, the continuous push operation for the SET/COAST switch can decrease the set vehicular velocity Vset without the tap down operation therefor. In this case, as shown in FIG. 9, when the vehicle is accelerated through the vehicular occupant&#39;s depression of the accelerator pedal in order to overtake the preceding vehicle and, thereafter, is returned to the same traffic lane as the preceding vehicle which is now behind the vehicle with the accelerator pedal released, the SET/COAST switch is started to be operated to decrease the set vehicular velocity Vset from 80 Km/h to 50 Km/h. 
     However, since the decrease of the set vehicular velocity Vset by means of the continuous push operation for the SET/COAST switch becomes invalid when the actual vehicular velocity V is higher than the set vehicular velocity Vset, the set vehicular velocity Vset is not modified until the actual vehicular velocity V is decreased to the set vehicular velocity of 80 Km/h. A time duration during the decrease of the vehicular velocity V to the previously set vehicular velocity vset of 80 Km/h becomes wasted so that the operation time duration becomes accordingly long. 
     Next, FIG. 1A shows a circuit block diagram of a vehicular velocity controlling apparatus in a preferred embodiment according to the present invention. 
     The inter-vehicle distance sensor  1  is constituted by a laser radar unit which sweeps a laser beam in a front width-wise direction and receives a reflected laser beam from an object present in the front width-wise direction, namely, a preceding vehicle which is running ahead of the vehicle so as to measure an inter-vehicle (spatial) distance from the vehicle to the preceding vehicle. It is noted that an ultrasonic wave or electromagnetic wave may be used as a distance measuring media to measure the inter-vehicle distance. The vehicular velocity sensor  2  is attached onto an output axle of a transmission to output a pulse train signal having a period corresponding to its revolution velocity. A period of the pulse train signal or the number of pulses is measured to enable a detection of a vehicular velocity labeled “V”. An accelerator sensor  3  detects a depression depth labeled “acc” of an accelerator pedal (not shown). A throttle position sensor  4  detects an opening angle labeled “θ” of an engine throttle valve. A braking liquid pressure sensor  5  detects a braking liquid pressure labeled “Pbrk.” 
     A main switch  6  supplies a power to a controller  13  and other vehicular velocity control pieces of equipment so that an inter-vehicle distance control mode and a vehicular velocity control mode are respectively in a wait state. The brake switch  7  serves as a switch to detect whether a brake pedal has depressed. It is noted that when the brake switch  7  has detected the depression of the brake pedal, the vehicular velocity control module is released in the same manner as the manipulation of the CANCEL switch SW 10  (SW 10 ′). 
     The detailed description on the SET/COAST switch SW 8  (SW 8 ′), the RESUME/ACCELERATE Switch SW 9  (SW 9 ′), the CANCEL switch SW 10  (SW 10 ′) will be made later. 
     The throttle actuator  11  includes a vacuum pump, vent valve, and a safety valve and actuates a pump actuator, and a valve solenoid to adjust an opening angle of the throttle valve to control an engine torque, namely, a vehicular driving force. The brake actuator  12  includes a negative pressure type booster so that the braking liquid pressure is adjusted to control the vehicular driving force. 
     The controller  13  includes a microcomputer having a CPU (Central Processing Unit)  13   a,  a timer interrupt controller having two timers TM 1  and TM 2 , a RAM (Random Access Memory)  13   b,  a ROM (Read Only Memory)  13   c,  an Input Port  13   d,  an Output Port  13   e,  a common bus, and an internal power supply circuit  13   f,  as shown in FIG.  1 B. 
     The controller  13  executes a control program routine as will be described later to perform either the inter-vehicle distance control or the vehicular velocity control, and to perform the setting and modification process of the set vehicular velocity Vset. A DC power is supplied from a battery  15  to the sensors  1  through  5 , the actuators  11  and  12 , and the controller  13  via an ignition switch  14 . 
     Next, the SET/COAST switch SW 8  (SW 8 ′), the RESUME/ACCELERATE switch SW 9  (SW 9 ′), and the CANCEL switch SW 10  (SW 10 ′) will be described below. 
     In the comparative example of the vehicular velocity controlling apparatus to the embodiment, when the SET/COAST switch SW 8  is operated during the execution of the vehicular velocity control procedure, the actual vehicular velocity V is set to the set vehicular velocity Vset irrespective of a magnitude relationship between the actual vehicular velocity V and the set vehicular velocity Vset. The SET/COAST switch SW 8  is disposed at the lowest position as shown in FIG. 10A in the case of the push button type switches. The SET/COAST switch SW 8 ′ is turned on when the lever lev is pivoted by the vehicular occupant toward the downward direction in the case of the lever type switches as shown in FIG.  10 B. In the setting method of the set vehicular velocity Vset during the above-described vehicular velocity control procedure, a case such that the actual vehicular velocity V is lower than the set vehicular velocity Vset means the increase of the set vehicular velocity Vset. Hence, this operation does not contradict with the push operation for the lowest positioned push button switch or the downward operation for the lever switch so that no mismatch to the vehicular occupant&#39;s sense of vehicular manipulation occurs. However, in the case where the actual vehicular velocity V is higher than the set vehicular velocity Vset, the set vehicular velocity Vset is, as a result, increased in the upward direction (toward the higher velocity side) so that this case contradicts with the push operation of the lowest positioned switch or the downward operation of the lever switch so as to give the mismatch to the vehicular occupants sense of vehicular manipulation. However, in the case where the actual vehicular velocity V is higher than the set vehicular velocity Vset, the set vehicular velocity Vset is, as a result, increased in the upward Direction (toward the higher velocity side) so that this case contradicts with the push operation for the lowest positioned switch or with the downward direction of the lever. Thus, the mismatch to the vehicular occupant&#39;s sense of the vehicular manipulation occurs. 
     In the embodiment described above, the positional arrangement of the SET/COAST switch SW 8 , the RESUME/ACCELERATE switch SW 9 , and the CANCEL switch SW 10  remains unchanged as shown in FIG. 10A but a new method of modification of the set vehicular velocity Vset during the vehicular velocity control procedure can be described as follows. 
     That is to say, if the actual vehicular velocity V is lower than the set vehicular velocity Vset during the vehicular velocity control procedure, a long-term push operation for the lowest positioned SET/COAST switch SW 8  causes the actual vehicular velocity V to be set to the set vehicular velocity Vset. If the actual vehicular velocity V is higher than the set vehicular velocity Vset during the vehicular velocity control procedure, the long-term push operation for the uppermost positioned RESUME/ACCELERATE switch SW 9  is carried out to set the actual vehicular velocity V to the set vehicular velocity Vset (the lever is pivoted in the upward direction so that the RESUME/ACCELERATE switch SW 9 ′ is turned on). Thus, the actual vehicular velocity V is set to the set vehicular velocity Vset. 
     It is noted that the long-term push operation means such a manipulation that its operation time duration is longer than the short-term push operation but is not continuous push operation which is continued to be pushed. In this embodiment, the operation to push either of the switches for a time duration equal to or longer than, for example, 350 milliseconds is called the long-term push operation and the operation to push either of the switches (the SET/COAST and RESUME/ACCELERATE switches SW 8  and SW 9 ) for a time duration shorter than 350 milliseconds is called the short-term push operation. The modification operation for the set vehicular velocity control procedure is that this operation causes the set vehicular velocity Vset to be largely varied. 
     Hence, the operation time duration is made longer to match with the vehicular occupant&#39;s consciousness to remarkably modify the set vehicular velocity Vset. 
     According to the preferred embodiment, since when the modification of the set value of the set vehicular velocity during the execution of the vehicular velocity control, the set vehicular velocity Vset is decreased when the SET/COAST switch SW 8  placed at the lowest position is operated and, on the other hand, is increased when the RESUME/ACCELERATE switch SW 9  placed at the uppermost position is operated, the vertical arrangement of the operational switches matches with the increase and decrease of the set vehicular velocity Vset so as to match with the vehicular occupant&#39;s sense of vehicular manipulation and no disagreeable feeling is given to the vehicular occupant. 
     It is noted that, in the case of the lever type switches shown in FIG. 10B, with the lever operated to be pivoted in the downward direction to turn on the SET/COAST switch SW 8 ′, the set vehicular velocity Vset is decreased and, on the other hand, with the lever operated to be pivoted in the upward direction to turn on the RESUME/ACCELERATE switch SW 9 ′, the set vehicular velocity Vset is increased. Hence, the same advantage as described in the case of the button type switches in the embodiment can be achieved. 
     FIG. 2 shows procedure and result of the modification of the set vehicular velocity Vset in the case of the embodiment when the first vehicular run situation occurs (for the first vehicular run situation in the case of the comparative example, refer to FIGS.  6  and  7 ). 
     Suppose that while the accelerator pedal is depressed and the vehicle is running at the vehicular velocity of 80 Km/h at the same pace as the vehicular stream on the overtake traffic lane, the vehicular occupant operates the RESUME/ACCELERATE switch SW 9 . At this time, after 350 msec., the present vehicular velocity V of 80 Km/h is again set to the set vehicular velocity Vset. When the RESUME/ACCELERATE switch SW 9  is continued to be pushed, the set vehicular velocity Vset is increased at the predetermined acceleration (a predetermined rate of increase in the vehicular velocity with respect to time). 
     The same result is, naturally, obtained if the long-term operation is carried out for the time duration equal to or longer than 350 milliseconds, thereafter, the RESUME/ACCELERATE switch SW 9  is released, and again the continuous push operation is carried out for the RESUME/ACCELERATE switch SW 9  is continued to be pushed, the set vehicular velocity Vset is increased at the predetermined acceleration (a predetermined rate of increase in the vehicular velocity with respect to time). 
     The same result is, naturally, obtained if the long-term push operation is carried out for the time duration equal to or longer than 350 milliseconds, thereafter, the RESUME/ACCELERATE switch SW 9  is released, and again the continuous push operation is carried out for the RESUME/ACCELERATE switch SW 9 . In either case, since in such a first vehicular run situation that the set vehicular velocity is increased, only the RESUME/ACCELERATE switch SW 9  placed at the uppermost position may be operated. Hence, this series of operations match with the vehicular occupant&#39;s sense of vehicular manipulation and the operability can be improved. 
     It is noted that, in the case of the lever type switches, the lever may be operated to be pivoted in the upward direction like the continuous push operation so that the same effect as the case of the push button type switches can be achieved. 
     FIG. 3 shows the procedure and result of the modification of the set vehicular velocity Vset in the case of the embodiment in the second vehicular run situation. For the comparative example in the second vehicular run situation, refer to FIGS. 8 and 9. 
     Suppose that when the accelerator pedal is depressed to accelerate the vehicle and to overtake the preceding vehicle, thereafter, the vehicle is returned to the original traffic lane, and the accelerator pedal is released. At this time, upon the start of the SET/COAST switch SW 8 , the set vehicular velocity Vset starts to immediately be decreased. Then, if the SET/COAST switch SW 8  is continued to be operated, the set vehicular velocity Vset is decreased at a predetermined deceleration (a predetermined rate of decrease in the vehicular velocity with respect to time). It is noted that the same result is obtained through the tap down operation of the SET/COAST switch SW 8 . 
     In such a second vehicular run situation that the set vehicular velocity Vset is lowered (decreased), only the SET/COAST switch SW 8  placed at the lowest position may be operated so as to match with the vehicular occupant&#39;s sense of vehicular manipulation and the operability can be improved. It is noted that in the case of the lever type switches, the continuous operation for the lever to the lowest position may be carried out. The same result and effect can be achieved. 
     It is noted that the other functions of both SET/COAST switch SW 8  and RESUME/ACCELERATE switch SW 9  are the same as those described in the comparative example. 
     In details, before the vehicular velocity control is started, namely, when the main switch SW 6  is turned on so that the vehicular velocity switch is in the wait (standby) state (preparation completed state) and, then, the SET/COAST switch SW 8  is operated, the actual vehicular Velocity V is set to the set vehicular velocity Vset to start the vehicular velocity control. In addition, when the continuous push operation for the SET/COAST switch SW 8  is carried out during the execution of the vehicular velocity control the set vehicular velocity Vset is decreased at the predetermined deceleration. 
     Furthermore, in the case where after the vehicular velocity control is released, the short-term push operation is carried out for the RESUME/ACCELERATE switch SW 9 . At this time, the vehicular velocity control is resumed at the set vehicular velocity Vset which corresponds to the vehicular velocity before the release of the vehicular velocity control. 
     If the continuous push for the RESUME/ACCELERATE switch SW 9  is carried out during the execution of the vehicular velocity control, the set vehicular velocity vset is increased at the predetermined at the predetermined acceleration. 
     It is noted that the CANCEL switch SW 10  serves to release the vehicular velocity control. 
     FIGS. 4 and 5 integrally show an operational flowchart representing a vehicular velocity control program routine executed in the vehicular velocity, controlling apparatus of the embodiment. 
     The flowchart shown in FIGS. 4 and 5 describes an operation of the embodiment. 
     When the main switch  6  is operated to turn on thereof the program routine shown in FIGS. 4 and 5 is started to be executed. 
     That is to say, at a step S 1 , the controller  13 , i.e., the CPU  13   a  of the microcomputer shown in FIG. 1B determines whether the SET/COAST switch SW 8  shown in FIG. 10 is operated (the short-term push operation). 
     If the SET/COAST switch SW 8  is operated (Yes) at the step S 1 , the routine goes to a step S 2 . At the step S 2 , the controller  13  sets the present vehicular velocity V to the set vehicular velocity Vset. 
     At a step S 3 , the controller  13  confirms the operation for the SET/COAST switch (turn on) SW 8 . If the SET/COAST switch SW 8  is confirmed to be operated (yes) at the step S 3 , the routine goes to a step S 4 . If the SET/COAST switch SW 8  is confirmed not to be operated (no) at the step S 3 , the routine goes to a step S 12 . 
     At the step S 4 , the controller  13  decreases the set vehicular velocity Vset by a predetermined velocity ΔV (Vset−ΔV→Vset, or Vset−MOD (Vset, ΔV)→Vset). It is noted that, in the embodiment, ΔV (the predetermined velocity) indicates 5 Km/h so that the set vehicular velocity Vset after the set vehicular velocity indicates a multiple of 5 Km/h. For example, when the SET/COAST switch SW 8  is operated during the vehicular run of 68 Km/h, the set vehicular velocity of 68 Km/h is once decreased to 65 Km/h which is a multiple of 5 and, thereafter, the set vehicular velocity Vset is decreased to a multiple of 5, i.e., 60 Km/h→55 Km/h→50 Km/h→in this sequence whenever the subsequent short-term push operation for the SET/COAST switch SW 8  is carried out. Furthermore, at the step S 4 , the controller  13  starts first and second timers TM 1  and TM 2 . The first timer TM 1  is a timer to measure a time duration of the operation on a determination of the long-term push operation. The second order TM 2  is a timer to measure a time duration on the determination of the continuous push operation and to measure a time interval for which the set vehicular velocity Vset is varied while the continuous push operation is carried out. 
     At a step S 5 , the CPU  13   a  of the controller  13  determines whether the first timer TM 1  indicates a pass of a predetermined time duration, for example, equal to or longer than 350 milliseconds. 
     In other words, the controller  13  confirms whether the SET/COAST switch SW 8  is operated for a time duration equal to or longer than 350 milliseconds (the long-term push operation is carried out: TM 1 ≧350 msec.). 
     If Yes at the step S 5 , the routine goes to a step S 6 . If No at the step S 5 , the routine goes to a step S 8 . 
     At the step S 6 , the controller  13  compares the present vehicular velocity V with the set vehicular velocity Vset to determine V&lt;Vset. If V&lt;Vset (Yes) at the step S 6 , the routine goes to a step S 7 . If V≧Vset (No) at the step S 6 , the routine goes to the step S 8 . 
     At the step S 7 , since the long-term push for the SET/COAST switch SW 8  is carried out and the present vehicular velocity V is lower than the set vehicular velocity Vset, the present vehicular velocity V is set to the set vehicular velocity (V→Vset). It is noted that, at the step S 7 , the actual vehicular velocity V is not directly set to the set vehicular velocity but a vehicular velocity value which is near to the actual vehicular velocity V, is a multiple of 5, and is higher than the actual vehicular velocity V. For example, if the actual vehicular velocity V is 57 Km/h, the vehicular velocity value of 60 Km/h which is near to 57 Km/h, is the multiple of 5, and is higher than V=57 Km/h is set to the set vehicular velocity Vset (Vset=60 Km/h). Then, at the step S 7 , the first timer TM 1  is reset and the routine goes to the step S 8 . 
     At the step S 8 , the controller  13  determines whether the second timer TM 2  indicates a predetermined time duration or longer, for example, 1.4 seconds or longer. The controller  13  confirms whether the continuous push operation for the SET/COAST switch SW 8  is confirmed to be carried out at the step S 8  (TM 2 ≧1.4 seconds) so as to determine whether the time duration is taken to decrease the set vehicular velocity Vset. 
     If the continuous push operation for the SET/COAST switch SW 8  is advanced and the time has passed to decrease the set vehicular velocity V, the routine goes to a step S 9 . If not so (No) at the step S 8 , the routine skips the step S 9 . At the step S 9 , the controller  13  decreases the set vehicular velocity Vset by the predetermined velocity ΔV (=5 Km/h). At this time, the set vehicular velocity Vset after the decrease of the set target vehicular velocity indicates the multiple of the set vehicular velocity Vset. 
     For example, suppose that the vehicular velocity V is, initially, 68 Km/h, the continuous push operation for the SET/COAST switch SW 8  causes the set vehicular velocity Vset to be decreased in the sequence of 65 Km/h, 60 Km/h, 55 Km/h→ - - - whenever the predetermined time duration of 1.4 seconds has passed. At the step S 9 , the second timer TM 2  is reset to start again. 
     In the embodiment, when the continuous push operation of the SET/COAST switch SW 8  is carried out, the set vehicular velocity Vset is decreased by 5 Km/h for each elapse of 1.4 second. 
     The predetermined deceleration of the set vehicular velocity Vset indicates approximately 0.06G and becomes substantially equal to a vehicular deceleration which would be developed by a general vehicular occupant. 
     At a step S 10 , the controller  13  confirms whether the SET/COAST switch SW 8  is confirmed to be turned off (Yes at the step S 10 ), the routine goes to a step S 11 . If the SET/COAST switch SW 8  remains to be turned on (No) at the step S 10 , the routine goes to the step S 12 . 
     At the step S 11 , the first and second timers TM 1  and TM 2  are reset as TM 1 =0 and TM 2 =0. 
     Then, the routine goes to a step S 12 . 
     At the step S 12 , the controller  13  confirms if the RESUME/ACCELERATE switch SW 9  is in the operation state (turned on). If the RESUME/ACCELERATE switch SW 9  is turned on (Yes) at the step S 12 , the routine goes to a step S 13 . If NO at the step S 12 , the routine jumps to the step S 3 . At the step S 13 , the set vehicular velocity Vset is increased by the predetermined velocity value of ΔV. 
     In the embodiment, the predetermined velocity value of ΔV is set to 5 Km/h in the same manner as the case of the decrease in the set vehicular velocity through the switch SW 8  and the set vehicular velocity Vset after the increase in the set vehicular velocity Vset is advanced indicates the multiple of 5 (Km/h). For example, suppose now that, during the vehicular run at 53 Km/h, the RESUME/ACCELERATE switch SW 9  is operated, the vehicular velocity V is once increased from 53 Km/h to 55 Km/h which is near to 53 Km/h, and the multiple of 5, and, thereafter, whenever the shortterm push operation for the RESUME/ACCELERATE switch SW 9  is carried out, the set vehicular velocity Vset is set to each multiple of 5 in such a sequence as 60 Km/h→65 Km/h→70 Km/h. 
     It is noted that the predetermined velocity ΔV is set which may separately be set in the case of the modification of the set vehicular velocity Vset. At the step S 13 , both of the first and second timers TM 1  and TM 2  are started. 
     At the step S 14 , the controller  13  determines whether the first timer TM 1  indicates a predetermined time duration, for example, 300 milliseconds or longer, in other words, the controller  13  determines whether the long-term push operation for the time duration equal to or longer than 350 milliseconds is carried out. If the long-term push operation is carried out (yes) at the step S 14 , the routine goes to a step S 15 . If the long-term operation is not carried out (No) at the step S 14 , the routine goes to a step S 17 . 
     At the step S 15 , the controller  13  compares the present vehicular velocity V with the present set vehicular velocity Vset to determine if V&gt;Vset. If the present vehicular velocity V is higher than the set vehicular velocity Vset (Yes) at the step S 15 , the routine goes to a step S 16  in which V Vset (namely, the present vehicular velocity V is set to the set vehicular velocity Vset), the first timer TM 1  is reset to zero and the routine goes to a step S 17 . 
     At the step S 17 , the controller  13  determines if the second timer TM 2  indicates a value equal to or longer than a predetermined time duration, for example, 1.4 seconds. In other words, the controller  13  confirms whether the continuous push operation for the RESUME/ACCELERATE switch SW 9  is carried out and it has reached to a time of 1.4 seconds to increase the set vehicular velocity Vset. 
     If the controller  13  determines that TM 2 ≧1.4 seconds (Yes) at the step S 17 , the routine goes to a step S 18 . If No (TM 2 &lt;1.4 seconds at the step S 17 , the routine skips the step S 18  and goes to a step S 19 . 
     At the step S 18 , the controller  13  increases the set vehicular velocity Vset by the predetermined velocity value ΔV (=5 Km/h). At this time, the increased set vehicular velocity Vset is set to the multiple of 5. For example, suppose that the actual vehicular velocity V is, initially, 53 Km/h. The continuous push operation for the RESUME/ACCELERATE switch SW 9  is increased in such a sequence as 55 Km/h→60 Km/h→65 Km/h for each elapse of time of 1.4 seconds. 
     At the step S 18 , the controller  13  further executes to reset the second timer TM 2  to restart the measurement of the time duration. 
     It is noted that, in the embodiment, the set vehicular velocity Vset is increased by 5 Km/h for each 1.4 seconds when the continuous push operation for the RESUME/ACCELERATE switch SW 9  is carried out, the set vehicular velocity Vset is increased by 5 Km/h for each 1.4 seconds. This acceleration for the set vehicular velocity Vset generally corresponds to 0.06 G which can be approximated to the vehicular acceleration which would be developed by the general vehicular occupant through the accelerator pedal. 
     Referring back to FIG. 5, at the step S 19 , the controller  13  determines whether the RESUME/ACCELERATE switch SW 9  is turned off from the turn on state. 
     If turned off (Yes) at the step S 19 , the routine goes to a step S 20 . If the switch SW 9  remains turned on (No) at the step S 19 , the routine skips the step S 20 . 
     At the step S 20 , both of the first and second timers TM 1  and TM 2  are reset to restart its time duration measurement. Thereafter, the routine returns to the step S 3 . 
     As described above with reference to FIGS. 4 and 5, the SET/COAST switch SW 8  which is placed at the lowest position than the RESUME/ACCELERATE switch SW 9  or the SET/COAST switch SW 8 ′ is operated when the lever lev is pivoted in the downward direction and the RESUME/ACCELERATE switch SW 9  which is placed at the uppermost position or which is operated when the lever lev is pivoted in the upward direction are installed on the vehicle body as shown in FIGS. 10A and 10B. 
     Then, the actual vehicular velocity V is set to the set vehicular velocity Vset when the operation time duration for the SET/CAOST switch SW 8  (SW 8 ′) is equal to or longer than the predetermined time duration (for example, 350 milliseconds) and the actual vehicular velocity V is lower than the set vehicular velocity Vset. On the other hand, the actual vehicular velocity V is set to the set vehicular velocity Vset when the operation time duration for the RESUME/ACCELERATE switch SW 9  (SW 9 ′) is equal to or longer than the predetermined time duration (350 milliseconds) and the actual vehicular velocity V is higher than the set vehicular velocity Vset. 
     In a case where the operation time duration for the SET/COAST switch SW 8  is shorter than the predetermined time duration (for example, 350 milliseconds) by the predetermined vehicular velocity value ΔV, the set vehicular velocity Vset is decreased when the operation time duration of the SET/COAST switch SW 8  is equal to or longer than the predetermined time duration (for example, 350 milliseconds) and when the actual vehicular velocity V is equal to or longer than the set vehicular velocity Vset. 
     Furthermore, in a case where the operation time duration for the RESUME/ACCELERATE switch SW 9  is shorter than the predetermined time duration (for example, 350 milliseconds), the set vehicular velocity Vset is increased by the predetermined velocity value ΔV (for example, 5 Km/h as described above). In a case where the operation time duration for the RESUME/ACCELERATE switch SW 9  is equal to or longer than the predetermined time duration (for example, 350 milliseconds) and the actual vehicular velocity V is lower than the set vehicular velocity Vset, the set vehicular velocity Vset is increased by the predetermined acceleration (the predetermined rate of increase to time). 
     Thus, the relative arrangement or operational directions of the SET/COAST switch SW 8  (SW 8 ′) and the RESUME/ACCELERATE switch SW 9  (SW 9 ′) match with the modification direction, namely, the increase or decrease of the set vehicular velocity Vset along with these operations. 
     Consequently, the modification operation for the set vehicular velocity Vset matches with the general vehicular occupant&#39;s sense of the vehicular manipulation and no disagreeable feeling is given to the vehicular occupant. 
     In addition, the increase or decrease of the set vehicular velocity Vset can be carried out through only one of the two switches, namely, the SET/COAST switch SW 8  (SW 8 ′) and the RESUME/ACCELERATE switch SW 9  and its operability can be improved. 
     In the embodiment, the vehicular velocity sensor  2  constitutes vehicular velocity detecting means, the SET/COAST switch SW 8  (SW 8 ′) constitutes a first switch, the RESUME/ACCELERATE switch SW 9  constitutes a second switch, and the controller  13  constitutes vehicular velocity controlling means, and the set vehicular velocity modifying means. 
     It is noted that although, in the embodiment, a reference time duration to determine each of either the short-term push operation for the first or second switches or the long-term push operation indicates 350 milliseconds, the value of the reference time duration is not limited to 350 milliseconds. It is also noted that although, in the embodiment, the predetermined velocity value ΔV and the predetermined time duration to determine the acceleration and the deceleration when the continuous push operation for each of the first and second switches indicates 5 Km/h and 1.4 seconds, the predetermined velocity value ΔV and the predetermined time duration are not limited to these values. 
     It is noted that a first predetermined velocity ΔV 1  in the claims corresponds to the predetermined velocity value ΔV, a second predetermined velocity ΔV 2  corresponds to the predetermined velocity value ΔV, but the following case may occur ΔV 1 ≠ΔV 2  other than ΔV 1 =ΔV 2 . 
     It is also noted that a first time duration ΔT 1  in the claims corresponds to the predetermined time duration ΔT and a second predetermined time duration ΔT 2  in the claims corresponds to the predetermined time duration ΔT but the following case may occur ΔT 1  ΔT 2  other than ΔT 1 =ΔT 2 . 
     The entire contents of a Japanese Patent Application No. Heisei 11-176895 (filed in Japan on Jun. 23, 1999) are herein incorporated by reference. Although the invention has been described above by reference to certain embodiment of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art in the light of the above teachings. The scope of the invention is defined with reference to the following claims.