Road test simulator

Claim 2

A road test simulator for a vehicle with a drive wheel coupled to an engine through a semi-automatic change-speed transmission comprising: a. a hydraulic pump-motor; b. means for temporarily coupling the drive wheel with said pump-motor; c. a reservoir; d. means including a hydraulic loop for interconnecting said pump-motor and said reservoir; and, e. means in said loop on the outlet side of said pump-motor for imposing a continuously variable resistance to hydraulic flow through said loop to simulate the load imposed upon the transmission by accelerating the vehicle from a stopped condition, said load gradually decreasing from an initial high factor to allow the transmission to shift upwardly through its gears as the drive wheel speed increases.

Claim 3

A device as in claim 1 including a pump in said loop at the outlet of said reservoir for charging said loop with hydraulic fluid from said reservoir.

Claim 4

A device as in claim 1 in which said means for imposing a continuously variable resistance includes: a valve body having a valve seat; a valve stem; and, means for moving said stem toward and away from said seat.

Claim 5

A device as in claim 3 in which said valve stem moving means translates said stem along an axis concentric with said valve seat and in which said stem has a taper proportioned to afford only a relatively small change in valve opening for a relatively large axial movement of said valve stem.

Claim 6

A road test simulator for a vehicle with a drive wheel coupled to an engine through a semi-automatic change-speed transmission comprising: a. a hydraulic pump-motor; b. means for temporarily coupling the drive wheel with said pump motor; c. a reservoir; d. means including a hydraulic loop for interconnecting said pump-motor and said reservoir; e. means in said loop on the outlet side of said pump-motor for imposing a resistance in said loop to simulate the vehicle load under a condition of acceleration, as the drive wheel actuates said pump motor; f. a first check valve in said loop between the outlet of said reservoir and the inlet of said pump-motor, said first check valve being normally open toward said inlet; g. an accumulator; h. a line connecting said accumulator to said inlet of said pump-motor at a location downstream of said first check valve; i. a first normally closed control valve in said line for selectively isolating said accumulator from said inlet; j. a conduit connecting the outlet of said pump-motor to said accumulator; k. a second check valve in said conduit and normally open toward said accumulator to permit the charging of said accumulator; and, l. means for opening said first normally closed control valve to permit the discharge of hydraulic fluid from said accumulator into said inlet of said pump-motor to simulate the vehicle load under a condition of deceleration, as said pump-motor actuates the drive wheel.

Claim 7

A road test simulator for a vehicle with a drive wheel coupled to an engine through a semi-automatic change-speed transmission comprising: a. a hydraulic pump-motor; b. means for temporarily coupling the drive wheel with said pump motor; c. a reservoir; d. means including a hydraulic loop for interconnecting said pump-motor and said reservoir; e. means in said loop on the outlet side of said pump-motor for imposing a resistance in said loop to simulate the vehicle load under a condition of acceleration, as the drive wheel actuates said pump motor; f. a first check valve in said loop between the outlet of said reservoir and the inlet of said pump-motor, said first check valve being normally open toward said inlet; g. an accumulator; h. a line connecting said accumulator to said inlet of said pump-motor at a location downstream of said first check valve; i. a first normally closed control valve in said line for selectively isolating said accumulator from said inlet; j. a conduit connecting the outlet of said pump-motor to said accumulator; k. a second check valve in said conduit and normally open toward said accumulator to permit the charging of said accumulator; and, l. means for opening said first normally closed control valve to permit the discharge of hydraulic fluid from said accumulator into said inlet of said pump-motor to simulate the vehicle load under a condition of deceleration, as said pump-motor actuates the drive wheel.

Claim 8

A device as in claim 5 including a solenoid operable to open said first normally closed control valve.

Claim 9

A device as in claim 5 including a third check valve in said line between said first normally closed control valve and said inlet, said third check valve normally being open towards said inlet.

Claim 10

A device as in claim 5 including a branch in said line originating at a location between said first normally closed control valve and said third check valve and being operatively connected to said first check valve, said first check valve being positively seated in response to high pressure fluid discharged from said accumulator through said line with said first normally closed control valve in open position.

Claim 11

A device as in claim 5 including a pressure relief valve in said loop between the outlet of said resistance imposing means and the inlet of said reservoir and operable toward said reservoir in the event fluid pressure exceeds a predetermined amount.

Claim 12

A device as in claim 5 including a second normally closed control valve in said loop between the outlet of said resistance imposing means and said reservoir for isolating the input of said reservoir from the portion of said loop downstream of said resistance imposing means in order directly to charge said accumulator.

Claim 13

A device as in claim 10 including a solenoid operable to open said second normally closed control valve to permit selective recirculation of fluid in said loop.

Claim 14

A device as in claim 5 including means for selectively varying the resistance offered by said resistance imposing means to simulate a varying vehicle load.

Claim 15

A device as in claim 12 in which said resistance varying means includes a valve body having a valve seat and includes a valve stem and includes means for moving said stem toward and away from said seat.

Claim 16

A device as in claim 13 in which said valve stem moving means translates said stem along an axis concentric with said valve seat and in which said stem has a taper proportioned to afford only a relatively small change in valve opening for a relatively large axial movement of said valve stem.

Claim 17

A device as in claim 14 in which said moving means includes a relatively high speed motor and includes a gear reducer between said motor and said valve stem.

Claim 18

A device as in claim 1 or 5 including means for denoting the speed of said engine, means for denoting the speed of said wheel, means for denoting the vacuum within a vacuum line between said engine and said transmission, and means for denoting the pressure of hydraulic fluid produced within said transmission.

Claim 19

A device as in claim 16 including recorder means for producing a visual record of the simultaneous output of each of said denoting means.