Abstract: An apparatus includes a closed container having an inlet connected to a radiator of an engine cooling system. An outlet of the container is coupled to the suction port of a venturi that has an inlet port connected by a solenoid valve to a source of pressurized air. A controller opens the solenoid valve for a given interval whenever the engine is turned off. That action creates a negative pressure in the container which bleeds gas from the radiator. Any coolant that also is removed from the radiator is collected in the container.

Abstract: An evaporative emission tester is used to evaluate the integrity of a vehicle's evaporative emission control system, including determining the system's purge capability. The emission tester performs a purge flow test to determine whether fuel vapor stored in the vehicle's evaporative canister and present in the fuel tank is being drawn into the engine for combustion at a minimum amount. The emission tester also performs a pressure test of the vehicle's evaporative canister purge system, which includes the fuel tank and lines. The emission tester can function as a stand-alone unit or as an integrated product with a host computer.

Abstract: An evaporative emission tester is used to evaluate the integrity of a vehicle's evaporative emission control system, including determining the system's purge capability. The emission tester performs a purge flow test to determine whether fuel vapor stored in the vehicle's evaporative canister and present in the fuel tank is being drawn into the engine for combustion at a minimum amount. The emission tester also performs a pressure test of the vehicle's evaporative canister purge system, which includes the fuel tank and lines. The emission tester can function as a stand-alone unit or as an integrated product with a host computer.

Abstract: A battery and charging system tester includes an automatically-operated carbon pile for loading the battery, the pile having a shaft therethrough rotated by a stepper motor, and a compression nut threadedly engaged with the shaft for movement into and out of engagement with the carbon pile in response to rotation of the shaft for varying the compression of the pile and, thereby, the impedance thereof. Probes are provided for sensing battery load current and output voltage, and the output current of an alternator charging unit. A feedback control circuit including a microprocessor operating under stored program control converts the analog probe outputs to digital signals and compares the battery output voltage and load current to selectively variable references for controlling the stepper motor to vary the battery load so as to regulate either the battery load current or the battery output voltage to a predetermined reference value, depending upon the test being performed.

Abstract: A volt/frequency meter includes LED arrays which provide bar-graph style meter displays of the instantaneous voltage and the frequency of a variable electric analog signal. Each LED in the voltage array corresponds to a predetermined voltage range and each LED in the frequency array corresponds to a predetermined frequency range. The meter is switchable among three different voltage scales and three different frequency scales. A separate LED flashes momentarily in response to the input signal crossing a user-determined limit set point which is adjusted through a knob on the front panel. The limit set point controls the operation of the frequency display such that the displayed frequency is the rate at which the analog signal crosses the limit set point.

Abstract: A linearly moving external part of a multi-cylinder internal combustion engine is contacted with a hand-held contact tachometer for producing a waveform signal which, along with a signal responsive to the ignition of each cylinder, are applied to an engine analyzer processor for display of a single engine cycle of the waveform signal on the CRT oscilloscope of the engine analyzer. The variations and amplitude of the waveform signal correspond to speed variations of the moving part over an engine cycle to give an indication of the relative power contributions of the individual cylinders. Cylinder ignition markers and cylinder zone markers are respectively displayed at the top and bottom of the screen, respectively corresponding to the cylinders in their ignition order. Each cylinder zone marker is delayed a predetermined time from its corresponding cylinder ignition marker and indicates the time period during which the engine responds to the ignition event of the corresponding cylinder.

Abstract: The test probe comprises a handle and a rod, the rod including a flat face which can be placed against an electrical terminal to be tested. The rod includes a loop residing in a cavity in the handle. An alligator clip may be applied to the loop.

Abstract: A battery and charging system tester includes an automatically-operated carbon pile for loading the battery, the pile having a shaft therethrough rotated by a stepper motor, and a compression nut threadedly engaged with the shaft for movement into and out of engagement with the carbon pile in response to rotation of the shaft for varying the compression of the pile and, thereby, the impedance thereof. Probes are provided for sensing battery load current and output voltage, and the output current of an alternator charging unit. A feedback control circuit including a microprocessor operating under stored program control converts the analog probe outputs to digital signals and compares the battery output voltage and load current to selectively variable references for controlling the stepper motor to vary the battery load so as to regulate either the battery load current or the battery output voltage to a predetermined reference value, depending upon the test being performed.

Abstract: The pressure-testing apparatus comprises a manifold having a pair of conduits extending therefrom and being substantially parallel. Quick connectors at the free ends of the conduits have receptacles the axes of which are substantially parallel. A pair of adapters are respectively attached to the fittings of a broken coupler in a vehicle. The quick connectors are respectively applied to the adapter elements. The apparatus also comprises a pressure gauge on the manifold and/or means on the manifold for connection to a gauge.

Abstract: A linearly moving external part on a multi-cylinder internal combustion engine is contacted with a hand-held rotary encoder, contact tachometer having a hollow handle in which processing circuitry is disposed for converting the rotary encoder output to a waveform signal. This signal, along with a signal responsive to the firing of the number one cylinder, are applied to an engine analyzer processor for display of a single engine cycle of the waveform signal on the CRT oscilloscope of the engine analyzer. The variations in amplitude of the waveform signal correspond to speed variations of the moving part over an engine cycle to give an indication of the relative power contributions of the individual cylinders.