Cummins Engine Company, Inc.

Mary L Till

Jimmie J Trueblood

Peter Rauznitz

Charles E Goode

Lynn S Zopff

Erik M Widdifield

Bradly G Duffer

A method for controlling a vehicle engine coolant fan. Because operation of the engine coolant fan creates a power drain upon the engine, it is undesirable to operate the coolant fan when the engine is fueled. Conversely, a power drain upon the engine is desirable when an attempt is being made to slow the vehicle. Consequently, the present invention requests activation of the coolant fan whenever a power drain upon the engine is desirable. Not only is this desirable in order to slow the vehicle, but it also lowers the coolant temperature, thereby reducing the chance that the coolant fan will have to be operated in the future when such operation is undesirable.

Method for controlling a vehicle engine coolant fan

A fluid level sensor system for a vehicle oil pan includes a fluid level sensor assembled to the oil pan which has a first LED/phototransistor sensor electrically arranged and responsive to a low oil level in the oil pan for generating a low level voltage signal. The fluid level sensor also includes a second LED/phototransistor sensor which is electrically arranged and responsive to a high oil level in the oil pan for generating a high level voltage signal. The low level voltage signal and the high level voltage signal from the fluid level sensor are electrically connected to an electronic control module (ECM) which receives and processes the two signals and activates a warning lamp with a flashing illumination to identify a low oil level condition and a constantly on illumination to identify a high oil level condition. The operation of the ECM is controlled by a flow logic algorithm.

Oil level sensor system

A method for automatically resuming vehicle speed control after a gear change of the vehicle's manual transmission. The method may be implemented as a subroutine in the vehicle's general control software. After disengagement of the clutch, the subroutine suspends the automatic speed control system and then periodically checks to determine if the driver has shifted gears within a predetermined time period. This determination is made by checking to see if the clutch has once again been engaged with the transmission in gear. If this occurs within the predetermined time period, then the control system automatically resumes the speed control of the engine. The determination of whether the transmission has been placed into another gear is made by an examination of calculated gear ratios, rather than by the addition of a hardware sensor.

Control system for automatic resumption of speed control after gear

A cruise control based retarder control. If the vehicle speed exceeds the cruise control set speed, the cruise control system continuously checks the vehicle speed and acceleration order to determine the optimum auxiliary brake level based upon the amount of overspeed and acceleration. The cruise control system allows the vehicle driver to select which auxiliary brakes will be applied to slow down the vehicle to the desired speed by means of the normal cabin brake switches, limited by the determined optimum brake level. The driver can therefore control which auxiliary brakes are applied, however the application of these brakes is controlled by the cruise control system without the need to exit cruise control mode. Operation of the auxiliary brakes by the cruise control system will normally reset in increased fuel economy over prior art systems which require exiting of the cruise control system, manual activation of the auxiliary brakes and resumption of the cruise control system.

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Indianapolis, IN, United States of America

Mary L Till