Sales Engineering V-MAC IV Allows the Customer to Custom Program

Sales Code: EGT-MM / EGT-SPE Description: Engine Governor Type Date: April 27, 2017

Sales Engineering

Mack Trucks Inc. 2402 Lehigh Parkway South Allentown, PA 18103

Phone: 800-868-6225 Fax: 610-351-8791 Email: [email protected]

V-MAC IV allows the customer to custom program governor type and high idle speed in certain gears. Either a standard Min/Max or an All-Speed governor can be selected. The governor controls the way the engine responds to throttle input. A Min/Max governor delivers engine power in proportion to throttle position, just like a typical automobile governor. An All-Speed governor sets engine speed in proportion to throttle position, allowing power to go up/down across varying terrain while vehicle speed and throttle position remain relatively constant. This type of governor is used on mechanically governed engines and finds limited use in V-MAC vocational applications. An All-Speed governor is not available for purchase on vehicles equipped with Allison transmissions.

Terms and Definitions:

BHP: Brake Specific Horsepower, the power produced by the engine at the flywheel when tested under standard test conditions.

Engine Power Curve Line: This line defines the actual (or intended) power produced by the engine at each engine speed or RPM.

Low Idle RPM: The speed in which the engine runs with no throttle input and no horsepower output. Low Idle RPM is a V-MAC programmable parameter.

Peak Torque: The point on the Engine Power Curve (lbs-ft @ RPM) where the engine produces its maximum torque output. Note that BHP = (Torque x RPM) / 5252.

Maximum (Peak) Power: The point (BHP @ RPM) on the Engine Power Curve Line where the engine achieves its maximum power output.

Governed Speed: The point on the Engine Power Curve which the governor activates and engine power rapidly drops off.

The information in this document was accurate as of the date of release and pertains to the current version of Mack’s Sales Tool. Mack Trucks, Inc, reserves the right to make changes in specifications, equipment or design, or to discontinue models or options without notice. Page 1 of 5

High Idle RPM: The speed at which the engine runs at full throttle with zero horsepower output (clutch depressed).

Cruise RPM: the speed at which the engine operates in top gear while cruising. This speed provides the best combination of fuel efficiency and torque.

Useable Engine Power Band: Except during starts, if the vehicle is moving the engine should normally be operated within this speed range, between the Peak Torque and Governed Speed RPMs, unless the engine high idle has been reduced in upper gears.

High Idle RPM in Upper Gears: The speed at which the engine is limited to in upper gears (all gears with ratios numerically lower than 1.5). High Idle RPM in Upper Gears is a V-MAC programmable parameter.

A Min/Max Governor is the most common governor type found in both the automotive and trucking industry. With a Min/Max, horsepower delivered is roughly proportional to the amount of throttle applied, so it feels right while driving. Apply the throttle to accelerate, climb a grade, or otherwise increase engine power output. A Min/Max Governor is standard on all Mack vehicles.

An All-Speed Governor sets an engine speed (RPM) that is roughly proportional to throttle application. At any given speed/throttle position, power is allowed to go up or down, depending on the need. Older Mack mechanical governors were All- Speed. Some vocational customers still prefer an All-Speed since the vehicle can traverse a varying terrain with very little throttle pedal movement. An All-Speed Governor can be selected on all Mack engines through MSS or VCADS PC Service Support Software.

Mack uses a Min/Max governor as its default selection. Most customers feel more comfortable with the familiar automotive style arrangement, and it offers the best performance in the most situations. Depending on the application, there can be benefits to All Speed Governors as well. Generally Min/Max governors offer better tracking between the amount of throttle and engine torque output. Min/Max Governors are better suited for normal driving situations, as the throttle response is intuitive. All-speed governors generally provide excellent tracking between throttle amount and engine speed. All-speed governors are better suited for maintaining a constant vehicle speed over a varying terrain with minimal throttle input. Setting a lower High Idle Speed in Upper Gears can improve MPG by reducing engine operation in inefficient RPM ranges, and is recommended primarily for 13-18 speed transmissions. Fuel is saved without sacrificing the larger range of the lower gears that the operator needs to maintain speed during low- speed shifting or steep grades. This creates a dual advantage situationfor the operator. VLS needs to fall below governor (upper gear high idle) cut-in for effective operation.