How They Operate Now, And Will In '07
Here's operational data on current and '07-model diesels, as supplied by the engine manufacturers:
• Caterpillar – In addition to the C15s described in the main article, Cat's other heavy duty models should turn at these rpms at 65 mph: C13, 1,450; C13 Multi-Torque, 1,325; C11, 1,450; and C9, 1,650. Cat's medium-duty C7 should turn 2,000 rpm at 60 mph (not faster), or 2,200 at 60 if better low-end startability is needed.
• Cummins – The ISX's sweet spot is 1,400 to 1,500 rpm at 65 mph for linehaul applications; in vocational trucks, the ISX should run between 1,600 to 1,900 rpm at intended cruising speed. The ISM should run 1,500 to 1,600 rpm in linehaul and 1,700 to 2,000 rpm in vocational trucks. The ISL should operate between 1,600 and 1,900 rpm in linehaul and vocational trucks. For the higher-speed midrange ISC, it's 2,000 to 2,150 for steady 65-mph cruising and 2,150 to 2,300 for P&D and other urban applications. The even faster-running ISB, used in medium and light trucks and as the Dodge-Cummins Turbodiesel, should cruise at 2,100 to 2,400 rpm at 65 mph.
• Detroit Diesel – Series 60, in both 12.7- and 14-liter versions, and the 12.8-liter MBE 4000 should be operated between 1,200 and 1,600 rpm; the Series 60's sweet spot is 1,450 to 1,550 rpm at 65 mph and the MBE's is 1,400 to 1,500. The midrange 6-cylinder MBE 926 operates best at 1,400 to 1,800 rpm but should be geared for 1,800 to 2,000 at 65 mph.
• General Motors – The Duramax 6600 and 7800 diesels will keep their current operating ranges and sweet spots for '07. Like competitors' diesels, the '07-spec Duramaxes will get particulate filters and combustion enhancements to meet the new regs.
• International – Sweet spot for 65-mph cruising with the DT 570 and HT 570 inline-6 is 1,600 to 1,800. For the DT 466 I-6 and VT 365 V-8 (also Ford's Power Stroke V-8) the sweet spot is 1,800 to 2,000 rpm. For the VT 275 V-6 (also used by Ford) it's 2,100 to 2,300 rpm.
• Mack – Current 12-liter ASET (application-specific engine technology) engines in three versions have varying operating ranges and sweet spots. The Econodyne in various power ratings are available in all Mack chassis and used with Allison automatic transmissions; Maxicruise has a higher torque rise and peak power and is meant for highway operations; Maxidyne, a vocational engine, must run at higher speeds to allow its internal EGR to work. ASET engines will be phased out by the end of 2006.
In early '06, the first of the new Mack Power diesels, the 11-liter MP7, goes into production, at first without a particulate filter and in January '07, with one. There'll be three versions that will generally run at 100 to 150 rpm less than ASET engines. The MP7 Econodyne will be strictly for highway trucks and tractors with a sweet spot of 1,500. The MP7 Maxicruise moves to local and regional applications and becomes the Allison engine, with a sweet spot of 1,500 to 1,600, the same as the current ASET Maxicruise.
The MP7 Maxidyne vocational engine for on/off-highway trucks is even more different. It gets cooled external EGR (instead of internal EGR), heftier low-end torque (1,460 versus 1,200 for the ASET Maxidyne, but still at 1,300 rpm), an operating range starting at 1,550 rpm (50 less than now) to 2,100 rpm (the same as now) and sweet spot of 1,500 to 1,600 rpm (100 lower than now).
• Volvo – Will have 11-, 13- and 16-liter engines using the same basic designs as sister company Mack is employing for its MP engines. Volvo plans to announce power/torque ratings and operating details in March. For now it continues selling its D12 and D16 (the latter actually the first of the new-family engines) and Cummins ISX.
