Table 1 shows the wide variety of applications for diesel engines and their characteristic figures. No other type of heat engine offers an equivalent range of power outputs. The engines are categorised according to their speed and application and, therefore, also their size and power output. The smallest category of large engines consists of heavy-duty vehicle engines with a capacity per cylinder of 1.5 l or more. However, many people regard large engines as starting at a capacity per cylinder of 2.5 l. There are four categories of large engine: — engines for heavy-duty road vehicles and industrial and stationary engines: heavy-duty engines — engines for fast ships, locomotives, rail cars and heavy construction vehicles: high-performance diesel engines — medium-speed four-stroke diesel engines (two-stroke engines no longer play a role in this market segment) for marine applications and diesel-powered heat and power stations, some of which can be used with heavy oil — slow-speed two-stroke diesel engines for direct drive applications in maritime industries. MTZ focused on different engine sizes on the basis of the interest at the time from the fields of scientific research and industrial development. Figure 1 shows the number of articles on the individual engine segments. Initially the emphasis was on large engines for ships and locomotives. Stationary engines were a constant theme across all the different periods. However, in the last 20 to 30 years, the majority of MTZ articles have concerned diesel engines for commercial vehicles and cars. The introduction of the ATZ-Offhighway and MTZindustrial magazines have resulted in fewer pieces appearing in MTZ about engines for construction vehicles, marine applications and stationary machinery. It is not always possible to categorise the individual articles by engine size, which means that the figures only give a general overview. TABLE 1 Specific values from different diesel engines (© Helmut Tschoke) Engine \ Parameter Speed [rpm] Power [kW] Specific power [kW/dm3] Power per cylinder [kW/cyl.] Engine displacement [dm3] Number of cylinder [−] BMEP [bar] Small engine 3000 – 3600 1.5 – 12 7.5 – 14 1,5 – 12 0,2 – 0,85 1 3 – 5 Passenger cars 3000 – 4600 35 – 283 40 – 95 17 – 40 0,8 – 4.2 2 – 8 17 – 22 LD vehicle 3000 – 4000 70 – 160 40 – 66 17 – 32 2 – 3.2 4 – 5 12 – 15 HD vehicle 1400 – 2500 170 – 600 20 – 35 29 – 67 7.7 – 16.4 5 – 8 12 – 28 High speed / high performance 1100 – 2200 500 – 10,000 25 – 55 120 – 500 30 – 350 8 – 20 23 – 30 Medium speed 300 – 1200 550 – 21,600 8 – 22 100 – 2000 25 – 2300 4 – 20 22 – 28 Two-stroke low-speed 70 – 170 4300 – 87,000 1.1 – 3.2 870 – 6200 750 – 29,000 5 – 14 18 – 22 Open image in new window FIGURE 1 Number of MTZ reports per year for different diesel applications (© Helmut Tschoke) Using the example of commercial vehicle engines in Figure 2, it becomes clear that the capacity has essentially remained consistent over the years, while the power has increased six- to eightfold and the torque by a factor of seven because of the widespread use of turbocharging. Figure 3 shows the mean effective pressures for all engine sizes. The medium-speed and high-performance diesel engines have the highest mean pressures at over 25 bar. The data in Figure 3 and Figure 4 come from different sources within MTZ and do not cover every engine application. They are only intended to indicate trends. Open image in new window FIGURE 2 Displacement, power output and torque of truck engines — sources: [28] and own inquiry (© Helmut Tschoke) Open image in new window FIGURE 3 Trend curves of BMEP for different diesel engines (© Helmut Tschoke) Open image in new window FIGURE 4 History of diesel engine development (© Helmut Tschoke)
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May 31, 2016
Kyeong-Ju Kong + 3
Open Access