torque converter clutch) Transfer Case COMMAND-TRAC ROCK-TRAC Fuel Direct Injection Fuel Tank (litre) 700 814 700 814 DIMENSIONS (millimeters unless otherwise specified) Wheelbase 2460 3008 2460 3008 Overall Length (includes spare tire) 4237 4785 423
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Study of Fuel Economy Standard and Testing Procedure ... after a cold start) Type I : ... Test method Equivalent to ECE R
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Bio-economy and Green Economy ... Technology to manipulate biological systems 3. ... primarily to policy networks encompassing market actors
THE PHILIPPINES is again expected to be one of the fastest growing economies in Asia in 2016. It is seen to remain in a sweet spot, as robust
石 油 学 会 誌
A commercial The
of an fuel
as oil makers
require motor octane
The recent advent of incentive for finding ways for improving fuel economy of a car has brought about a new aspect of the problem to reassess the deposit effect on fuel economy. One paper mentioned some beneficial effects of engine deposits on fuel economy13). We reported an accelerated test method to investigate the effects of engine deposits on octane requirement increase of an engine using a mini-engine14). This paper reports some observations relevant to the engine deposits and their effects on fuel economy. 2.
Mini-engine test: A commercial mini-engine (one cylinder, L-head, 4 cycle, 200cc, compression ratio 6.5) used in the present study was equipped with thermocouples, a knockmeter, a speedReceived †
amounts It was
in this that
ometer, and a power generator. A constant speed operating mode (2,000rpm., brake load 750W; ca. 1/3 of its full load) was employed to accumulate deposits in the combustion chamber of the miniengine. The fuel employed in this test contained a certain amount of lubricant (0-300g oil/20l fuel) to accelerate the deposit buildup. Teflon coated cylinder heads (0.05mm and 0.08mm thick, respectively) were also used in the miniengine tests to examine their thermal insulation effects on fuel economy. Chassis dynamometer test: A commercial passenger car (4 cylinders, 4 cycle, 1,600cc, compression ratio 8.4) on a chassis dynamometer was run under 60km/hr constant speed conditions to accumulate 10,000km. Octane requirements and 10 mode fuel consumption of the respective cars were measured on a chassis dynamometer at every 2,500km. Field test: Details refer to a previous paper1). Briefly, eleven employee-cars were made to cover 10,000-15,000km. Octane requirements and 10 mode fuel consumption of the respective cars were measured on a chassis dynamometer at every 2,500 km. Octane requirements were measured using the primary reference fuels of one RON increments.
efficiency to the
in a combus-
a fuel of higher octane number to avoid knock1). The deposit effect on an engine requirement
Fuel economy improvements of 11 cars obtained in the field tests are summarized in Fig. 1. The fuel economy improvement (%) was calculated by dividing the actual 10 mode fuel consumption Inst.,
When the combustion chamber deposits were completely removed from those engines, only 2% or less fuel economy improvement (virtually no improvement) was observed which confirmed again that fuel benefit was brought about by the engine deposits. Mini-engine tests with a Teflon coated cylinder head afforded a large fuel economy improvement depending upon the thickness of the Teflon layer over the uncoated reference head. The results obtained in these tests are shown in Table 1. Teflon employed in the present experiment had the
of 0.25cal/g・ with
10 mode Improvement
ONR was measured by accelerating with full throtle after bringing the engine to steady operating conditions (2,000rpm, 750W). Fuel economy was measured under steady operating conditions (1,400rpm, 350W) with isooctane.
by the base value which was determined before deposit accumulation of the car. It was rather surprising to observe from Fig. 1 that 10 mode fuel economy improved in almost all measurements at respective deposit accumulation and that this improvement correlated well with the octane requirement increase (ORI). Since ORI is thought to be caused almost entirely by combustion chamber deposits, the above observation is most likely to be due to engine deposits. Table
and 0.23-0.371) the
ingly small volume contraction of the combustion chamber (an insignificant increase in the compression ratio) by these coatings, the large improvement on fuel economy would account for the decreased heat flow through the Teflon layer, and, thus, in turn through the engine deposit layer. To confirm this aspect of engine deposits, some deposit accumulation test runs were carried out. Thermocouples were embedded in the combustion chamber walls of the mini-engine. After a deposit accumulation run, only the deposits on top of the thermocouple tips were removed, and the accumulation run was continued. In these cases, higher temperatures than those at the start of the test run were normally observed. However, by removing the entire deposits from the combustion chamber, the temperatures resumed the levels at the start. These results are shown in Table 2 from which it is obvious that although the wall temperature decreases with deposit accumulation, the temperature of the deposit surface rises. This decrease in the observed wall temperature is obviously due to the thermal insulation effect of the deposits. Additional mini-engine tests were carried out to pursue this aspect further, and the temperature
cal/g・ ℃, Fuel
of 0.26W/m・ ℃,
Temperature Changes of Cylinder Head Wall in Mini-Engine with Commercial Unleaded Gasoline (RON 91) and Mineral Oil (SAE 10W-30)
changes at two locations (end-gas region and cavity) in the combustion chamber were measured. Fig. 2 shows the results obtained in the miniengine test, indicating that the wall temperature at the end-gas region decreased rapidly relative to that of the cavity wall as deposits developed. A similar result was also obtained by the use of leaded gasoline. The ORI is reported to be principally caused by the deposits at the end-gas region4),14)and its appeared interesting to see what would
Data were obtained by running the mini-engine for 22hrs, and rate of deposit buildup was controlled by permutating fuel and lubricant used (effects of fuel and lubricant composition on ORI and deposit formation refer to the previous paper14)). Fig. 3 Relation between Cylinder Head Wall Temperature Difference (at End-Gas Region) and ORI with Mini-Engine
石 油 学 会 誌
(cylinder head wall temperature difference at the end-gas region before and after the deposit buildup). This is shown in Fig. 3. This observation indicates that engine deposits are operating as thermal insulator which is reflected in ORI. Moreover, Fig. 3 strongly suggests that engine deposits influence, by some manner, the incoming fuel charge temperature, combustion rate etc., which would be reflected in the fuel consumption of
Change of ONR and Fuel Consumption during 10,000kms. Running on Chassis Dynamometer using a Passenger Car (1,600cc) under 60km/hr Plain Road Constant Speed Conditions with Commercial Unleaded Gasoline and SAE 10W-30
an engine. Evidence for this is given in Fig. 4. Using a commercial passenger car, a chassis roll test was carried out to accumulate 10,000km, and the engine octane requirement and fuel consumption under the 60km/hr, constant speed conditions were measured at every 2,500km. As obvious from Fig. 4, the engine octane requirement increased as driving distances increased and it levelled off at around 5,000km. The result of fuel consumption which was almost parallel to the behavior of the octane requirement obtained in the experiment was consistent with the above speculation. The experimental observations (Figs. 1, 4, and Table 1) on fuel consumption are effected by engine deposits; thus, combustion analyses with and without engine deposits will be desirable. This aspect of the engine deposits will be discussed in our next paper.
4) 5) 6) 7)
8) 9) 10) 11) 12)
1) Nakamura, Y., Yonekawa,Y., Okamoto, N., J. Japan Petrol.Inst, 22, 105 (1979).
Newby, W. E., Dumont, L. E., I. E. C., 45, 1336 (1953). Mikita, J. J., Sturgis, B. M., Proceedings of the 4th World Petroluem Congress Section V1/F Paper. 1. Presented on June 18th (1955). Benson, J. D., SAE Paper, 750933 (1975). Alquist, H. E., Holman, C. E., Wimmer, D. B., SAE Paper, 750932 (1975). Shore, L. B., Ockert, K. E., SAE Trans., 66, 285 (1958). Lee, R. C., Tohmas, P., Symposium on Octane in the 1980's Car. Presented at ACS Miami Beach Meeting, Sept., 10-15 (1978), Division of Petroleum Chemistry INC. Lauer, J. L., Friel, P. J., Combst. Flame, 4, 107 (1960). McNab, J. G., Moody, L. E., SAE Trans., 66, 285 (1958). Barber, P. A., Lonstrup, T. F., Tunkel, N., SAE Paper, 750449 (1975). Marciante, P., Chiampo, P., SAE Paper, 750449 (1975). Bartleson, J. D., Hughes, F. C., I. E. C., 45, 1503 (1953). Graiff, L. B., SAE Paper, 790938 (1979). Yonekawa, Y., Nakamura, Y., Okamoto, N., J. Japan Petrol. Inst. 24, 85 (1981).