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240 Landmarks TopTransmission and Drive Train > NAVI-5 (electronically controlled automatic 5-speed transmission)
 NAVI-5 (electronically controlled automatic 5-speed transmission)
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Features: This device was the world's first electronically controlled automatic 5-speed transmission (named the NAVI-5) developed by Isuzu for full mass production. It used a conventional manual transmission and a dry single disc clutch. The driving operation and experience of veteran drivers were analyzed in terms of ergonomics, and the system replaced most operations usually performed by the hands and feet with an electro-mechanical system. In some cases it performed these operations more sophisticatedly than people could.
1. Automatic or manual shifting could be selected.
In the automatic shift mode, a series of operations was controlled automatically by the control unit (ECU), from intermittent clutch engaging and selection of the optimal gear to the throttle operations on shifting and speed change. The transmission performed shift operations similar to a manual transmission vehicle by actively operating the shift lever (double clutch operation, etc.), and drivers could enjoy driving as if they were a professional.
2. Good fuel efficiency without variations
Due to constant optimal control by ECU, fuel efficiency varied less according to the driver's technique. Normal drivers could obtain almost the same fuel efficiency performance as a veteran.
3. Easy even for novice drivers to easily drive a manual vehicle
Even a novice driver could easily and steadily operate a car with this system because the transmission had the same shift patterns as a manual vehicle but only required a light shifting force. If a mis-shift occurred due to driver error, the ECU protected the system to allow the vehicle to be driven safely.
4. Less creep and high safety
Unlike torque converter type automatic transmissions, this system blocked power completely with the clutch to prevent creep. Accordingly, it was possible to reduce accidents caused by carelessness.
5. Push-start made possible for automatic vehicles
The engine could be started by push-start, which had been impossible for automatic transmissions. This made it less likely that the vehicle would become inoperable.
6. Other features included HSA and auto cruise. Although it was an integrated system, it had high reliability and durability using various new technologies in its hardware and software.
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Storage location:ISUZU ADVANCED ENGINEERING CENTER. LTD. (8 Tsuchidana, Fujisawa-shi, Kanagawa-ken 252-8501)
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Year manufactured:1984
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Manufacturer:Isuzu Motors Limited
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Classification:Mass-production part
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Current status:In use: open to the public
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Name / Manufacture
Model name:None
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Company name:Isuzu Motors Limited
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Applied model:Passenger car (Isuzu Aska)
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Application year:1984
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Device structure:1. Actuator unit: Integrated hydraulic unit for clutch and transmission control 2. Power unit: Accumulator type hydraulic pump unit with self-pressure control function 3. Control unit: Ultra small ECU with chip elements mounted on a large ceramic 4-layer
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Specification
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Potency
Function, effect, etc.:1. Automatic shift and manual shift functions: Automatic shift to optimal gear by ECU according to the driving state in the D3 and D4 ranges. Manual operation in the D1 to D4 ranges changed the gear speed corresponding to the lever position.
2. Automatic clutch intermittent engaging function: Optimal operation of clutch engagement suitable to each operation state (start, slow speed, speed change, stop)
3. Throttle opening/closing function: Automatic correction with respect to engine load when the acceleration pedal is used at start and during driving
4. HAS function: Braking force retained when the vehicle is stopped on a slope, etc., and automatically released braking force by detecting the torque transmission point at start
5. Auto cruise function: Speed maintained accurately even on hills, etc. using the automatic shift function with respect to the set speed.
6. Self diagnosis and backup functions: Accurate failure diagnosis, reliable backup, and prevention of mis-shifts and overrunning
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Effect:1. The system achieved the ease of operation of an automatic transmission using electronics, while maintaining the advantages of a manual transmission such as fuel economy.
2. It comprehensively and precisely controlled the engine, clutch, transmission, brakes, etc. and greatly contributed as a groundbreaking drive-by-wire technology for modern integrated control and mechatronic technologies.
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Points of interest, topicality:The world's first full automatic 5-speed transmission, this system used electronic control to totally automate a manual transmission. It was not only praised by the automotive industry but also by the hydraulics, pneumatics, mechanical, and electronics industries.
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Features:It used a conventional manual transmission and a dry single disc clutch. The driving operation and experience of veteran drivers were analyzed in terms of ergonomics, and the system replaced most operations usually performed by the hands and feet with an electro-mechanical system. In some cases it performed these operations more sophisticatedly than people could.
1. Automatic or manual shifting could be selected.
2. Good fuel efficiency without variations
3. Easy even for novice drivers to easily drive a manual vehicle.
4. Less creep and high safety
5. Push-start made possible for automatic vehicles
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Reference materials:1. Akira Watanabe, Masashi Kubota, Junzo Kuroyanagi, Hideo Saito, Eiichi Kijima, "Isuzu Aska You Iji-doraibu-shisutemu No Kaihatsu (Tokushu)" Isuzu Technical Journal Vol. 72, 1984
2. Junzo Kuroyanagi, et al., "Maikuro-konputa Niyoru Kikaishiki Kuracchi Oyobi Toransumisshon Seigyo" JSAE "Kudokei No Keisoku To Seigyo" sympodium, 1984
3. A. Watanabe, J. Kuroyanagi, H. Saito, T. Hattori "Isuzu New Transmission Control System", JSAE Review, 1984-11
4. A. Watanabe, J. Kuroyanagi, T. Hattori, "Microcomputer Mechanical Clutch and Transmission Control", SAE Paper No. 840055
5. Hideo Akima, et al., Fujitsu Vol. 35, No. 3, 1984
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