Apparatus for improving fuel economy of multi-cylinder I. C. engine followed by automatic transmission via hydrokinetic unit

• US 4,194,417 A
• Filed: 09/26/1978
• Issued: 03/25/1980
• Est. Priority Date: 10/12/1977
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Matsumoto, Junichiro, Sugasawa, Fukashi, Kato, Fumiaki, Itzuka, Haruhiko
• Primary Examiner(s): Husar, G. J.
• Assistant Examiner(s): McKenzie, Frank
• Application Number:
  US05/945,877
• Time in Patent Office: 546 Days
• Field of Search: 74/859, 74/860, 74/866, 123/198 F, 123/32 EA
• US Class Current: 477/110
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04

Abstract

Fuel economy of a multi-cylinder internal combustion engine has been improved by allowing, when a vehicle is at a standstill, the engine to run on selected cylinders of all. The idling operation of the engine on the selected cylinders has been made smooth by the provision of a switch valve in a control circuit of the transmission. With the switch valve, as soon as an accelerator pedal is released when the vehicle is at a standstill, hydraulic fluid will be drained from the control circuit to render a gearing of the transmission in a neutral condition even if a manually selector valve in the control circuit is held in a drive range position. This prevents transmission of load to the engine through the hydrokinetic unit which otherwise would occur when the manually selector valve is in the drive range position.

Claims

1. In a vehicle comprising a multi-cylinder internal combustion engine which is provided with means for operating the engine on selected cylinders of all, and an automatic transmission connected to the engine via a hydrokinetic unit to be driven by the engine through the hydrokinetic unit, the automatic transmission including a hydraulic control circuit having a source of hydraulic pressure, a sump, a control unit, each for operating a friction element and a manually operable selector valve having an inlet port connected to the source of hydraulic pressure, a drain port connected to said sump and an outlet port connectable to said control unit the manually operable selector valve having a first position in which communication between the outlet port and the inlet port is cut off and communication between the outlet port and the drain port is established and having a second position in which the communication between the outlet port and the inlet port is established and the communication between the outlet port and the drain port is cut off:

switch valve means disposed in said fluid line means and having a drain port connected to said sump, said switch valve means being operative to permit communication between said manually operable selector valve and said drain port thereof when actuated;

solenoid means for actuating said switching valve means when energized;

vehicle speed sensing means for detecting that said vehicle is at a standstill;

load sensing means for detecting that load applied to said engine is below a predetermined level;

selector valve condition sensing means for detecting that said selector valve means is in the first position thereof;

switch valve condition sensing means for detecting that said switch valve means has been actuated;

means for producing a signal supplied to said solenoid means to energize the same when said vehicle speed sensing means detects that said vehicle is at a standstill and said load sensing means detects that load applied to said engine is below the predetermined level;

means for producing a second signal when said selector valve condition sensing means detects that said selector valve means is in the first position thereof or when said switch valve condition sensing means detects that said switch valve means has been actuated; and

means for causing said engine operating means to permit said engine to operate on the selected cylinders of all in response to said signals.

2. The combination as claimed in claim 1, in which said switch valve means is disposed intermediate said manually operable selector valve means at the inlet port thereof and said source of hydraulic pressure.